Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT", "TAMDAR", or "AMDAR" received at FSL on 03/02/07


AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
215 PM PST THU MAR 1 2007 .SYNOPSIS... FAIR WEATHER AND A SLOW WARMING TREND WILL CONTINUE THROUGH FRIDAY WITH GUSTY NORTH WINDS BELOW THE CANYONS AND PASSES OF THE SAN BERNARDINO MOUNTAINS FRIDAY. OVER THE WEEKEND STRONG HIGH PRESSURE OVER THE GREAT BASIN WILL BRING CLEAR SKIES...GUSTY SANTA ANA WINDS...AND WARMER WEATHER WEST OF THE MOUNTAINS. THE RIDGE BREAKS DOWN EARLY NEXT WEEK WITH A RETURN TO COOLER ONSHORE FLOW MONDAY AND TUESDAY. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... NORTHWEST FLOW ALOFT WITH A EMBEDDED SHORT WAVE BRUSHING AREA WILL CAUSE A FEW HIGH CLOUDS THIS AFTERNOON THROUGH TONIGHT OTHERWISE SKIES CLEAR. ON FRIDAY BUILDING HIGH PRESSURE RIDGE ALONG WEST COAST AND SURFACE HIGH PRESSURE OVER NORTHERN GREAT BASIN WILL CAUSE NORTHERLY FLOW ACROSS SOUTHERN CALIFORNIA. PRESSURE GRADIENT OF 10 MB EXPECTED TO GENERATE GUSTS AROUND 30 MPH FOR WIND PRONE AREAS OF INLAND EMPIRE AND SANTA ANA MOUNTAINS. THICKNESS RISES AND DOWNSLOPE EFFECTS FRIDAY WILL BE SLIGHTLY OFFSET BY COLD AIR ADVECTION IN MID LEVELS...SO WENT ABOUT 7 DEGREES WARMER FOR WEST OF MOUNTAINS AND ONLY A FEW DEGREES OVER MOUNTAINS AND DESERTS. FRIDAY NIGHT THE OFFSHORE PRESSURE GRADIENT INCREASES RAPIDLY...REACHING +20 MB...AND STAYS HIGH THROUGH SUNDAY. UPPER LEVEL SUPPORT IS BRIEFLY IN PLACE SATURDAY MORNING BUT THEN ERODES QUICKLY DUE TO THE RIDGE AXIS SHIFTING OVER AND EAST OF THE AREA...EXCEPT OVER SAN DIEGO COUNTY WHERE BOTH FACTORS SHOULD CONTINUE IN PHASE AND RESULT IN STRONGEST WINDS. THIS IS BASIS FOR THE HIGH WIND WATCH FOR SAN DIEGO COUNTY MOUNTAINS...WHILE REMAINDER OF AREA EXPECTED TO EXPERIENCE A WIND ADVISORY EVENT...WITH SUSTAINED WINDS AROUND 35 MPH AND GUSTS UP TO 55 MPH. TEMPERATURES WEST OF THE MOUNTAINS WILL BE MUCH HIGHER SATURDAY AND SUNDAY WITH HIGHS IN THE 70S TO LOWER 80S...AND THIS IS APPROACHING RECORD VALUES FOR SAN DIEGO COUNTY VALLEYS...ELSEWHERE WEST OF THE MOUNTAIN ABOUT 15 DEGREES ABOVE NORMAL BUT NOT HIGH ENOUGH TO SET RECORDS. ONLY SLIGHT WARMING IS EXPECTED OVER THE MOUNTAINS AND DESERTS DUE TO THE COLD AIR ADVECTION OUT OF THE GREAT BASIN. ONSHORE FLOW RETURNING MONDAY SHOULD COOL AND MOISTEN THE COAST AND VALLEYS DUE TO THE INFLUX OF MARINE AIR WHILE THE MOUNTAINS AND DESERTS SHOULD WARM UP DUE TO WARM AIR ADVECTION AND DOWNSLOPE EFFECTS FROM THE INCREASING SOUTHWEST WINDS. THE TROUGH MOVING ACROSS THE AREA THURSDAY STILL LOOKS TOO DRY TO GENERATE ANY PRECIPITATION SO NONE FORECAST FOR NEXT SEVEN DAYS. && .FIRE WEATHER... CRITICAL FIRE WEATHER PATTERN SATURDAY THROUGH MONDAY. STRONG OFFSHORE WINDS SATURDAY...OVER 35 MPH AT MOST LOCATIONS. VERY LOW RELATIVE HUMIDITY...BELOW 10 PERCENT DURING THE DAY. LITTLE TO NO RECOVERY SATURDAY NIGHT WITH MAX RELATIVE HUMIDITY 12 TO 22 PERCENT. WINDS JUST AS STRONG ACROSS SAN DIEGO COUNTY SUNDAY WHILE A LITTLE LOWER ELSEWHERE AND CONTINUED VERY DRY ALL AREAS WITH POOR HUMIDITY RECOVERY AGAIN SUNDAY NIGHT. INLAND VALLEYS AND COASTAL AREAS WILL MOISTEN AND COOL MONDAY...BUT MOUNTAIN AND DESERT AREAS WILL STILL BE IN A CRITICAL FIRE WEATHER PATTERN WITH LINGERING DRY MASS AND INCREASING SOUTHWEST WINDS. && .AVIATION... 012005Z...LATE MORNING ACARS SOUNDINGS FROM KSAN AND KSNA INDICATE THE MARINE LAYER REMAINS VERY SHALLOW AND DISRUPTED. A MOSTLY CLEAR SKY WILL DOMINATE THROUGH FRIDAY WITH UNRESTRICTED VISIBILITIES AT ALL AREA AIRPORTS. DEVELOPING OFFSHORE FLOW WILL BRING LOCAL GUSTY NORTHEAST WINDS THROUGH AND BELOW MOUNTAIN PASSES AND CANYONS LATE TONIGHT AND FRIDAY WITH ASSOCIATED UP AND DOWN DRAFTS AND LOW LEVEL WIND SHEAR. && .SGX WATCHES/WARNINGS/ADVISORIES... HIGH WIND WATCH...4 AM SAT-2 PM SUN SAN DIEGO COUNTY MOUNTAINS. SEE LAXNPWSGX. && $$ PUBLIC/FIRE WEATHER...BALFOUR AVIATION/MARINE.......HORTON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1212 PM CST THU MAR 1 2007 .EARLY AFTERNOON DISCUSSION... SEVERE WEATHER...FLOODING POTENTIAL...AND WINDS ARE THE MAIN CONCERNS LATE THIS MORNING. OCCLUDING FRONTAL BOUNDARY ACROSS WEST CENTRAL ILLINOIS IS NOW BECOMING ACTIVE WITH CONVECTION AND THE STORM PREDICTION CENTER HAS RECENTLY ISSUED A SEVERE THUNDERSTORM WATCH FOR THE ENTIRE FORECAST AREA THROUGH 01Z. HIGHEST SEVERE THREAT DOES APPEAR TO BE SOUTH OF INTERSTATE 80 WHERE INSTABILITY AND BETTER MOISTURE RETURN ARE EXPECTED TO BE MORE SUBSTANTIAL...ALONG WITH BETTER PROSPECTS OF NEAR SURFACE BASED CONVECTION FOR A BRIEF TIME THIS AFTERNOON. WINDS ALSO BECOME A CONCERN THIS EVENING AS THE OCCLUDED BOUNDARY PASSES WITH STEEPENING LOW LEVEL LAPSE RATES AND COLD AIR ADVECTION. HAVE ISSUED A WIND ADVISORY IN EFFECT FROM EARLY THIS EVENING THROUGH FRIDAY. MAY NEED TO TWEAK TIMING OF WIND ADVISORY HEADLINES A BIT LATER THIS AFTERNOON. .PREVIOUS DISCUSSION FOR ZONES/GRIDS... 410 AM CST MAJOR LATE WINTER/EARLY SPRING STORM CONTINUES TO DEEPEN EARLY THIS MORNING. POWERFUL JET MAX MEASURED AT 160KTS ON OUN 00Z RAOB CONTINUES TO PUNCH NORTHEASTWARD ACROSS THE MID MS VALLEY...WITH CLOSED UPPER CIRCULATION NOW FORMED OVER THE EASTERN KS/NE BORDER. SURFACE LOW...CURRENTLY ON THE KS/MO BORDER...CONTINUES TO DEEPEN AS IT MOVES NORTHEAST. STRONG PRESSURE FALLS NOTED INTO CENTRAL IL WHERE WAA MAXIMIZED BUT PROGGED SLOWING AND TURN TO MORE NORTHWARD TRACK OF THE LOW ACROSS EASTERN IA LATER THIS MORNING AND THIS AFTERNOON APPEARS TO BE CORRECT NOW THAT CLOSED UPPER LOW HAS FORMED. LAREG AREA OF RAIN AND THUNDERSTORMS CONTINUES TO SPREAD ACROSS NORTHERN IL EARLY THIS MORNING AS 75KT LOW LEVEL JET PROVIDES FORCING ABOVE THE SURFACE WARM FRONT EXTENDING EASTWARD ACROSS CENTRAL IL. STRONG ISENTROPIC LIFT AND THETA-E ADVECTION THRU MID LEVELS COUPLED WITH DIVERGENCE ALOFT AT LEFT EXIT REGION OF UPPER JET RESULTING IN STRONG DEEP UVV. WITH MID LEVEL LAPSE RATES NEAR MOIST ADIABATIC CAPE ABOVE BOUNDARY LAYER LIMITED THOUGH VERTICAL EXTENT OF STRONGER CELLS AND FREEZING LEVEL ACROSS NORTHERN IL BETWEEN 8-9K FT AGL...SOME SMALL HAIL REACHING THE GROUND. WAA AREA OF RAIN TO MOVE NORTH WITH H8 FRONT PROGGED TO SOUTHERN WI AND LOWER MI BY 18Z BUT CONTINUED CONVECTIVE DEVELOPMENT UPSTREAM OCCURRING AND EXPECTED TO CONTINUE WITH DESTABALIZATION AS MID LEVELS START TO COOL AS MID-UPPER TROUGH AXIS CROSSES THE MS VALLEY. SEVERE POTENTIAL FROM CENTRL IL INTO SOUTHERN PORTION OF FA THIS AFTERNOON WHERE DESTABILIZATION WILL BE GREATEST. STRONG WIND FIELD PRESENTS DAMAGING WIND THREAT UNTIL OCCLUDED FRONT SWEEPS NORTHEASTWARD THROUGH NORTHERN IL. FROPA WILL USHER IN STRONG SW SURFACE WINDS FOR TONIGHT AND FRI...SLOWLY DROPPING OFF AS THE STACKED SYSTEM GRADUALLY WEAKENS AS IT MOVCES ACROSS THE GREAT LAKES FRI NIGHT. RADAR ESTIMATES UP TO .5 INCH RAIN FROM HEAVIER CELLS ALREADY EARLY THIS MORNING AND WITH AN ADDITIONAL 1 AVERAGE EXPECTED LATER THIS MORNING AND THIS AFTERNOON THE FLOOD WATCH WILL CONTINUE. COLD AIR RAPIDLY WRAPS AROUND THE LOW. H8 TEMPS PLUNGE FROM PLUS 7 TO PLUS 10C ACROSS THE FA AT 18Z TO MINUS 7 TO MINUS 9 BY 06Z. FROPA LATE TODAY SHOULD END MOST/ALL PRECIP BUT WITH SYSTEM SLOWING AS IT MOVES FROM IA TO SOUTHERN WI TONIGHT MOISTURE WILL ALSO WRAP AROUND THE CIRCULATION BRINGING SOME LIGHT SNOW TO THE FA LATE TONIGHT AND FRI. TRS && .AVIATION... THE FIRST ROUND OF THUNDERSTORMS WILL MOVE THROUGH BY 9 AM CST. LOOKING AT THE ACARS SOUNDING THE THUNDERSTORMS THIS MORNING ARE ELEVATED. THE LOCAL WRF ARW SHOWS THE WARM FRONT MOVING NORTH INTO THE TAF FORECAST AREA BY 21 UTC. WE CAN EXPECT MORE THUNDERSTORMS LATER TODAY. WILL HAVE A TEMPO GROUP FOR MODERATE SHOWERS FROM 15 TO 18 UTC AS THE WARM FRONT APPROACH NORTHEAST ILLINOIS. THEN A DRY SLOT MAY MOVE INTO THE AREA AS THE LOW MOVE INTO WISCONSIN AND TO MICHIGAN. AS THE COLD AIR MOVES INTO NORTHERN ILLINOIS SNOW IS EXPECTED AFTER 07 UTC. THE WIND IS NOT FORECAST TO SWITCH TO THE NORTHWEST UNTIL FRIDAY AFTERNOON. && .LOT WATCHES/WARNINGS/ADVISORIES... .IL...FLOOD WARNING PORTIONS KANKAKEE AND UPPER IL RIVERS. FLOOD WATCH THRU 12Z FRIDAY. WIND ADVISORY 23Z TODAY THROUGH 00Z SATURDAY. .IN...FLOOD WARNING PORTIONS KANKAKEE RIVER. FLOOD WATCH THRU 12Z FRIDAY. WIND ADVISORY 23Z TODAY THROUGH 00Z SATURDAY. .LM...GALE WARNING OPEN WATERS 09Z THURSDAY THRU 09Z FRIDAY. SMALL CRAFT ADVISORY NEARSHORE 02Z THURSDAY THRU 09Z FRIDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
630 AM CST WED FEB 28 2007 .DISCUSSION... 420 AM CST POWERFUL JET MAX OF 160KTS PER AIRCRAFT REPORTS CROSSING NORTHERN BAJA AT BASE OF WESTERN NOAM UPPER TROF. SATELITE SHOWS MULTIPLE CIRCULATIONS IN THE TROF. ONE LIFTING NORTHWARD ACROSS THE NORTHERN HI PLAINS WITH A TROF AXIS EXTENDING SOUTHEASTWARD ALL THE WAY TO THE LOWER MO VALLEY WHERE STRONG WAA HAS REGENTLY GENERATED ELEVATED TSRA. THE WAA PATTERN AND ASSOCIATED UVV WILL LIFT NORTHWARD INTO THE MID MS VALLEY BY THIS EVE AS THE JET MAX CROSSES THE SOUTHERN ROCKIES AND TURNS NORTHEASTWARD ACROSS THE SOUTHERN PLAINS. MODELS SHOW H8 WARMFRONT LIFTING INTO SOUTHERN WI AND LOWER MI BY 06Z AND EXPECT INITIAL ROUND OF PRECIP TO CONTINUE TO MOVE NORTHWARD INTO THE UPPER MIDWEST AND GREAT LAKES. LOWER LEVELS REMAIN RELATIVELY DRY AS THIS PRECIP AREA MOVES IN DURING THE LATER AFTERNOON AS H8 DEW POINT DEPRESSIONS WERE 20 TO 30 DEG C ACROSS THE LOWER MS VALLEY LAST EVE. 00Z RAOBS DID SHOW MARGINAL MID LEVEL MOISTURE OVER THE OZARKS AHEAD OF THE LEAD SHORT WAVE TROF WHILE LOWER LEVELS WERE DRY EXCEPT FOR SHALLOW MOISTURE ALONG THE WESTERN GULF COAST. THIS MOISTURE HAS SPREAD RAPIDLY INTO THE SOUTHERN PLAINS WHERE SURFACE DEW POINTS APPROACHING 60F AS SOUTHERLY LOW LEVEL WINDS CONTINUE TO INCREASE AHEAD OF THE RAPIDLY DEVELOPING LEE SIDE LOW BUT THIS LOWER LEVEL MOISTURE DOES NOT REACH THE MID MS VALLEY UNTIL THIS EVE. AFTER THE INITIAL SHOT OF WAA PRECIP EXPECT A BREAK UNTIL INGREDENTS COME TOGETHER OVERNIGHT. THIS INCLUDES GULF MOISTURE SPREADING INTO CENTRAL IL...DIFLUENT UPPER FLOW AS TROF BECOMES NEGATIVELY TILTED AND DIVERGENCE ALOFT AT LEFT EXIT OF STRONG JET. STEEP MID LEVEL LAPSE RATES AND STRONG DYNAMICS WILL RESULT IN CONVECTIVE RAIN BREAKING OUT AND SPREADING ACROSS THE MID MS VALLEY. PRECIPITABLE WATER VALUES CLIMB TO AROUND 1 INCH AND MODERATE TO HEAVY RAINFALL POTENTIAL DUE TO EXPECTED CONVECTIVE NATURE AND FLOOD WATCH WILL BE CONTINUED GIVEN ALREADY SOME FLOODING PROBLEMS AND MOISTURE CONTENT OF SNOWPACK. UPPER LOW LINGERING OVER THE CANADIAN MARITIMES SLOWS THE PROGRESS OF THIS STORM AND IT BECOMES STACKED DURING THU AS IT LIFTS INTO IA. WINDS WILL GRADUALLY DIE DOWN AS LOW STARTS GRADUAL FILLING. DRY SLOT PUNCHES NORTHWARD DURING THU WITH OCCLUDED FRONT SWEEPING EAST AND NORTHEAST THRU THE FA. THIS WILL CURTAIL RAIN BUT WITH COLD AIR WRAPPED INTO SYSTEM AND IT/S SLOW MOVEMENT INTO THE CENTRAL GREAT LAKES THU NIGHT AND FRI WILL KEEP A CHANCE OF OCCASIONAL LIGHT SNOW AND SNOW SHOWERS GOING. TRS && .AVIATION DISCUSSION FOR 06Z TAFS... 630 AM CST THE CYCLONE WAS OVER COLORADO THIS MORNING AS SEEN ON THE SURFACE MAP AT 12 UTC. THE 850 MB 12 UTC ANALYSIS SHOWS A 50 KNOT WIND IN WESTERN MISSOURI. THE WATER VAPOR LOOP SHOW THE RAPID EASTWARD MOVEMENT OF THE TROUGH INTO THE WESTERN UNITED STATES. THIS CYCLONE IS GOING TO BE A VERY DYNAMIC SYSTEM. THE LOCALLY RUN WRF ARW MODEL SHOWS THE STRONG 850 MB WIND WILL MOVE INTO ILLINOIS. THE EQUIVALENT POTENTIAL TEMPERATURE HAS A LARGE GRADIENT TONIGHT AS THE WARM AIR RETURNS TO CENTRAL ILLINOIS. THE NEGATIVE OMEGA AT 700 MB IS FORECAST TO BE LARGE BETWEEN 09 AND 12 UTC THURSDAY MORNING. THE LIFTED INDEX GRADIENT IS LARGE IN CENTRAL ILLINOIS AS WELL. WILL KEEP THE WIND FORECAST 15 KNOTS WITH GUST TO 24 KNOTS TONIGHT. WE EXPECT SOME REAL UNSTABLE AIR MOVING INTO THE TAF FORECAST AREA. SO WILL ADD THUNDERSTORMS TO THE FORECAST BETWEEN 8 TO 12 UTC. THIS EVENING... AS THE ISENTROPIC LIFT BEGINS MIXED PRECIPITATION MAY OCCUR WITH RAIN AND SNOW AND POSSIBLY ICE PELLETS. THE WRF FROM NCEP...GFS AND NGM MODELS WERE USED AND THE LOCAL WRF ARW WAS ALSO USED. && .LOT WATCHES/WARNINGS/ADVISORIES... .IL...FLOOD WARNING PORTIONS KANKAKEE AND UPPER IL RIVERS. FLOOD WATCH TONIGHT THRU THU. .IN...FLOOD WARNING PORTIONS KANKAKEE RIVER. FLOOD WATCH TONIGHT THRU THU. .LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
420 AM CST WED FEB 28 2007 .DISCUSSION... 420 AM CST POWERFUL JET MAX OF 160KTS PER AIRCRAFT REPORTS CROSSING NORTHERN BAJA AT BASE OF WESTERN NOAM UPPER TROF. SATELITE SHOWS MULTIPLE CIRCULATIONS IN THE TROF. ONE LIFTING NORTHWARD ACROSS THE NORTHERN HI PLAINS WITH A TROF AXIS EXTENDING SOUTHEASTWARD ALL THE WAY TO THE LOWER MO VALLEY WHERE STRONG WAA HAS REGENTLY GENERATED ELEVATED TSRA. THE WAA PATTERN AND ASSOCIATED UVV WILL LIFT NORTHWARD INTO THE MID MS VALLEY BY THIS EVE AS THE JET MAX CROSSES THE SOUTHERN ROCKIES AND TURNS NORTHEASTWARD ACROSS THE SOUTHERN PLAINS. MODELS SHOW H8 WARMFRONT LIFTING INTO SOUTHERN WI AND LOWER MI BY 06Z AND EXPECT INITIAL ROUND OF PRECIP TO CONTINUE TO MOVE NORTHWARD INTO THE UPPER MIDWEST AND GREAT LAKES. LOWER LEVELS REMAIN RELATIVELY DRY AS THIS PRECIP AREA MOVES IN DURING THE LATER AFTERNOON AS H8 DEW POINT DEPRESSIONS WERE 20 TO 30 DEG C ACROSS THE LOWER MS VALLEY LAST EVE. 00Z RAOBS DID SHOW MARGINAL MID LEVEL MOISTURE OVER THE OZARKS AHEAD OF THE LEAD SHORT WAVE TROF WHILE LOWER LEVELS WERE DRY EXCEPT FOR SHALLOW MOISTURE ALONG THE WESTERN GULF COAST. THIS MOISTURE HAS SPREAD RAPIDLY INTO THE SOUTHERN PLAINS WHERE SURFACE DEW POINTS APPROACHING 60F AS SOUTHERLY LOW LEVEL WINDS CONTINUE TO INCREASE AHEAD OF THE RAPIDLY DEVELOPING LEE SIDE LOW BUT THIS LOWER LEVEL MOISTURE DOES NOT REACH THE MID MS VALLEY UNTIL THIS EVE. AFTER THE INITIAL SHOT OF WAA PRECIP EXPECT A BREAK UNTIL INGREDENTS COME TOGETHER OVERNIGHT. THIS INCLUDES GULF MOISTURE SPREADING INTO CENTRAL IL...DIFLUENT UPPER FLOW AS TROF BECOMES NEGATIVELY TILTED AND DIVERGENCE ALOFT AT LEFT EXIT OF STRONG JET. STEEP MID LEVEL LAPSE RATES AND STRONG DYNAMICS WILL RESULT IN CONVECTIVE RAIN BREAKING OUT AND SPREADING ACROSS THE MID MS VALLEY. PRECIPITABLE WATER VALUES CLIMB TO AROUND 1 INCH AND MODERATE TO HEAVY RAINFALL POTENTIAL DUE TO EXPECTED CONVECTIVE NATURE AND FLOOD WATCH WILL BE CONTINUED GIVEN ALREADY SOME FLOODING PROBLEMS AND MOISTURE CONTENT OF SNOWPACK. UPPER LOW LINGERING OVER THE CANADIAN MARITIMES SLOWS THE PROGRESS OF THIS STORM AND IT BECOMES STACKED DURING THU AS IT LIFTS INTO IA. WINDS WILL GRADUALLY DIE DOWN AS LOW STARTS GRADUAL FILLING. DRY SLOT PUNCHES NORTHWARD DURING THU WITH OCCLUDED FRONT SWEEPING EAST AND NORTHEAST THRU THE FA. THIS WILL CURTAIL RAIN BUT WITH COLD AIR WRAPPED INTO SYSTEM AND IT/S SLOW MOVEMENT INTO THE CENTRAL GREAT LAKES THU NIGHT AND FRI WILL KEEP A CHANCE OF OCCASIONAL LIGHT SNOW AND SNOW SHOWERS GOING. TRS && .AVIATION DISCUSSION FOR 06Z TAFS... 1050 PM CST SFC HIGH OVERHEAD THIS EVENING WILL MOVE EAST OF THE LOCAL TERMINALS OVERNIGHT. WINDS NEARLY CALM AT MOST REPORTING SITES. THOSE CALM WINDS UNDER A SUBSIDENT AIRMASS ARE TRAPPING MOISTURE IN THE 2-3KFT ALTITUDE...WITH MVFR CONDITIONS PREVAILING AT MOST LOCATIONS. A FEW POCKETS OF CLEARING JUST W OF AN RFD-DPA LINE THIS EVENING SHOWING UP IN THE SATELLITE IMAGERY...BUT IS EXPANDING LITTLE. AREAS NEAR THAT CLEARING HAVE SEEN VIS DROP INTO THE 2-4SM RANGE...BUT AGAIN DON`T EXPECT THOSE TO REACH ORD OR MDW. OTHER THAN A BRIEF SCATTERING OUT OF CLOUDS...EXPECT MVFR CIGS TO HOLD THROUGH THE NIGHT AND INTO TOMORROW. WARM FRONT LIFTING NORTHWARD AHEAD OF APPROACHING AND DEEPENING LOW TOMORROW EVENING. ATMOSPHERIC COLUMN SATURATES RAPIDLY AS LEAD SHORTWAVE APPROACHES AROUND 00Z. TEMP PROFILES LOOK LIKE THEY SHOULD BE JUST WARM ENOUGH TO BEGIN AS RAIN AND NOT FREEZING RAIN GIVEN STRONG WAA AND LOW LEVEL TEMPS A DEGREE OR TWO ABV FREEZING...WHILE WET BULB AND DEWPOINT TEMPS START OUT INITIALLY AT 0C. FAIRLY STRONG FORCING...AND EVEN SOME WEAK INSTABILITY WITH THIS BAND...SO ADDED A TEMPO MDT RA TOWARD MIDNIGHT WED NT. && .LOT WATCHES/WARNINGS/ADVISORIES... .IL...FLOOD WARNING PORTIONS KANKAKEE AND UPPER IL RIVERS. FLOOD WATCH TONIGHT THRU THU. .IN...FLOOD WARNING PORTIONS KANKAKEE RIVER. FLOOD WATCH TONIGHT THRU THU. .LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
330 PM EST THU MAR 1 2007 .DISCUSSION... 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WELL DVLPD SHRTWV/ NORWEGIAN CYC OVER IA TRACKING TOWARD THE UPR GRT LKS TO THE E OF DEEPENING TROF OVER THE W AND S OF PERSISTENT BLOCKING RDG OVER HUDSON BAY HELD IN PLACE BY TROF IN SE CAN. POCKET OF H5 TEMPS -35C TO -40C ACCOMPANYING REINFORCING SHRTWV DIGGING SE THRU THE NRN ROCKIES HELPING TO DEEPEN THE TROF FURTHER...00Z-12Z H3 HGT FALLS IN THE CNTRL PLAINS APRCHD 200M. SHARP DIFFERENCE IN PRES BTWN ASSOCIATED 985MB LO IN IA (12Z-15Z PRES FALLS AHEAD OF LO AOB 4MB) AND HUDSON BAY HI CAUSING E GALES UP TO 40 KT AT A NUMBER OF CMAN SITES ON LK SUP EARLY THIS AFTN. STLT IMAGERY SHOWS DRY SLOT IN ADVANCE OF POTENT SHRTWV MOVING INTO SW WI (H5 WIND SPEED WITHIN JET MAX LIFTING NE INTO MO UP TO 100KT AT 12). OTRW...ELY ADVCTN OF RELATIVELY DRY LLVL AIR (SEE 12Z APX SDNG AND 15Z TAMDAR SDNG FM PLN) HAS PREVENTED MUCH PCPN FM BREAKING OUT THRU EARLY THIS AFTN OVER THE FA WITH PWAT ONLY 0.60 INCH OR SO AS FAR N AS DVN/DTX AND 12Z GRB SDNG SHOWING DRY LYRS FM H85-75/H67-45. BUT VIGOROUS SLY H85 LLJ (WIND SPEED UP TO 70 KTS AT DAYTON OH) SHOULD ADVECT H85 DWPTS UP TO 13C AT JACKSON MS QUICKLY TO THE N. IN FACT...CLD TOP TEMPS OVER SCNTRL WI IN ADVANCE OF DRY SLOT/PSBL DESTABILIZATION ALF IN ADVANCE OF DRY SLOT/LOWER LVL MSTR BEGINNING TO COOL QUICKLY. MAIN FCST CONCERNS REVOLVE ARND HOW QUICKLY RELATIVELY DRY AIRMASS IN THE UPR GRT LKS CAN SATURATE THEN PCPN/SN AMTS AND GOING HEADLINES ASSOCIATED WITH IMPRESSIVE CYC APRCHG FM THE SW. SYNOPTIC SETUP CERTAINLY THERE FOR MAJOR SN/WIND EVENT AS LO PRES FM THE SW GRINDS INTO BLOCKING HUDSON BAY HI PRES. ALTHOUGH AIRMASS INITIALLY DRY OVER THE FA...12Z GFS/NAM HINT THAT INCRSG MSTR ADVECTION RELATED TO STRG H85 WINDS OVER THE OH VALLEY WL ALLOW INCRSG DYNAMICS TO PHASE BETTER WITH THIS INCRSG MSTR. GFS/NAM SHOW VIGOROUS DEEP LYR H85-3 QVECTOR CNVGC AHEAD OF SHRTWV AND COUPLING OF LEFT EXIT OF UPR JET ROTATING NE AHEAD OF SHRTWV WITH RRQ OF UPR JET IN CONFLUENCE ZN TO THE SW OF TROF IN SE CAN/ INCRSD UPR DVGC/SHARP H7-5 FGEN WITHIN LYR FAVORING DENDRITIC SN GROWTH QUICKLY SATURATING THE AIRMASS S-N THIS EVNG AS AXIS OF H7-75 SPECIFIC HUMIDITY (4-5 G/KG) SHOOTS TOWARD THE FA COINCIDENT WITH SE WINDS ON THE 280-300K ISENTROPIC SFCS (H85-65 OR SO) INCRSG TO 50-70KT. EXPECT A BAND OF HVY SN ASSOCIATED WITH THESE DYNAMICS/ MSTR ADVCTN TO MOVE S-N ACRS THE FA AT THE NOSE OF THE APRCHG DRY SLOT. IN FACT...CROSS SECTION SHOWS THETA-E LAPSE RATE NEGLIGIBLE ABV FGEN MAX AT 00Z OVER THE SCNTRL...SO POTENTIAL FOR ELEVATED TS/ENHANCED SN RATES WL BE THERE WITHIN THIS BAND DURING THE EVNG. 6HR GFS/NAM QPF ARND 1.00 INCH BTWN 00Z-06Z DOES NOT APPEAR UNRSNBL CONSIDERING THIS PHASING OF DYNAMICS/MSTR. ALTHOUGH THERE MAY BE A PD WHERE THE SN DIMINISHES WITH THE ARRIVAL OF THE DRY SLOT ESPECIALLY OVER THE SRN TIER FOLLOWING THE PASSAGE OF THE FGEN MAX...STEADY SN SHOULD PERSIST THRU THE NGT FARTHER N CLOSER TO THE TROWALL/AXIS OF HIER SPECIFIC HUMIDITY/DEEP LYR H85-3 QVECTOR CNVGC WITHIN THE ESE LLJ N OF THE OCCLUDED LO FCST TO REACH SW WI BY 12Z FRI. FCST LLVL WIND SPEEDS SUPPORT GOING STORM WRNG ON LK SUP TNGT. AS BETTER JET DYNAMICS SHIFT TO THE E ON FRI...VIGOROUS UPR DYNAMICS FCST TO FADE STEADILY THRU THE DAY AS OCCLUSION SHIFTS TO CNTRL LK MI PER NCEP FVRD GFS SOLN AND WEAKENS THRU THE DAY. WINDS ON LK SUP SHOULD DIMINISH BLO STORM FORCE AS THE LO WEAKENS A BIT. AFT SYNOPTIC SCALE HVY SN OVER THE N IN THE MRNG FADES WITH LOSS OF UPR DVGC/SHARPEST FGEN...EXPECT THE BEST CHC OF SGNFT SN OVER THE NCNTRL AND W IN SHARPER NE CYC FLOW WHERE LK ENHANCEMENT AND/OR UPSLOPE WL CONTRIBUTE TO HIER PCPN TOTALS. THE HEAVIER LK ENHANCED SN WL CONT FRI NGT IN THESE SAME AREAS AS CYC NNE FLOW LINGERS BEHIND OCCLUSION FCST TO MOVE OVER LK HURON BY 12Z SAT. DRYING ALF AFT 09Z PER THE GFS FCST WOULD CAUSE THE SN INTENSITY OVER THE FAR W TO DIMINISH LATE. GOING HEADLINES WL LIKELY NEED TO BE EXTENDED OVER THE NCTNRL AND W THRU FRI NGT...BUT WL NOT DO SO NOW TO AVOID VERIFICATION PENALTY. AS DEEP UPR MSTR DEPARTS WITH WEAKENING OCCLUSION TO THE E ON SAT...EXPECT STEADIER SN TO END. SINCE MODELS HAVE BEEN TRENDING TOWARD A QUICKER DEPARTURE OF THE LO...FOLLOWED THE FASTER UKMET TIMING FOR MSTR TRENDS (WHICH HAS THE BACK EDGE OF THE DEEP MSTR JUST E OF ANJ BY 00Z SUN). WITH WEAKENING CYC FLOW AND STEADILY SUBSIDING INVRN PER GFS FCST SDNGS (TO BLO 3K FT)...LOWERED POPS W-E FASTER THAN PREVIOUS FCST CONSIDERING INCRSG SUN ANGLE/DISRUPTION OF PURE LES BANDS. SAME TRENDS FOR SAT NGT WITH APRCHG RDG AXIS/ LOWERING INVRN HGTS. MEDIUM/EXTENDED RANGE GUIDANCE HAS TRENDED TO EXIT DEEP LO PRES QUICKER ON SUN. IN FACT...THE 00Z/06Z GFS AND 00Z CNDN WITH SUPPORT FM THE MAJORITY OF THE 00Z ENSEMBLE MEMBERS NOW SHOW GENERAL ACYC FLOW OVER THE UPR GRT LKS ON SUN. THE UKMET/ECMWF ARE A LTL SLOWER... BUT WL FOLLOW THE NCEP TREND TOWARD THE FASTER TRANSITION. OPTED TO CONT CHC POPS IN THE MRNG FOR LINGERING LES OVER THE E NR LK SUP...OTRW WENT WITH A DRY DAY. THEN FA LOOKS TO GET A GLANCING BLOW AS NEXT NRN BRANCH SHRTWV CUTS THRU ONTARIO SUN NGT/EARLY MON AND DRAGS AN ARCTIC FNT THRU THE UPR LKS. THIS SYS WL BE STARVED FOR MSTR... BUT WL MAINTAIN CHC POPS DURING THIS TIME BEFORE NEXT SHOT OF ARCTIC AIR ARRIVES LATE MON (06Z GFS FCSTG H85 TEMPS AS LO AS -24C OVER THE E AT 00Z TUE...PREFERRED ECMWF SHOWS -20C). AS ARCTIC HI PRES SLIPS TO THE E THRU ONTARIO ON TUE...ECMWF/GFS SHOW INCRSG MID LVL MSTR WITH DVLPG ISENTROPIC LIFT. ECMWF IS FASTER AT RETURNING THIS MSTR AS IT SHOWS AN ALBERTA CLIPPER LO PRES PASSING THRU THE UPR LKS ON TUE NGT. MAJORITY OF GFS ENSEMBLE MEMBERS/NCEP MANUAL GUIDANCE HINT THIS WAVE WL BE WEAKER...SO WL FOLLOW THE SLOWER SCENARIO WHICH WOULD SUPPORT LINGERING LES NR LK SUP ON TUE MRNG. WL CONT SLGT CHC POPS OVER THE REST OF THE INTERIOR TO ACCOUNT FOR UNCERTAINTY. NEXT CLIPPER DUE TO TRACK INTO ONTARIO NEXT THU. SINCE AIRMASS LOOKS TO BE QUITE DRY...SEE NO REASON TO DEVIATE FM NCEP DRY FCST OVER THE SRN TIER WITH JUST LO CHC POPS ON THU ACRS THE NR CLOSER TO CLIPPER TRACK. TEMPS GENERALLY AOB MOS GUIDANCE INTO WED...THEN TEMPS ABV MOS GUIDANCE PER NCEP MANUAL GUIDANCE NEXT THU WITH CLIPPER PASSING TO THE N. COORDINATED WITH APX/GRB/DLH. && .MQT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 00Z SAT MIZ002-004>007-009>014-084-085. BLIZZARD WARNING UNTIL 00Z SAT FOR MIZ001-003. STORM WARNING FOR LAKE SUPERIOR. && $$ KC
AREA FORECAST DISCUSSION
NWS PORTLAND OR
820 PM PST THU MAR 01 2007 .SYNOPSIS...A WEAK WARM FRONT WILL CONTINUE TO MOVE SLOWLY ACROSS SOUTHWEST WASHINGTON AND NORTHWEST OREGON TONIGHT. A STRONGER FRONTAL SYSTEM WILL IMPACT THE FORECAST AREA FRIDAY...FOLLOWED BY A DRYING TREND THIS WEEKEND. A WEAK FRONT IS EXPECTED TO MOVE ACROSS THE REGION MONDAY...BUT A MUCH STRONGER AND WETTER SYSTEM CAN BE EXPECTED TUESDAY. && .SHORT TERM...NWS PORTLAND DOPPLER RADAR SHOWING LIGHT PRECIPITATION ACROSS THE FORECAST AREA THIS EVENING ASSOCIATED WITH A WEAK WARM FRONT. PRECIPITATION AMOUNTS HAVE BEEN QUITE MEAGER. A QUICK LOOK AT METARS AND RAWS SHOWS QPF HAS BEEN ON THE ORDER OF A FEW HUNDRETHS PER HOUR. THE ONLY EXCEPTION HAS BEEN THE CENTRAL COAST RANGE WHERE HOURLY RATES HAVE BEEN A TENTH OR SO. AVALANCHE DATA ALSO CONFIRMS THE LIGHT AMOUNTS FOR THE CASCADES. WILL ALLOW THE CASCADE FOOTHILL SNOW ADVISORY TO END ON SCHEDULE DUE TO THE MINIMAL PRECIP AND RISING SNOW LEVELS. 00Z KSLE SOUNDING INDICATED A FREEZING LEVEL OF 2600 FT. AN ACARS SOUNDING NR KPDX GAVE A FREEZING LEVEL OF 2100 FT. RAWS SITES NEAR 2000 FEET IN THE NORTH OREGON CASCADES NEAR FREEZING. WILL CONTINUE THE CASCADE SNOW ADVISORY THROUGH 4 AM PST. QUESTION IS WHETHER THE ADVISORY WILL NEED EXTENDED INTO FRI AM. NEWEST MODEL GUIDANCE SHOWS SLIGHTLY BUILDING 500 MB RIDGE CENTERED ALONG 130W. ANY OVER-RUNNING PRECIP FRI AM SHOULD BE QUITE MINIMAL. ALSO...850 MB FLOW FRI AM NOT AS FAVORABLE FOR OROGRAPHIC SUPPORT. MODELS SHOWS SW 850 MB WIND OF ONLY ABOUT 10 KT. WILL LET MIDNIGHT SHIFT EVALUATE FURTHER. WARM AIR ADVECTION TO CONTINUE FRI. MODELS SHOW MAIN CHUNK OF QPF TO IMPACT THE FORECAST AREA FRI AFTERNOON. SHOULD BE A 6-9 HOUR PERIOD OF DECENT QPF. MAIN ENERGY DIRECTED AT WRN WA AND EXTREME NW OREGON. AT THIS POINT PRECIP DURATION DOES NOT LOOK TO BE LONG ENOUGH TO BE OF CONCERN DESPITE LOW ELEVATION SNOW PACK IN THE COAST RANGE AND RISING FREEZING LEVELS. NWRFC RIVER GUIDANCE HOLDS RIVERS WELL BELOW FLOOD STAGES. 500 MB RIDGE CONTINUES TO AMPLIFY ALONG THE COAST FRI NIGHT AND SAT. THIS WILL FORCE THE BAROCLINIC ZONE OUT OF THE FORECAST AREA. NEED TO LEAVE SOME POPS SAT MORNING...BUT AFTERNOON LOOKS RELATIVELY DRY. BUMPED UP SAT AND SUN MAX TEMPS A COUPLE DEGREES. GFS INDICATES 850 MB TEMPS NEAR +6C SAT AFTERNOON AND SIMILAR ON SUN. MAY NEED TO GO A LITTLE HIGHER. NOT SO SURE ABOUT THE CHANCE OF RAIN SUN AS MOST GFS ENSEMBLE MEMBERS ARE SLOWER WITH THE NEXT SYSTEM. .LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS... MODELS IN FAIR AGREEMENT IN HOLDING A LARGE UPPER TROUGH OVER THE NE PACIFIC WITH SHORTWAVES ROTATING OVER THE PACNW THROUGH THE FIRST HALF OF THE EXTENDED. TODAY`S 00Z AND 12Z GFS HAS SLOWED THE SHORTWAVE FROM SUN NIGHT TO MON AND HAVE LOWERED POPS ACCORDINGLY. ANOTHER SHORTWAVE FOLLOWS TUE. AFTER TUE - GFS ENSEMBLES REDEVELOP THE UPPER TROUGH FURTHER WEST WITH WEAK ANTICYCLONIC FLOW ALOFT DEVELOPING OVER THE PACNW SO COULD SEE LOWER CHANCES FOR PRECIPITATION OR AT LEAST LOWER RAIN AMOUNTS WED-THU. HOWEVER ENSEMBLE MEMBERS SHOW LARGE VARIATION AT THAT TIME PERIOD SO CONFIDENCE NOT VERY HIGH. AT THIS POINT WILL NOT DEVIATE TOO MUCH FROM CLIMATOLOGY. FREEZING LEVELS REMAIN HIGH ENOUGH TO LIMIT SNOW FALL TO THE MOUNTAINS. && .AVIATION...EXPECT LIGHT RAIN TO BECOME MORE INTERMITTENT OVERNIGHT WITH WIDESPREAD MVFR CONDITIONS AS THE TRAILING END OF A WARM FRONT PASSES OVER THE AREA. SOME IFR CONDITIONS ARE POSSIBLE...ESPECIALLY OVER THE NORTH COAST AND NORTH WILLAMETTE VALLEY. RAIN WILL DECREASE BY FRI MORNING BUT CEILINGS MAY NOT IMPROVE MUCH. CEILINGS AND VISIBILITY MAY HAVE A LITTLE TIME TO RECOVER FRIDAY AFTERNOON...BUT WILL GROW WORSE IN THE LATE AFTERNOON AS A STRONGER WARM FRONT APPROACHES THE AREA. && .MARINE...WINDS WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA TONIGHT...THEN INCREASE TO SCA CRITERIA FRI MORNING AS A STRONGER WARM FRONT APPROACHES. SEAS WILL REMAIN BELOW 10 FT TONIGHT AND FRI...THEN BUILD TO AROUND 10 FT SAT AND HOVER THERE THROUGH THE WEEKEND. && .PQR WATCHES/WARNINGS/ADVISORIES... .OR/WA....SMALL CRAFT ADVISORY FOR WIND FRI MORNING CAPE SHOALWATER TO FLORENCE. SNOW ADVISORY FOR THE CASCADES OF SW WASHINGTON AND NW OREGON THROUGH TONIGHT. && .PRELIMINARY POINT POPS... AST 6+9513 PDX 788412 SLE 887212 EUG 8861-1 $$ MORE WEATHER INFORMATION ONLINE AT... Http://weather.gov/portland THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
730 PM CST THU MAR 1 2007 .UPDATE...PLAN TO DOWNGRADE THE WINTER STORM WARNING TO A WINTER WX ADVISORY OVER C/EC WI THIS EVG. SNOW IS ALREADY TAPERING OFF THERE... AND ONLY PATCHY LIGHT SNOW...FREEZING DRIZZLE OR DRIZZLE IS ANTICIPATED UNTIL THE UPPER LOW APPROACHES LATE TONIGHT. THERE IS SOME CONCERN FOR MORE ACCUMULATING SNOW WITH THE UPPER LOW LATE TONIGHT INTO FRIDAY...BUT NOT SURE WHETHER ACCUMS WOULD BE GREAT ENOUGH TO WARRANT A TIME EXTENSION OF THE ADVISORY THROUGH FRIDAY. FARTHER NORTH...EXPECT PERIODS OF MODERATE TO HEAVY SNOW TO CONTINUE THIS EVENING...THEN TAPER OFF NEAR THE UPPER MICHIGAN BORDER BEFORE MIDNIGHT. SNOWFALL RATES OF AN INCH AN HOUR APPEAR LIKELY...ESP IN FAR NE WI...WHERE A STEADIER SNOWFALL IS ANTICIPATED. MAY BE ABLE TO DOWNGRADE THE WARNING TO AN ADVISORY IN NC/NE WI LATER IN THE EVG...BUT WILL SEE HOW THE PCPN TRENDS EVOLVE OVER THE NEXT SEVERAL HOURS BEFORE MAKING ANY DECISION THERE. IT IS INTERESTING TO NOTE THAT THE GFS QUICKLY ROTATES THE DRY SLOT INTO N WI LATER THIS EVG...THEN LINGERS IT THERE THROUGH MIDDAY ON FRIDAY. IT IS DOUBTFUL THAT SNOWFALL RATES WILL WARRANT A WARNING LATER TONIGHT INTO FRIDAY MORNING...BUT COMBO OF LIGHTER ACCUMS AND SOME FZDZ MIGHT BE ENOUGH TO KEEP CURRENT HEADLINES. WILL MAKE SOME ADJUSTMENTS TO THE FCST GRAPHICS TO ACCOUNT FOR SHORT- TERM PCPN TRENDS...AND MAKE DECISIONS ON MOST OBVIOUS HEADLINE CHANGES OVER THE HOUR OR TWO. KIECKBUSCH REST OF DISCUSSION FROM PREVIOUS SHIFT... .SHORT TERM...TONIGHT AND FRIDAY...MAIN CONCERN IS PRECIPITATION TYPE OVER THE REGION EARLY THIS EVENING AND SNOW AMOUNTS FOR THIS EVENING AND TONIGHT. CURRENT RADAR SHOWING MODERATE PCPN ACROSS CENTRAL WI LATE THIS AFTERNOON. HAVE SEEN A VARIETY OF PCPN TYPES AS THIS AREA OF PCPN MOVES NORTH INTO THE REGION. FARTHER TO THE S IN SRN WI...PCPN STARTED AS RAIN. AS IT MOVED FARTHER TO THE NORTH AND MOVED INTO THE COLDER AIR... BEGAN TO SEE FREEZING RAIN ACROSS CENTRAL WISCONSIN...WITH SOME LOCATIONS QUICKLY RECEIVING AROUND A QUARTER OF AN INCH OF ICE ACCUMULATION. PRESENTLY SEE SOME SNOW AND SLEET REPORTS AROUND MARSHFIELD...CLINTONVILLE...AND OSHKOSH. SPOTTERS IN THESE LOCATIONS REPORTED INITIAL RAIN BEFORE QUICKLY TURNING OVER TO SNOW OR SLEET. PRETTY CONFIDENT ON THE LOCATION OF THIS CHANGE OVER...WITH 20Z CWA TAMDAR SOUNDING SHOWING LIMITED WARM AIR ALOFT...WITH VALUES ONLY RISING TO 0.5C AT 825MB AND PLENTY OF BELOW FREEZING AIR BELOW THAT. THEREFORE...HAVE MADE SOME TWEAKS TO ADD A LITTLE MORE FREEZING RAIN TO THE FORECAST FOR EARLY THIS EVENING OVER CENTRAL AND EAST CENTRAL WISCONSIN...BEFORE TRANSITIONING IT TO ALL SNOW. EXPECT THE PCPN INTENSITY TO CONTINUE AS THIS WAVE PUSHES NORTH ACROSS NE WISCONSIN THIS EVENING. VERY GOOD LIFT SEEN WITH THIS STRONG SHORTWAVE AND FRONTOGENESIS ALONG A NW TO SE LINE ACROSS WI. WITH BEST OMEGA AND FRONTOGENIC FORCING IN THE SNOW GROWTH ZONE...EXPECT THE EXISTING FORECAST OF HEAVY SNOW OVER FAR NE WI AND ACROSS NRN WI TO BE IN GOOD SHAPE. SREF...NAM...AND GFS SUPPORT HEAVY SNOW IN THIS REGION... WITH A COUPLE OF INCHES AN HOUR SNOWFALLS POSSIBLE ALONG THE WI AND UPPER MICHIGAN BORDER. HAVE MADE A FEW MINOR TWEAKS TO THE SNOWFALL FORECAST...BUT HAVE LEFT IT MAINLY INTACT. BEHIND THE SURGE OF PCPN THIS EVENING...MID LEVEL DRY AIR FROM THE DRY SLOT PUSHES ACROSS NE WI. EXPECT THIS TO DECREASE SNOW ACROSS THE AREA AFTER MIDNIGHT TONIGHT FROM SOUTH TO NORTH...WITH LIGHT SNOW OR FREEZING DRIZZLE REMAINING ACROSS THE AREA. THINK ANOTHER AREA OF LIGHT SNOW IS POSSIBLE DURING THE DAY ON FRIDAY AS WEAK WAVE ROTATES AROUND THE LOW CENTERED OVER CENTRAL WISCONSIN. WITH WEAKER FRONTOGENIC FORCING AND SHALLOW MOISTURE...ONLY BELIEVE AND INCH OR TWO OF ACCUMULATION IS POSSIBLE DURING THE DAY FRIDAY CENTRAL AND EAST CENTRAL WISCONSIN...BUT BELIEVE STILL COULD SEE ANOTHER 2-4 OVER THE FAR NORTHERN COUNTIES AND HAVE EXTENDED THE WINTER STORM WARNING AN ADDITIONAL 6 HOURS TO COMPENSATE FOR THAT SNOWFALL. ALSO...LEFT THE EXISTING MENTION OF FREEZING DRIZZLE OVER EAST CENTRAL WI AS MOISTURE LAYER IS BELOW 10KFT AND SNOW GROWTH REGION IS AT THE VERY TOP OF THIS LAYER. WITH TEMPS SLIGHTLY COOLER OVER NC WI...BELIEVE THAT PCPN WILL BE MAINLY SNOW. .LONG TERM...FRI NGT THRU NXT THU. A GRADUAL DEAMPLIFICATION OF THE MEAN FLOW IS STILL EXPECTED TO TAKE PLACE TOWARD THE MIDDLE OF NXT WEEK WHICH WL LEAD TO A GRADUAL WARM-UP IN TEMPS. THERE ARE PLENTY OF UNCERTAINTIES AS TO BOTH THE SPD OF THIS WARM-UP AND THE HANDLING OF INDIVIDUAL SHRTWVS RACING THRU THE MEAN FLOW FOR ANY PCPN CHCS WED OR THU. INITIAL SFC LOW SLOWLY TRACKS E-NE INTO N-CNTRL LWR MI FRI NGT AND HAVE TRENDED TOWARD THE SLOWER MOVEMENT OF THE NAM/NGM/CANADIAN. NE WI TO GET INTO THE COLD CYCLONIC SIDE OF THE STORM WITH WNDS BACKING NORTH AND CAA DEVELOPING ESP LTR FRI NGT. EXPECT LGT SNOW TO PERSIST AS VARIOUS SHRTWVS ROTATE AROUND THE UPR LOW AND TRAILING DEFORMATION ZN STILL IN THE PROCESS OF EXITING THE RGN. CURRENT THINKING IS THAT ANOTHER INCH OF ACCUMULATION IS PSBL AND WITH WNDS SLOWLY INCREASING THRU THE NGT...SOME DRIFTING SNOW IS EXPECTED. WL CON TO FAVOR THE WARMER GUID FOR MIN TEMPS AS COLDER AIR JUST PUSHING INTO WI BY 12Z SAT. EVEN AS THE STORM BEGINS TO WEAKEN AND ACCELERATE NE INTO SRN QUEBEC ON SAT...INITIAL CYCLONIC FLOW TO KEEP SCT LGT SNOW SHWRS GOING ACROSS NE WI DURING THE MORNING HRS. AS THE CYCLONIC FLOW STARTS TO WEAKEN IN THE AFTERNOON...THE SNOW SHWRS SHOULD DIMINISH TO SCT FLURRIES. AN EXCEPTION TO THIS WL BE OVR VILAS CNTY WHERE NW WNDS AND COLD AIR MOVG OVR LK SUPERIOR WL GENERATE ALL SNOW SHWR ACTIVITY. BLUSTERY CONDITIONS AND CLD CVR SHOULD LIMIT THE DIURNAL RISE IN TEMPS...THUS HAVE KEPT READINGS TOWARD THE COOLER GUID VALUES. OTHER THAN SOME LINGERING LGT SNOW SHWRS OR FLURRIES ACROSS N-CNTRL WI SAT NGT...THE REST OF THE FCST AREA WL QUIET DOWN WEATHER-WISE. SOME BREAKS IN THE CLDS AND DIMINISHING WNDS WL BRING A COLD NGT TO THE RGN. PREFER THE COOLER GUID VALUES WHICH MATCHES WHAT THE PREV SHIFT ALREADY HAD. AN UPR RDG OVR THE ROCKIES AND AN UPR TROF OVR THE ERN U.S. PLACES NE WI IN A NW FLOW ALOFT ON SUNDAY. NO REAL WEATHER FEATURES (EITHER A THE SFC OR ALOFT) TO DEAL WITH...THUS WL KEEP SUNDAY DRY. COLD START TO THE DAY WL OFFSET THE EXPECTED MIXED SUNSHINE AND PREFER TO KEEP MAX TEMPS A FEW DEGS BLO THE MEX GUID. AS A STG UPR TROF/SHRWTV DIGS SEWD ACROSS ONTARIO SUNDAY NGT...A CDFNT IS FCST TO DROP THRU WI. WHILE THE BETTER UPR DYNAMICS WL REMAIN TO OUR NORTH AND EAST...THE STRENGTH OF THE CAA BEHIND THE FNT MAY BE ABLE TO SQUEEZE OUT SOME LGT SNOW SHWRS OR FLURRIES. THE MORE PREVALENT SNOW SHWRS TO EXIST OVR N-CNTRL WI WHERE NW WNDS WL COMBINE WITH 8H TEMPS AROUND -20C TO PRODUCE LK EFFECT SNOW. THIS LK EFFECT POTENTIAL WL THEN CARRY OVR INTO MON AS TRAJS REMAIN FAVORABLE. THE REST OF NE WI SHOULD SEE PARTLY SUNNY SKIES MON WITH TEMPS ABT 3 TO 5 DEGS BLO NORMAL. LRG CANADIAN HI PRES TO BUILD ACROSS THE GREAT LKS RGN MON NGT INTO TUE. WHILE NW WNDS TO PERSIST INTO MON EVENING...WNDS EXPECTED TO BE BACKING MORE EAST MON NGT. DO NOT SEE ENUF OF A FETCH TO WARRANT ANY LK EFFECT SNOW AND WL KEEP FCST DRY. WE SHOULD SEE CLDS THICKEN ON TUE AS WARMER AIR OVR THE PLAINS BEGINS TO MAKE A MOV TO THE EAST. THE FCST BY THE MIDDLE OF NXT WEEK IS QUITE MUDDLED AS THE MEAN FLOW TURNS ZONAL ACROSS THE LWR 48. DIFFICULT TO TIME WEAK IMPULSES MOVG THRU THIS FAST FLOW... AS WELL AS THE STRENGTH OF THE WAA AND AMT OF MSTR PRESENT. WHILE SOME KIND OF POPS MAY BE NEEDED IN FUTURE FCSTS...PREFER TO WAIT AND TRY TO PIN DOWN A TIME FRAME. MDLS ARE ALL OVR THE PLACE WHICH DOES NOT HELP MUCH. THEREFORE...WL LEAVE WED AND THU DRY FOR NOW WITH THE CAVEAT BEING THAT THIS IS A SHAKY DRY FCST. AVIATION...IFR CONDITIONS EXPECTED ACROSS THE REGION THROUGH FRIDAY MORNING...WITH THE POTENTIAL FOR FREEZING RAIN AND ICING EARLY THIS EVENING. && .GRB WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 6 AM FRIDAY WIZ020>022-030-031-035>040-045-048>050-073-074- WINTER STORM WARNING UNTIL 12 PM FRIDAY WIZ005-010>013-018-019- && $$ WEATHER.GOV/GREENBAY
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
345 PM CST THU MAR 1 2007 .SHORT TERM...TONIGHT AND FRIDAY...MAIN CONCERN IS PRECIPITATION TYPE OVER THE REGION EARLY THIS EVENING AND SNOW AMOUNTS FOR THIS EVENING AND TONIGHT. CURRENT RADAR SHOWING MODERATE PCPN ACROSS CENTRAL WI LATE THIS AFTERNOON. HAVE SEEN A VARIETY OF PCPN TYPES AS THIS AREA OF PCPN MOVES NORTH INTO THE REGION. FARTHER TO THE S IN SRN WI...PCPN STARTED AS RAIN. AS IT MOVED FARTHER TO THE NORTH AND MOVED INTO THE COLDER AIR... BEGAN TO SEE FREEZING RAIN ACROSS CENTRAL WISCONSIN...WITH SOME LOCATIONS QUICKLY RECEIVING AROUND A QUARTER OF AN INCH OF ICE ACCUMULATION. PRESENTLY SEE SOME SNOW AND SLEET REPORTS AROUND MARSHFIELD...CLINTONVILLE...AND OSHKOSH. SPOTTERS IN THESE LOCATIONS REPORTED INITIAL RAIN BEFORE QUICKLY TURNING OVER TO SNOW OR SLEET. PRETTY CONFIDENT ON THE LOCATION OF THIS CHANGE OVER...WITH 20Z CWA TAMDAR SOUNDING SHOWING LIMITED WARM AIR ALOFT...WITH VALUES ONLY RISING TO 0.5C AT 825MB AND PLENTY OF BELOW FREEZING AIR BELOW THAT. THEREFORE...HAVE MADE SOME TWEAKS TO ADD A LITTLE MORE FREEZING RAIN TO THE FORECAST FOR EARLY THIS EVENING OVER CENTRAL AND EAST CENTRAL WISCONSIN...BEFORE TRANSITIONING IT TO ALL SNOW. EXPECT THE PCPN INTENSITY TO CONTINUE AS THIS WAVE PUSHES NORTH ACROSS NE WISCONSIN THIS EVENING. VERY GOOD LIFT SEEN WITH THIS STRONG SHORTWAVE AND FRONTOGENESIS ALONG A NW TO SE LINE ACROSS WI. WITH BEST OMEGA AND FRONTOGENIC FORCING IN THE SNOW GROWTH ZONE...EXPECT THE EXISTING FORECAST OF HEAVY SNOW OVER FAR NE WI AND ACROSS NRN WI TO BE IN GOOD SHAPE. SREF...NAM...AND GFS SUPPORT HEAVY SNOW IN THIS REGION... WITH A COUPLE OF INCHES AN HOUR SNOWFALLS POSSIBLE ALONG THE WI AND UPPER MICHIGAN BORDER. HAVE MADE A FEW MINOR TWEAKS TO THE SNOWFALL FORECAST...BUT HAVE LEFT IT MAINLY INTACT. BEHIND THE SURGE OF PCPN THIS EVENING...MID LEVEL DRY AIR FROM THE DRY SLOT PUSHES ACROSS NE WI. EXPECT THIS TO DECREASE SNOW ACROSS THE AREA AFTER MIDNIGHT TONIGHT FROM SOUTH TO NORTH...WITH LIGHT SNOW OR FREEZING DRIZZLE REMAINING ACROSS THE AREA. THINK ANOTHER AREA OF LIGHT SNOW IS POSSIBLE DURING THE DAY ON FRIDAY AS WEAK WAVE ROTATES AROUND THE LOW CENTERED OVER CENTRAL WISCONSIN. WITH WEAKER FRONTOGENIC FORCING AND SHALLOW MOISTURE...ONLY BELIEVE AND INCH OR TWO OF ACCUMULATION IS POSSIBLE DURING THE DAY FRIDAY CENTRAL AND EAST CENTRAL WISCONSIN...BUT BELIEVE STILL COULD SEE ANOTHER 2-4 OVER THE FAR NORTHERN COUNTIES AND HAVE EXTENDED THE WINTER STORM WARNING AN ADDITIONAL 6 HOURS TO COMPENSATE FOR THAT SNOWFALL. ALSO...LEFT THE EXISTING MENTION OF FREEZING DRIZZLE OVER EAST CENTRAL WI AS MOISTURE LAYER IS BELOW 10KFT AND SNOW GROWTH REGION IS AT THE VERY TOP OF THIS LAYER. WITH TEMPS SLIGHTLY COOLER OVER NC WI...BELIEVE THAT PCPN WILL BE MAINLY SNOW. .LONG TERM...FRI NGT THRU NXT THU. A GRADUAL DEAMPLIFICATION OF THE MEAN FLOW IS STILL EXPECTED TO TAKE PLACE TOWARD THE MIDDLE OF NXT WEEK WHICH WL LEAD TO A GRADUAL WARM-UP IN TEMPS. THERE ARE PLENTY OF UNCERTAINTIES AS TO BOTH THE SPD OF THIS WARM-UP AND THE HANDLING OF INDIVIDUAL SHRTWVS RACING THRU THE MEAN FLOW FOR ANY PCPN CHCS WED OR THU. INITIAL SFC LOW SLOWLY TRACKS E-NE INTO N-CNTRL LWR MI FRI NGT AND HAVE TRENDED TOWARD THE SLOWER MOVEMENT OF THE NAM/NGM/CANADIAN. NE WI TO GET INTO THE COLD CYCLONIC SIDE OF THE STORM WITH WNDS BACKING NORTH AND CAA DEVELOPING ESP LTR FRI NGT. EXPECT LGT SNOW TO PERSIST AS VARIOUS SHRTWVS ROTATE AROUND THE UPR LOW AND TRAILING DEFORMATION ZN STILL IN THE PROCESS OF EXITING THE RGN. CURRENT THINKING IS THAT ANOTHER INCH OF ACCUMULATION IS PSBL AND WITH WNDS SLOWLY INCREASING THRU THE NGT...SOME DRIFTING SNOW IS EXPECTED. WL CON TO FAVOR THE WARMER GUID FOR MIN TEMPS AS COLDER AIR JUST PUSHING INTO WI BY 12Z SAT. EVEN AS THE STORM BEGINS TO WEAKEN AND ACCELERATE NE INTO SRN QUEBEC ON SAT...INITIAL CYCLONIC FLOW TO KEEP SCT LGT SNOW SHWRS GOING ACROSS NE WI DURING THE MORNING HRS. AS THE CYCLONIC FLOW STARTS TO WEAKEN IN THE AFTERNOON...THE SNOW SHWRS SHOULD DIMINISH TO SCT FLURRIES. AN EXCEPTION TO THIS WL BE OVR VILAS CNTY WHERE NW WNDS AND COLD AIR MOVG OVR LK SUPERIOR WL GENERATE ALL SNOW SHWR ACTIVITY. BLUSTERY CONDITIONS AND CLD CVR SHOULD LIMIT THE DIURNAL RISE IN TEMPS...THUS HAVE KEPT READINGS TOWARD THE COOLER GUID VALUES. OTHER THAN SOME LINGERING LGT SNOW SHWRS OR FLURRIES ACROSS N-CNTRL WI SAT NGT...THE REST OF THE FCST AREA WL QUIET DOWN WEATHER-WISE. SOME BREAKS IN THE CLDS AND DIMINISHING WNDS WL BRING A COLD NGT TO THE RGN. PREFER THE COOLER GUID VALUES WHICH MATCHES WHAT THE PREV SHIFT ALREADY HAD. AN UPR RDG OVR THE ROCKIES AND AN UPR TROF OVR THE ERN U.S. PLACES NE WI IN A NW FLOW ALOFT ON SUNDAY. NO REAL WEATHER FEATURES (EITHER A THE SFC OR ALOFT) TO DEAL WITH...THUS WL KEEP SUNDAY DRY. COLD START TO THE DAY WL OFFSET THE EXPECTED MIXED SUNSHINE AND PREFER TO KEEP MAX TEMPS A FEW DEGS BLO THE MEX GUID. AS A STG UPR TROF/SHRWTV DIGS SEWD ACROSS ONTARIO SUNDAY NGT...A CDFNT IS FCST TO DROP THRU WI. WHILE THE BETTER UPR DYNAMICS WL REMAIN TO OUR NORTH AND EAST...THE STRENGTH OF THE CAA BEHIND THE FNT MAY BE ABLE TO SQUEEZE OUT SOME LGT SNOW SHWRS OR FLURRIES. THE MORE PREVALENT SNOW SHWRS TO EXIST OVR N-CNTRL WI WHERE NW WNDS WL COMBINE WITH 8H TEMPS AROUND -20C TO PRODUCE LK EFFECT SNOW. THIS LK EFFECT POTENTIAL WL THEN CARRY OVR INTO MON AS TRAJS REMAIN FAVORABLE. THE REST OF NE WI SHOULD SEE PARTLY SUNNY SKIES MON WITH TEMPS ABT 3 TO 5 DEGS BLO NORMAL. LRG CANADIAN HI PRES TO BUILD ACROSS THE GREAT LKS RGN MON NGT INTO TUE. WHILE NW WNDS TO PERSIST INTO MON EVENING...WNDS EXPECTED TO BE BACKING MORE EAST MON NGT. DO NOT SEE ENUF OF A FETCH TO WARRANT ANY LK EFFECT SNOW AND WL KEEP FCST DRY. WE SHOULD SEE CLDS THICKEN ON TUE AS WARMER AIR OVR THE PLAINS BEGINS TO MAKE A MOV TO THE EAST. THE FCST BY THE MIDDLE OF NXT WEEK IS QUITE MUDDLED AS THE MEAN FLOW TURNS ZONAL ACROSS THE LWR 48. DIFFICULT TO TIME WEAK IMPULSES MOVG THRU THIS FAST FLOW... AS WELL AS THE STRENGTH OF THE WAA AND AMT OF MSTR PRESENT. WHILE SOME KIND OF POPS MAY BE NEEDED IN FUTURE FCSTS...PREFER TO WAIT AND TRY TO PIN DOWN A TIME FRAME. MDLS ARE ALL OVR THE PLACE WHICH DOES NOT HELP MUCH. THEREFORE...WL LEAVE WED AND THU DRY FOR NOW WITH THE CAVEAT BEING THAT THIS IS A SHAKY DRY FCST. AVIATION...IFR CONDITIONS EXPECTED ACROSS THE REGION THROUGH FRIDAY MORNING...WITH THE POTENTIAL FOR FREEZING RAIN AND ICING EARLY THIS EVENING. && .GRB WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 6 AM FRIDAY WIZ020>022-030-031-035>040-045-048>050-073-074- WINTER STORM WARNING UNTIL 12 PM FRIDAY WIZ005-010>013-018-019- && $$ SRF/KALLAS WEATHER.GOV/GREENBAY

AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
417 AM EST FRI MAR 2 2007 SHORT TERM /TODAY THROUGH SUNDAY/... RAIN MOVED IN ON SCHEDULE. DID HAVE A FEW RUMBLES OF THUNDER EARLY OVER SOUTHERN NJ AND SE PA. COULD HAVE SOME MORE WITHIN THE NEXT 4 TO 6 HOURS. MODELS ARE MOVING THE HEAVY RAIN RAPIDLY OUT OF OUR AREA BY MIDDAY...SO WILL CUT BACK THE ENDING TIME FOR THE FLOOD WATCH TO 1 PM. IN AREAS WHERE THERE IS A CONSIDERABLE SNOW PACK... MAINLY POCONOS...ANY SIGNIFICANT SNOWMELT AND ICE JAM BREAKUPS COULD CAUSE FLOODING LATER IN THE DAY. WE WILL HANDLE THAT, IF IT OCCURS WITH WARNINGS. RAINFALL AMOUNTS, SO FAR, MAY BE PUSHING ONE INCH IN SOME LOCATIONS. THE ONLY AREA WARNED ATTM IS CHESTER COUNTY IN PA...THE BRANDYWINE CREEK IN PARTICULAR. WITH THE MILD AIR STREAMING INTO OUR AREA...WE HAVE LET OUR ADVISORY EXPIRE IN THE NORTH. WHILE THERE MAY STILL BE A FEW ISOLATED POCKETS OF FREEZING TEMPERATURES, MOST READINGS HAVE CLIMBED ABOVE THAT MARK. AND WHERE THEY ARE STILL AT OR SLIGHTLY BELOW, THEY SHOULD RISE ABOVE WITHIN THE NEXT HOUR OR TWO. ONCE THE FRONTAL SYSTEM MOVES OUT OF OUR AREA, RAPID CLEARING IS EXPECTED. SHOULD SEE PLENTY OF SUNSHINE THIS AFTERNOON. A SECONDARY SURGE OF COLD AIR WILL CROSS THE REGION SATURDAY AS THE UPPER TROUGH MOVES EAST NORTHEAST FROM THE GREAT LAKES. SCATTERED SHOWERS MAY PRECEED AND ACCOMPANY THIS COLD PUSH. THERE MAY EVEN BE A FEW SCATTERED TSTMS SATURDAY AFTERNOON OR EVENING AS THE CONVERGENCE ZONE INCREASES. AFTER ALL, THIS IS MARCH. A NW FLOW OF COLDER AIR MOVES INTO OUR REGION SATURDAY NIGHT THROUGH SUNDAY. && LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... THE EAST COAST TROUGH HANGS AROUND FOR THE EARLY PART OF THE EXTENDED. ANOTHER, EVEN COLDER, SURGE DROPS ACROSS THE REGION LATE MONDAY INTO MONDAY NIGHT. LATER IN PERIOD, THE FLOW BECOMES MORE ZONAL, BRINGING MILDER AIR BACK INTO THE REGION BY WEDNESDAY NIGHT AND THURSDAY. && .AVIATION... AT 1230 AM, CEILINGS WERE GENERALLY IN THE IFR CATEGORY WITH A FEW LOCATIONS TOUCHING LIFR. VSBYS WERE GENERALLY MVFR WITH IFR CONDITIONS IN THE HEAVIER PRECIPITATION. MOS GUIDANCE DID NOT CAPTURE WELL THE DEVELOPMENT AND INLAND PUSH OF COASTAL FRONT...WITH SSE WINDS TO THE SOUTH OF THE FRONT AND NE WINDS TO THE NORTH. 06Z TAF ISSUANCE PLAYED UP THIS WIND DIRECTION DIFFERENCE AND BROUGHT COASTAL FRONT UP INTO VICINITY OF I95 CORRIDOR AIRPORTS (ILG...PHL...PNE...TTN). THE HEAVIEST OF THE RAIN SHOULD FALL FROM NOW UNTIL AROUND 9:00 AM. IFR CONDITIONS ARE LIKELY THOUGH MOST OF THAT PERIOD...PARTICULARLY IN THE SECTOR NORTH AND WEST OF THE COASTAL FRONT. FOR THE EARLY MORNING HOURS, WE`VE ALSO KEPT THE MENTION OF CUMULONIMBUS CLOUDS (CB) TO SUGGEST THE POSSIBILITY OF SCATTERED TSTMS ALONG WITH THE MENTION OF LOW LEVEL WIND SHEAR. 00Z MODEL RUNS CONTINUE TO SUGGEST THE DEVELOPMENT OF A STRONG SOUTH SOUTHEAST LOW LEVEL JET OVER OUR REGION...AND THIS IS SUPPORTED BY LATEST ACARS DATA FROM PHL. MOVED START TIME OF LLWS IN THE TAFS SOONER BY ABOUT AN HOUR BASED ON ACARS DATA. 06Z NAM MODEL RUN CONTINUES TO SUPPORT HIGH CONFIDENCE FORECAST OF RAPID IMPROVEMENT TO VFR CONDITIONS. TIMING SLIGHTLY SLOWER...EXPECTED NOW 16Z TO 19Z TIMEFRAME. WINDS WILL SWING AROUND TO WEST IN THE LATE MORNING AND GUST TO 25 KT DURING THE AFTERNOON. && .MARINE... GALE WARNING HEADLINES CONTINUE. NO CHANGE TO PREVIOUS COVERAGE AND TIMING. SE FLOW OVER COLD WATER HAVING TROUBLE REACHING SPEEDS ADVERTISED IN MODELS...BUT STILL EXPECT TO SEE GALE FORCE GUSTS. NEW WAVEWATCH SUPPORTS PREVIOUS SEAS FORECAST SO NO SIGNIFICANT CHANGE IN THAT AREA EITHER. GUIDANCE SUGGESTS THE GALES WOULD HOLD ON A BIT LONGER NORTH THAN SOUTH AS THE SYSTEM LIFTS NORTHEAST, AND WE ACCOUNT FOR THAT. && TIDES... HAVE DROPPED COASTAL FLOOD ADVISORY FOR ATLANTIC COAST SECTIONS OF NEW JERSEY AND DELAWARE AS WELL AS FOR MARYLAND PORTION OF CHESAPEAKE BAY. DEPARTURES ARE NOT RUNNING AS HIGH AS PREVIOUSLY ANTICIPATED. HAVE LEFT ADVISORY UP FOR TIDAL DELAWARE AREA AS STRONG SSE LOW LEVEL FLOW STILL HAS POTENTIAL TO PUSH WATER UP INTO THAT REGION AND ACHIEVE MINOR TIDAL FLOODING LEVELS DURING HIGH TIDE LATER TODAY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR PAZ054-055- 060>062-067>071. COASTAL FLOOD ADVISORY FROM 7 AM THIS MORNING TO 1 PM EST THIS AFTERNOON FOR PAZ070-071. NJ...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR NJZ001-007>010- 012-015-017>019. COASTAL FLOOD ADVISORY FROM 7 AM THIS MORNING TO 1 PM EST THIS AFTERNOON FOR NJZ016>019-021. DE...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR DEZ001. COASTAL FLOOD ADVISORY FROM 7 AM THIS MORNING TO 1 PM EST THIS AFTERNOON FOR DEZ001-002. MD...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR MDZ008. MARINE...GALE WARNING UNTIL 11 AM EST THIS MORNING FOR ANZ430-431- 452>455. GALE WARNING UNTIL 3 PM EST THIS AFTERNOON FOR ANZ450-451. && $$ SHORT TERM/LONG TERM...RPW AVIATION/MARINE/TIDES...GSS
AREA FORECAST DISCUSSION...UPDATED
NWS MOUNT HOLLY NJ
124 AM EST FRI MAR 2 2007 .UPDATE... AVIATION /06Z-06Z/... AT 1230 AM, CEILINGS WERE GENERALLY IN THE IFR CATEGORY WITH A FEW LOCATIONS TOUCHING LIFR. VSBYS WERE GENERALLY MVFR WITH IFR CONDITIONS IN THE HEAVIER PRECIPITATION. MOS GUIDANCE DID NOT CAPTURE WELL THE DEVELOPMENT AND INLAND PUSH OF COASTAL FRONT...WITH SSE WINDS TO THE SOUTH OF THE FRONT AND NE WINDS TO THE NORTH. 06Z TAF ISSUANCE PLAYED UP THIS WIND DIRECTION DIFFERENCE AND BROUGHT COASTAL FRONT UP INTO VICINITY OF I95 CORRIDOR AIRPORTS (ILG...PHL...PNE...TTN). THE HEAVIEST OF THE RAIN SHOULD FALL FROM NOW UNTIL AROUND 9:00 AM. IFR CONDITIONS ARE LIKELY THOUGH MOST OF THAT PERIOD. FOR THE EARLY MORNING HOURS, WE`VE ALSO KEPT THE MENTION OF CUMULONIMBUS CLOUDS (CB) TO SUGGEST THE POSSIBILITY OF SCATTERED TSTMS ALONG WITH THE MENTION OF LOW LEVEL WIND SHEAR. 00Z MODEL RUNS CONTINUE TO SUGGEST THE DEVELOPMENT OF A STRONG SOUTH SOUTHEAST LOW LEVEL JET OVER OUR REGION...AND THIS IS SUPPORTED BY LATEST ACARS DATA FROM PHL. MOVED START TIME OF LLWS IN THE TAFS SOONER BY ABOUT AN HOUR BASED ON ACARS DATA. 00Z MODEL RUNS CONTINUE TO SUPPORT HIGH CONFIDENCE FORECAST OF RAPID IMPROVEMENT TO VFR CONDITIONS IN 15Z TO 18Z TIMEFRAME. WINDS WILL SWING AROUND TO WEST IN THE LATE MORNING AND GUST TO 25 KT DURING THE AFTERNOON. THESE CONDITIONS REFLECTED IN TAFS. PREV DISCUSSION... /ISSUED 952 PM EST THU MAR 1 2007/ THE PUBLIC PRODUCTS HAVE BEEN REISSUED TO INCLUDE A WINTER WEATHER ADVISORY FOR CARBON, MONROE AND NORTHAMPTON COUNTIES OF NORTHEAST PENNSYLVANIA AND SUSSEX AND WARREN COUNTIES OF NEW JERSEY. WE HAVE RECEIVED A FEW CALLS FROM SPOTTERS WITH REPORTS OF FREEZING RAIN AND LIGHT ACCUMULATIONS. THE WSW WILL BE IN EFFECT UNTIL 2 AM... BY THEN THE WARMER AIR WILL HAVE CAUSED THE MIXED PRECIP TO CHANGE TO ALL RAIN. AFTER THAT... THE RAIN HEAVY AT TIMES WORDING WILL REMAIN FOR THE OVERNIGHT IN ALL AREAS AND THE FLOOD WATCH CONTINUES. THE COASTAL FLOOD ADVISORY HAS BEEN EXPANDED TO INCLUDE THE REMAINDER OF OUR WATERS THROUGH THE FIRST HALF OF FRIDAY. PREV DISCUSSION... /ISSUED 650 PM EST THU MAR 1 2007/ AVIATION /00Z-24Z/... AT 6:45 PM, CEILINGS WERE GENERALLY IN THE VFR CATEGORY WITH MAINLY UNRESTRICTED VSBY AT OUR EIGHT TAF SITES. THE LEADING EDGE OF THE RAIN WAS ALREADY UP INTO EASTERN MARYLAND. AS A RESULT, WE`LL CONTINUE WITH THE IDEA OF GRADUALLY DETERIORATING CONDITIONS THROUGH MIDNIGHT. THE HEAVIEST OF THE RAIN SHOULD FALL FROM MIDNIGHT UNTIL AROUND 9:00 AM. IFR CONDITIONS ARE LIKELY THOUGH MOST OF THAT PERIOD. FOR THE LATE NIGHT AND EARLY MORNING HOURS ON FRIDAY, WE`VE ALSO KEPT THE MENTION OF CUMULONIMBUS CLOUDS (CB) TO SUGGEST THE POSSIBILITY OF SCATTERED TSTMS ALONG WITH THE MENTION OF LOW LEVEL WIND SHEAR. THE MODELS CONTINUE TO SUGGEST THE DEVELOPMENT OF A STRONG SOUTH SOUTHEAST LOW LEVEL JET OVER OUR REGION. DURING THE HOURS RIGHT AROUND DAYBREAK IT SHOULD BE WITHIN 2000 FEET OF THE SURFACE AND SO THE LLWS HAS BEEN INCLUDED IN THE TAFS. THE GUIDANCE CONTINUES TO INDICATE THAT THE PRECIP WILL SHUT OFF AROUND MID MORNING WITH SOME LINGERING LOW CLOUDS BEFORE RAPID CLEARING IN THE EARLY AFTERNOON. PREV DISCUSSION... /ISSUED 329 PM EST THU MAR 1 2007/ LONG TERM /SUNDAY THROUGH THURSDAY/... EAST COAST TROUGH HANGS AROUND FOR THE EARLY PART OF THE EXTENDED. LATER IN PERIOD FLOW BECOMES MORE ZONAL. DRY QUIET WEATHER WITH NEAR SEASONABLE TEMPERATURES EXPECTED. MARINE... WE HAVE DROPPED THE SCA HEADLINE AND GONE TO STRAIGHT GALES. THE WRF IS LESS EMPHATIC ABOUT GALE FORCE WINDS/GUST OVER THE NRN WATERS THAN THE GFS; THE GFS HAS BACKED OFF A BIT FROM THE PREVIOUS RUN AND WE ARE LOOKING AT A SERLY FLOW OVER COLD WATER. HOWEVER, WE THINK WE`LL GET TO GALES REGARDING GUSTS. LEANED MORE TOWARD WAVEWATCH REGARDING THE SEAS, WHICH MEANS WE UPPED THEM A LTL IN THE PRE-SYSTEM ENVIRONMENT. GUIDANCE SUGGESTS THE GALES WOULD HOLD ON A BIT LONGER NORTH THAN SOUTH AS THE SYSTEM LIFTS NORTHEAST, AND WE ACCOUNT FOR THAT. HYDROLOGY... EXPECTING A GOOD SOAKING RAIN WITH QPF IN THE 1.5 TO 2 INCH RANGE WITH LOCALLY HIGHER AMOUNTS. RAINFALL WILL BE QUICK SHOT WITH THE BULK OF IT FALLING IN A 6 TO 12 HOUR TIME FRAME. LOCAL PROCEDURES SHOW SMALL STREAMS IN NORTHERN DELAWARE AND SOUTHEAST PENNSYLVANIA REACHING MODERATE FLOOD LEVELS WITH THESE AMOUNTS. LARGER STREAMS AND RIVERS IN SOUTHEAST PENNSYLVANIA AND NEW JERSEY MAY REACH MINOR FLOOD LEVELS. AT PRESENT THE LARGE MAIN STEM RIVERS SUCH AS THE SCHUYLKILL...LEHIGH AND DELAWARE WILL SHOW SIGNIFICANT WITHIN BANKS RISES BUT NO FLOODING EXPECTED. TIDES... POSITIVE TIDAL DEPARTURES EARLY THIS AFTERNOON ARE RUNNING ABOVE THE SSE AND BELOW THE ECS GUIDANCE. A COMPROMISE BETWEEN THE TWO WOULD HAVE AREAS OF MINOR TIDAL FLOODING ALONG OUR MOST FLOOD-PRONE LOCATIONS. THE CBOFS FORECAST FOR CAMBRIDGE IS NOT TERRIBLY IMPRESSIVE, BUT THE FORECAST FOR TOLCHESTER HAS BEEN TAKING IT ABOVE MINOR TIDAL FLOODING FOR THE PAST TWO RUNS. HIGH TIDES OCCUR A FEW HOURS ON EITHER SIDE OF DAYBREAK ON THE CHESAPEAKE, EARLIER SOUTH THAN NORTH, AND THIS PUTS IT IN THE WINDOW FOR AN ADVISORY. ONE HAS BEEN ISSUED. ELSEWHERE, HIGH TIDES OCCUR FROM DAYBREAK INTO THE LATE MORNING FOR THE ATLANTIC COASTAL SECTIONS, ADJACENT BACK BAYS, RARITAN BAY AND DELAWARE BAY. THESE ARE BEYOND THE ADVISORY WINDOW AND SO WE HAVE ISSUED A SPS FOR THEM. WE ALSO HAVE INCLUDED THE TIDAL DELAWARE IN THAT SPS BECAUSE OF INDICATIONS FROM THE SSE, EVEN THOUGH HIGH TIDES THERE RUN FROM LATE MORNING INTO EARLY AFTERNOON WHEN THE SYSTEM SHOULD BE PAST US. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...FLOOD WATCH THROUGH FRIDAY EVENING FOR PAZ054-055-060>062- 067>071. COASTAL FLOOD ADVISORY FROM 7 AM TO 1 PM EST FRIDAY FOR PAZ070- 071. WINTER WEATHER ADVISORY UNTIL 2 AM EST FRIDAY FOR PAZ054-055- 062. NJ...FLOOD WATCH THROUGH FRIDAY EVENING FOR NJZ001-007>010-012-015- 017>019. COASTAL FLOOD ADVISORY FROM 7 AM TO 1 PM EST FRIDAY FOR NJZ016>019-021. COASTAL FLOOD ADVISORY FROM 3 AM TO 9 AM EST FRIDAY FOR NJZ012>014-020-022>027. WINTER WEATHER ADVISORY UNTIL 2 AM EST FRIDAY FOR NJZ001-007. DE...FLOOD WATCH THROUGH FRIDAY EVENING FOR DEZ001. COASTAL FLOOD ADVISORY FROM 7 AM TO 1 PM EST FRIDAY FOR DEZ001- 002. COASTAL FLOOD ADVISORY FROM 3 AM TO 9 AM EST FRIDAY FOR DEZ003- 004. MD...FLOOD WATCH THROUGH FRIDAY EVENING FOR MDZ008. COASTAL FLOOD ADVISORY FROM 3 AM TO 9 AM EST FRIDAY FOR MDZ008- 012-015-019-020. MARINE...GALE WARNING UNTIL 11 AM EST FRIDAY FOR ANZ430-431-452>455. GALE WARNING UNTIL 3 PM EST FRIDAY FOR ANZ450-451. && $$ UPDATE...PO/SZATKOWSKI
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
1045 PM CST THU MAR 1 2007 .UPDATE...FCST UPDATE IS FINALLY OUT. DECIDED TO DOWNGRADE THE ENTIRE CWA TO A WINTER WEATHER ADVISORY AND EXTEND THE END TIME TO 6 PM FRIDAY. DRY SLOT HAS PUSHED NORTH TO THE UPPER MICHIGAN BORDER...CAUSING THE PCPN TO BECOME MORE SCATTERED IN NATURE. ALTHOUGH SOME DECENT POCKETS OF SNOW ARE STILL FEEDING INTO FAR NE WI...BUT DON`T EXPECT ADDL ACCUMS TO TOP 2 INCHES THERE. FARTHER SOUTH...PCPN HAS TAPERED OFF TO OCNL LIGHT SNOW AND FREEZING DRIZZLE...WITH SOME DRIZZLE OVER THE FOX VALLEY AND LKSHR AREAS. FELT THAT COMBINATION OF ADDL LIGHT SNOW ACCUMS AND FREEZING DRIZZLE WAS SUFFICIENT TO WARRANT A WINTER WX ADVISORY TONIGHT. ON FRIDAY...THE UPPER LOW...WHICH IS CURRENTLY OVER FAR NE IA...WILL LIFT NORTHEAST INTO EAST CENTRAL WISCONSIN. EXPECT A STEADY LIGHT SNOW TO REDEVELOP OVER THE FA LATE TONIGHT INTO EARLY FRIDAY AS THE LOW APPROACHES...AND CONTINUE THROUGHOUT THE DAY. MOST PLACES SHOULD SEE ANOTHER 2-3 INCH OF ACCUMULATION...WITH LOCAL 4 INCH AMOUNTS BY EVG. GIVEN THE ADDL ACCUMULATION...FELT IT WAS PRUDENT TO EXTEND THE WINTER WX ADVISORY THROUGH 6 PM FRIDAY. WINDS HAVE BEEN STEADILY DECREASING OVER THE PAST HOUR OR TWO...ALTHOUGH OCNL GUSTS TO 30 TO 35 MPH ARE STILL BEING REPORTED. OVERALL...EXPECT THE DECREASING TREND TO CONTINUE...SO ANY THREAT OF BLOWING SNOW WILL DIMINISH OVERNIGHT. KIECKBUSCH REST OF DISCUSSION FROM PREVIOUS SHIFT... .SHORT TERM...TONIGHT AND FRIDAY...MAIN CONCERN IS PRECIPITATION TYPE OVER THE REGION EARLY THIS EVENING AND SNOW AMOUNTS FOR THIS EVENING AND TONIGHT. CURRENT RADAR SHOWING MODERATE PCPN ACROSS CENTRAL WI LATE THIS AFTERNOON. HAVE SEEN A VARIETY OF PCPN TYPES AS THIS AREA OF PCPN MOVES NORTH INTO THE REGION. FARTHER TO THE S IN SRN WI...PCPN STARTED AS RAIN. AS IT MOVED FARTHER TO THE NORTH AND MOVED INTO THE COLDER AIR... BEGAN TO SEE FREEZING RAIN ACROSS CENTRAL WISCONSIN...WITH SOME LOCATIONS QUICKLY RECEIVING AROUND A QUARTER OF AN INCH OF ICE ACCUMULATION. PRESENTLY SEE SOME SNOW AND SLEET REPORTS AROUND MARSHFIELD...CLINTONVILLE...AND OSHKOSH. SPOTTERS IN THESE LOCATIONS REPORTED INITIAL RAIN BEFORE QUICKLY TURNING OVER TO SNOW OR SLEET. PRETTY CONFIDENT ON THE LOCATION OF THIS CHANGE OVER...WITH 20Z CWA TAMDAR SOUNDING SHOWING LIMITED WARM AIR ALOFT...WITH VALUES ONLY RISING TO 0.5C AT 825MB AND PLENTY OF BELOW FREEZING AIR BELOW THAT. THEREFORE...HAVE MADE SOME TWEAKS TO ADD A LITTLE MORE FREEZING RAIN TO THE FORECAST FOR EARLY THIS EVENING OVER CENTRAL AND EAST CENTRAL WISCONSIN...BEFORE TRANSITIONING IT TO ALL SNOW. EXPECT THE PCPN INTENSITY TO CONTINUE AS THIS WAVE PUSHES NORTH ACROSS NE WISCONSIN THIS EVENING. VERY GOOD LIFT SEEN WITH THIS STRONG SHORTWAVE AND FRONTOGENESIS ALONG A NW TO SE LINE ACROSS WI. WITH BEST OMEGA AND FRONTOGENIC FORCING IN THE SNOW GROWTH ZONE...EXPECT THE EXISTING FORECAST OF HEAVY SNOW OVER FAR NE WI AND ACROSS NRN WI TO BE IN GOOD SHAPE. SREF...NAM...AND GFS SUPPORT HEAVY SNOW IN THIS REGION... WITH A COUPLE OF INCHES AN HOUR SNOWFALLS POSSIBLE ALONG THE WI AND UPPER MICHIGAN BORDER. HAVE MADE A FEW MINOR TWEAKS TO THE SNOWFALL FORECAST...BUT HAVE LEFT IT MAINLY INTACT. BEHIND THE SURGE OF PCPN THIS EVENING...MID LEVEL DRY AIR FROM THE DRY SLOT PUSHES ACROSS NE WI. EXPECT THIS TO DECREASE SNOW ACROSS THE AREA AFTER MIDNIGHT TONIGHT FROM SOUTH TO NORTH...WITH LIGHT SNOW OR FREEZING DRIZZLE REMAINING ACROSS THE AREA. THINK ANOTHER AREA OF LIGHT SNOW IS POSSIBLE DURING THE DAY ON FRIDAY AS WEAK WAVE ROTATES AROUND THE LOW CENTERED OVER CENTRAL WISCONSIN. WITH WEAKER FRONTOGENIC FORCING AND SHALLOW MOISTURE...ONLY BELIEVE AND INCH OR TWO OF ACCUMULATION IS POSSIBLE DURING THE DAY FRIDAY CENTRAL AND EAST CENTRAL WISCONSIN...BUT BELIEVE STILL COULD SEE ANOTHER 2-4 OVER THE FAR NORTHERN COUNTIES AND HAVE EXTENDED THE WINTER STORM WARNING AN ADDITIONAL 6 HOURS TO COMPENSATE FOR THAT SNOWFALL. ALSO...LEFT THE EXISTING MENTION OF FREEZING DRIZZLE OVER EAST CENTRAL WI AS MOISTURE LAYER IS BELOW 10KFT AND SNOW GROWTH REGION IS AT THE VERY TOP OF THIS LAYER. WITH TEMPS SLIGHTLY COOLER OVER NC WI...BELIEVE THAT PCPN WILL BE MAINLY SNOW. .LONG TERM...FRI NGT THRU NXT THU. A GRADUAL DEAMPLIFICATION OF THE MEAN FLOW IS STILL EXPECTED TO TAKE PLACE TOWARD THE MIDDLE OF NXT WEEK WHICH WL LEAD TO A GRADUAL WARM-UP IN TEMPS. THERE ARE PLENTY OF UNCERTAINTIES AS TO BOTH THE SPD OF THIS WARM-UP AND THE HANDLING OF INDIVIDUAL SHRTWVS RACING THRU THE MEAN FLOW FOR ANY PCPN CHCS WED OR THU. INITIAL SFC LOW SLOWLY TRACKS E-NE INTO N-CNTRL LWR MI FRI NGT AND HAVE TRENDED TOWARD THE SLOWER MOVEMENT OF THE NAM/NGM/CANADIAN. NE WI TO GET INTO THE COLD CYCLONIC SIDE OF THE STORM WITH WNDS BACKING NORTH AND CAA DEVELOPING ESP LTR FRI NGT. EXPECT LGT SNOW TO PERSIST AS VARIOUS SHRTWVS ROTATE AROUND THE UPR LOW AND TRAILING DEFORMATION ZN STILL IN THE PROCESS OF EXITING THE RGN. CURRENT THINKING IS THAT ANOTHER INCH OF ACCUMULATION IS PSBL AND WITH WNDS SLOWLY INCREASING THRU THE NGT...SOME DRIFTING SNOW IS EXPECTED. WL CON TO FAVOR THE WARMER GUID FOR MIN TEMPS AS COLDER AIR JUST PUSHING INTO WI BY 12Z SAT. EVEN AS THE STORM BEGINS TO WEAKEN AND ACCELERATE NE INTO SRN QUEBEC ON SAT...INITIAL CYCLONIC FLOW TO KEEP SCT LGT SNOW SHWRS GOING ACROSS NE WI DURING THE MORNING HRS. AS THE CYCLONIC FLOW STARTS TO WEAKEN IN THE AFTERNOON...THE SNOW SHWRS SHOULD DIMINISH TO SCT FLURRIES. AN EXCEPTION TO THIS WL BE OVR VILAS CNTY WHERE NW WNDS AND COLD AIR MOVG OVR LK SUPERIOR WL GENERATE ALL SNOW SHWR ACTIVITY. BLUSTERY CONDITIONS AND CLD CVR SHOULD LIMIT THE DIURNAL RISE IN TEMPS...THUS HAVE KEPT READINGS TOWARD THE COOLER GUID VALUES. OTHER THAN SOME LINGERING LGT SNOW SHWRS OR FLURRIES ACROSS N-CNTRL WI SAT NGT...THE REST OF THE FCST AREA WL QUIET DOWN WEATHER-WISE. SOME BREAKS IN THE CLDS AND DIMINISHING WNDS WL BRING A COLD NGT TO THE RGN. PREFER THE COOLER GUID VALUES WHICH MATCHES WHAT THE PREV SHIFT ALREADY HAD. AN UPR RDG OVR THE ROCKIES AND AN UPR TROF OVR THE ERN U.S. PLACES NE WI IN A NW FLOW ALOFT ON SUNDAY. NO REAL WEATHER FEATURES (EITHER A THE SFC OR ALOFT) TO DEAL WITH...THUS WL KEEP SUNDAY DRY. COLD START TO THE DAY WL OFFSET THE EXPECTED MIXED SUNSHINE AND PREFER TO KEEP MAX TEMPS A FEW DEGS BLO THE MEX GUID. AS A STG UPR TROF/SHRWTV DIGS SEWD ACROSS ONTARIO SUNDAY NGT...A CDFNT IS FCST TO DROP THRU WI. WHILE THE BETTER UPR DYNAMICS WL REMAIN TO OUR NORTH AND EAST...THE STRENGTH OF THE CAA BEHIND THE FNT MAY BE ABLE TO SQUEEZE OUT SOME LGT SNOW SHWRS OR FLURRIES. THE MORE PREVALENT SNOW SHWRS TO EXIST OVR N-CNTRL WI WHERE NW WNDS WL COMBINE WITH 8H TEMPS AROUND -20C TO PRODUCE LK EFFECT SNOW. THIS LK EFFECT POTENTIAL WL THEN CARRY OVR INTO MON AS TRAJS REMAIN FAVORABLE. THE REST OF NE WI SHOULD SEE PARTLY SUNNY SKIES MON WITH TEMPS ABT 3 TO 5 DEGS BLO NORMAL. LRG CANADIAN HI PRES TO BUILD ACROSS THE GREAT LKS RGN MON NGT INTO TUE. WHILE NW WNDS TO PERSIST INTO MON EVENING...WNDS EXPECTED TO BE BACKING MORE EAST MON NGT. DO NOT SEE ENUF OF A FETCH TO WARRANT ANY LK EFFECT SNOW AND WL KEEP FCST DRY. WE SHOULD SEE CLDS THICKEN ON TUE AS WARMER AIR OVR THE PLAINS BEGINS TO MAKE A MOV TO THE EAST. THE FCST BY THE MIDDLE OF NXT WEEK IS QUITE MUDDLED AS THE MEAN FLOW TURNS ZONAL ACROSS THE LWR 48. DIFFICULT TO TIME WEAK IMPULSES MOVG THRU THIS FAST FLOW... AS WELL AS THE STRENGTH OF THE WAA AND AMT OF MSTR PRESENT. WHILE SOME KIND OF POPS MAY BE NEEDED IN FUTURE FCSTS...PREFER TO WAIT AND TRY TO PIN DOWN A TIME FRAME. MDLS ARE ALL OVR THE PLACE WHICH DOES NOT HELP MUCH. THEREFORE...WL LEAVE WED AND THU DRY FOR NOW WITH THE CAVEAT BEING THAT THIS IS A SHAKY DRY FCST. AVIATION...IFR CONDITIONS EXPECTED ACROSS THE REGION THROUGH FRIDAY MORNING...WITH THE POTENTIAL FOR FREEZING RAIN AND ICING EARLY THIS EVENING. && .GRB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 PM FRIDAY WIZ030-031-035>040-045-048>050- WINTER WEATHER ADVISORY UNTIL 6 PM FRIDAY WIZ005-010>013-018>022-073-074- && $$ WEATHER.GOV/GREENBAY

AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
700 AM EST FRI MAR 2 2007 .UPDATE... AVIATION /12Z-12Z/... AT 630 AM, CEILINGS WERE GENERALLY IN THE IFR TO LOW MVFR CATEGORY AND VISIBILITIES WERE MAINLY MVFR. BULK OF PRECIPITATION IS NOW MOVING OUT OF THE AREA...A LITTLE FASTER THAN PREVIOUSLY ANTICIPATED. SOME NEW CONVECTION IS DEVELOPING TO OUR SOUTHWEST AND WE MAY STILL SEE SOME CONVECTION UP INTO OUR REGION ALTHOUGH IT IS A LOW PROBABILITY EVENT. SOUTHERLY SURFACE WINDS TO THE SOUTH OF THE COASTAL FRONT ARE BLOWING STRONGER THAN PREVIOUSLY FORECAST AND THE NEW 12Z TAF ISSUANCE HAS BEEN ADJUSTED BASED ON CURRENT CONDITIONS. WITH MOST PRECIPITATION IN THE PROCESS OF PULLING OUT...LOOKING FOR CEILINGS TO HOLD STEADY AND VISIBILITY TO HOLD STEADY OR IMPROVE SLIGHTLY LEADING UP TO 15Z TIMEFRAME. 06Z MODEL RUNS CONTINUE TO SUPPORT HIGH CONFIDENCE FORECAST OF RAPID IMPROVEMENT TO VFR CONDITIONS LATER TODAY. TRANSITION TO VFR EXPECTED IN 16Z TO 19Z TIMEFRAME. WINDS WILL SWING AROUND TO WEST IN THE LATE MORNING AND GUST TO 25 KT DURING THE AFTERNOON. PREVIOUS AFD ISSUED AT 417 AM MAR 2 2007 SHORT TERM /TODAY THROUGH SUNDAY/... RAIN MOVED IN ON SCHEDULE. DID HAVE A FEW RUMBLES OF THUNDER EARLY OVER SOUTHERN NJ AND SE PA. COULD HAVE SOME MORE WITHIN THE NEXT 4 TO 6 HOURS. MODELS ARE MOVING THE HEAVY RAIN RAPIDLY OUT OF OUR AREA BY MIDDAY...SO WILL CUT BACK THE ENDING TIME FOR THE FLOOD WATCH TO 1 PM. IN AREAS WHERE THERE IS A CONSIDERABLE SNOW PACK... MAINLY POCONOS...ANY SIGNIFICANT SNOWMELT AND ICE JAM BREAKUPS COULD CAUSE FLOODING LATER IN THE DAY. WE WILL HANDLE THAT, IF IT OCCURS WITH WARNINGS. RAINFALL AMOUNTS, SO FAR, MAY BE PUSHING ONE INCH IN SOME LOCATIONS. THE ONLY AREA WARNED ATTM IS CHESTER COUNTY IN PA...THE BRANDYWINE CREEK IN PARTICULAR. WITH THE MILD AIR STREAMING INTO OUR AREA...WE HAVE LET OUR ADVISORY EXPIRE IN THE NORTH. WHILE THERE MAY STILL BE A FEW ISOLATED POCKETS OF FREEZING TEMPERATURES, MOST READINGS HAVE CLIMBED ABOVE THAT MARK. AND WHERE THEY ARE STILL AT OR SLIGHTLY BELOW, THEY SHOULD RISE ABOVE WITHIN THE NEXT HOUR OR TWO. ONCE THE FRONTAL SYSTEM MOVES OUT OF OUR AREA, RAPID CLEARING IS EXPECTED. SHOULD SEE PLENTY OF SUNSHINE THIS AFTERNOON. A SECONDARY SURGE OF COLD AIR WILL CROSS THE REGION SATURDAY AS THE UPPER TROUGH MOVES EAST NORTHEAST FROM THE GREAT LAKES. SCATTERED SHOWERS MAY PRECEDE AND ACCOMPANY THIS COLD PUSH. THERE MAY EVEN BE A FEW SCATTERED TSTMS SATURDAY AFTERNOON OR EVENING AS THE CONVERGENCE ZONE INCREASES. AFTER ALL, THIS IS MARCH. A NW FLOW OF COLDER AIR MOVES INTO OUR REGION SATURDAY NIGHT THROUGH SUNDAY. && LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... THE EAST COAST TROUGH HANGS AROUND FOR THE EARLY PART OF THE EXTENDED. ANOTHER, EVEN COLDER, SURGE DROPS ACROSS THE REGION LATE MONDAY INTO MONDAY NIGHT. LATER IN PERIOD, THE FLOW BECOMES MORE ZONAL, BRINGING MILDER AIR BACK INTO THE REGION BY WEDNESDAY NIGHT AND THURSDAY. && .AVIATION... AT 1230 AM, CEILINGS WERE GENERALLY IN THE IFR CATEGORY WITH A FEW LOCATIONS TOUCHING LIFR. VSBYS WERE GENERALLY MVFR WITH IFR CONDITIONS IN THE HEAVIER PRECIPITATION. MOS GUIDANCE DID NOT CAPTURE WELL THE DEVELOPMENT AND INLAND PUSH OF COASTAL FRONT...WITH SSE WINDS TO THE SOUTH OF THE FRONT AND NE WINDS TO THE NORTH. 06Z TAF ISSUANCE PLAYED UP THIS WIND DIRECTION DIFFERENCE AND BROUGHT COASTAL FRONT UP INTO VICINITY OF I95 CORRIDOR AIRPORTS (ILG...PHL...PNE...TTN). THE HEAVIEST OF THE RAIN SHOULD FALL FROM NOW UNTIL AROUND 9:00 AM. IFR CONDITIONS ARE LIKELY THOUGH MOST OF THAT PERIOD...PARTICULARLY IN THE SECTOR NORTH AND WEST OF THE COASTAL FRONT. FOR THE EARLY MORNING HOURS, WE`VE ALSO KEPT THE MENTION OF CUMULONIMBUS CLOUDS (CB) TO SUGGEST THE POSSIBILITY OF SCATTERED TSTMS ALONG WITH THE MENTION OF LOW LEVEL WIND SHEAR. 00Z MODEL RUNS CONTINUE TO SUGGEST THE DEVELOPMENT OF A STRONG SOUTH SOUTHEAST LOW LEVEL JET OVER OUR REGION...AND THIS IS SUPPORTED BY LATEST ACARS DATA FROM PHL. MOVED START TIME OF LLWS IN THE TAFS SOONER BY ABOUT AN HOUR BASED ON ACARS DATA. 06Z NAM MODEL RUN CONTINUES TO SUPPORT HIGH CONFIDENCE FORECAST OF RAPID IMPROVEMENT TO VFR CONDITIONS. TIMING SLIGHTLY SLOWER...EXPECTED NOW 16Z TO 19Z TIMEFRAME. WINDS WILL SWING AROUND TO WEST IN THE LATE MORNING AND GUST TO 25 KT DURING THE AFTERNOON. && .MARINE... GALE WARNING HEADLINES CONTINUE. NO CHANGE TO PREVIOUS COVERAGE AND TIMING. SE FLOW OVER COLD WATER HAVING TROUBLE REACHING SPEEDS ADVERTISED IN MODELS...BUT STILL EXPECT TO SEE GALE FORCE GUSTS. NEW WAVEWATCH SUPPORTS PREVIOUS SEAS FORECAST SO NO SIGNIFICANT CHANGE IN THAT AREA EITHER. GUIDANCE SUGGESTS THE GALES WOULD HOLD ON A BIT LONGER NORTH THAN SOUTH AS THE SYSTEM LIFTS NORTHEAST, AND WE ACCOUNT FOR THAT. && TIDES... HAVE DROPPED COASTAL FLOOD ADVISORY FOR ATLANTIC COAST SECTIONS OF NEW JERSEY AND DELAWARE AS WELL AS FOR MARYLAND PORTION OF CHESAPEAKE BAY. DEPARTURES ARE NOT RUNNING AS HIGH AS PREVIOUSLY ANTICIPATED. HAVE LEFT ADVISORY UP FOR TIDAL DELAWARE AREA AS STRONG SSE LOW LEVEL FLOW STILL HAS POTENTIAL TO PUSH WATER UP INTO THAT REGION AND ACHIEVE MINOR TIDAL FLOODING LEVELS DURING HIGH TIDE LATER TODAY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR PAZ054-055- 060>062-067>071. COASTAL FLOOD ADVISORY FROM 7 AM THIS MORNING TO 1 PM EST THIS AFTERNOON FOR PAZ070-071. NJ...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR NJZ001-007>010- 012-015-017>019. COASTAL FLOOD ADVISORY FROM 7 AM THIS MORNING TO 1 PM EST THIS AFTERNOON FOR NJZ016>019-021. DE...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR DEZ001. COASTAL FLOOD ADVISORY FROM 7 AM THIS MORNING TO 1 PM EST THIS AFTERNOON FOR DEZ001-002. MD...FLOOD WATCH UNTIL 1 PM EST THIS AFTERNOON FOR MDZ008. MARINE...GALE WARNING UNTIL 11 AM EST THIS MORNING FOR ANZ430-431- 452>455. GALE WARNING UNTIL 3 PM EST THIS AFTERNOON FOR ANZ450-451. && $$ SHORT TERM/LONG TERM...RPW AVIATION/MARINE/TIDES...GSS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1015 AM EST FRI MAR 2 2007 .SHORT TERM... WATER VAPOR LOOP SHOWS AN UPPER LOW SPINNING OVER THE MIDWEST...WITH A DRY INTRUSION PROGRESSING NORTHEAST THROUGH THE APPALACHIANS AND EASTERN GREAT LAKES. ACARS 400-250MB WIND OBSERVATIONS REVEAL A 150-190KT WESTERLY JET ACROSS THE SOUTHERN CONUS...WHICH CURLS NORTHEAST THROUGH THE MID ATLANTIC. 11Z SURFACE ANALYSIS PLACED A 979MB OCCLUDED CYCLONE ACROSS CENTRAL WISCONSIN. THE OCCLUDED/COLD FRONT EXTENDED FROM THE CYCLONE EAST ACROSS THE EASTERN GREAT LAKES...THEN SOUTH THROUGH THE EASTERN PORTION OF THE CAROLINAS AND SOUTHWEST INTO THE CENTRAL GULF OF MEXICO. A WARM FRONT EXTENDED NORTHEAST FROM MANASSAS TOWARD LONG ISLAND. SEVERAL SECONDARY COLD FRONTS STRETCH SOUTHWEST AND WEST FROM THE OCCLUDED CYCLONE ACROSS THE CENTRAL CONUS. A TROUGH WAS NOTED IN THE LEE OF THE APPALACHIANS. THE COLD FRONT HAS JUST REACHED THE WESTERN SHORELINE OF THE CHESAPEAKE BAY. SIGNIFICANT SUBSIDENCE ON THE SYNOPTIC SCALE EVIDENT FROM WATER VAPOR IMAGERY WILL LEAD TO SUNNY SKIES THIS AFTERNOON. GRADIENT WILL STILL ALLOW FOR 25 MPH WIND GUSTS INTO THE EARLY AFTERNOON JUDGING FROM THE 12Z KIAD RAOB AND MORNING ACARS SOUNDINGS. GIVEN WARM MORNING READINGS...FURTHER MIXING WILL YIELD HIGHS NEAR 60F IN MANY LOCATIONS. LOWER 40S EXPECTED IN THE HIGHER TERRAIN WITH COLD ADVECTION THIS AFTERNOON. && .AVIATION... CEILING AND VISIBILITY RESTRICTIONS WILL CONTINUE TO IMPROVE TO VFR WITH THE COLD FRONTAL PASSAGE. MIXING WILL ENCOURAGE 25KT WIND GUSTS THROUGH THE AFTERNOON. && .MARINE... 00Z ETA/06 GFS MOS AT THOMAS POINT INDICATE SUSTAINED WINDS WILL FALL INTO THE 15-20KT RANGE BY MIDDAY. 12Z NAM/06Z GFS PROXIMITY FORECAST SOUNDINGS INDICATE WIND GUST POTENTIAL OF 25-30 KNOTS THROUGH THE AFTERNOON. && .TIDES... CURRENT TIDAL DEPARTURES ARE ONE AND A HALF TO TWO AND A HALF FEET ABOVE ASTRONOMICAL PREDICTIONS. THE LUNAR CYCLE IS NEAR A FULL MOON (98 PERCENT FULL). THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM INDICATES WATER LEVELS WILL RECEDE TO WITHIN A HALF FOOT OF ASTRONOMICAL PREDICTIONS DURING THE EVENING. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR ANZ530>537. && $$ SHORT TERM/AVIATION/MARINE/TIDES...ROGOWSKI