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

AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
230 PM PST TUE MAR 6 2007 .SYNOPSIS... WEAK UPPER LEVEL LOW PRESSURE WILL BRING VARIABLE HIGH CLOUDINESS THROUGH WEDNESDAY. THERE WILL ALSO BE AREAS OF COASTAL LOW CLOUDS AND FOG IN THE NIGHTS AND MORNINGS THROUGH FRIDAY ALONG WITH COOLER DAYS. FAIR AND WARMER THIS WEEKEND AND EARLY NEXT WEEK UNDER HIGH PRESSURE WITH WEAK OFFSHORE FLOW. THERE COULD BE A FEW RECORED HIGH TEMPERATURES INLAND SUNDAY AND MONDAY. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (TONIGHT-FRI)... THERE WERE LOTS OF MID AND HIGH CLOUDS TODAY. EARLY AFTERNOON ACARS SOUNDINGS SHOWED SW WINDS ALOFT. WEAK GRADIENTS BUT TRENDING ONSHORE. A WEAK UPPER LEVEL TROUGH OF LOW PRESSURE WILL MOVE THROUGH WED. THIS WILL CONTINUE VARIABLE MID TO HIGH CLOUDINESS. CANNOT COMPLETELY RULE OUT THE POSSIBILITY OF A FEW LIGHT SHOWERS OR SPRINKLES WED...MAINLY IN THE MOUNTAINS DURING THE MORNING AS AN AREA OF MID TO HIGH LEVEL MOISTURE MOVES IN FROM THE SW. HOWEVER...PROBABILITIES WILL REMAIN LESS THAN 15 PERCENT SO WILL NOT MENTION IN THE ZONES. ONSHORE FLOW WILL INCREASE THROUGH THU BRINGING A RETURN OF THE MARINE LAYER. COASTAL LOW CLOUDS AND FOG TONIGHT AND WED MORNING WILL BE BROKEN UP THE BY HIGHER CLOUDS AND IT WILL TAKE SOME TIME FOR THE SURFACE DEW POINTS TO INCREASE. THE MARINE LAYER SHOULD BECOME BETTER ESTABLISHED WED NIGHT INTO THU MORNING AND RETURN THU NIGHT INTO FRI MORNING. LESS HIGH CLOUDINESS THU AND FRI. THERE COULD BE SOME LOW VISIBILITIES IN FOG IN THE COASTAL AREAS SINCE THE MARINE LAYER WILL INITIALLY BE SHALLOW WHEN IT RETURNS. THE PASSING TROUGH AND STRONGER ONSHORE FLOW WILL CAUSE LOCAL GUSTY WINDS IN THE MOUNTAINS AND DESERTS...MAINLY WED AFTERNOON AND NIGHT. HOWEVER...WINDS ARE EXPECTED TO REMAIN BELOW ADVISORY STRENGTH. COOLER WED AND THU. BUILDING HIGH PRESSURE ALOFT AND WEAKER ONSHORE FLOW START A WARMING TREND INLAND FRI. && .LONG TERM (SAT-TUE)... BROAD HIGH PRESSURE ALOFT AND WEAK OFFSHORE FLOW WILL BRING MOSTLY CLEAR SKIES AND MUCH WARMER WEATHER THIS WEEKEND AND EARLY NEXT WEEK. THERE COULD BE A FEW RECORD HIGH MAX TEMPS INLAND SUN AND MON WITH MON LIKELY THE WARMEST DAY. A LITTLE COOLER TUE AS THE HIGH WEAKENS. && .AVIATION... 061930Z...LATE MORNING ACARS SOUNDINGS FROM KSAN AND KSNA ARE NOT INDICATING ANY MARINE INVERSION BUT STILL EXPECT A WEAK AND VERY SHALLOW ONE TO DEVELOP THROUGH THE AFTERNOON AS THE SEA BREEZES BEGIN TO TAKE HOLD OVER THE AREA. SOME STRATUS/FOG DEVELOPMENT IS POSSIBLE OVERNIGHT WHICH COULD MOVE TO THE VICINITY OF THE COASTAL AIRPORTS BEFORE SUNRISE BUT CONFIDENCE IS LOW ON THIS. MORE SIGNIFICANT DEVELOPMENT IS EXPECTED WEDNESDAY AFTERNOON AS THE MARINE LAYER BEGINS TO DEEPEN. ABOVE THE MARINE LAYER...VARIABLE AMOUNTS OF ALTOCU AND CIRRUS ABOVE FL150 THROUGH WEDNESDAY WITH UNRESTRICTED VISIBILITIES. && .SGX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...DVA AVIATION...HORTON
AREA FORECAST DISCUSSION
NWS MIAMI FL
938 AM EST MON MAR 5 2007 .UPDATE...HIGH PRESSURE RIDGING BUILDING IN FROM THE NORTHWEST. DRY CONDITIONS JUST ABOVE THE SURFACE IS SHOWN ON TBW ROAB AND ACARS IN THE MIA AREA (MFL MISG THIS AM). THIS DRYER AIR WILL MIX DOWN TO THE SURFACE TO CREATE A FIRE DANGER. THE ONLY CHANGE MADE WAS TO UP THE WINDS TO SCEC FOR THE LAKE DUE TO NW WINDS 15 TO 20 KNOTS AND GUSTY. NO OTHER CHGS EXPECTED. && .PREV DISCUSSION... /ISSUED 442 AM EST MON MAR 5 2007/ DISCUSSION...A QUIET AND TRANQUIL WEATHER PATTERN WILL PREVAIL ACROSS THE AREA THROUGH MID WEEK AS HIGH PRESSURE BUILDS ACROSS THE SOUTHEAST STATES THEN MOVES EAST INTO THE WESTERN ATLANTIC...SO NOT MUCH TO DISCUSS. HAVE DEPICTED DRY WEATHER IN THE FORECAST ALL THE WAY THROUGH THURSDAY NIGHT. TEMPS WILL RUN BELOW NORMAL TODAY...THEN GRADUALLY WARM THROUGHOUT THE WEEK...GOING BACK ABOVE NORMAL BY LATE IN THE WEEK. TONIGHT WILL BE THE COLDEST NIGHT...WITH LOWS RANGING FROM AROUND 40 ACROSS GLADES AND HENDRY COUNTIES TO THE 50S SOUTHEAST COAST. THE LATEST GUIDANCE KEEPS TEMPS AT 40 OR ABOVE OVER GLADES/HENDRY COUNTIES...BUT SOME UPPER 30S ARE STILL POSSIBLE...BUT 36F OR LOWER IS UNLIKELY SO WILL OMIT FROST FROM THE FORECAST. OTHERWISE...NO SIGNIFICANT CHANGES WERE MADE TO THE FORECAST. GFS SHOWS AN INVERTED SURFACE TROUGH DEVELOPING TO OUR EAST FRI AND MOVING CLOSER TO THE AREA THIS WEEKEND...BUT MOISTURE CONTINUES LIMITED...SO WILL CONTINUE WITH ONLY SLIGHT CHANCE POPS...IN LINE WITH THE GFS EXTENDED NUMBERS. WITH THE LIMITED MOISTURE AND LACK OF LIFT THIS WEEKEND...REMOVED THUNDER FROM THE FCST AS THIS LOOKS UNLIKELY AT THIS TIME. LOOKING FAR OUT IN TIME...IT WILL BE INTERESTING TO SEE HOW THINGS PLAY OUT EARLY NEXT WEEK. GFS AND ECMWF AND DGEX ALL SHOW SUBSTANTIAL TROUGHING MOVING ACROSS THE GULF OF MEXICO AND EVENTUALLY ACROSS THE AREA SOMETIME NEXT MON- WED. DEPENDING ON THE AMOUNT OF MOISTURE RETURN...A ROUND OF THUNDERSTORMS COULD BE IN THE OFFING DAY 7 OR BEYOND. WE SHALL SEE. AVIATION...CLEARING SKIES FROM N TO S AS MID LEVEL CLOUDINESS MOVES. SOME LOW LEVEL CUMULUS ALONG E COAST TERMINAL THIS AFTERNOON AS A NE WIND FLOW DEVELOPS OFF OF THE ATLC. VFR CONDITIONS THOUGH TO PERSIST THROUGH THE PERIOD. MARINE...NORTH WINDS WILL PREVAIL ACROSS THE COASTAL WATERS TODAY AND TONIGHT...BECOMING NE TUESDAY. SPEEDS OF NEAR 15 KT WILL CONTINUE THE HAZARDOUS SEAS IN THE GULF STREAM THROUGH TUE AFTERNOON BEFORE SUBSIDING. NO HIGHLIGHTS NEEDED ACROSS THE REST OF THE WATERS. FIRE WEATHER...DEWPOINTS HAVE TAKEN A NOSE DIVE ACROSS THE EAST COAST AREAS OVER THE PAST FEW HOURS. AMAZINGLY...AT 3 AM FT. LAUDERDALE WAS REPORTING A 33% RH! NEEDLESS TO SAY...DRY AIR IS IN PLACE ACROSS THE AREA...SO WE ARE GOING WITH A RED FLAG WARNING ACROSS ALL ZONES FOR THIS AFTERNOON. ALL GUIDANCE....INCLUDING THE NAM12 AND NAM-WRF...SHOW DEWPOINTS REBOUNDING RAPIDLY ACROSS THE EASTERN HALF OF THE AREA DURING THE MORNING AS LOW LEVEL WINDS JUST ABOVE THE SFC ADVECT MOISTURE INTO THE AREA...BUT WE THINK THIS IS OVERDONE. THIS TREND WAS REFLECTED IN THE FCST...BUT LESS AGGRESSIVELY. THE LOWEST RH`S WILL OCCUR OVER GLADES/HENDRY/COLLIER COUNTIES THIS AFTERNOON...WITH MIN RH`S THERE IN THE UPPER TEENS TO LOWER 20S. SIDED WITH THE NAM12 DEWPOINTS FOR TUESDAY...WHICH SHOW DRY AIR REMAINING OVER WESTERN AREAS...POSSIBLY LEADING TO RED FLAG CONDITIONS ACROSS GLADES/HENDRY/COLLIER COUNTIES...SO WILL ISSUE A FIRE WX WATCH FOR THOSE ZONES FOR TUE AFTERNOON. BY WEDNESDAY...EXPECT THAT MOISTURE LEVELS WILL MODERATE ENOUGH TO PRECLUDE ANY CRITICAL RH CONCERNS THEN. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 72 55 74 63 / - 0 - - FORT LAUDERDALE 72 58 75 65 / - 0 - - MIAMI 72 58 75 63 / - 0 - - NAPLES 69 47 74 57 / - 0 0 0 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...RED FLAG WARNING UNTIL 7 PM EST THIS EVENING FOR FLZ063-FLZ066- FLZ067-FLZ068-FLZ069-FLZ070-FLZ071-FLZ072-FLZ073-FLZ074- FLZ075. FIRE WEATHER WATCH TUESDAY AFTERNOON FOR FLZ063-FLZ066-FLZ069- FLZ070. AM...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EST TUESDAY FOR AMZ650-AMZ651-AMZ670-AMZ671. GM...NONE. && $$ LONG TERM...18/GR SHORT TERM/AVIATION...60/BD
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1015 AM EST MON MAR 5 2007 .SHORT TERM UPDATE(THIS AFTERNOON).... COLD FRONT OVER LAKE ERIE WILL CONTINUE MOVE SOUTH INTO THE LOCAL AREA. TAMDAR DATA THIS MORNING INDICATING PLENTY OF LOW LEVEL MOISTURE AND NORTHWEST WINDS FROM 25 TO 35 KNOTS. SNOW ACCUMULATIONS WILL RANGE FROM LESS THAN A HALF INCH IN MOST AREAS WITH 1 TO 3 INCHES OVER THE SNOWBELT COUNTIES OF NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA... WITH WINDS GUSTING AT TIMES TO AROUND 35 TO 40 MPH WILL CAUSE BLOWING AND DRIFTING SNOW. ONCE COLD FRONT GOES BY THE WINDS WILL SHIFT INTO THE NORTHWEST AND TEMPERATURES WILL FALL THROUGH THE 20S. && .AVIATION(12Z-12Z)... AN ARCTIC COLD FRONT STRETCHED ACROSS SOUTHERN LOWER MICHIGAN WILL ACROSS NRN OH/NW OH THIS MORNING...AND REACH THE OHIO RIVER BY THIS EVENING. BEST CHC FOR SNOW TODAY IS SNOWBELT NE OH/NW PA WHERE YOU COULD PICK UP 1-3 INCHES...ESPECIALLY ALONG THE HIGH TERRAIN. MOST OF THE REST OF NE OH EXPECTED TO PICK UP AROUND AN INCH. BUT DRY AIR PUSHES IN SO FAST BEHIND THE FRONT THAT SNOW SHOULD BE OVER BY THE AFTERNOON PUSH. BIGGEST CONCERN THIS MORNING WILL BE THE WIND. GUSTY WEST FLO WILL BECOME STRONG NW FLO BEHIND THE FRONT WITH GUSTS INTO THE LOWER 30S. WINDS WILL BEGIN TO TAPER OFF AFTER SUNSET AND DIE DOWN OVERNIGHT AS HIGH PRESSURE CURRENTLY IN MANITOBA...DROPS INTO THE CENTRAL GREAT LAKES BY THIS TIME TOMORROW. && .SHORT TERM(TODAY-TUESDAY)... BLAST OF COLD ARCTIC AIR FOR THE 1ST PART OF THE WEEK. COLD FRONT MOVES THROUGH THIS MORNING. SOME SYNOPTIC SNOW ASSOCIATED WITH IT BUT TRANSITION TO LAKE EFFECT SNOW SHOWERS THIS AFTERNOON AND TONIGHT. RATHER LIMITED LOW LEVEL MOISTURE AND LOWERING INVERSION LATER THIS AFTERNOON SHOULD LIMIT SNOW FALL BUT NE OH AND NW PA SHOULD SEE LOCALLY 1 TO 3 INCHES. WINDS PICKING UP EVEN THIS MORNING WILL BE GUITE GUSTY BEHIND FRONT CAUSING BLOWING SNOW. DONT BELIEVE WIDESPREAD VSBY 1/4 MILE OR LESS WILL OCCUR NEEDED FOR A BLOWING SNOW ADVISORY BUT BLOWING SNOW WILL BE A PROBLEM FOR SNOW REMOVAL ESPECIALLY AREAS RECIEVING HEAVIER SNOW AMOUNTS. LAKE SNOW SHOWERS TAPER OFF TONIGHT. STILL LOCALLY AN INCH OR 2 NE AREA. TEMPERTURES WILL FALL TO AROUND 5 TO 10 DEGREES. HAVE WIND CHILL TEMPS NEAR -10 IN E. FEW LINGER SNOW FLURRIES NE TUESDAY MORNING BEFORE HIGH PRESSURE MOVE ACROSS THE FORECAST AREA. THE HIGH WILL BRING A BRIEF PERIOD OF FAIR WEATHER BEFORE ALBERTA CLIPPER BRINGS ANOTHER ROUND OF SNOW TUESDAY NIGHT INTO WEDNESDAY ALONG WITH A REENFORCEMENT OF COLD AIR. && .LONG TERM (TUE NIGHT THROUGH SUNDAY)... CLIPPER SYSTEM TUE NGT INTO WEDNESDAY ROUNDING INTO SHAPE AND LOOKING HEALTHIER. SINCE MODELS HAVE BEEN CONSISTENT ON THE TRACK OF SYSTEM I FEEL MORE CONFIDENT WE CAN GO WITH LIKELY POPS ALTHOUGH THE EXACT TRACK WILL STILL DETERMINE WHO GETS ANY ACCUMULATING SNOW. SYSTEM WILL HAVE LIMITED MOISTURE BUT DECENT DYNAMICS AND IF ATMOSPHERE BECOMES EVEN A LITTLE BIT UNSTABLE ALOFT WILL HAVE SOME LOCATIONS WHICH WILL AT LEAST SEE A FEW INCHES OF SNOW. MOST FAVORABLE LOCATION AT THIS TIME SEEMS TO BE NORTH CENTRAL TO NE OH BUT WILL HAVE TO WATCH AS WE GET CLOSER TO EVENT. REINFORCING PUSH OF COLDER AIR BEHIND CLIPPER ON WEDNESDAY AND IF THERE IS FRESH SNOW ON THE GROUND WEDNESDAY WILL BE ANOTHER COLD DAY WITH SUBREEZING TEMPS. RETURN FLOW DOES NOT DEVELOP UNTIL THURSDAY NIGHT/FRIDAY MORNING SO FRIDAY SHOULD BE THE DAY TEMPERATURES START TO REALLY REBOUND. GFS SEEMS A BIT COLD BUT ECMWF AND CANADIAN SEEM A BIT TOO WARM THURSDAY INTO FRIDAY. GFS ENSMEBLE MAX/MIN TEMPS HAVE A HUGE RANGE BY LATE WEEK AS MODEL STRUGGLES TO PIN DOWN COLD AIR VS WARM AIR SO RATHER THAN BEING AS WARM AS I WAS YESTERDAY WILL COMPROMISE MORE WITH COLDER SOLUTION AT LEAST THROUGH THURSDAY. SO IT SEEMS AS IF THE REAL WARM UP WILL HAVE TO WAIT UNTIL FRIDAY AND SATURDAY AND ALL MODELS A BIT FASTER WITH COLD FRONT ON SATURDAY SO THE WARMEST AIR MAY GET CUT OFF BEFORE REACHING THE FCST AREA BY SATURDAY ALTHOUGH EVEN BEHIND FRONT THE AIRMASS IS PACIFIC IN ORIGIN SO SHOULD STILL BE A RATHER MILD DAY SATURDAY. SHOWERS SEEM LIKELY AT SOME POINT FRI NGT INTO SATURDAY. BACK DOWN TO NEAR NORMAL TEMPS SATURDAY NIGHT INTO SUNDAY AND A FEW FLURRIES NOT OUT OF THE QUESTION AS TROUGH ALOFT EXITS. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...RIVER FLOOD WARNINGS REMAIN IN EFFECT FOR SCIOTO RIVER AT PROSPECT. GALE WARNING LAKE ERIE THROUGH THIS EVENING. PA...GALE WARNING LAKE ERIE THROUGH THIS EVENING. && $$ SHORT TERM...THOMPSON LONG TERM...KOSARIK AVIATION...DJB
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1255 AM EST MON MAR 5 2007 .AVIATION /06Z-06Z/... MAIN ITEM OF INTEREST THE NEXT 24 HOURS WILL BE THE STRONG AND GUSTY WINDS. INCREASING W-NW 850 MB WINDS INTO THE 40 TO 50 KT RANGE WILL YIELD VERY GUSTY CONDITIONS IN THE MOUNTAINS THROUGH TONIGHT. EAST OF THE BLUE RIDGE...LOW LEVEL WIND SHEAR WILL EXIST THROUGH THE EARLY MORNING UNTIL MIXING ALLOWS GUSTY CONDITIONS TO REACH THE SURFACE. ONLY PARTS OF SOUTHEAST WEST VIRGINIA LOOK TO HAVE ANY CONCERN FOR A CEILING. BY THE LATE AFTERNOON INTO THE EVENING MVFR CONDITIONS MAY EXIST FROM KBLF TO KLWB. SOME ISOLATED VFR SNOW SHOWERS WILL ACCOMPANY THESE CLOUDS. && .PREV DISCUSSION... /ISSUED 927 PM EST SUN MAR 4 2007/ UPDATE... SHORT TERM /REST OF TONIGHT INTO MONDAY/... STILL A FFW CLOUDS FROM GREENBRIER NORTHWARD...ELSE CLEAR SKIES ENTIRE CWA. WILL UPDATE ZFP TO GET RID OF EVENING WORDING. WILL ALSO GO WITH...CLEAR...FOR THE PREDOMINATE SKY FCST OVERNIGHT. WINDS WILL REMAIN A BIT BRISK OVERNIGHT...ESP HIGHER TERRAIN. WIND WILL BECOME A FIRE WEATHER CONCERN MONDAY AS RH DIPS DURING THE AFTN. CONCERN IS EAST OF BLUE RIDGE WHERE GRASSES AND LEAF LITTER ARE DRYER. MAIN THREAT WILL BE DURING THE AFTERNOON WHEN SFC TEMPS ARE THE WARMEST AND RH THE DRYEST. PREV DISCUSSION... /ISSUED 623 PM EST SUN MAR 4 2007/ UPDATE... AVIATION /00Z-24Z/... HIGH PRESSURE WILL BE MOVING INTO THE REGION FROM THE NORTHWEST THROUGH THE PERIOD BUT A PRESSURE GRADIENT WILL REMAIN. WINDS ARE EXPECTED TO INCREASE AGAIN TONIGHT AS PRESSURE RISES AND LOW LEVEL JET INTENSIFIES AFTER 06Z MON. THIS LOW LEVEL JET IS EXPECTED TO STRENGTHEN TO 50-60 KTS ACROSS THE AREA BETWEEN 09Z AND 18Z MON. NAM DEPICTING A 60-70 KT LOW LEVEL JET NORTH OF THE AREA FROM KHSP TO KCBE DURING THIS TIME AS WELL. AIRCRAFT TRAVELING TO OR ALONG THE APPALACHIAN MOUNTAINS SHOULD BE PREPARED FOR TURBULENCE AND WIND SHEAR INTO MONDAY AFTERNOON. THERE STILL MAY BE A FEW LIGHT SNOW SHOWERS FALLING ALONG WESTERN SLOPES THROUGH THIS EVENING. ANY MVFR CEILING THIS EVENING WILL LIKELY BE ALONG WESTERN SLOPES ACROSS SE WV. AFTER 06Z MON...CEILING ARE EXPECTED TO REBOUND TO VFR. PREV DISCUSSION... /ISSUED 240 PM EST SUN MAR 4 2007/ SHORT TERM /TONIGHT THROUGH WEDNESDAY/... MORE SHORTWAVE ENERGY WILL BE DROPPING DOWN THRU THE AREA WITHIN THE LONGER WAVE TROF WHICH WILL REMAIN ANCHORED OVER THE EASTERN U.S. THROUGH MIDWEEK. THIS WILL BASICALLY KEEP PERIODS OF COLD AIR ADVECTION AND BREEZY OR WINDY CONDITIONS GOING THRU THURSDAY MORNING MORNING. THE FIRST OF THE TWO MAIN WAVES DROPPING INTO THE TROF OVER THE NEXT FEW DAYS WILL DO SO MONDAY OVER THE UPPER MID-ATLANTIC...BRINGING A MODEST INCREASE IN LOW LEVEL MOISTR TO THE NORTHWEST BY MONDAY AFTERNOON AND EVENING. RIGHT NOW THINKING THAT IT WILL BE MAINLY FLURRIES. HEIGHTS RISE A LITTLE TUESDAY THEN A STRONGER...CLIPPER...WAVE DROPS DOWN INTO THE TROF WED AND PASSES THRU THE LOWER MID-ATLANTIC. THIS MAY BRING A BETTER CHANCE OF PCPN...LIKELY MIXED PCPN...TO THE NORTH AND COULD SPREAD IT EAST OF THE MOUNTAINS ACROSS CENTRAL VA BEFORE A BRIEF COLD SHOT AND UPSLOPE SNOW SHOWERS WEDNESDAY NIGHT. LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... APPEARS FOR NOW THAT THURSDAY AND FRIDAY WILL REMAIN DRY AS HEIGHTS BUILD AGAIN AND STRONG SFC RIDGE TRACKS ACROSS NEW ENGLAND AND NOSES DOWN THE EAST COAST. THERE IS QUITE A DIFFERENCE IN THE MODELS CONCERNING TEMPERATURES FOR THE PERIOD AS THE ECMWF AND CANADIAN MODELS KEEP COLD AIR BOTTLED UP ACROSS THE GREAT LAKES FOLLOWING THE PASSAGE OF WEDNESDAYS CLIPPER THRU THE OHIO VALLEY. THE GFS ADVECTS MORE COLD AIR INTO THE REGION. IF THE GFS IS WRONG THIS COULD BE QUITE A WARM UP FOR LATE IN THE WEEK. ON FRIDAY ONSHORE FLOW BEGINS DEVELOPING AS THE SFC RIDGE MOVES OFF THE COAST...LEADING TO AN INCREASE IN CLOUDINESS AND A CHANCE OF UPSLOPE RAIN AND DRIZZLE FRIDAY NIGHT AHEAD OF THE NEXT FRONT. LONG RANGE MODELS ARE IN DECENT AGREEMENT ON BRINGING PACIFIC ENERGY ALONG WITH A COLD FRONT...ACROSS THE COUNTRY AND INTO THE EASTERN U.S. BY NEXT SATURDAY OR SUNDAY. TIMING OF COURSE IS THE MAIN ISSUE FOR NOW. THE AIRMASS BEHIND THIS FRONT DOES NOT APPEAR TO BE SIGNIFICANTLY COLD THANKS TO ITS PACIFIC ORIGIN. AVIATION /20Z-18Z/... BUFKIT DATA HAS SNOW SHOWERS ENDING AT BLF AND LWB BETWEEN 21 AND 00Z WHICH IS SUPPORTED BY RADAR TRENDS. MVFR CEILINGS WILL DISSIPATE AROUND 03Z AT BLF AND LWB. WINDS WILL DECOUPLE IN THE VALLEYS WITH LOW LEVEL WIND SHEAR OVERNIGHT AT DAN...LYH...AND LWB. DEEP MIXING IS EXPECTED AGAIN ON MONDAY LEADING TO GUSTY WINDS AFT 14Z. FIRE WEATHER... ISSUING A FIRE WEATHER WATCH FOR MONDAY AFTN DUE TO THE RAPID DRYING OF THE PAST COUPLE DAYS...CONTINUED STIFF WINDS AND HUMIDITIES DURING THE AFTN TMRW APPROACHING MINIMUMS IN THE UPPER TEENS AND LOWER 20S. THE LIMITING FACTOR MAY BE THE WINDS...AS VALUES MAY FALL SHORT OF THE 15 TO 20 MPH THRESHOLD FOR SUSTAINED WINDS. HOWEVER OVERALL FIRE DANGER REMAINS IN THE VERY HIGH TO EXTREME CATEGORY OVER MUCH OF THE AREA. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...FIRE WEATHER WATCH FROM 11 AM EST THIS MORNING THROUGH THIS AFTERNOON FOR VAZ022>024-032>035-043>047-058-059. NC...FIRE WEATHER WATCH FROM 11 AM EST THIS MORNING THROUGH THIS AFTERNOON FOR NCZ003>006-019-020. WV...NONE. && $$ AVIATION...DS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1038 PM CST TUE MAR 6 2007 .UPDATE... 1005 PM CST THE RADAR SHOWS SOME SNOW FALL OF UP TO 1 TO 1.5 INCHES OVER PARTS OF SOUTHEAST WINNEBAGO COUNTY AND NORTHERN DEKALB COUNTY AT 0352 UTC. USING THE ACARS SOUNDING WE SEE AN INVERSION AROUND 812 MB. THIS MAY BE A WEAK FRONTAL INVEERSION. THE RUC80 MODEL SHOWS LARGE FRONTALGENSIS VALUES OF 30 K/MS OR MORE FROM 800 MB TO 850 MB. THE CROSS SECTION SHOWS UPWARD VERTICAL MOTION FROM THE AGEOSTROPHIC CIRCULATION AS WELL. THE SOUNDING AT DVN SHOW A DRIER LAYER BELOW THE MINUS 6 DEGREE C LEVEL AROUND 700 MB. THERE IS PLENTY OF MOISTURE BETWEEN MINUS 10 AND MINUS 20 DEGREE C LAYERS. WE EXPECT A DRY TYPE OF SNOW. THE FORECAST AREA IS ON THE WESTERN SIDE OF A JET STREAK HENCE THE AGEOSTROPHIC CIRCULATION AND MID LEVEL FRONTALGENESIS. THE JET STREAK WILL MOVE EAST BY 12 UTC TO REDUCE ITS EFFECTS AND THE UPWARD VERTICAL MOTION. WE EXPECT THE SNOW TO DECREASE AFTER MIDNIGHT. WE RAISED THE AMOUNT OF SNOW TO AROUND AN INCH IN THE NORTHWEST PORTION OF OUR FORECAST AREA AND AROUND CHICAGO. && .DISCUSSION FOR AFTERNOON GRIDS/ZONES... 238 PM CST UPR JET DIVING DOWN NW FLOW THE MAIN FOCUS TONIGHT. SNOW SHOWERS IN CENTRAL MN DIVING INTO WRN WI NOW AND SHUD MOVE INTO NRN IL THIS EVENING. HAVE UPPED POPS IN FAR NE IL AND NW INDY TNGT TO LIKELY SINCE TRAJECTORY FROM MN LOOKS ON TARGET THERE. AM OPTING FOR LESS THAN AN INCH NORTH OF I-90 AND LITTLE OR NONE SOUTH OF THERE. MAY BE SOME LINGERING SNOW SHOWERS IN CNTYS ARND SRN LK MICH AT DAYBREAK BUT SHUD BE OUT OF HERE SHORTLY THEREAFTER. OTHER MODELS FAVORING THE FAST MOVING GFS WHICH APPEARS MORE VIGOROUS THAN THE NAM. BUT GREATEST ENERGY NORTH OF IL AND WILL FAVOR NON-SIGNIFICANT SNOWFALL AMOUNTS FOR HERE. HIGH PRESSURE DIVING CLOSE BEHIND AND CLEARING SKIES IN THE AFTN WEDNESDAY AS ANTICYCLONIC FLOW CROSSES THE MS VLY. WINDS NOT BLUSTERY ENUF BEHIND FROPA TO ADVECT STRONG CAA INTO AREA AND SHUD BE WARMING BACK UP OVERNIGHT WED NGT AS HIGH SHIFTS EAST AND WAA MAKES A QUICK RETURN. IN FACT...WARMING WELL INTO 40S FOR MAX TEMPS FRI AND SAT AFTER UPR RIDGE SPREADS EAST OF THE MS VLY...OPENING UP REGION TO WARMER PLAINS TEMPS. MODELS HAVE BACKED OFF ON VIGOROUS DEVELOPMENT OF UPR TROF IN PLAINS DURING THAT TIME. WHILE GATHERING SOME GULF MSTR UP THE MS VLY THURSDAY NIGHT AND FRIDAY...LOW LVL JET OF YDA NO LONGER APPEARS TO EXIST IN THE REGION. THIS LIMITING MSTR ADVECTION TO THIS AREA AND DUMBING DOWN TSTM DYNAMICS. SO WILL LEAVE SMALL CHC POPS FOR RAIN FRI AND FRI NGT. ANOTHER HIGH MOVES IN BEHIND THE WEAKENING UPR TROF FOR THE WEEKEND. SHUD BE A DRY AND MILD WEEKEND. OUT WEST THRU THIS TIME...GOOD UPR RIDGING IN THE ROCKIES ALLOWS WAA TO INVADE SRN CANADA. WE RETURN TO A NW UPR FLOW REGIME FOR THE WEEKEND BUT COLD AIR HAS RETREATED WELL INTO CANADA AND IMPACT OF ANOTHER CLIPPER RIDING DOWN THIS UPR FLOW ON MONDAY HAS LITTLE COOLING AFFECT BEHIND IT. AS WE MOVE INTO TUESDAY...GFS IS PROJECTING H8 TEMPS IN THE MID TEENS IN THE DAKOTAS. UPR RIDGING FOCUSES THIS WAA INTO NRN IL FOR MIDWEEK. WITH SUN ANGLE GETTING HIGHER...ANY APPRECIABLE SUNSHINE WILL MAKE AN ADDED IMPACT. VERNAL EQUINOX BY THE WAY WILL AT 707 PM CDT ON MARCH 20TH. RLB && .AVIATION... 06Z TAFS...BAND OF MODERATE SNOW DEVELOPED ACROSS THE I-88 CORRIDOR A FEW HRS AGO...BRIEFLY LOWERING VIS/CIGS TO IFR. THIS HAS LIFTED NE WITH GENERALLY VFR CONDITIONS AGAIN. BULK OF SNOW IS QUICKLY MOVING EAST AND EXPECT SEVERAL HRS OF FLURRIES WITH POSSIBLY THE BACK EDGE OF SNOW SWINGING THRU BEFORE 08Z AND DROPPING CIGS/VIS BACK TO MVFR BRIEFLY. JUST A MID LEVEL DECK TOWARD DAWN THEN STRATOCU ACROSS IA/MN WILL SWING THRU DURING THE MID/LATE MORNING HRS...LIKELY DROPPING CIGS TO 2-3KFT BEFORE SCATTERING OUT EARLY WED AFTERNOON WITH SKC EXPECTED WED EVENING. WINDS ARE BEGINNING TO SHIFT ENE NOW AND WILL CONTINUE TURNING MORE NNE BY DAWN AND INCREASE TO 10-12KTS. WINDS STAY NORTH WEDNESDAY AND DIMINISH WITH SUNSET LIKELY BECOMING LIGHT AND VRB TOWARD THE END OF THE PERIOD. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... .IL...NONE. .IN...NONE. .LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
310 AM CST WED MAR 7 2007 .SYNOPSIS... EARLY THIS MORNING LOW PRESSURE WAS LOCATED OVER ECNTRL MO. THE LOW WAS MOVING ALONG A STATIONARY FRONT THAT EXTENDS FROM OK THROUGH SRN IN AND OH. HIGH PRESSURE WAS CENTERED OVER NERN ND. THE LAST OF THE -SN THAT BRUSHED THE NERN CWA TUE EVENING WAS OVER NERN IL. CLR SKIES DOMINATED MOST OF THE CWA EARLY THIS MORNING OTHER THAN THE BACK EDGE OF AN AC DECK EAST OF THE MS RIVER AND STRATUS THAT HAS ENTERED THE NWRN COUNTIES. && .SHORT TERM...TODAY AND TONIGHT... CLOUD TRENDS AND TEMPS ARE THE MAIN CONCERN TODAY. THE LOW PRESSURE OVER ERN MO WILL MOVE EAST THIS MORNING AS THE NRN PLAINS HIGH MOVES INTO NCNTRL IA BY 00Z. THE STRATUS JUST ENTERING THE CWA WAS TIED TO THE LOW LEVEL CAA IN ADVANCE OF THE HIGH PRESSURE. BASED ON A TAMDAR SOUNDING OUT OF KMCW AROUND 06Z THE STRATUS IS ONLY ABOUT 1200 FT THICK. USING THE RECENT MOVEMENT...THE LEADING EDGE OF THE ST EXTRAPOLATES TO AN KOTM...KMLI...KSQI AROUND 13Z. BY THIS TIME THE SUN WILL BE UP AND STRATUS WILL BE MOVING OVER BARE GROUND. CURRENT THINKING IS THAT THE LEADING EDGE WILL MIX OUT SOME AS THE LOW LEVELS WARM...KEEPING THE CLOUDS FROM REACHING THE FAR SRN CWA. ALSO...CLEARING IS CURRENTLY WORKING ITS WAY SE THROUGH NRN WI SHOULD REACH THE NERN CWA EARLY THIS AFTERNOON. THIS COMBINED WITH SUBSIDENCE ASSOCIATED WITH THE HIGH PRESSURE...SHOULD HELP ERODE CLOUDS OVER THE NRN CWA DURING THE MID TO LATE AFTERNOON. SO AFTER A CLOUDY MORNING OVER MOST THE CWA...WE SHOULD SOME BREAKING OUT DURING THE AFTERNOON IN MOST AREAS. CLOUD TRENDS WILL HAVE AN IMPACT ON TEMPS TODAY. FAVORED THE WARMER GUIDANCE IN THE FAR SOUTH WHERE SUN IS EXPECTED MOST OF THE DAY. A COMBINATION OF CLOUDS AND SNOW COVER IN THE NORTH SHOULD LIMIT THE TEMP REBOUND TO 5 TO 10 DEGREES OR IN THE MID TO UPPER 20S. TONIGHT...EXPECT MAINLY CLEAR SKIES WITH HIGH PRESSURE MOVING OVER THE CWA. WE SHOULD SEE A GOOD DROP IN TEMPS WITH CONDITIONS FAVORABLE FOR RADIATIONAL COOLING. WENT JUST UNDER THE COLDEST MOS IN MOST AREAS. ...DLF... && .LONG TERM...THURSDAY THROUGH NEXT TUESDAY... HIGH PRESSURE EXITS THE REGION BY TUESDAY EVENING AS A WEAK STORM SYSTEM MOVES INTO THE AREA. START OF THE PRECIP IS IN QUESTION. MODELS SHOW LOWERING CONDENSATION PRESSURE DEFICITS LATE THURSDAY NIGHT BUT THE OVERALL FORCING IS EITHER WEAK OR NON-EXISTENT. MODEL KINEMATICS SUGGEST PRECIP DEVELOPING DURING THE DAY FRIDAY AND CONTINUING INTO FRIDAY NIGHT. SINCE MODELS DO NOT HANDLE WAA WELL...WILL CONTINUE WITH SCHC POPS IN THE FAR WEST LATE THURSDAY NIGHT. WOULD NOT BE SURPRISED IF PRECIP DEVELOPMENT IS PUSHED BACK BY 6-12 HOURS. AFTER FRIDAY...GLOBAL MODELS AGREE ON A NICE PUSH OF WARM AIR REACHING THE AREA AS A ZONAL PATTERN SETS UP ACROSS THE CONTINENT. NET RESULT IS THAT THE CURRENT BELOW NORMAL WEATHER SHOULD END AND BE REPLACED WITH INITIALLY NORMAL AND THEN ABOVE NORMAL WEATHER BY EARLY NEXT WEEK. ONLY CHANGES DONE IN THE EXTENDED WAS TO START TRENDING TO WELL ABOVE NORMAL TEMPERATURES BY NEXT WEEK. IF THE RIGHT CONDITIONS OCCUR...CURRENT MAX TEMPS BY NEXT WEEK MAY BE TOO COOL. ...08... && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. $$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1018 PM EST TUE MAR 6 2007 .UPDATE... A WEAK MID LEVEL SHORT WAVE CURRENTLY MOVING ACROSS THE NORTHERN GREAT LAKES IS HELPING TO ENHANCE FRONTOGENETICAL FORCING ALONG THE LOW TO MID TROPOSPHERIC FRONT SITUATED ACROSS THE SOUTHERN GREAT LAKES. AREA RADAR DATA SHOW WIDESPREAD LIGHT SNOW STRETCHING FROM SOUTHEAST LOWER MI TO CENTRAL WISCONSIN. THUS FAR THIS EVENING...SNOWFLAKE SIZE HAS BEEN QUITE SMALL. SINCE 7 PM...BARELY A HALF AN INCH HAS FALLEN HERE AT THE NWS OFFICE. BASED ON THE 00Z DTX SOUNDING...MOST OF THE LIFT HAS BEEN OCCURRING NEAR THE 600MB LEVEL. THE 00Z NAM CONTINUES TO SHOW A STRENGTHENING IN THE FRONTAL FORCING IN THE 800-700MB LAYER FROM NORTHERN IL THROUGH NORTHERN OHIO OVERNIGHT. RADAR TRENDS ARE BEGINNING TO SUPPORT THIS. THIS WOULD SUPPORT SOME BETTER SNOWFLAKE SIZE ACROSS THE SOUTH OVERNIGHT. GIVEN THE LATEST TRENDS AND 00Z NAM AND RUC...WILL UPDATE TO LOWER TOTAL SNOWFALL AMOUNTS TONIGHT...FROM LESS THAN AN INCH IN THE THUMB TO 1 TO 3 INCHES SOUTH OF M 59. && .PREV DISCUSSION...ISSUED 619 PM EST TUE MAR 6 2007 AVIATION... LIGHT SNOW HAS QUICKLY BEEN EXPANDING ACROSS SOUTHERN MICHIGAN OVER THE LAST COUPLE OF HOURS AS A MID LEVEL SHORT WAVE APPROACHES. DESPITE LATEST ACARS SOUNDINGS OUT OF DTW SHOWING PLENTY OF LOW LEVEL DRY AIR...CEILINGS CONTINUE TO LOWER ACROSS SOUTHEAST MICHIGAN...WITH LIGHT SNOW NOW BEING REPORTED AT AMN...LAN AND TEW. THE LIFT ASSOCIATED WITH THE SHORT WAVE IS EXPECTED TO PERSIST THROUGH 09Z...THEN WANE TOWARD 12Z. BASED ON UPSTREAM CONDITIONS...WOULD EXPECT PRIMARILY MVFR CONDITIONS IN LIGHT SNOW THROUGH MUCH OF THE NIGHT...WITH SOME BRIEF PERIODS OF IFR CEILING AND VISIBILITY POSSIBLE. CONDITIONS WILL IMPROVE TO VFR BY 15Z AS THE SYSTEM EXITS TO THE EAST AND HIGH PRESSURE BUILDS INTO THE WESTERN GREAT LAKES. PREV DISCUSSION...ISSUED 318 PM EST TUE MAR 6 2007 SHORT TERM...TONIGHT AND WEDNESDAY A LIGHT SNOWFALL EXPECTED TONIGHT. SURFACE RIDGE REMAINS IN PLACE OVER SOUTHEAST MICHIGAN THIS AFTERNOON. DESPITE A GOOD DEAL OF SUNSHINE...TEMPERATURE HAVE ONLY RESPONDED INTO THE MIDDLE TEENS TO AROUND 20 DEGREES. IN FACT...WITH A CURRENT READING OF 16 DEGREES...IT LOOKS LIKE FLINT WILL SET THE RECORD LOW MAX FOR THE DATE...AS THE PREVIOUS RECORD AT FLINT WAS 19 DEGREES SET BACK IN 1943. THE AIRMASS OVER SOUTHEAST MICHIGAN REMAINS VERY DRY...AS THE 12Z DTX SOUNDING REVEALED AN 850 MB DEW POINT DEPRESSION OF 25 C. SURFACE DEW POINTS ALSO REMAIN MOSTLY BELOW ZERO AT THIS HOUR. BASED ON CURRENT TEMP READINGS AND WITH THE HIGH CLOUDS STILL SOMEWHAT THIN...HAVE ALLOWED FOR MINS TO DIP DOWN INTO THE MID SINGLE NUMBERS (NORTHERN THUMB) TO MID TEENS (SOUTH THIRD). UPPER WAVE AS SEEN ON THE DYNAMIC TROPOPAUSE AND WATER VAPOR IMAGERY ALONG THE SOUTHERN MANITOBA/ONTARIO BORDER TO SWING THROUGH NORTHERN LOWER MICHIGAN TONIGHT. THUS...THERE SHOULD BE GOOD UPPER LEVEL LIFT. HOWEVER...AIRMASS IS VERY DRY AND STABLE AND REALLY NEED TO FOCUS IN ON THE 850 MB FGEN/GOOD SNOW GROWTH REGION WHICH LOOKS TO BE CONFINED TO FAR SOUTHERN LOWER MICHIGAN. THIS IS WHERE THE 12Z NAM IS INDICATING A QPF MAX OF .2 INCHES...WHILE THE GFS INDICATES 15 INCHES. WITH SPECIFIC HUMIDITIES REMAINING BELOW 2 G/KG OVER THE CWA...4 INCHES LOOKS TO BE THE HIGHEST TOTAL WE CAN REASONABLY EXPECT. HOWEVER...THE PERIOD OF GOOD LIFT OVER ANY GIVEN LOCATION LOOKS TO BE 6 HOURS OR LESS...WHICH MAKES THE WIDESPREAD FOUR INCH TOTALS A BIT OF STRETCH. DESPITE THE UPSTREAM OBS/RADAR OVER THE WESTERN GREAT LAKES LOOKING LESS THAN IMPRESSIVE...LAKE MICHIGAN MAY PROVIDED THE NEEDED BOOST AND WILL CONTINUE TO MENTION 2-4 INCHES OVER ARB/OZW AREAS...WITH 1-3 INCHES FOR THE MAJORITY OF SOUTHEAST MICHIGAN. PER GRR RADAR...ALREADY SEEING SIGNS OF LAKE MICHIGAN COMING INTO PLAY. GENERAL SUBSIDENCE TOMORROW IN THE WAVES WAKE WILL LEAVE NOTHING MORE THAN LIGHT SNOW SHOWERS OR FLURRIES...MAINLY DURING THE MORNING. WITH NEAR NEUTRAL TEMPERATURE ADVECTION AND LIMITED AFTERNOON SUNSHINE...MAXES LOOK TO BE A GOOD 10 DEGREES BELOW NORMAL (MID 20S TO AROUND 30 DEGREES). LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY UPPER PATTERN MAKES A TRANSITION TO A MORE OR LESS FAST ZONAL FLOW AS UPPER TROUGH OVER EASTERN NORTH AMERICA LIFTS ON INTO GREENLAND AND A PARADE OF WEAK PACIFIC SHORTWAVES TRACK ALONG THE US/CANADIAN BORDER. THE ONE EXCEPTION TO THIS WILL BE THE DECENT SHORTWAVE THAT IS STILL SLATED TO BRING RAIN/SNOW TO THE AREA AROUND FRIDAY NIGHT. THIS FEATURE IS HANDLED MORE OR LESS THE SAME BY THE 12Z MODEL RUNS IN TERMS OF WAVE STRENGTH AND THE AMOUNT OF MOISTURE. TEMPERATURES ARE A BIT COOLER IN THE MOST RECENT RUNS THOUGH...LENDING SUPPORT TO KEEPING THE RAIN/SNOW MIXTURE IN THE FORECAST AS H85 TEMPERATURES OSCILLATE NEAR 0C. BEYOND THIS WAVE...SEVERAL OTHER WEAKER WAVES TRACK GENERALLY NORTH OF THE AREA...BRINGING A GLANCING BLOW OF LIGHT PRECIPITATION LATE THIS WEEKEND INTO EARLY NEXT WEEK...WITH BOTH RAIN/SNOW POSSIBLE IN THAT TIMEFRAME. TEMPERATURES WILL START OUT CHILLY ON THURSDAY WITH THE UPPER LEVEL TROUGH STILL IN PLACE JUST TO OUR EAST/NORTHEAST. AS FLOW BECOMES MORE ZONAL...AND MORE PACIFIC AIR MAKES AN INTRUSION INTO THE LAKES REGION...MAXIMUM TEMPERATURES WILL CLIMB INTO THE 40S OVER THE WEEKEND...AND PERHAPS TO AROUND 50 IN SOME AREAS BY THE END OF THE FORECAST (EARLY NEXT WEEK). WITH ONLY A FEW INCHES OF NEW SNOW NOW EXPECTED EARLY IN THE FORECAST...DO NOT FEEL AS PESSIMISTIC ABOUT THIS MODERATION...ALTHOUGH THE EXISTING SNOW PACK WITH DEFINITELY HAVE AN INFLUENCE OVER PARTS OF THE AREA. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION/UPDATE...CONSIDINE SHORT TERM...SF LONG TERM....DG YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
619 PM EST TUE MAR 6 2007 .AVIATION... LIGHT SNOW HAS QUICKLY BEEN EXPANDING ACROSS SOUTHERN MICHIGAN OVER THE LAST COUPLE OF HOURS AS A MID LEVEL SHORT WAVE APPROACHES. DESPITE LATEST ACARS SOUNDINGS OUT OF DTW SHOWING PLENTY OF LOW LEVEL DRY AIR...CEILINGS CONTINUE TO LOWER ACROSS SOUTHEAST MICHIGAN...WITH LIGHT SNOW NOW BEING REPORTED AT AMN...LAN AND TEW. THE LIFT ASSOCIATED WITH THE SHORT WAVE IS EXPECTED TO PERSIST THROUGH 09Z...THEN WANE TOWARD 12Z. BASED ON UPSTREAM CONDITIONS...WOULD EXPECT PRIMARILY MVFR CONDITIONS IN LIGHT SNOW THROUGH MUCH OF THE NIGHT...WITH SOME BRIEF PERIODS OF IFR CEILING AND VISIBILITY POSSIBLE. CONDITIONS WILL IMPROVE TO VFR BY 15Z AS THE SYSTEM EXITS TO THE EAST AND HIGH PRESSURE BUILDS INTO THE WESTERN GREAT LAKES. && .PREV DISCUSSION...ISSUED 318 PM EST TUE MAR 6 2007 SHORT TERM...TONIGHT AND WEDNESDAY A LIGHT SNOWFALL EXPECTED TONIGHT. SURFACE RIDGE REMAINS IN PLACE OVER SOUTHEAST MICHIGAN THIS AFTERNOON. DESPITE A GOOD DEAL OF SUNSHINE...TEMPERATURE HAVE ONLY RESPONDED INTO THE MIDDLE TEENS TO AROUND 20 DEGREES. IN FACT...WITH A CURRENT READING OF 16 DEGREES...IT LOOKS LIKE FLINT WILL SET THE RECORD LOW MAX FOR THE DATE...AS THE PREVIOUS RECORD AT FLINT WAS 19 DEGREES SET BACK IN 1943. THE AIRMASS OVER SOUTHEAST MICHIGAN REMAINS VERY DRY...AS THE 12Z DTX SOUNDING REVEALED AN 850 MB DEW POINT DEPRESSION OF 25 C. SURFACE DEW POINTS ALSO REMAIN MOSTLY BELOW ZERO AT THIS HOUR. BASED ON CURRENT TEMP READINGS AND WITH THE HIGH CLOUDS STILL SOMEWHAT THIN...HAVE ALLOWED FOR MINS TO DIP DOWN INTO THE MID SINGLE NUMBERS (NORTHERN THUMB) TO MID TEENS (SOUTH THIRD). UPPER WAVE AS SEEN ON THE DYNAMIC TROPOPAUSE AND WATER VAPOR IMAGERY ALONG THE SOUTHERN MANITOBA/ONTARIO BORDER TO SWING THROUGH NORTHERN LOWER MICHIGAN TONIGHT. THUS...THERE SHOULD BE GOOD UPPER LEVEL LIFT. HOWEVER...AIRMASS IS VERY DRY AND STABLE AND REALLY NEED TO FOCUS IN ON THE 850 MB FGEN/GOOD SNOW GROWTH REGION WHICH LOOKS TO BE CONFINED TO FAR SOUTHERN LOWER MICHIGAN. THIS IS WHERE THE 12Z NAM IS INDICATING A QPF MAX OF .2 INCHES...WHILE THE GFS INDICATES 15 INCHES. WITH SPECIFIC HUMIDITIES REMAINING BELOW 2 G/KG OVER THE CWA...4 INCHES LOOKS TO BE THE HIGHEST TOTAL WE CAN REASONABLY EXPECT. HOWEVER...THE PERIOD OF GOOD LIFT OVER ANY GIVEN LOCATION LOOKS TO BE 6 HOURS OR LESS...WHICH MAKES THE WIDESPREAD FOUR INCH TOTALS A BIT OF STRETCH. DESPITE THE UPSTREAM OBS/RADAR OVER THE WESTERN GREAT LAKES LOOKING LESS THAN IMPRESSIVE...LAKE MICHIGAN MAY PROVIDED THE NEEDED BOOST AND WILL CONTINUE TO MENTION 2-4 INCHES OVER ARB/OZW AREAS...WITH 1-3 INCHES FOR THE MAJORITY OF SOUTHEAST MICHIGAN. PER GRR RADAR...ALREADY SEEING SIGNS OF LAKE MICHIGAN COMING INTO PLAY. GENERAL SUBSIDENCE TOMORROW IN THE WAVES WAKE WILL LEAVE NOTHING MORE THAN LIGHT SNOW SHOWERS OR FLURRIES...MAINLY DURING THE MORNING. WITH NEAR NEUTRAL TEMPERATURE ADVECTION AND LIMITED AFTERNOON SUNSHINE...MAXES LOOK TO BE A GOOD 10 DEGREES BELOW NORMAL (MID 20S TO AROUND 30 DEGREES). LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY UPPER PATTERN MAKES A TRANSITION TO A MORE OR LESS FAST ZONAL FLOW AS UPPER TROUGH OVER EASTERN NORTH AMERICA LIFTS ON INTO GREENLAND AND A PARADE OF WEAK PACIFIC SHORTWAVES TRACK ALONG THE US/CANADIAN BORDER. THE ONE EXCEPTION TO THIS WILL BE THE DECENT SHORTWAVE THAT IS STILL SLATED TO BRING RAIN/SNOW TO THE AREA AROUND FRIDAY NIGHT. THIS FEATURE IS HANDLED MORE OR LESS THE SAME BY THE 12Z MODEL RUNS IN TERMS OF WAVE STRENGTH AND THE AMOUNT OF MOISTURE. TEMPERATURES ARE A BIT COOLER IN THE MOST RECENT RUNS THOUGH...LENDING SUPPORT TO KEEPING THE RAIN/SNOW MIXTURE IN THE FORECAST AS H85 TEMPERATURES OSCILLATE NEAR 0C. BEYOND THIS WAVE...SEVERAL OTHER WEAKER WAVES TRACK GENERALLY NORTH OF THE AREA...BRINGING A GLANCING BLOW OF LIGHT PRECIPITATION LATE THIS WEEKEND INTO EARLY NEXT WEEK...WITH BOTH RAIN/SNOW POSSIBLE IN THAT TIMEFRAME. TEMPERATURES WILL START OUT CHILLY ON THURSDAY WITH THE UPPER LEVEL TROUGH STILL IN PLACE JUST TO OUR EAST/NORTHEAST. AS FLOW BECOMES MORE ZONAL...AND MORE PACIFIC AIR MAKES AN INTRUSION INTO THE LAKES REGION...MAXIMUM TEMPERATURES WILL CLIMB INTO THE 40S OVER THE WEEKEND...AND PERHAPS TO AROUND 50 IN SOME AREAS BY THE END OF THE FORECAST (EARLY NEXT WEEK). WITH ONLY A FEW INCHES OF NEW SNOW NOW EXPECTED EARLY IN THE FORECAST...DO NOT FEEL AS PESSIMISTIC ABOUT THIS MODERATION...ALTHOUGH THE EXISTING SNOW PACK WITH DEFINITELY HAVE AN INFLUENCE OVER PARTS OF THE AREA. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION...CONSIDINE SHORT TERM...SF LONG TERM....DG YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1000 AM CST WED MAR 7 2007 .DISCUSSION...UPDATED AT 1000 AM TRAILING CLOUD BAND FROM LAST NIGHTS SHORT WAVE IS INTEREACTING WITH SHALLOW LAKE PLUME UNDER A BROAD NE FLOW. ACARS SOUNDINGS SHOW STRONG INVERSION TO 800MB OR SO THUS CLOUDS ARE SHALLOW BUT WILL LKLY BE PERSISTENT THROUGH THE AFTERNOON. RADAR DETECTS A FEW PATCHES OF LIGHT SNOW APPROACHING IL SHORELINE FROM THE NE AND A FEW FLAKES HAVE BEEN REPORTED AT MDW THIS MRNG. GIVEN PERSISTENCE OF CLOUDS AND ORIGIN OFF LAKE HAVE UPDATED FIRST PERIOD FCST TO REFLECT MORE CLOUDS ALL AREAS AND A FEW LIGHT SNOW FLURRIES ALONG THE LAKE SHORE AND JUST INLAND UNTIL MID AFTN. TEMPS ARE STRUGGLING THIS MORNING BUT FCST MAXS LOOK REASONABLE SINCE ANOTHER 3-5 DEG RISE EVEN UNDER CLOUDS BUT STRONGER MARCH SUN ANGLE IS DOABLE. KML PREVIOUS DISCUSSION 345 AM CST LT SNOW COMING TO AN END ACROSS NW INDIANA EARLY THIS MORNING AS WAA SLIDES EAST TOWARD ERN INDIANA AND OHIO. ALL PRECIP IS WELL NORTH OF SFC LOW CENTER STILL BACK NEAR STL. STRONG 1033 MB HIGH PRESSURE BUILDING SOUTHEASTWARD OUT OF ND/MN WILL BRING CLEARING SKIES TO THE AREA BY EVENING. HIGH PASSES DIRECTLY OVERHEAD LATE TONIGHT AND THURS MORNING. ONCE HIGH MOVES TO OUR EAST...THE DOOR OPENS WIDE TO WARM ADVECTION AS A LONGWAVE RIDGE PUSHES EAST ACROSS THE PLAINS. H8 TEMPS WARM FROM CURRENT -5C TO +3C BY FRI AFTN. AMPLE INSOLATION ON THURS SHOULD ALLOW SFC TEMPS TO CLIMB ABV 40 DEG RFD-PNT...THOUGH A LAKE BREEZE MAY DEVELOP IN RESPONSE TO LAND/LAKE TEMP DIFF GREATER THAN 10 DEG...KEEPING TEMPS COOLER BY THE LAKE. MID/UPR TROPOSPHERIC DISTURBANCES AND ASSOCIATED SFC TROUGH ARRIVING ON FRI OR SAT LOOK RATHER ANEMIC AND DISORGANIZED. 00Z GFS SUGGESTS SOME WEAK FROPA ON FRI...BUT FOCUSES MOST QPF WELL TO THE NORTH AND SOUTH OF OUR LOCAL AREA. THE 06Z NAM CONCENTRATES THE H3 JET STREAK AND ACCOMPANYING SHORTWAVE OVR NRN IL...BUT DELAYS ARRIVAL TIL SAT. WILL MAINTAIN THE STATUS QUO WITH CHANCE POPS FRI/FRI NT WITH SOMEWHAT MORE DEFERENCE GIVEN TO THE GFS SOLN. FAIRLY NEUTRAL TEMP ADVECTION THROUGH THE WEEKEND. TREMENDOUS WARM ADVECTION INDICATED BY THE BY BOTH THE ECMWF AND THE GFS COULD DRAW +20C H8 AIR INTO KS WITH THE 10 DEG C ISOTHERM INTO OUR AREA. THUS...TEMPS INTO THE 50S SEEMS QUITE PLAUSIBLE. RRH && .AVIATION...UPDATE 825 AM CST LATEST METARS INDICATING CEILINGS AND VISIBILITIES DROPPING NEAR THE SOUTHWESTERN LAKE MICHIGAN SHORE. RUC LOW LEVEL WIND AND RH PROGS INDICATE NORTHEAST FLOW OFF OF THE LAKE PERSISTING WELL INTO THE AFTERNOON. WITH BASE OF STRONG INVERSION AROUND 1KM ANY LES TO BE OF LIGHT INTENSITY. TRS PREVIOUS DISCUSSION FOR 12Z TAFS... 650 AM CST MAIN CONCERN FOR THE 12Z TAF PERIOD WILL BE CLOUDS DURG THE MORNING HRS. STARTING OUT WITH SOME REMNANT MVFR FROM THE SYSTEM THAT BROUGHT THE LIGHT SNOW TO NRN IL OVERNIGHT. THESE CLOUDS ARE BREAKING UP PER LATEST SATELLITE IMAGERY...BUT BASED ON UPSTREAM OBS...WILL KEEP THE LOW MVFR DECK FOR A COUPLE MORE HRS. HAVE BEEN MONITORING THE LOW VFR STRATOCU DECK MOVING SWD OUT OF WISCONSIN AND OVR LAKE MICHIGAN. HAVE STARTED OUT GYY LOWER SINCE THEY HAVE A DIRECT FETCH OFF THE COLD LAKE WATERS...BUT WILL GO WITH LOW VFR AT THE REMAINDER OF THE SITES. THE CLOUD DECK IS EXPECTED TO SCT OUT BY LATE MORNING. WITH A LARGE AREA OF HIGH PRESSURE AND ASSOCIATED LARGE SCALE SUBSIDENCE BUILDING OVER THE REGION...EXPECT SKIES TO GO SKC BY EARLY AFTERNOON. SKIES SHOULD REMAIN SKC THROUGH THE REMAINDER OF THE PERIOD. WINDS WILL START OUT NLY-ENELY AT ARND 10KT AND TURN MORE NELY THROUGH THE DAY. WINDS SHOULD GO LIGHT AND VARIABLE OVERNIGHT AS THE SFC HIGH BUILDS OVER THE AREA. KREIN && .LOT WATCHES/WARNINGS/ADVISORIES... .IL...NONE. .IN...NONE. .LM...NONE. && $$