Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT" or "AMDAR" received at FSL on 02/08/04


AREA FORECAST DISCUSSION
NWS PUEBLO CO
AFDPUB 230 PM MST SAT FEB 7 2004

.SHORT TERM... (TONIGHT AND SUNDAY)

..STRONG TROUGH MOVING THROUGH FOR SOME WIND AND SNOW...

CURRENTLY...MOSTLY SUNNY AND MILD OVER MUCH OF THE FORECAST AREA. SOME OF THE HIGH MOUNTAIN PASSES HAVE WINDS OF 20 KNOTS OR HIGHER. STRONG WARM AIR ADVECTION ALOFT WARMED MANY OF THE PLAINS LOCATIONS DESPITE WEAK UPSLOPE FLOW.

A STRONG TROUGH WILL MOVE ACROSS THE REGION TONIGHT AND SUNDAY. THERE IS SOME MOISTURE AND INSTABILITY WITH THIS SYSTEM WITH SOME SNOW EXPECTED IN THE SOUTHWEST AND CENTRAL MOUNTAINS TONIGHT AND SUNDAY. WITH THE SOUTHWEST FLOW AHEAD OF THIS SYSTEM TONIGHT...SOME SNOW WILL DEVELOP OVER THE EASTERN SAN JUANS AN LA GARITA OVERNIGHT. AS THE STORM MOVES EAST OF THE AREA...NORTHWEST FLOW WILL BRING SOME SNOW TO THE CENTRAL MOUNTAINS. THE STORM WILL BE RELATIVELY FAST MOVING AND NOT HAVE ABUNDANT MOISTURE...SO I KEPT AMOUNTS BELOW ADVISORY CRITERIA.

THE MAIN PROBLEMS WITH THIS STORM ARE THE WINDS AND HOW THIS SYSTEM WILL EVOLVE ON THE PLAINS. BOULDER NOTICED THAT THE JET STREAM FEATURE WITH THIS STRONG SYSTEM WAS NOT WELL INITIALIZED. JET STREAK WINDS WERE INITIALIZED WEAKER THAN SOME OF THE ACARS OBSERVATIONS WOULD SUGGEST. SYSTEM SEEMS TO BE MOVING SLIGHTLY FURTHER SOUTH AND BE A LITTLE SLOWER THAN 12Z ETA RUN. THE 18Z ETA SEEMED TO HAVE THE SYSTEM INITIALIZED A LITTLE BIT BETTER SO I BASED THE FORECAST ON THIS MODEL RUN.

THE JET CORE WILL PASS OVER THE SOUTHERN PORTION OF THE FORECAST AREA TONIGHT...WITH THE STRONGEST CORE OVER THE SOUTHERN SANGRE DE CRISTO MOUNTAINS. THE VERTICAL PROFILES OF THE WIND AND STABILITY ARE NOT THE MOST FAVORABLE FOR A MOUNTAIN WAVE HIGH WIND EVENT. THERE IS A FAR AMOUNT OF FORWARD SHEAR AND THE STRONG SOUTHWEST WINDS ALOFT DO NOT COINCIDE WITH AN WEAKLY STABLE LAYER ABOVE THE MOUNTAIN TOP. 500MB WINDS ARE STRONG REACHING 70 KNOTS. THERE IS NO DOUBT IT WILL BE WINDY OVER THE MOUNTAINS AND NEARBY EAST SLOPES TONIGHT AND EARLY SUNDAY MORNING...BUT I THINK THE CHANCES FOR A WIDESPREAD DAMAGING HIGH WIND EVENT ARE FAIRLY LOW. I DID NOT ISSUE ANY WATCH AT THIS TIME BUT EVENING SHIFT WILL HAVE TO KEEP AN EYE ON THE SITUATION. TEMPERATURES ON THE PLAINS AND SAN LUIS VALLEY WILL BE TOUGH. THE ATMOSPHERE WILL DECOUPLE THIS EVENING OVER THE SAN LUIS VALLEY. I PUT IN SUB ZERO LOWS BEFORE CLOUDS AND POSSIBLY WINDS CAN MODERATE THE TEMPERATURES. ON THE PLAINS...I PUT IN MID 20S WITH LOW LEVEL JET PROBABLY NOT REACHING THE GROUND.

AS THE TROUGH MOVES EAST OF THE REGION SUNDAY...UNSTABLE NORTHWEST FLOW ALOFT WILL DEVELOP OVER THE REGION. WITH COLD UNSTABLE AIR OVER THE PLAINS...ANY REGION OF CONVERGENCE OR WEAK UPSLOPE CAN PRODUCE SOME SNOW. THE BEST CHANCES FOR SNOW ON THE PLAINS LOOKS TO STAY TO OUR NORTH. WITH THE QUESTIONABLE ANALYSIS...THERE STILL IS A CHANCE THAT THE STORM MAY MOVE FURTHER SOUTH THAN EXPECTED. FOR NOW...I KEPT SOME SLIGHT CHANCE POPS ON THE PLAINS SUNDAY FOR SOME SNOW SHOWERS. IT WILL ALSO BE BREEZY ON THE PLAINS AS WELL AS IN THE MOUNTAINS. --PGW--

.LONG TERM... (SUNDAY NIGHT THROUGH SATURDAY).

FORECAST CONCERNS POPS AND TEMPERATURES ACROSS REGION WITH RATHER UNSETTLED WX PATTERN THROUGH MID WEEK.

SUN NIGHT AND MON...QUICK MOVING UPPER TROUGH ACROSS THE REGION SUNDAY MERGES WITH SYSTEM MOVING ACROSS THE NORTHERN TIER AND INTO THE UPPER GREAT LAKES REGION...WITH ANOTHER SHORT WAVE PROGGED TO DIVE ACROSS THE GREAT BASIN...CARVING OUT BROAD UPPER TROUGH ACROSS THE INTERMOUNTAIN WEST. BACKDOOR COLD FRONT MOVES ACROSS THE PLAINS AS SFC HIGH PRESSURE BUILDS ACROSS THE CENTRAL HIGH PLAINS SUN NIGHT. WILL KEEP SCATTERED POPS ACROSS THE CENTRAL AND SW MTS AS WEST TO NORTHWEST FLOW SETS UP BEHIND PASSING SYSTEM...WITH ISOLATED EVENING POPS ACROSS THE EASTERN MTS AND PLAINS. MODELS DIFFER ON STRENGTH AND LOCATION OF DIGGING SHORT WAVE ACROSS THE GREAT BASIN...WITH LATEST GFS FURTHER SOUTH AND WEST TAKING VORT MAX ACROSS SW ARIZONA AT 00Z TUE. AT ANY RATE...HIGHS TO REMAIN ON COOL SIDE OF GUIDANCE WITH LEE TROUGHING ACROSS THE I-25 CORRIDOR KEEPING LOW LEVEL UPSLOPE ACROSS THE EASTERN PLAINS. WITH BROAD TROUGH IN PLACE AND H5 TEMPS BETWEEN -25C AND -30C KEEPING RATHER UNSTABLE ATMOSPHERE IN PLACE... WILL GO WITH SCATTERED POPS ACROSS THE MTS...AND ISOLATED ACROSS THE I-25 CORRIDOR AND HIGH MT VALLEYS.

MON NIGHT-WED...MODEL DIFFERENCES CONTINUE THROUGH THE PERIOD...WITH GFS SLOWER MOVING VORT MAX ACROSS CENTRAL NEW MEXICO...KEEPING WEAK NE UPSLOPE FLOW ACROSS THE REGION THROUGH 00Z WED...WHEREAS ETA KEEPS BROAD NW FLOW ALOFT. AGAIN WITH A BROAD UPPER TROUGH PERSISTING ACROSS THE STATE...HAVE KEPT ISOLATED TO SCATTERED POPS ACROSS THE MTS TUE...WITH ISOLATED POPS ACROSS THE I-25 CORRIDOR. ANOTHER SHORT WAVE PROGGED TO MOVE OUT OF WESTERN CANADA TUE...WITH LATEST GFS MOVING TROUGH ACROSS OUT ACROSS THE NORTHERN HIGH PLAINS WITH ANOTHER STRONG VORT MAX DIGGING ACROSS THE FOUR CORNERS REGION BY 00Z THU. LATEST GFS POSITIONING INDICATING POTENTIAL FOR DECENT SNOWS ACROSS THE SOUTHEAST MTS AND FOOTHILLS WITH DEEP EASTERLY FLOW ALOFT. WITH CONFIDENCE LACKING IN TIMING OF SHORT WAVES...WILL NOT JUMP TO HARD ON THIS AS OF YET...THOUGH WILL BUMP POPS TO CHANCES ACROSS THE SANGRE DE CRISTOS AND RATON MESA REGION. AGAIN WITH BROAD TROUGH ACROSS THE REGION...WILL CONTINUE TO KEEP ISOLATED TO SCATTERED POPS ACROSS THE REST OF THE MTS AND ADJACENT PLAINS...WITH TEMPS REMAINING BELOW SEASONAL NORMS.

THU-SAT...BROAD UPPER TROUGH ACROSS THE CENTRAL CONUS BACK THROUGH THE ROCKIES CONTINUES TO MOVE EAST THU...AS UPPER LEVEL RIDGE ACROSS THE GREAT BASIN BUILDS ACROSS THE STATE THROUGH SAT. WILL KEEP ISOLATED POPS ACROSS THE MTS THROUGH THE DAY THU...WITH A DRYING AND WARMING TREND TO AT OR ABOVE SEASONAL NORMS THROUGH THE PERIOD. -MW

&&

.PUB...WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$




AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
AFDLWX 945 PM EST SAT FEB 7 2004

.UPDATE: HAVE OPENED UP TEMPERATURE RANGES EAST OF THE MOUNTAINS AS TEMPERATURES WILL FALL MORE EASILY WHERE DECOUPLING BETTER ESTABLISHES...WHICH WILL LIKELY RESULT IN A RANGE OF LOW TEMPERATURES OVERNIGHT.

00Z SURFACE ANALYSIS PLACES A DECAYING SECONDARY COLD FRONTAL BOUNDARY ACROSS THE METRO AREA SOUTHWEST INTO THE CENTRAL GULF COAST STATES. ONLY EXPECT A SUBTLE WIND SHIFT AND CONTINUED COLD ADVECTION AS THIS FRONT CONTINUES TO PASS.

ORGANIZED BAND OF FRONTAL SNOW SHOWERS DISSIPATED NICELY AS IT APPROACHED THE NORTHERN FORECAST AREA THIS EVENING...WITH LOSS OF UPPER LEVEL SUPPORT AND INCREASING DOWNSLOPE COMPONENT. HOWEVER...DID SEE AN INCREASE IN RADAR RETURNS OFF THE KPBZ RADAR EVEN AS THE ECHOES CONTINUED TO TRAVEL FURTHER BELOW THE RADAR BEAM ALONG THE MOUNTAINS. CURRENT SNOW SHOWER WORDING IN THE MOUNTAINS LOOKS ON TARGET.

ISSUED A SPECIAL WEATHER STATEMENT FOR BLACK ICE FORMATION (WBCSPSLWX)...WHICH IS OCCURRING AS MELTED SNOW REFREEZES ON SURFACES AS TEMPERATURES FALL BELOW FREEZING. THIS PROCESS WILL LIKELY REPEAT ITSELF FOR ANOTHER NIGHT OR TWO.

ONLY TWEAKED TEMPERATURE GRIDS...ALL OF WHICH HAVE BEEN SENT. UPDATED ZFP/EOL HAVE BEEN ISSUED.

.HYDROLOGY: WE CONTINUE TO MONITOR AREA RIVERS FOR FLOODING...WITH EMPHASIS NOW BEING PLACED ON ICE JAM IMPACT ON THE RISING RIVERS. HAVE RECENTLY CANCELLED FLOOD WARNINGS AT FREDERICK AND SPRINGFIELD (SEE WBCFLSLWX FOR DETAILS). WILL CONTACT MORGAN COUNTY SHORTLY FOR AN UPDATED STATUS.

.MARINE: EXPECT WINDS TO INCREASE SLIGHTLY BEHIND THE SECONDARY FRONTAL BOUNDARY OVERNIGHT...PRESENTING A MARGINAL SMALL CRAFT ADVISORY SCENARIO. CWF HAS BEEN ISSUED.

.AVIATION: NO VISIBILITY OR CEILING CONCERNS AS NORTHWEST WINDS CONTINUE TO LOSE GUSTINESS.

&&

LWX... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY ON ALL WATERS.

ROGOWSKI

*********PREVIOUS DISCUSSION*********

.SHORT TERM (TONIGHT THROUGH TOMORROW): WATER VAPOR LOOP SHOWS THE LAST WAVE SPEEDING NORTHEAST AWAY FROM NEW ENGLAND WITH A DRY SLOT IMPINGING INTO THE NEW ENGLAND COAST. A POSITIVELY TILTED TROUGH REMAINS OVER THE GREAT LAKES REGION...WITH A RIDGE OVER THE NORTHERN PLAINS AS THE NEXT SYSTEM DIVING INTO THE SOUTHWEST CONUS. 300MB ANALYSIS PLACES A 155KT JET OVER EASTERN CANADA...WITH 105KT JETS LOCATED NORTH OF LAKE SUPERIOR AND OVER CENTRAL CALIFORNIA. 15Z SURFACE ANALYSIS SHOWS THE COLD FRONT WELL OFFSHORE...WITH A SECONDARY COLD FRONT LOCATED ACROSS THE SOUTHERN GREAT LAKES. ALSO NOTED ARE A LEE TROUGH EAST OF THE APPALACHIANS...AND A 1033MB HIGH OVER THE CENTRAL PORTION OF THE COUNTRY.

MOIST UPSLOPE FLOW CONTINUES TO SUPPORT SNOW SHOWERS ACROSS THE HIGHEST TERRAIN...MAINLY WEST OF THE ALLEGANY FRONT...WITH NEAR SURFACE FLOW REMAINING CYCLONIC AHEAD OF THE SECONDARY COLD FRONT. KCCX AND KPBZ RADARS SHOW A BAND OF HEAVIER SNOW MOVING SOUTHEAST WITH VISIBILITIES REDUCED RECENTLY TO 1/4SM WITH +SN AT KJST. THIS FRONTAL PRECIPITATION APPEARS TO BE ENHANCED BY FRONTOGENESIS AND INCREASED INSTABILITY IN THE VICINITY OF A MIDLEVEL TROUGH PULLING NORTHEAST ACROSS PENNSYLVANIA. MODELS DO NOT RESOLVE THIS FEATURE...BUT THINKING IS THAT THE PRECIPITATION WILL WANE EAST OF THE MOUNTAINS AS IT APPROACHES DUE TO A DECREASING OF THE ENHANCING FACTOR BY THE MIDLEVEL TROUGH AND AN INCREASED DOWNSLOPE COMPONENT. AM A BIT CONCERNED THAT UPSLOPE SNOW SHOWERS IN THE FAR NORTHWEST MOUNTAINS MAY BE ENHANCED BY THE FRONTAL SLOPE. HAVE ISSUED A SPECIAL WEATHER STATEMENT (WBCSPSLWX) FOR THE FAR NORTHWEST MOUNTAINS WHERE ONE TO TWO INCHES OF SNOW MAY ACCUMULATE BY MORNING.

IAD ACARS SOUNDING FROM 1430Z SHOWS STRONG COLD ADVECTION BETWEEN 800-950MB WHEN COMPARED TO 12Z KIAD RAOB RELEASED AROUND 11Z. THIS WILL CONTINUE TO SUPPORT FLATTENING CU WITH NEARLY DRY ADIABATIC LOW LEVEL LAPSE RATES. ALSO EXPECT SOME MIDLEVEL CLOUDS TO STREAM INTO THE AREA WITH THE TROUGH AXIS SWINGING TROUGH. GUSTY WINDS WILL SLACKEN THIS EVENING AS BUFKIT FORECAST SOUNDINGS SHOW DECOUPLING DURING THE EVENING HOURS.

RISING HEIGHTS BEHIND THE DEPARTING TROUGH WILL ALLOW HIGH PRESSURE TO QUICKLY BUILD OVER THE REGION SUNDAY. LOW LEVEL FLOW WILL RAPIDLY BECOME ANTICYCLONIC LATE OVERNIGHT...DISSIPATING THE MOUNTAIN SNOW SHOWERS/CLOUDS. EXPECT SLIGHTLY COOLER TEMPERATURES TOMORROW WITH CALMING WINDS AND SUNNY CONDITIONS AS THE HIGH BUILDS INTO THE REGION.

.HYDROLOGY: WE CONTINUE TO MONITOR AREA RIVERS FOR FLOODING...WITH EMPHASIS NOW BEING PLACED ON ICE JAM IMPACT ON THE RISING RIVERS.

.MARINE: SMALL CRAFT WIND CONDITIONS EXPECTED AS NORTHWEST FLOW INCREASES BEHIND THE SECONDARY COLD FRONT OVERNIGHT.

.AVIATION: NO VISIBILITY OR CEILING CONCERNS AS NORTHWEST WINDS LOSE GUSTINESS THIS EVENING.

ROGOWSKI

&&

.LONG TERM...

SUN NGT SFC HI PRES CENTERED OVER HATTERAS. HGTS AND THKNS RISING AS 5H RDG MOVES ACRS. LGT WNDS AND FEW IF ANY CLOUDS.

FOR MON LOW OVR GREAT LAKES AREA SWINGS A S/W TROF E BUT MSTR AND DYNAMICS IS LIMITED BUT PERHAPS ENOUGH FOR A FEW CLOUDS BY LATE IN THE DAY.

12Z RUN GFS BRINGS UP MSTR FM NEXT SRN BRANCH SYSTEM BY TUE MORNING WHERE THE 00Z RUN HAD NOTHING. GIVEN THE POSITIVE 5H TROF THINK DEEPER MSTR SRN SYSTEM WILL STAY S OF FA. BRING CLDS IN BUT ONLY SLGT CHC PCPN SRN AND WRN ZNS.

WED WK RDG ACRS AREA WITH TROF ACRS SE STATES AND ANOTHER ACRS MAINE. NEXT SYSTEM TO EFFECT US DROPS S ACRS UPR PLAINS WED TO MID WEST THU AND OHIO VLY LATE THU SPREADING CLDS INTO FA AND BRINGING CHC S- WRN MTN ZNS AND SLGT CHC REMAINDER FA DURING DAY FRI.

WATSON

$$




AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
AFDLWX 400 PM EST SAT FEB 7 2004

.SHORT TERM (TONIGHT THROUGH TOMORROW): WATER VAPOR LOOP SHOWS THE LAST WAVE SPEEDING NORTHEAST AWAY FROM NEW ENGLAND WITH A DRY SLOT IMPINGING INTO THE NEW ENGLAND COAST. A POSITIVELY TILTED TROUGH REMAINS OVER THE GREAT LAKES REGION...WITH A RIDGE OVER THE NORTHERN PLAINS AS THE NEXT SYSTEM DIVING INTO THE SOUTHWEST CONUS. 300MB ANALYSIS PLACES A 155KT JET OVER EASTERN CANADA...WITH 105KT JETS LOCATED NORTH OF LAKE SUPERIOR AND OVER CENTRAL CALIFORNIA. 15Z SURFACE ANALYSIS SHOWS THE COLD FRONT WELL OFFSHORE...WITH A SECONDARY COLD FRONT LOCATED ACROSS THE SOUTHERN GREAT LAKES. ALSO NOTED ARE A LEE TROUGH EAST OF THE APPALACHIANS...AND A 1033MB HIGH OVER THE CENTRAL PORTION OF THE COUNTRY.

MOIST UPSLOPE FLOW CONTINUES TO SUPPORT SNOW SHOWERS ACROSS THE HIGHEST TERRAIN...MAINLY WEST OF THE ALLEGANY FRONT...WITH NEAR SURFACE FLOW REMAINING CYCLONIC AHEAD OF THE SECONDARY COLD FRONT. KCCX AND KPBZ RADARS SHOW A BAND OF HEAVIER SNOW MOVING SOUTHEAST WITH VISIBILITIES REDUCED RECENTLY TO 1/4SM WITH +SN AT KJST. THIS FRONTAL PRECIPITATION APPEARS TO BE ENHANCED BY FRONTOGENESIS AND INCREASED INSTABILITY IN THE VICINITY OF A MIDLEVEL TROUGH PULLING NORTHEAST ACROSS PENNSYLVANIA. MODELS DO NOT RESOLVE THIS FEATURE...BUT THINKING IS THAT THE PRECIPITATION WILL WANE EAST OF THE MOUNTAINS AS IT APPROACHES DUE TO A DECREASING OF THE ENHANCING FACTOR BY THE MIDLEVEL TROUGH AND AN INCREASED DOWNSLOPE COMPONENT. AM A BIT CONCERNED THAT UPSLOPE SNOW SHOWERS IN THE FAR NORTHWEST MOUNTAINS MAY BE ENHANCED BY THE FRONTAL SLOPE. HAVE ISSUED A SPECIAL WEATHER STATEMENT (WBCSPSLWX) FOR THE FAR NORTHWEST MOUNTAINS WHERE ONE TO TWO INCHES OF SNOW MAY ACCUMULATE BY MORNING.

IAD ACARS SOUNDING FROM 1430Z SHOWS STRONG COLD ADVECTION BETWEEN 800-950MB WHEN COMPARED TO 12Z KIAD RAOB RELEASED AROUND 11Z. THIS WILL CONTINUE TO SUPPORT FLATTENING CU WITH NEARLY DRY ADIABATIC LOW LEVEL LAPSE RATES. ALSO EXPECT SOME MIDLEVEL CLOUDS TO STREAM INTO THE AREA WITH THE TROUGH AXIS SWINGING TROUGH. GUSTY WINDS WILL SLACKEN THIS EVENING AS BUFKIT FORECAST SOUNDINGS SHOW DECOUPLING DURING THE EVENING HOURS.

RISING HEIGHTS BEHIND THE DEPARTING TROUGH WILL ALLOW HIGH PRESSURE TO QUICKLY BUILD OVER THE REGION SUNDAY. LOW LEVEL FLOW WILL RAPIDLY BECOME ANTICYCLONIC LATE OVERNIGHT...DISSIPATING THE MOUNTAIN SNOW SHOWERS/CLOUDS. EXPECT SLIGHTLY COOLER TEMPERATURES TOMORROW WITH CALMING WINDS AND SUNNY CONDITIONS AS THE HIGH BUILDS INTO THE REGION.

.HYDROLOGY: WE CONTINUE TO MONITOR AREA RIVERS FOR FLOODING...WITH EMPHASIS NOW BEING PLACED ON ICE JAM IMPACT ON THE RISING RIVERS.

.MARINE: SMALL CRAFT WIND CONDITIONS EXPECTED AS NORTHWEST FLOW INCREASES BEHIND THE SECONDARY COLD FRONT OVERNIGHT.

.AVIATION: NO VISIBILITY OR CEILING CONCERNS AS NORTHWEST WINDS LOOSE GUSTINESS THIS EVENING.

ROGOWSKI

&&

.LONG TERM...

SUN NGT SFC HI PRES CENTERED OVER HATTERAS. HGTS AND THKNS RISING AS 5H RDG MOVES ACRS. LGT WNDS AND FEW IF ANY CLOUDS.

FOR MON LOW OVR GREAT LAKES AREA SWINGS A S/W TROF E BUT MSTR AND DYNAMICS IS LIMITED BUT PERHAPS ENOUGH FOR A FEW CLOUDS BY LATE IN THE DAY.

12Z RUN GFS BRINGS UP MSTR FM NEXT SRN BRANCH SYSTEM BY TUE MORNING WHERE THE 00Z RUN HAD NOTHING. GIVEN THE POSITIVE 5H TROF THINK DEEPER MSTR SRN SYSTEM WILL STAY S OF FA. BRING CLDS IN BUT ONLY SLGT CHC PCPN SRN AND WRN ZNS.

WED WK RDG ACRS AREA WITH TROF ACRS SE STATES AND ANOTHER ACRS MAINE. NEXT SYSTEM TO EFFECT US DROPS S ACRS UPR PLAINS WED TO MID WEST THU AND OHIO VLY LATE THU SPREADING CLDS INTO FA AND BRINGING CHC S- WRN MTN ZNS AND SLGT CHC REMAINDER FA DURING DAY FRI.

WATSON

&&

LWX... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY ON ALL WATERS.

$$




AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
AFDLWX 1110 AM EST SUN FEB 8 2004

WATER VAPOR LOOP SHOWS THE TROUGH CONTINUING TO MOVE OFF THE EAST COAST. HEIGHTS HAVE RISEN +110M TO +230M ACROSS THE OHIO VALLEY OVERNIGHT...AS THE RIDGE MOVES FROM THE CENTRAL CONUS EASTWARD. THE NEXT STORM SYSTEM IS SEEN ON WATER VAPOR AS AN UPPER LOW OVER THE CENTRAL ROCKIES IN THE SOUTHERN STREAM...AND A WAVE NEAR LAKE WINNIPEG IN THE NORTHERN STREAM. 300MB ANALYSIS PLACES A 165KT JET OVER THE SOUTHEAST CONUS/WESTERN ATLANTIC...WITH A 100KT JET ACROSS THE SOUTHWEST CONUS. 14Z SURFACE ANALYSIS SHOWS A 1037MB HIGH DOMINATING THE EASTERN CONUS...WITH THE NEXT STORM SYSTEM ORGANIZING ACROSS THE PLAINS.

RISING HEIGHTS CONTINUE TO ALLOW HIGH PRESSURE OVER THE TENNESSEE VALLEY TO BUILD EASTWARD. THIS INCREASING ANTICYCLONIC FLOW AND SUBSIDENCE HAS ENDED SNOWS ON OUR SIDE OF THE MOUNTAINS. FROSTBURG MARYLAND ENDED UP WITH 1.4 INCHES FROM THE EVENT. EXPECT ONLY LIMITED CU OVER THE MOUNTAINS FROM ANY REMAINING UPSLOPE. OTHERWISE SUNNY CONDITIONS ARE EXPECTED EAST OF THE MOUNTAINS WITH BONE DRY KIAD RAOB SOUNDING. A FEW THIN CIRRUS MAY ADVECT INTO THE REGION DURING THE EVENING FROM THE NEXT STORM SYSTEM.

KIAD RAOB AND 1140Z IAD ACARS SOUNDING SHOW WELL MIXED BOUNDARY LAYER UP TO 880-920MB...ABOVE A VERY SLIGHT NOCTURNAL INVERSION. THEREFORE...ONLY EXPECT TEMPERATURES TO CREEP UP A FEW DEGREES TODAY UNDER COLD ADVECTION (ALBEIT WEAKENING COLD ADVECTION). HAVE LOWERED TEMPERATURES BY ABOUT 5 DEGREES TO ACCOUNT FOR THIS. OBSERVED SOUNDINGS SHOW ABOUT 35KTS AT THE TOP OF THE MIXED LAYER...WHICH WILL SUPPORT WIND GUSTS AROUND 25 MPH DURING THE MID DAY. AS THE HIGH CENTERS ITSELF OVER THE MID ATLANTIC LATE THIS AFTERNOON...EXPECT WINDS TO BECOME LIGHT AND VARIABLE.

UPDATED GRIDS/ZFP/EOL HAVE BEEN SENT.

.HYDROLOGY: WE CONTINUE TO MONITOR AREA RIVERS FOR FLOODING...WITH EMPHASIS NOW BEING PLACED ON ICE JAM IMPACT ON THE RISING RIVERS. MAIN PROBLEM AT THIS POINT IS NEAR WILLIAMSPORT MD ON THE POTOMAC. RAPID RISES OCCURRED OVERNIGHT WITH AN APPARENT SIGNIFICANT ICE JAM. AWAITING WORD FROM THE OBSERVER BEFORE AN UPDATE TO THE WARNING IS ISSUED. IF A SIGNIFICANT JAM HAS OCCURRED...RAPID RISES AND POSSIBLE FLOODING MAY OCCUR DOWNSTREAM WHEN THE JAM AT WILLIAMSPORT BREAKS.

.MARINE: EXPECT WINDS DECREASE TODAY WITH THE HIGH BUILDING IN. HAVE DISCONTINUED THE SMALL CRAFT ADVISORY. CWF HAS BEEN ISSUED.

.AVIATION: NO CONCERNS THIS FORECAST CYCLE.

ROGOWSKI

&&

LWX... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE.

$$




AREA FORECAST DISCUSSION
NWS SEATTLE WA
AFDSEW 245 AM PST SUN FEB 8 2004

.SYNOPSIS...THE STRONG UPPER LEVEL RIDGE BUILDING OVER THE REGION TODAY WILL REMAIN IN PLACE AND PRODUCE DRY WEATHER THROUGH THURSDAY. WEAK WEATHER SYSTEMS PASSING TO THE NORTH WILL BRING SOME CLOUDS TO THE AREA AT TIMES TODAY THROUGH TUESDAY. AREAS OF NIGHT AND MORNING FOG WILL FORM UNDER THE INFLUENCE OF THE RIDGE.

&&

.DISCUSSION...00Z RAOB SHOWS A STRONG SUBSIDENCE INVERSION HAS FORMED WHICH SHOULD CAP ANY CONVECTION TODAY AROUND 7000 FEET. ACARS SOUNDINGS SHOW THE CAP HASN'T DEVELOPED QUITE AS STRONGLY YET OVER CENTRAL PUGET SOUND...BUT THIS WILL CHANGE TODAY AS THE OFFSHORE RIDGE CONTINUES TO BUILD. 00Z MESOETA FORECAST SOUNDINGS SHOW THE SUBSIDENCE INVERSION EVENTUALLY DECENDING BELOW 5000 FEET TONIGHT AND GENERALLY MERGING WITH THE DIURNAL SURFACE BASED INVERION MONDAY NIGHT.

SATELLITE IMAGERY SUPPORTS THE MODEL SOLUTIONS BRINGING A WEAK SHORT WAVE TROUGH DOWN ACROSS THE AREA TODAY. THE CLOUD COVER IS RATHER DISORGANIZED BUT LATEST 06Z GFS MOS POPS REMAIN IN THE 20 PERCENT CHANCE RANGE. HATE TO STICK A CHANCE OF SHOWERS BACK INTO THE FORECAST BUT LITTLE DRIBBLES ARE STILL SHOWING UP IN THE OBS AND ON RADAR. WILL SURRENDER AND STICK IN SOME CHICKEN CHANCE POPS FOR THIS MORNING FOR ALL BUT THE SW INTERIOR AND CENTRAL MOUNTAINS. DRY FROM THIS AFTERNOON ON. BOTH GFS AND MESOETA TIME-HEIGHT SECTIONS INDICATE HIGH LEVEL MOISTURE PERSISTING OVER THE AREA THROUGH TUESDAY. WILL INCREASE THE CLOUD COVER TO ACCOMODATE THE EXPECTED CIRRUS OVER THE AREA.

THE STRONG RIDGE CONTINUES OVER THE AREA THROUGH THURSDAY WITH LIGHT GRADIENTS AND A DIURNAL FOG PROBLEM. GRADIENTS COLLAPSE TODAY AND REMAIN FLAT THROUGH TUESDAY. SLIGHTLY STRONGER OFFSHORE FLOW DEVELOPS TUESDAY NIGHT AS THE UPPER RIDGE SHIFTS...DRAGGING THE SURFACE HIGH WITH IT...BUT THE RESULTING VENTILATION REALLY ISN'T ALL THAT STRONG. WILL KEEP SOME FOG AROUND THROUGH THURSDAY.

EXTENDED...NOT SURPRISINGLY THE LONGER RANGE MODELS HAVE BACKED OF ON PRECIP FOR THURSDAY NIGHT...THOUGH THERE ARE STILL SOME TIMING DIFFERENCES BETWEEN THE MODELS. 00Z GFS IS NOW THE SLOWEST AND HOLDS OFF PRECIP UNTIL FRIDAY NIGHT. EARLIER 12Z ECMWF IS A LITTLE FASTER IN PROGRESSING THE PATTERN AND SUPPORTS PRECIP ON FRIDAY. 00Z CANADIAN SEEMS TO BE THE FASTEST. WILL USE ECMWF TIMING AND PUSH THE CHANCE OF RAIN BACK TO FRIDAY. KAM

&&

.SEW...NONE.

.KATX...VCP21/CSR21...OPERATIONAL.

&&

$$