Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT" or "AMDAR" received at FSL on 01/21/04

...MINOR UPDATE TO LOWER TEMPERATURES AND TWEAK SKY COVER WORDING FOR THIS AFTERNOON...

WATER VAPOR LOOP SHOWS AN UPPER LOW CONTINUING TO MOVE NORTHEAST AWAY FROM NEW ENGLAND. ANOTHER UPPER LOW APPEARS TO BE FORMING OVER THE SOUTHWEST CONUS...WHILE THE NEXT WAVE BEGINS TO DROP SOUTH OUT OF CENTRAL CANADA. 300MB ANALYSIS PLACES THE SOUTHERN BRANCH JET ACROSS MEXICO...EAST ACROSS THE GULF OF MEXICO...AND NORTHEAST OVER THE WESTERN ATLANTIC (WITH A 180 KT JET OVER BAJA CALIFORNIA...AND A 190KT JET OVER THE ATLANTIC OCEAN). MEANWHILE...THE NORTHERN STREAM FEATURES TWO JETS OF INTEREST...A 115KT JET OVER THE OHIO VALLEY...AND A 120KT JET OVER WESTERN CANADA. 12Z SURFACE MAP REVEALS SEVERAL SECONDARY COLD FRONTAL BOUNDARIES ACROSS THE EASTERN GREAT LAKES REGION...A WARM/STATIONARY BOUNDARY OVER THE PLAINS...AND A 1032MB HIGH CENTERED OVER THE NORTHERN GREAT LAKES.

HIGH PRESSURE WILL CONTINUE TO BUILD SOUTHEAST GIVEN 500MB HEIGHT RISES OF 30M AND 2-3MB PRESSURE RISES OVER THE OHIO VALLEY. THIS WILL CONTINUE TO DAMPEN LAKE EFFECT ACROSS THE REGION AS THE BUILDING HIGH BRINGS INCREASED LOW LEVEL SHEAR...LOW LEVEL DRY AIR...WHILE BUILDING ANTICYCLONIC FLOW. EXPECT ANY REMAINING SNOW SHOWERS WEST OF THE ALLEGANY FRONT TO NOT ACCUMULATE TODAY.

WITH LOSS OF LOW LEVEL MOISTURE SOURCE...STRATO-CU ARE EXPECTED TO GRADUALLY DISSIPATE DURING THE COURSE OF THE DAY...WITH THE EXCEPTION BEING ACROSS THE FAR NORTHEAST ZONES WHERE ADVECTION OFF SNOWPACK ACROSS SOUTHERN PENNSYLVANIA WILL MAINTAIN PARTLY CLOUDY SKIES. MARGINALLY INCREASING DIURNAL HEATING MAY ALLOW AREAS OF BROKEN CLOUDS TO HANG AROUND THE MOUNTAINS MOST OF THIS AFTERNOON.

KIAD AND AREA ACARS SOUNDINGS SHOW A WELL MIXED LAYER JUST ABOVE A SLIGHT NOCTURNAL INVERSION TO 5KFT. ERODING THE SLIGHT INVERSION WILL ONLY LEAD TO SEVERAL DEGREES OF WARMING...AND THE LOW LEVELS OF THE 12Z SOUNDINGS ARE A FEW DEGREES (F) COOLER THAN YESTERDAY AT THIS TIME. THEREFORE...EXPECT TEMPERATURES TO STRUGGLE TO REACH 30 AGAIN TODAY.

SOUNDINGS ALSO INDICATE ABOUT 30KTS OF WIND AT 5KFT. EXPECT ONLY SLIGHT GUSTS TO 25 MPH TODAY...TOO MINOR TO MENTION IN ZONES SINCE SUSTAINED WINDS ARE AROUND 10 TO 20 MPH.

UPDATED GRIDS/ZFP/EOL/REC/PFM/AFM HAVE BEEN ISSUED.

.MARINE: SMALL CRAFT ADVISORY REMAINS IN EFFECT WITH 15 TO 20KT OF NORTHWEST WIND ON THE WATERS. THIS MAY BE ABLE TO BE TAKEN DOWN WITH THE AFTERNOON PACKAGE...OR THIS EVENING AT LATEST AS HIGH PRESSURE BEGINS TO CENTER ITSELF ACROSS THE REGION.

UPDATED CWF HAS BEEN ISSUED.

ROGOWSKI

.LWX... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY TIDAL POTOMAC AND ALL OF UPPER CHESAPEAKE BAY.

$$



.SYNOPSIS...HIGH PRESSURE ALOFT ALONG WITH OFFSHORE LOW LEVEL FLOW WILL RESULT IN DRY WEATHER OVER THE REGION THROUGH EARLY THURSDAY. A STORM SYSTEM WILL BRING PRECIPITATION BACK TO THE AREA THURSDAY INTO FRIDAY. THIS SYSTEM WILL THEN BE FOLLOWED BY A MUCH COLDER ONE DROPPING OUT OF CANADA. THUS EXPECT TEMPERATURES TO FALL BELOW NORMAL THIS WEEKEND.

&&

.DISCUSSION...SATELLITE IMAGERY SHOWS DISSIPATING UPPER LEVEL SYSTEM SPREADING CIRRUS OVER WESTERN WASHINGTON AT 04Z. THIS FEATURE WILL BE OUT OF THE AREA BY 08Z. UNDERNEATH THE CIRRUS..STRATUS NEVER DID CLEAR OUT THE THE SOUTH SOUND AND PORTIONS OF THE SOUTHWEST INTERIOR TODAY. STRATUS REFORMING OVER MOST OF WESTERN WASHINGTON WITH THE EXCEPTION OF THE CASCADE FOOTHILLS. LITTLE CHANGE IN THE FORECAST TONIGHT WITH LIGHT SURFACE GRADIENTS. ACARS SOUNDINGS AND THE SANDPOINT PROFILER SHOW VERY LIGHT WINDS FROM 850 MB DOWN TO THE SURFACE. NOT MUCH OF AN INVERSION PRESENT IN THE ACARS SOUNDINGS OR THE MODEL SOUNDINGS FOR WEDNESDAY SO WILL LEAVE THE FORECAST OF SOME SUNSHINE WEDNESDAY AFTERNOON ALONE. 00Z MODELS RUNS CONTINUE WITH THE TREND OF SPEEDING UP THE TIMING OF THE SYSTEM FOR LATER IN THE WEEK. CURRENT FORECAST HAS A CHANCE OF RAIN FOR THURSDAY. THIS LOOKS GOOD AT THIS POINT. NEW 00Z GFS IS COOLER AGAIN WITH 850 MB TEMPS FOR LATER SATURDAY INTO SUNDAY WITH SURFACE PATTERN INDICATING THE POSSIBILITY OF SOME ARCTIC OUTFLOW BY THE END OF THE WEEKEND. WILL LET THE MID SHIFT SORT THIS OUT. WILL ADD SOME CLOUD COVER TO A COUPLE OF ZONES AND BUMP THE MINS UP OVER THE SOUTHWEST INTERIOR TONIGHT. NO CHANGES TO THE REST OF THE FORECAST. FELTON

&&

.SEW...SMALL CRAFT ADVISORY COAST FOR ROUGH BAR CONDITIONS.

.KATX...VCP32/CSR32...OPERATIONAL.

&&

$$



WATER VAPOR LOOP SHOWS A WAVE DIVING INTO THE NORTHERN GREAT LAKES FROM CENTRAL CANADA WITHIN NORTHERN STREAM OF EASTERN CONUS PHASED FLOW. A CUTOFF UPPER LEVEL LOW IS LOCATED OVER SOUTHERN CALIFORNIA. 300MB ANALYSIS SHOWS A DOMINATE SOUTHERN STREAM JET FROM BAJA CALIFORNIA NORTHEAST INTO THE SOUTHEAST CONUS AND NORTH THROUGH THE WESTERN ATLANTIC (WITH A 170KT JET STREAK ACROSS THE SOUTHEAST CONUS). THE OTHER JET OF INTEREST IS A 180KT JET LOCATED IN THE NORTHERN STREAM OVER WESTERN CANADA. 12Z SURFACE ANALYSIS PLACES A TROUGH OVER THE APPALACHIANS INDICATIVE OF LOWER LEVEL WARM ADVECTION. 1026MB HIGH PRESSURE IS LOCATED FROM THE SOUTH CENTRAL STATES NORTHEAST INTO THE OHIO VALLEY. A CLIPPER SYSTEM IS NEARING THE UPPER GREAT LAKES REGION...WITH ITS ASSOCIATED WARM/STATIONARY BOUNDARY ACROSS THE NORTHERN GREAT LAKES...AND A COLD FRONT CUTTING THROUGH MINNESOTA.

KIAD AND REGIONAL ACARS SOUNDINGS SHOW STRONG WARM ADVECTION BETWEEN 750-900MB DURING THE PAST 24HRS. THIS IS SUPPORTING MIDLEVEL CLOUDS WHICH ARE TIMED TO CROSS THE MOUNTAINS BETWEEN 15-18Z...WITH THE CLOUD SHIELD GRADUALLY OVERSPREADING THE I95 CORRIDOR...METRO AREAS AND LOWER SOUTHERN MARYLAND BETWEEN 19-22Z.

TEMPERATURES ARE ON TRACK...AS LIMITED WARMING IN THE 850-950MB LAYER TODAY SHOULD SUPPORT NEAR FREEZING READINGS EAST OF THE MOUNTAINS AND POSSIBLY UPPER 30S ACROSS CENTRAL VIRGINIA AND LOWER SOUTHERN MARYLAND...AS THE NOCTURNAL INVERSION IS ERODED DURING THE MID TO LATE MORNING.

UPDATED GRIDS/ZFP/EOL/AFM/PFM/REC HAVE BEEN ISSUED.

.MARINE: SMALL CRAFT CONDITIONS EXPECTED THURSDAY AFTERNOON BEHIND COLD FRONT.

UPDATED CWF HAS BEEN ISSUED.

ROGOWSKI

$$

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