Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 290757 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 357 AM EDT WED OCT 29 2014 .SYNOPSIS... A COLD FRONT WILL PASS THROUGH THE AREA TODAY. HIGH PRESSURE WILL RETURN FOR THURSDAY. LOW PRESSURE AND ITS ASSOCIATED COLD FRONT WILL PASS THROUGH THE AREA FRIDAY INTO SATURDAY BEFORE CANADIAN HIGH PRESSURE BUILDS OVERHEAD EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... SFC CDFNT ENTERING THE SHEN VLY ELY THIS MRNG. PCPN ALIGNED BHD THE FNT. WHILE DEWPTS IN THE MID-UPR 50S ATYPICAL FOR LT OCT...00Z RAOB WAS STILL QUITE DRY. NO DOUBT...THE LEADING EDGE OF PCPN WORKING TO SATURATE ATMOS. SYNOP AND MESOSCALE GDNC IN GOOD AGREEMENT IN TAKING FNT /AND PCPN/ THRU CWFA SLOWLY TDA. EVEN THO WE/RE NOT MAKING THE MOST OF SFC CNVGNC...THERE/S MORE THAN ENUF LIFT FM THERMAL DISCONTINUITY AND RRQ OF UPR JET. HV INCRSD POPS SOMEWHAT...ALTHO HV HELD BACK FM FULL-FLEDGED CATEGORICAL. HV A DECENT SURGE OF CAA IMMEDIATELY BHD PCPN...AND CAA WL CONT THRU TNGT. TOOK MAXT DOWN BY PERHAPS A DEGF OR TWO TDA...AND THEN MIN-T DOWN BY A CPL TNGT. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... HIPRES WL BE CRESTING OVER CWFA THU. NO PCPN XPCTD. FOR THAT MATTER...THERE WL BE VERY FEW CLDS TO START THE DAY THU. DO THINK THAT THERE WL BE DIURNAL CU AS WELL AS AN ADVCTV MID DECK BY EVNG. GOOD MOS AGREEMENT ON MAXT...MID-UPR 50S WL BE IT. MIN-T A BIT MORE OF A CHALLENGE. ALL DEPENDS UPON HOW QUICKLY CLDS/WAA COME IN. IF EITHER HOLDS OFF...THEN TEMPS CAN PLUMMET QUITE QUICKLY. HV GONE LWR THAN PRVS FCST. && .LONG TERM /FRIDAY THROUGH TUESDAY/... ON FRIDAY HIGH PRESSURE WILL BEGIN TO WEAKEN AS THE UPPER LEVEL PATTERN UNDERGOES SIGNIFICANT AMPLIFICATION. A SHORTWAVE TROUGH WILL DIG SOUTHWARD FROM THE GREAT LAKES WITH AN ATTENDANT SURFACE LOW. PRECIPITATION CHANCES WILL INCREASE IN THE MOUNTAINS DURING THE AFTERNOON. HIGH TEMPERATURES EXPECTED TO BE SLIGHTLY BELOW NORMAL. INCREASING AGREEMENT BETWEEN OPERATIONAL AND ENSEMBLE MODELS OF A CLOSED MID LEVEL LOW DEVELOPING IN THE VICINITY OF THE CAROLINAS. THIS WILL THEN INDUCE CYCLOGENESIS OFF THE COAST. THE GREATEST FORCING WILL BE ACROSS SOUTHWESTERN PORTIONS OF THE CWA. WRAP-AROUND FROM THE OFFSHORE LOW MAY NOT MAKE IT TOO FAR WEST. BUT GIVEN THE OVERALL SYNOPTIC SETUP...AT LEAST A CHANCE OF SHOWERS AREA-WIDE. AS COLDER AIR WRAPS IN...SOME SNOW SHOWERS ARE POSSIBLE ACROSS THE POTOMAC HIGHLANDS BY SATURDAY. THE SATURDAY-SUNDAY PERIOD WILL ALSO BE BREEZY DUE TO THE STRENGTHENING PRESSURE GRADIENT. DUE TO THE MORE AMPLIFIED SYSTEM...THE COLDEST READINGS OF THIS SURGE MAY WAIT UNTIL SUNDAY NIGHT NOW AS HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST...ALTHOUGH IT MAY NOT BE DIRECTLY OVERHEAD. LOW TEMPERATURES NEAR THE FREEZING MARK ARE STILL POSSIBLE. THE HIGH DOMINATES INTO TUESDAY WITH TEMPERATURES MODIFYING BUT REMAINING BELOW NORMAL. A FRONT MAY APPROACH FROM THE NORTHWEST LATE TUESDAY. && .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/... CDFNT CROSSING TERMINALS TDA. THE WSHFT TO NW WL COME FIRST...LKLY DURING THE MRNG PUSH. PCPN WL FLLW. AS OF 06Z TAFS...WASNT CERTAIN ABT ANY RESTRICTIONS. WHILE STILL FEEL VFR WL GNLY PREVAIL...WUDNT RULE OUT LCL MVFR. SKIES WL CLR TNGT. NW FLOW WL CONT INTO THU...W/ DIURNAL CU SCT050. VFR CONDITIONS ARE EXPECTED THROUGH FRIDAY. A LOW PRESSURE SYSTEM MAY BRING MVFR CEILINGS ON SATURDAY. && .MARINE... TPLM2 STILL G20KT AHD OF CDFNT IN SLY FLOW. HV SCA TIL 6AM FOR MID BAY AND LWR PTMC. WSHFT TO NW WL COME DURING THE DAY. WHILE HV A GOOD SURGE OF CAA BHD FNT...MIXING NOT THAT GREAT DUE TO PCPN LAGGING BHD FNT. HV OPTED TO CAP GUSTS BLO SCA CRITERIA FOR THE DAYTIME-EVNG HRS. GRADIENT DROPS AFTR THAT AS HIPRES BLDS. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED BEGINNING LATE FRIDAY NIGHT AND CONTINUING THROUGH THE DAY SATURDAY AS LOW PRESSURE MOVES OFF THE CAROLINA COAST. A GALE WARNING MAY ALSO BE NECESSARY SATURDAY EVENING AND NIGHT...AND POTENTIALLY INTO SUNDAY. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR ANZ532>534-537-540>543. && $$ SYNOPSIS...HTS NEAR TERM...HTS SHORT TERM...HTS LONG TERM...ADS AVIATION...HTS/ADS MARINE...HTS/ADS

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