Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 261433 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1033 AM EDT TUE APR 26 2016 .SYNOPSIS... A COLD FRONT WILL MOVE ACROSS THE AREA THIS EVENING THEN BECOME STATIONARY ACROSS SOUTHERN VIRGINIA WEDNESDAY NIGHT. HIGH PRESSURE BUILD IN ITS WAKE AND HOLDS THROUGH THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... DYING CNVCTV CMPLX SPREADING SHRA OVER THE PTMC HIGHLNDS ATTM AND THICK BLOWOFF CLDCVR OVER THE REST OF THE NRN AND CENTRAL CWFA. HV CONFINED MRNG SHRA THREAT TO THE MTNS AND PERHAPS /CHC POPS/ N-CENTRL MD. ALSO HV A BRIEF WIND GUST /TO NEAR 25 KT/ NEAR THIS BNDRY. BY 16Z...ONLY THE CLDS SHUD BE LEFT...AND THESE SHUD THIN THRU THE ELY AFTN. THAT LEAVES THE CONUNDRUM OF WHAT TO DO W/ THE AFTN CNVCTN THREAT. IT REMAINS TRUE THAT FCST SNDGS CONTAIN A DRY SUB-CLOUD LAYER/INVERTED-V PROFILES AND FAST STORM MOTION OF 35-40 KT. HWVR...RESIDUAL CLDS CUD BE A MITIGATING FACTOR. HV TRIMMED MAXT BACK A CPL DEGF IN LIGHT OF POTL HEATING...WHICH BRINGS FCST MAXT ABOUT EQUAL TO CNVCTV TEMP FM 12Z IAD RAOB. THE MODIFIED SNDG DOES SQUEAK OUT 1200 J/KG MLCAPE. GIVEN FCST SNDG AND LINGERING OUOTFLOW/DIFF HTG BNDRYS...DO BELIEVE THAT A 2ND ROUND OF TSRA WL DVLP...AND THAT THESE WILL SUPPORT GUSTY WINDS. CANNOT RULE OUT LCLLY DMGG WINDS IN THIS ENVIRONMENT. T-STORMS WILL LIKELY LINGER INTO THE EARLY EVENING ACROSS THE CHARLOTTESVILLE THEN WANE BY MIDNIGHT AS COOLER MORE STABLE AIR MOVES IN BEHIND FRONT. A STRATUS LAYER FCST TO DEVELOP LATE TONIGHT. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... MUCH COOLER WED AS COOL WEDGE ESTABLISHES. INCREASING CHANCES OF RAIN WED NIGHT THROUGH THU NIGHT AS WARM AIR OVERRUNS SFC FRONT ACROSS VA. BENEFICIAL RAINS EXPECTED OF GENERALLY HALF TO ONE INCH THROUGH EARLY FRI. BEST CHANCE FOR RAIN APPEARS TO BE ON THU AS WEAK LOW MOVES ALG STALLED OUT FRONT. && .LONG TERM /FRIDAY THROUGH MONDAY/... SLOWLY MOVING/STALLED FRONT WILL STILL BE LOCATED TO OUR SOUTH. A COUPLE WEAK SFC WAVES WILL BE TRACKING ALONG THE FRONT...AND A 500 MB VORT MAX WILL SWING ACROSS DURING THE AFTERNOON. THIS WILL PROMOTE CONTINUED CHANCES FOR SHOWERS. THE SHOWERS WILL TAPER TO DRIZZLE FRIDAY NIGHT AS HIGH PRESSURE BUILDS DOWN FROM THE NORTH. WHILE SATURDAY AND SATURDAY NIGHT WILL FEATURE RISING HEIGHTS ALOFT...SFC HIGH PRESSURE TO THE NE WILL MAINTAIN LLVL EASTERLY FLOW...ESSENTIALLY A CAD WEDGE. THEREFORE EXPECT CONSIDERABLE CLOUDS TO PERSIST AND CAN/T RULE OUT A LITTLE DRIZZLE. DESPITE SIMILAR SYNOPTIC EVOLUTION OF LOW PRESSURE OVER THE PLAINS...00Z GFS DIVERGES A BIT ON WARM FRONTAL STRUCTURE AND OVERRUNNING MOISTURE REACHING THE MID-ATLANTIC ON SUNDAY. ECMWF...GEM...AND SOME GEFS MEMBERS KEEP PRECIP TO A MIN...BUT WOULD EXPECT A RELATIVELY CLOUDY DAY REGARDLESS. BETTER CHANCES OF RAIN WILL ARRIVE SUNDAY NIGHT INTO MONDAY AS THE LOW LIFTS TOWARD THE GREAT LAKES. FOR TEMPERATURES...POSSIBLE GUIDANCE MAY BE TOO WARM OVER THE WEEKEND WITH EASTERLY FLOW AND CLOUDS. HIGHS SHOULD RUN BELOW NORMAL. MONDAY TEMPERATURES WILL DEPEND ON LOW TRACK/WARM FRONTAL PROGRESSION...AND THIS WILL ALSO HELP DETERMINE POTENTIAL FOR THUNDER. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... HIGH DECK OVC XPCTD INTO ELY AFTN. SHUD HV PRTL SUN AGN BY MID AFTN. RESULTANT HEATING WL YIELD A REASONABLY UNSTBL ATMOS. BELIEVE THERES A GOOD CHC AT AFTN SHRA/TSRA...SOME OF WHICH MAY CONTAIN STRONG WIND GUSTS. BEST ESTIMATE ATTM THAT PEAK GUST POTL RANGES SOMEWHERE ARND 30-35 KT. AN ISOL GUST MAY GET TO 50 KT... BUT THAT THREAT LOCALIZED AT BEST. STORMS SHUD EXIT BY 00Z...PERHAPS AN HR OR TWO LATER CHO /AND LKLY ERLR MRB/. STRATUS DECK FORECAST TO DEVELOP LATE TONIGHT WITH MVFR CIGS. MVFR CIGS THROUGH FRI ALONG WITH RAIN UNDER COOL SFC WEDGE. MVFR (PERHAPS LOCALLY IFR) CONDITIONS POSSIBLE FRIDAY INTO FRIDAY NIGHT WITH LOW CLOUDS...SHOWERS AND DRIZZLE. CIGS MAY IMPROVE SATURDAY INTO THE VFR CATEGORY BUT LIKELY WON/T SCATTER OUT. && .MARINE... SCA CONDITIONS THROUGH MIDNIGHT TONIGHT. T-STORMS LKLY TO DVLP MID-LT AFTN...PERHAPS INTO ELY EVNG FOR MID BAY/LWR PTMC. XPCTG GUSTY WINDS INVOF TSRA...AND MAY REQUIRE ISSUANCE OF SMW/S. NE FLOW MAY ENHANCE SLIGHTLY ON FRIDAY AS WEAK LOW PRESSURE MOVES ALONG A STALLED FRONT. FORECAST WILL REMAIN BELOW SCA LEVELS FOR NOW. LIGHT NE/E FLOW WILL PERSIST FRIDAY NIGHT INTO SATURDAY WITH HIGH PRESSURE TO THE NORTH. && .FIRE WEATHER... GUSTY WINDS AND WARM TEMPERATURES WILL CREATE FIRE WX CONCERNS TODAY. MUCH COOLER WED AND THROUGH THE END OF THE WEEK WITH THICK CLOUDS AND RAIN. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR ANZ530>543. && $$ SYNOPSIS...LFR NEAR TERM...HTS/LFR SHORT TERM...LFR LONG TERM...ADS AVIATION...HTS/LFR/ADS MARINE...HTS/LFR/ADS FIRE WEATHER...HTS/LFR

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