Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 301845 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 245 PM EDT SAT AUG 30 2014 .SYNOPSIS... HIGH PRESSURE OFF CAPE COD WILL MOVE SOUTHEAST AND BECOME A BERMUDA HIGH THROUGH TUESDAY. A COLD FRONT WILL CROSS THE AREA TUESDAY NIGHT. HIGH PRESSURE WILL FOLLOW FOR THE SECOND HALF OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... SFC HIPRES REMAINS OFF ACK TAFTN. HWVR...MRNG CLDS BROUGHT ONSHORE ARND PERIPHERY OF HIGH HV HELD TOUGH ALONG AND E OF BLURDG... TRAPPED UNDER H8 RDGG. LTST VSBL SATPIX DEPICT SOME CLRG ALONG I-95. W OF THERE...IN THE LEE OF THE RDGS...A BKN TO ALMOST OVC LYR OF CLDS REMAIN. TRENDS...AND LAV...SUGGEST THAT CLRG WL COME DURING THE AFTN. OBVIOUSLY...THIS HAS HELD TEMPS DOWN. BUT WUD XPCT A RAPID WARM UP ONCE INSOLATION APPEARS...AS THERES PLENTY OF SNDG SUPPORT FOR IT. MEANWHILE...AMPLE SUN IN THE PTMC HIGHLANDS HV LED TO DIURNAL CU. LTST MESO GDNC RUNS STILL SUGGEST PCPN WL DVLP THERE...MID AFTN INTO ELY EVNG. HWVR...SUPPORT TO ALLOW FOR THESE CELLS TO EMERGE FM THE MTNS WL BE LACKING. HV OPTED TO SCALE BACK POPS OKV-MRB- HGR. THE REST OF THE CWFA WL BE RAIN FREE THRU THE EVNG. DP SWLY FLOW TNGT WL BRING THE HUMIDITY. THINK THAT/LL SUPPORT PLENTY OF CLDS OVNGT. THE ADDED CLDCVR AND DEWPTS UP NEAR 70F SUGGEST THAT WARMER MIN-T GDNC THE WAY TO GO. ALSO CANT RULE OUT PATCHY FOG AS WE/LL BE QUITE SATD. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... CWFA WL BE W/IN SWLY FLOW FOR THE FRIST PARTS OF THE WK. HWVR THE FLOW WL BECOME A BIT MORE WLY MON...AND SPCLY TUE. THE PLUME OF MSTR EVIDENT ON WATER VAPOR IMGRY WL BE RUNNING ATOP THE RDG. LTST GDNC SUGGESTING THAT THE SETUP WONT BE QUITE AS IDEAL AS PRVS CYCLES. THATS NOT TO SAY THERE WONT BE A MOIST/UNSTBL AMS. BUT THTE RDG/ADVTN AS WELL AS PVA DURING THE AFTN WL BE BETTER IN THE MTNS AND PTS WEST. STILL WL HV A CORRIDOR OF PWAT AOA 2 INCHES...BUT THERE/S NOT AS MUCH TO ORGANIZE/FORCE THE PCPN. AND IN THE SERN CWFA...RDGG WL ACTUALLY SURPRESS IT. HV THEREFORE BACKED OFF ON POPS SUN...STILL FOCUSING ON THE AFTN-EVE HRS. LKLY POPS WONT APPEAR TIL EVNG...WHEN LIFT ARRIVES. NOCTURNAL STABILITY WL ALLOW PVA TO SNEAK THRU OVNGT. AM FCSTG A GOOD DEAL OF CLDCVR SUN...WHICH SHUD ONCE AGN IMPEDE STRONG WARMING. HV SHADED DOWN MAXT A DEGF OR TWO. WHILE THERE WL BE A SHARP LEE TROF MON...ALL OTHER FEATURES APPEAR TO BE EITHER WEAK OR SUBTLE. WLY FLOW WL PROVIDE A LTL BIT OF DRYING...WHICH IS EVIDENT IN PROGGED PWAT VALUES. THE IMPACT IS EVIDENT IN POP VALUES...WHICH ARE LWR THAN SUN. THAT SEEMS QUITE RESONABLE. AM GNLY IN THE 30-40 PCT RANGE...AND AM KEEPING A DRY FCST IN CENTRL VA. WHATEVER TSRA THAT DO DVLP SHUD MV TO THE ERN SHORE BY NIGHTFALL...AND HV A DRY FCST FOR MON NGT-- WHICH LARGELY WL CONT INTO TUE DUE TO DOWNSLOPING. THINK THAT THE BEST CHC AT A 90 DEG DAY WL COME ON TUE...AS WLY FLOW WL KEEP POPS LOW AND PROVIDE COMPRESSIONAL WARMING. HV LWRD MON MAXT BY A CPL...AND RAISED TUE MAXT ALSO BY A CPL. MIN-T FCSTS ON TRACK...IN STEP W/ PROGGED DEWPTS. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... 500MB SHORTWAVE WILL TRACK FROM THE GREAT LAKES TO SOUTHERN QUEBEC AND DRAG A WEAK TROUGH THROUGH THE CWA TUESDAY NIGHT THROUGH WEDNESDAY. 500MB HIGH WILL BUILD OVER MID ATLANTIC REGION WEDNESDAY THROUGH THURSDAY. THE HIGH WILL WEAKEN ALLOWING A COLD FRONT TO ENTER NORTHWEST PA BY SATURDAY NIGHT. BAND OF MOISTURE...PVA...AND PASSAGE OF THE COLD FRONT WILL SUPPORT A SLIGHT CHANCE DEVELOPMENT OF SHOWERS/THUNDERSTORMS TUESDAY NIGHT THROUGH WEDNESDAY MORNING. MUCH DRIER AIRMASS ASSOCIATED WITH SURFACE HIGH WILL CROSS THE CWA LATER WEDNESDAY THROUGH EARLY FRIDAY. INCREASING MOISTURE DUE TO THE RETURN SOUTH TO SOUTHWEST FLOW ASSOCIATED WITH THE HIGH AND PVA OUT AHEAD OF AN APPROACHING COLD FRONT FROM THE WEST WILL SUPPORT AN INCREASED CHANCE OF MORE SHOWERS AND THUNDERSTORMS SATURDAY. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... MVFR CIGS STILL HOLDING ON...AS MSTR TRAPPED BLO H8 INVRSN. AM STILL HOPEFUL THAT RESTRICTIONS WL CLR BY MID AFTN. SLY FLOW WL PROVIDE INCREASING LOW LVL HUMIDITY. THEREFORE... OVERNIGHT FOG SHUD BE AN ISSUE. FLLWG CLIMO BY KEEPING DCA AT VFR. OTRW...HV MVRG VSBYS ACRS THE BOARD PRE-DAWN. IFR A PSBLTY...BUT THINK THERE WL BE TOO MUCH HIER LVL CLDCVR FOR THICKER FOG TO DVLP. ONCE MRNG RESTRICTIONS CLR...ATM WL BE UNSTBL FOR SCT TSRA TO DVLP. CUD HV LCL IFR IN HVR RAINERS...BUT LOW CONFIDENCE IN A SPOT FCST PRECLUDE A TAF INCLUSION. OUTLOOK... MON...TARGETED IFR POSSIBLE AT TIMES WITH SCT TSRA. CVRG SHUD BE LESS THAN SUN. TUE-THU...PRIMARILY VFR. && .MARINE... SLY FLOW ACRS THE MARINE AREA THRU THE WKND. WITH DIURNAL MIXING... INCRSD SPDS IN THE AFTN-EVE. SCA IN EFFECT LT TAFTN-TNGT FOR BAY SANDY PT-SMITH PT DUE TO POTL OF 20 KT GUSTS. IT/LL BE A SIMLR SITUATION SUNDAY...THO DONT THINK THE MIXING WL BE QUITE AS GOOD. IN ADDITION...POTL TSRA WUD PROVIDE STRONGER WIND GUSTS. OFFSHORE HIGH PRES WILL CONTINUE TO STEER WARM/HUMID AIR UP ACROSS THE ERN SEABOARD. SETUP WUD SUPPORT PDS OF SLY CHANNELING...BUT GDNC NOT PICKING UP ON ANY JUST YET. WK CDFNT LT TUE/ELY WED... MARKED BY A SLGT SHIFT IN WIND DIRECTION FM SW TO NW. && .TIDES/COASTAL FLOODING... TIDAL DEPARTURES JUMPED UP YDA AFTN-EVNG. DEPARTURES HV BEEN FAIRLY STEADY BTWN A 1/2 FT AND 1 FT ABV NORMAL. WINDS SHOULD REMAIN SLY...SO ANTICIPATE ADDTL INCREASES THROUGH THE WKND. THE NEXT HIGH TIDE /OVNGT INTO SUN MRNG/ WL NEED TO BE WATCHED FOR POSSIBLE MINOR FLOODING. GDNC RIGHT NOW MAKING FOR A CLOSE CALL AT ANNAPOLIS...BUT SUSPECT ITS OVERDONE BY A FEW INCHES. NONETHELESS... THIS WL BE AN ISSUE THROUGH THE WKND. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EDT SUNDAY FOR ANZ532>534. && $$ SYNOPSIS...HTS NEAR TERM...HTS SHORT TERM...HTS LONG TERM...MEADOWS AVIATION...HTS MARINE...HTS TIDES/COASTAL FLOODING...HTS

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