Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 051854 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 254 PM EDT TUE MAY 5 2015 .SYNOPSIS...
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A COLD FRONT OVER SOUTHERN PENNSYLVANIA WILL SINK SOUTH TODAY... STALLING NEAR THE MASON-DIXON LINE TONIGHT...POSSIBLY GETTING INTO NORTHERN VIRGINIA WEDNESDAY. HIGH PRESSURE IS EXPECTED TO RETURN TO THE REGION LATE IN THE WEEK WHILE LOW PRESSURE DEVELOPS OFF THE CAROLINA COAST.
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&& .NEAR TERM /TONIGHT/...
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FOR THE NEXT SVRL HRS WE`LL BE WATCHING FOR DVLPMNT OF RW ON THE S SIDE OF THE FNTL BNDRY ALONG THE MASON DIXON LN. CAPE IS LOW...AND WIND FIELD IS VERY LGT. THIS ARE NOT CONDUCIVE TO VERTICAL DVLPMNT OF STORMS...AND THE ONE CELL WE`VE SEEN SO FAR - IN ERN WV...HAS FALLEN APART. W99 XPRNCD A TEMP DROP OF 80 TO 66 WHEN THE RW WENT THRU BTWN 16 AND 17Z. OVRNGT THE BNDRY IS XPCTD TO RMN IN THE NR PART OF THE FCST AREA. NGT SHOULD BE PRIMARILY DRY - AM CONTINUING ISOLD RW OVRNGT ACROSS THE NRN 1/3 OF THE FCST AREA. LOW TEMPS IN THE U50S W OF THE BLU RDG...L60S E.
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&& .SHORT TERM /WEDNESDAY/...
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AND THERE IS LTL MVMNT SYNOPTICALLY WED. HOW FAR THE FNT IS ABLE TO TREK S IS THE PRIMARY QUSTN. NONE OF THE MAIN MDLS PROJECT IT MOVG VERY FAR S...PERHAPS TO THE PTMC? THIS WL LEAD TO ANOTHER DAY OF VARYING CLDNS - THE MOST OF IT ACROSS MD...W/ CHC AFTN POPS. WIND FIELD AGN IS LGT. AREA IS OUTLOOKED IN GNRL TSTMS...THE SVR THREAT RMNS AT BAY. HIGH TEMPS SHOULD BE QUITE SIMILAR TO TDA - WARMEST IN THE CENTRAL SHEN VLLY..COOLER N WHERE THE CLD CVR WL BE MOST XTNSV.
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&& .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
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FRONTAL ZONE WILL BE FAIRLY ILL-DEFINED BY WEDNESDAY EVENING. HIGH PRESSURE WILL BE LOCATED TO THE NORTH WHILE A LOW TAKES PLACE OFF THE GA COAST. FOR THE MAJORITY OF THE SYNOPTIC MODELS...A LLVL NE FLOW IS EVIDENT PUSHING INTO NE MD...PERHAPS AS FAR AS DC...WHICH SERVES TO STABILIZE THE ATMOSPHERE. HOWEVER THE 12Z NAM AND NMM...AS WELL AS THE 00Z ARW DEPICT CONVECTION FORMING ALONG A CONVERGENCE ZONE IN PA AND DROPPING SOUTH DURING THE EVENING...AFFECTING MORE OF THE AREA. WILL CONTINUE BROAD BRUSHED CHANCE POPS THROUGH THE EVENING...ALTHOUGH DID EXTEND THUNDER MENTION A LITTLE LONGER TO ACCOUNT FOR CONVECTIVE UNCERTAINTY. DEW POINTS WILL REMAIN ELEVATED OVERNIGHT SO LOWS WILL ONLY FALL INTO THE UPPER 50S TO LOWER 60S. ON THURSDAY THE SFC HIGH MOVES OFFSHORE WITH LIGHT RETURN FLOW DEVELOPING. MID/UPPER RIDGE AXIS WILL BECOME CENTERED OVER APPALACHIANS. EXPECT THIS TO SQUASH MOST CONVECTION...BUT DID CONTINUE TO CARRY LOW END POPS IN THE MOUNTAINS WHERE BUILDING (BUT MEAGER) INSTBY WILL COMBINE WITH TERRAIN CIRCULATIONS. ANY ACTIVITY WILL DIMINISH WITH SUNSET. ELSEWHERE ATMOSPHERE DOESN/T TOTALLY DRY OUT...SO PARTLY TO MOSTLY CLOUDY AT TIMES. HIGHS IN THE 70S...AND LOWS MID 50S TO LOWER 60S. RIDGING MAIN WX FEATURE THROUGH THE EXTENDED WITH HIGH/LOW TEMPS GENERALLY 10 DEGREES ABOVE CLIMO NORMS. HOWEVER...RESIDUAL DEEP LAYER MOISTURE WILL ALLOW FOR A CHC OF AFTN SHRA OR T-STORMS SOMEWHERE IN THE CWA NEARLY EACH DAY. BEST PRECIP CHANCES ON FRI AND SAT IN THE FAVORED ELEVATED TERRAIN IN THE WEST...WITH VERY LOW CHANCES AS YOU APPROACH THE 95 CORRIDOR. LOW PRECIP CHANCES THEN SPREAD EASTWARD FOR SUN...AND EVEN MORE SO FOR MON...AS RIDGING BEGINS TO LOOSEN ITS GRIP ON THE REGION AND A CLD FRNT APPROACHES. ORGANIZED SVR CHANCES THRU THE PERIOD VERY LOW...AS DEEP LAYER SHEAR REMAINS RATHER ANEMIC....AND INSTABILITY IS MARGINAL.
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&& .AVIATION /18Z TUESDAY THROUGH SUNDAY/...
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WHILE SKIES ACROSS THE NRN HALF OF THE FCST AREA WL BE M CLDY CIGS ARE XPCTD TO RMN IN THE VFR LVL. RW/ISOLD TRW ARE PSBL... ESPECIALLY THIS EVE. NO STRONG WIND GUSTS ARE XPCTD. WED SHOULD BE FAIRLY SIMILAR TO TDA WX WISE...BCMG M CLDY W/ ISOLD RW/AFTN TRW. CHANCES OF SHOWERS AND PERHAPS A THUNDERSTORM WILL LINGER INTO WED EVENING...BUT CONFIDENCE LOW ON COVERAGE. LOW LEVEL MOISTURE PRESENT EARLY THU MORNING...WHICH MAY RESULT IN FOG...ESPECIALLY IF A TERMINAL SEES RAIN DURING THE EVENING. ISOLATED SHOWER POSSIBLE THU AFTERNOON AT MRB/CHO. FOG POSSIBLE...MAINLY AT PRONE LOCATIONS...FRIDAY MORNING. WINDS LIGHT/VRB WED NIGHT-THU NIGHT. EXPECT VFR COND FRI THRU SUN. HOWEVER...LOW LEVEL MOISTURE COULD ALLOW FOR SOME PREDAWN FOG AT CLIMO FAVORED LOCATIONS.
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&& .MARINE...
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WINDS SHOULD RMN BLO SCA LVLS TNGT AND WED. ISOLD RW/TRW ARE PSBL LATE THIS AFTN/EVE AND AGN ON WED. GUSTS INTO THE 20-30 KT RNG COULD BE PSBL W/ THESE. WITH WEAK SFC PRESSURE PATTERN...SUSTAINED STRONG WINDS ARE NOT EXPECTED WED NIGHT-THU NIGHT. SURGE WITH HIGH PRESSURE BUILDING TO NORTH MAY BRING BEST CHANCE AT NEAR-SCA GUSTS WED EVENING. SCATTERED SHOWERS AND STORMS ARE ALSO POSSIBLE THROUGH WED EVENING. WINDS LIGHT UNDER HIGH PRESSURE...SO NOT EXPECTING SCA CONDS FRI THRU SUN.
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&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ PRODUCTS...WOODY!/ADS/MSE

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