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...

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.

&&

.NEAR TERM /TONIGHT/...

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.

&&

.SHORT TERM /WEDNESDAY/...

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.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...

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.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...

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.

&&

.MARINE...

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.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
PRODUCTS...WOODY!/ADS/MSE



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