Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 041444
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1044 AM EDT WED MAY 4 2016

.SYNOPSIS...
SURFACE LOW PRESSURE WILL REMAIN ACROSS THE AREA TODAY. UPPER
LEVEL LOW PRESSURE IS EXPECTED TO IMPACT THE AREA THURSDAY AND
FRIDAY BEFORE HIGH PRESSURE RETURNS SATURDAY EVENING. A WEAK COLD
FRONT IS EXPECTED TO PUSH THROUGH THE REGION SUNDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
HEIGHTS ALOFT WILL FALL STEADILY THROUGH THE DAY AS LONGWAVE
PATTERN AMPLIFIES AND A DEEP CLOSED LOW ALOFT FORMS OVER THE UPPER
MIDWEST TO THE OH VALLEY TONIGHT. INCREASING LARGE SCALE ASCENT
AND SFC CONVERGENCE OVER THE MTNS WILL LEAD TO WIDESPREAD SHOWERS
AND ISOLATED THUNDERSTORMS. ACTIVITY WILL SLOWLY SPREAD EASTWARD
TONIGHT BUT BE MORE CONCENTRATED ALONG AND WEST OF THE BLUE RIDGE.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
A CLOSED LOW SWINGS OVER THE AREA TONIGHT THROUGH THURSDAY...THEN
STALLS AT LEAST INTO SATURDAY. THIS WILL BRING ABOUT A NOTABLY WET
STRETCH WITH INTERMITTENT RAIN. DESPITE IT HAVING ALREADY BEEN WET
RECENTLY...THERE IS A SPRING RAINFALL DEFICIT ACROSS THE AREA OF ONE
TO THREE INCHES. SO THIS SHOULD BE SEEN AS A BENEFICIAL STRETCH.

POTENTIAL HAZARDOUS WEATHER IN THIS STRETCH. RAIN MAY BECOME
EXCESSIVE...PARTICULARLY LATE TONIGHT THROUGH THURSDAY AS THE UPR LOW
OVER ERN KY TRANSFERS ENERGY TO A COASTAL LOW. MOISTURE CONVERGENCE
ALONG THIS LINE (GUIDANCE CONSENSUS CURRENTLY FEATURES THIS
CONVERGENCE ACROSS CNTRL VA) COULD ALLOW MODERATE TO LOCALLY HEAVY
RAIN OVER THE SAME AREAS FOR HOURS. THIS...WITH TERRAIN ENHANCEMENT
IN THE AREA COULD LEAD TO A FEW TO SEVERAL INCHES OF RAIN AND
FLOODING. CURRENT SIX-HOUR FFG IS 1.5 TO 3 INCHES OVER SWRN ZONES. A
NOTE ABOUT THIS WILL BE ADDED TO THE HWO.

THE LOW BECOMES VERTICALLY STACKED OVER THE AREA THURSDAY NIGHT AND
PERSISTS FRIDAY. FOCUS OF RAIN SHIFTS ACROSS THE BALT-WASH METRO.
THIS LOOKS LESS INTENSE AS THE THURSDAY AREA WITH QPF AN INCH OR SO.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
THE UPR CUTOFF LOW OVR THE ERN U.S. WHICH WE`VE BEEN WRITING ABT
FOR THE PAST SVRL DAYS SEEMS TO BE EARNING THE TERM "OMNIPRESENT"
AS LATEST MDLS NOW KEEP IT OVR THE MID ATLC THRU SAT...KEEPING
THE 1ST HALF OF THE WKND A CLDY COOL RAINY CONTINUATION OF WHAT
THIS WK HAS BEEN AS A WHOLE. SUPERBLEND GIVING HIGHS IN THE LM70S
SAT - THIS MAY BE A STRETCH AND WL BE DEPENDENT ON WHETHER BRKS
DVLP IN THE AFTN CLDS...AND IF BRKS DO DVLP WL RW FORM AS A
RESULT OF THE HTG IN THE MOIST ENVIRONMENT?

A CD FNT IS PROGGED TO MOVE INTO THE RGN SUNDAY/UPR LVL SHORT WV
DIVE INTO THE ERN GRT LKS. THIS TOO MAY LEAD TO A CHC OF RW/ISOLD
TRW.

IT LOOKS LK WE`LL FINALLY BE ABLE TO SAY "BON VOYAGE" TO THE UPR
LOW MON...AND THE UPR RIDGE WHICH WL HV BEEN OVR THE ROCKIES FOR
MULTIPLE DAYS. SUNNIER SKIES NEXT MON AND TUE.

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
ONSHORE FLOW THROUGH THURSDAY AS LOW PRESSURE MOVES EAST OFFSHORE
AND DEEP LOW PRESSURE MOVES SOUTH INTO THE CAROLINAS. INTERMITTENT
IFR/MVFR CONDS TODAY THROUGH FRIDAY NIGHT. RAIN DEVELOPS THIS
MORNING WITH PERIODIC SHOWERS THEN THIS AFTERNOON THROUGH FRIDAY
NIGHT.

ISOLATED THUNDER INVOF KCHO THIS AFTERNOON AND THURSDAY AFTERNOON.

LWRD CIGS AGN PSBL SAT...THEN IMPRVG CONDS SUNDAY.

&&

.MARINE...
LIGHT ONSHORE FLOW THROUGH THURSDAY AS LOW PRESSURE MOVES EAST THIS
MORNING AND DEEP LOW PRESSURE MOVES SOUTH INTO THE CAROLINAS. SCA MAY
BE NECESSARY AS LOW DEVELOPS THURSDAY NIGHT INTO FRIDAY. WILL NEED
TO MONITOR FOR POTENTIAL SCA ALSO INTO THIS WEEKEND AS LOW MOVES
OUT.

NO PROBS XPCTD ON THE WATERS SAT.

&&

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

&&

$$
SYNOPSIS...LFR
NEAR TERM...LFR
SHORT TERM...BAJ
LONG TERM...ABW
AVIATION...LFR/ABW
MARINE...LFR/ABW


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