Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 040118
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
918 PM EDT TUE MAY 3 2016

.SYNOPSIS...
A SURFACE TROF WILL REMAIN ACROSS THE AREA THROUGH THURSDAY. UPPER
LEVEL LOW PRESSURE IS EXPECTED TO IMPACT THE AREA THURSDAY AND
FRIDAY BEFORE HIGH PRESSURE RETURNS FOR THE WEEKEND.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
A BROAD AREA OF LOW PRESSURE IS ACROSS THE SOUTHERN MID-ATLANTIC
THIS EVENING. CALM TO LIGHT N-NE FLOW WILL CONTINUE THIS EVENING AND HIGH
PRESSURE WILL BUILD INTO THE REGION FROM THE NORTHEAST OVERNIGHT.
AN AXIS OF 100-500 J/KG OF MUCAPE AND 30-35KTS EFF SHEAR IS
LOCATED NEAR THE SHENANDOAH VALLEY/BLUE RIDGE MTNS. SHOWERS AND
THUNDERSTORMS HAVE FORMED THIS EVENING AND SOME HAVE PRODUCED PEA
SIZE HAIL. AS THE ACTIVITY MOVES EASTWARD...LOSS OF INSTABILITY
AND WIND WILL CAUSE CONVECTION TO WANE TO SHOWERS AS THEY MOVE
EAST TOWARDS THE METROS. SHOWERS WILL END FROM WEST TO EAST
THROUGH THE NIGHT. LOW CEILINGS EXPECTED TONIGHT AND INTO
WEDNESDAY MORNING AS HIGH PRESSURE BUILDS INTO THE REGION.

CLOUDS WILL SLOWLY ERODE FROM SOUTH TO NORTH WEDNESDAY. THE
SHENANDOAH VALLEY AND CENTRAL FOOTHILLS WILL LIKELY SEE CLEARING
BY AFTERNOON WHERE EAST OF THE BLUE RIDGE STAYS CLOUDY FOR MUCH OF
THE DAY. A DEEP TROUGH WILL APPROACH THE MID- ATLANTIC WEDNESDAY.
A SFC TROUGH IS EXPECTED ACROSS THE SOUTHERN MID- ATLANTIC TO OHIO
VALLEY WEDNESDAY AFTERNOON AND SHOWERS ARE EXPECTED MAINLY WEST OF
THE BLUE RIDGE MTNS WHERE MORE HEATING DUE TO CLEARING IS
EXPECTED. A FEW THUNDERSTORMS ARE POSSIBLE IN THIS REGION. COLD
500 MB TEMPS WILL SPREAD INTO THE OH/TN VALLEY WEDNESDAY.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
A SHORTWAVE-TROUGH OVER THE WRN GREAT LKS WILL DIG INTO THE OH
VALLEY WED AND FORM A DEEP CLOSED LOW ALOFT. LARGE SCALE LIFT
INCREASES OVER THE AREA WED NIGHT WITH RAIN DEVELOPING NORTH OF
THE H5 LOW TRACK. A SWATH OF 1 TO 2 INCHES OF RAIN APPEARS LIKELY
ALONG AND WEST OF THE BLUE RIDGE MTNS WHERE MODELS SHOW A
CONVERGENT UPSLOPE NORTHEAST LOW-LEVEL FLOW SETTING UP. THIS
APPEARS A PROLONGED PERIOD OF MDT RAINS WHICH COULD RESULT IN SOME
FLOODING ISSUES GIVEN INCREASINGLY SOGGY CONDITIONS AND VERY SLOW
MOVEMENT OF PRECIP AREA. WE`LL NEED TO MONITOR RAINFALL TOTALS
OVER THE NEXT DAY OR SO.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
AN UPPER LEVEL DISTURBANCE WILL
MEANDER ABOUT THE NEW JERSEY COAST FRIDAY AND FRIDAY NIGHT. THE
CHANCE FOR RAIN SHOWERS WILL EXIST THROUGHOUT THE PERIOD.
TEMPERATURES WILL BE COOLER THAN NORMAL.

AS THE DISTURBANCE WEAKENS AND SLIDES SLIGHTLY TO THE NORTH...A
BRIEF RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE REGION
SATURDAY. CONDITIONS WILL BE TEMPORARILY DRY BEFORE THE NEXT
DISTURBANCE MOVES ACROSS THE GREAT LAKES...DRAGGING A COLD FRONT
SOUTHWARD INTO OUR REGION. THE RAIN CHANCES RETURN SATURDAY
NIGHT. TEMPERATURES WILL REMAIN COOLER THAN NORMAL.

THE CHANCE OF RAIN SHOWERS LINGER SUNDAY AND IN THE WEST SUNDAY
NIGHT WITH THE SURFACE FRONT AND AFFILIATED DISTURBANCE NEARBY.

THE FRONT WILL TRY TO MOVE NORTHWARD AS A WARM FRONT MONDAY
INTO TUESDAY. THIS WILL BRING BACK THREAT FOR SHOWERS OR A
THUNDERSTORM. THE BIGGER THREAT WILL BE TUESDAY. TEMPERATURES
WILL BE SLIGHTLY ABOVE NORMAL.

&&

.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
SHRA EXPECTED TO MOVE EASTWARD THIS EVENING. BRIEF PERIODS OF MVFR
EXPECTED IN HEAVIER SHRA HOWEVER ACTIVITY SHOULD WEAKEN AS IT
MOVES E TOWARDS DCA-BWI-MTN. IFR CIGS WILL MOVE INTO THE REGION
FROM THE NE TONIGHT. MVFR VSBYS ALSO EXPECTED INTO WED MORNING.

IFR CONDITIONS EXPECTED WEDNESDAY AS LOW CIGS SLOWLY ERODE FROM S
TO N... SHRA EXPECTED WED AFTERNOON WITH VCTS EXPECTED AT MRB/CHO.
SMALL HAIL AND GUSTY WINDS ARE POSSIBLE IN TS. SUB-VFR CONDITIONS
EXPECTED AGAIN WEDNESDAY NIGHT THROUGH THURSDAY.

MVFR TO IFR CONDITIONS WITH THE CHANCE OF RAIN SHOWERS FRIDAY INTO
FRIDAY NIGHT. WINDS NORTHWEST AROUND 10 KNOTS FRIDAY. WINDS
NORTHWEST 5 TO 10 KNOTS FRIDAY NIGHT.

&&

.MARINE...
E-NE WINDS EXPECTED ON THE WATERS TONIGHT INTO WEDNESDAY. A BRIEF
SURGE IS EXPECTED LATE TONIGHT AND SCA CONDITIONS ARE EXPECTED
FOR SOUTH OF POOLES ISLAND AND THE LOWER TIDAL POTOMAC. WINDS
SHOULD RELAX WEDNESDAY AND BECOME LESS THAN 10 KTS. THIS SHOULD
CONTINUE THROUGH THURSDAY. SHOWERS ARE EXPECTED TONIGHT.

SMALL CRAFT CONDITIONS LIKELY FRIDAY AS PRESSURE GRADIENT
TIGHTENS.


.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR ANZ531>534-
     537>543.

&&

$$
SYNOPSIS...LFR
NEAR TERM...HAS
SHORT TERM...LFR
LONG TERM...KLW
AVIATION...HAS/KLW
MARINE...HAS/KLW


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