Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 260111
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
911 PM EDT MON APR 25 2016

.SYNOPSIS...
HIGH PRESSURE WILL MOVE FURTHER OFFSHORE THROUGH TUESDAY. A COLD
FRONT OVER ILLINOIS WILL CROSS THE AREA TUESDAY EVENING. HIGH
PRESSURE BUILDS INTO THE AREA TUESDAY NIGHT THROUGH EARLY
THURSDAY. ANOTHER COLD FRONT IS EXPECTED THURSDAY NIGHT. HIGH
PRESSURE BUILDS IN FOR THE WEEKEND.

&&

.NEAR TERM /THROUGH TUESDAY/...

HIGH PRESSURE MOVES FURTHER OFF THE COAST TONIGHT AS LOW PRESSURE
MOVES ACROSS THE GREAT LAKES. AN ASSOCIATED FRONTAL BOUNDARY OVER
NRN PA WILL SLOWLY APPROACH THE MID-ATLANTIC RGN. MOST SHOWERS
ARE EXPECTED NORTH OF THE MD/PA BORDER OVERNIGHT. KEPT CHANCES
LOW.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
AN ACTIVE PERIOD BEGINS TUESDAY AS THE FRONT MOVES SOUTHWARD ACROSS
PA. THE MID-ATLANTIC WILL BE IN THE WARM SECTOR WITH BREEZY SW FLOW
DURING THE DAY. TEMPS WILL CLIMB INTO THE 80S. SW FLOW WILL ALSO
DRIVE DEWPTS UP ON TUESDAY SO IT WILL FEEL WARMER. AN UPPER LEVEL
WIND MAX WILL DIVE SOUTHWARD BY TUESDAY AFTERNOON AND 0-6KM BULK
SHEAR WILL INCREASE TO 30-40KTS. THIS COUPLED WITH SBCAPE OF 1-2K
K/JG WILL RESULT IN CONVECTIVE DEVELOPMENT. THE BEST FORCING SEEMS
TO BE ACROSS PA WITH SOME ACTIVITY DROPPING INTO MD SO THE BEST
CHANCE FOR STRONG TO SEVERE STORMS TUESDAY WILL LIKELY BE IN THE
NRN HALF OF THE LWX CWA.

THE FRONT SINKS SOUTHWARD TUESDAY NIGHT AND NRLY WINDS WILL MOVE IN
BEHIND. SHOWERS WILL DIMINISH OVERNIGHT HOWEVER THERE WILL STILL BE
OVERRUNNING ALONG THE FRONT AND A FEW SHOWERS WILL BE POSSIBLE INTO
WEDNESDAY MORNING. AS THE NEXT SYSTEM APPROACHES WEDNESDAY HIGH
PRESSURE WILL LIKELY GET WEDGED ACROSS THE EASTERN HALF OF THE
REGION RESULTING IN A COOL AND CLOUDY DAY. HIGH TEMPS WILL BE ABOUT
15 DEG COOLER WEDNESDAY THAN TUESDAY. THE WEDGE OF HIGH PRESSURE
WILL LIKELY PERSIST WED NIGHT AS SHOWERS MOVE INTO THE REGION FROM
THE WEST.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
A WARM FRONT WILL MOVE NORTHWARD ACROSS THE MID ATLANTIC REGION
THURSDAY...BRINGING AN INCREASED CHANCE OF SHOWERS AND A FEW
THUNDERSTORMS. HIGH PRESSURE PERSISTENTLY TO THE NORTH OF THE
FRONT WILL KEEP THE THUNDERSTORM THREAT MAINLY TO THE CENTRAL AND
SOUTHERN SHENANDOAH VALLEY.

AN AREA OF LOW PRESSURE WILL CONNECT TO THE WARM FRONT NEAR
WESTERN VIRGINIA...ALLOWING FOR THE CHANCE OF RAIN SHOWERS TO
LINGER THURSDAY NIGHT.

SOME MID LEVEL ENERGY IS EXPECTED TO PUSH EAST ACROSS THE LOWER
GREAT LAKES AND ALONG THE MASON-DIXON LINE FRIDAY. ADDITIONAL
RAIN SHOWERS AND A THUNDERSTORM OR TWO CANNOT BE RULED OUT WITH
THIS PASSING DISTURBANCE.

WET CONDITIONS SHOULD BRIEFLY DRY OUT FRIDAY NIGHT AND SATURDAY AS
HIGH PRESSURE BECOMES WEDGED ALONG THE EASTERN SLOPES OF THE
APPALACHIAN MOUNTAINS. COOLER TEMPERATURES WILL DEVELOP.

THE THREAT FOR SHOWERS AND A FEW THUNDERSTORMS WILL MOVE BACK INTO
THE REGION SATRUDAY NIGHT AND SUNDAY AS THE NEXT MODEST MID LEVEL
DISTURBANCE PIVOTS ACROSS THE OHIO AND TENNESSEE VALLEYS. AT THIS
POINT...IT APPEARS THAT THE BEST CHANCE FOR RAIN WILL BE IN THE
POTOMAC HIGHLANDS AND ACROSS THE VIRGINIA PIEDMONT.

THE MAIN DISTURBANCE WILL SLOWLY MOVE ACROSS THE REGION LATER SUNDAY
NIGHT INTO MONDAY. THE EUROPEAN MODEL TAKES THE SURFACE LOW WELL
NORTH ACROSS NORTHERN PENNSYLVANIA BEFORE MOVING EAST...WHILE THE
GFS MODEL KEEPS THE LOW ACROSS THE VIRGINIAS. THERE IS A LIKELIHOOD
OF ENCOUNTERING SHOWERS AND PERHAPS A FEW THUNDERSTORMS. THE
SEVERITY OF THE THUNDERSTORMS WILL DEPEND ON HOW FAR NORTH WILL THE
SURFACE LOW TRACK.

&&

.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS TONIGHT. LIGHT S WINDS BECOME SW TUESDAY WITH
GUSTS UP TO 25 KTS TUE AFTERNOON. SHRA EXPECTED FROM NORTH TO
SOUTH TUESDAY WITH THE POTENTIAL FOR TSRA. HIGHER GUSTS EXPECTED
IN SHRA/TSRA TUESDAY. BEST CHANCE FOR TSRA WILL BE ACROSS THE
NORTH...MRB/IAD/MTN/BWI. FRONT WILL CROSS THE REGION FROM N TO S
TUESDAY AND WINDS WILL BECOME N BEHIND FRONT AND INTO WEDNESDAY.

SUB-VFR CIGS POSSIBLE WED-WED NIGHT AS NE FLOW INCREASES AT THE
SFC.

IFR TO LIFR CONDITIONS POSSIBLE WITH SHOWERS AND PERHAPS A FEW
THUNDERSTORMS THURSDAY INTO THURSDAY EVENING. THERE MAY BE A
BRIEF PERIOD OF MVFR CONDITIONS THURSDAY OVERNIGHT. WINDS EAST 5
KNOTS THURSDAY. WINDS BECOMING NORTHEAST 5 KNOTS THURSDAY NIGHT.

&&

.MARINE...
WINDS WILL STRENGTHEN OVERNIGHT. SCA CONDITIONS EXPECTED SOUTH OF
SANDY PT AND THE LOWER TIDAL POTOMAC. SHOWERS ARE EXPECTED TO
CROSS THE WATERS FROM NORTH TO SOUTH TUESDAY. THERE IS A CHANCE OF
THUNDERSTORMS AS WELL. ACTIVITY IS EXPECTED TO PRODUCE GUSTY WINDS
ON THE WATERS AND SMW MAY BE WARRENTED. A SCA IS IN EFFECT FOR ALL
THE WATERS TUESDAY.

SHOWERS MOVE SOUTH TUES NIGHT AND GUSTY WINDS WILL DIMINISH INTO
THE EVENING. WINDS BECOME NRLY LATE TUESDAY AND SCA ARE LIKELY. AT
THIS TIME...CONFIDENCE IS LOW ON THE TIMING OF THE GUSTY WINDS DUE
TO NRLY FLOW.

NE WINDS EXPECTED WEDNESDAY AND LOOK BELOW SCA CONDITIONS.

NO MARINE HAZARDS EXPECTED THURSDAY AND THURSDAY NIGHT.

&&

.TIDES/COASTAL FLOODING...
ANOMALIES WILL STAY ELEVATED TONIGHT THROUGH TUESDAY. THE MRNG HIGH
TIDE WILL NEED TO BE WATCHED MAINLY FROM ANNAPOLIS NORTH.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 9 PM EDT TUESDAY FOR ANZ530-
     531-535-536-538-539.
     SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 9 PM EDT TUESDAY
     FOR ANZ532>534-537-540>543.

&&

$$
UPDATE...WOODY!
PRVS...HAS/KLW



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