Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 091840
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
240 PM EDT WED APR 9 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVERHEAD THROUGH TONIGHT BEFORE MOVING OFF
THE COAST THURSDAY. A COLD FRONT WILL STALL OUT OVER THE AREA FRIDAY
AND A WAVE OF LOW PRESSURE WILL RIDE ALONG THE BOUNDARY...PASSING
THROUGH OUR AREA FRIDAY NIGHT. HIGH PRESSURE WILL RETURN FOR
SATURDAY BEFORE MOVING OFF THE COAST EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH THURSDAY/...
AN UPPER-LEVEL TROUGH IS MOVING THROUGH THE AREA THIS AFTERNOON.
COLD AIR ALOFT ASSOCIATED WITH THE TROUGH HAS CAUSED A BROKEN CU
DECK TO DEVELOP. A FEW SHOWERS ARE POSSIBLE AS WELL...ESPECIALLY
ACROSS CENTRAL VIRGINIA INTO THE POTOMAC HIGHLANDS. BREEZY
CONDITIONS WILL CONTINUE DUE TO A DEEP MIXING LAYER.

WINDS WILL QUICKLY DIMINISH AROUND SUNSET AND HIGH PRESSURE WILL
BUILD OVERHEAD TONIGHT AS THE UPPER-LEVEL TROUGH MOVES OFF TO OUR
EAST. DRY AND SEASONABLY CHILLY CONDITIONS ARE EXPECTED TONIGHT.

THE HIGH WILL MOVE OFF THE COAST THURSDAY AND A RETURN FLOW FROM THE
SOUTHWEST WILL DEVELOP. THE SOUTHWEST WIND WILL COMBINE WITH PLENTY
OF SUNSHINE TO USHER IN WARMER CONDITIONS. HOWEVER...IT WILL TURN
OUT BREEZY DURING THE AFTERNOON DUE TO A DEEP MIXING LAYER AND
TIGHTENING PRESSURE GRADIENT BETWEEN HIGH PRESSURE OFF THE COAST AND
A COLD FRONT MOVING INTO THE OHIO VALLEY. SOUTHWEST WINDS WILL GUST
AROUND 20 TO 30 MPH THURSDAY AFTERNOON. MAX TEMPS WILL RANGE FROM
THE 50S IN THE MOUNTAINS TO THE LOWER AND MIDDLE 70S IN THE
WASHINGTON METROPOLITAN AREA AS WELL AS CENTRAL VIRGINIA. A BAY
BREEZE WILL KEEP TEMPS A BIT COOLER ALONG THE WESTERN SHORE...WITH
MAX TEMPS GENERALLY IN THE 60S.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
SOUTHWEST 50 KT LOW LEVEL JET DEVELOPS OVERHEAD THURSDAY NIGHT AHEAD
OF APPROACHING TRAILING COLD FRONT ASSOCIATED WITH UPPER LOW OVER
HUDSON BAY. THIS FRONT LOSES MOMENTUM AND STALLS OVER THE REGION
FRIDAY/FRIDAY NIGHT. LOW PRESSURE DEVELOPS AND TRAVERSES THE FRONT
FRIDAY INTO FRIDAY NIGHT WITH SHORT WAVE IN FLOW ALOFT. SOME
INSTABILITY IS PRESENT BOTH NORTH OF THE SURFACE FRONT ACROSS E
WV/NORTHERN MD AND SOUTH OF THE SURFACE FRONT WHERE MLCAPES OF A
COUPLE HUNDRED J/KG ARE PRESENT FRIDAY AFTERNOON. HAVE INTRODUCED A
SCHC OF THUNDER ACCORDINGLY. FORECAST SOUNDINGS SHOW A THIN CAPE
PROFILE ALTHOUGH DEEP MIXING SOUTH OF THE FRONT COULD RESULT IN SOME
GUSTY WINDS WITH ANY SHOWERS/TSTMS. SOUNDING PROFILES ARE MORE
STABLE NORTH OF THE FRONT. AS SHORT WAVE EXITS ENE
SATURDAY...THERMAL RIDGE BEGINS TO BUILD ONCE AGAIN WITH WARM AIR
ADVECTION.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A STALLED FRONT WILL MOVE NORTH AS A WARM FRONT SATURDAY NIGHT.
ISOLATED SHOWERS CANNOT BE RULED OUT ALONG AND AHEAD OF THE WARM
FRONT SATURDAY NIGHT INTO EARLY SUNDAY.

TEMPERATURES TO THE SOUTH OF THE FRONT SHOULD REACH THE MIDDLE TO
UPPER 70S...WHILE TEMPERATURES TO THE NORTH OF THE FRONT WILL ABOUT
5 TO 10 DEGREES COOLER. DEWPOINT TEMPERATURES ARE EXPECTED TO BE IN
THE 50S SATURDAY NIGHT INTO SUNDAY.

A LOW PRESSURE SYSTEM WILL CONNECT TO THE WEST END OF THE WARM FRONT
ACROSS THE LOWER GREAT LAKES SUNDAY INTO SUNDAY NIGHT BEFORE MOVING
TO NEW ENGLAND SUNDAY NIGHT.

THIS LOW SHOULD HAVE A TRAILING COLD FRONT...AS WELL. THE FRONT
WOULD FOLLOW SUIT LIKE THE PREVIOUS FRONT AND PUSH TO OUR SOUTH
MONDAY AND MONDAY NIGHT. ADDITIONAL SHOWERS AND THUNDERSTORMS COULD
FORM ALONG THE FRONT AS AN APPROACHING UPPER LEVEL STORM SYSTEM
MOVES TOWARD THE REGION AND FORMS A SURFACE LOW ON TUESDAY.

HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT ON WEDNESDAY. COOLER
TEMPERATURES ARE EXPECTED TUESDAY INTO WEDNESDAY.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS ARE EXPECTED THROUGH THURSDAY. A BKN CU DECK AROUND
5KFT WILL DISSIPATE WITH THE LOSS OF DAYTIME HEATING TOWARD SUNSET.
A COUPLE SHOWERS CANNOT BE RULED OUT THIS AFTERNOON...ESPECIALLY
ACROSS KCHO. NORTHWEST WINDS WILL GUST AROUND 20 KNOTS THIS
AFTERNOON BEFORE DIMINISHING TOWARD SUNSET. WINDS WILL BE LIGHT
TONIGHT BEFORE SHIFTING TO THE SOUTHWEST AND GUSTING AROUND 20 TO 25
KNOTS THURSDAY AFTERNOON.

AREAS OF MVFR RESTRICTIONS MAY BE PRESENT FRIDAY/FRIDAY NIGHT DUE
TO SHOWERS AND POSSIBLE ISOLATED TSTMS ALONG A SLOW MOVING COLD
FRONT.

HIGH PRESSURE WILL BUILD OVER THE TERMINALS SATURDAY BEFORE MOVING
OFF THE COAST SUNDAY. A SOUTHERLY FLOW WILL INCREASE AHEAD OF A
COLD FRONT EARLY NEXT WEEK.

&&

.MARINE...
A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE WATERS THROUGH LATE THIS
AFTERNOON. WINDS WILL DIMINISH BY SUNSET AND HIGH PRESSURE BUILDING
OVER THE WATERS WILL ALLOW FOR LIGHT WINDS TONIGHT.

A COUPLE SHOWERS/SPRINKLES MAY DEVELOP THIS AFTERNOON. LOCALLY GUSTY
WINDS ARE POSSIBLE IN ANY SHOWERS OR SPRINKLES DUE TO DRY AIR NEAR
THE SURFACE.

THE HIGH WILL MOVE OFF THE COAST THURSDAY AND A RETURN FLOW FROM THE
SOUTH WILL DEVELOP. A DEEP MIXING LAYER AND TIGHTENING PRESSURE
GRADIENT WILL CAUSE THE POTENTIAL FOR GUSTY WINDS AROUND 20 TO 25
KNOTS. A SMALL CRAFT ADVISORY IS IN EFFECT THURSDAY AFTERNOON FOR
THE NORTHERN PORTION OF THE MARYLAND CHESAPEAKE BAY AND THE UPPER
TIDAL POTOMAC RIVER. FARTHER SOUTH...THE GRADIENT MAY NOT BE AS
STRONG AND THE RELATIVELY COOLER WATERS MAY PREVENT THE DEEP MIXING
LAYER FROM DEVELOPING. THEREFORE...WINDS HAVE BEEN CAPPED AROUND 15
KNOTS FOR NOW.

SCA CONDITIONS ARE EXPECTED WITH SOUTHWEST WINDS THURSDAY
NIGHT AHEAD OF AN APPROACHING COLD FRONT. SCA CONDITIONS MAY BE MET
AGAIN AS WINDS INCREASE FRIDAY AFTERNOON SOUTH OF A COLD FRONT.
HIGH PRESSURE WILL BUILD OVERHEAD SATURDAY BEFORE MOVING OFF THE
COAST EARLY NEXT WEEK.



&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
     ANZ530>543.
     SMALL CRAFT ADVISORY FROM NOON THURSDAY TO 6 AM EDT FRIDAY FOR
     ANZ530>532-538>540.
     SMALL CRAFT ADVISORY FROM 6 PM THURSDAY TO 6 AM EDT FRIDAY FOR
     ANZ533-534-537-541>543.
     SMALL CRAFT ADVISORY FROM NOON TO 8 PM EDT THURSDAY FOR ANZ535-
     536.

&&

$$
SYNOPSIS...BJL
NEAR TERM...BJL
SHORT TERM...AEB
LONG TERM...KLW
AVIATION...BJL/KLW
MARINE...BJL/KLW







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