Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 230123
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
923 PM EDT FRI APR 22 2016

.SYNOPSIS...
AN UPPER LEVEL LOW AND ASSOCIATED COLD FRONT WILL MOVE EAST
ACROSS THE AREA TONIGHT INTO SATURDAY MORNING. HIGH PRESSURE
WILL BUILD OVERHEAD SATURDAY AFTERNOON THROUGH SUNDAY MORNING
BEFORE SHIFTING OFFSHORE. A COLD FRONT WILL DROP SOUTH ACROSS THE
AREA TUESDAY. LOW PRESSURE MOVES EAST ACROSS THE MID-ATLANTIC
THURSDAY INTO FRIDAY.

&&

.NEAR TERM /THROUGH SATURDAY/...
AS OF 9PM...UPR LOW OVER OH WITH 1008MB SFC LOW OVER MAINE...AND
ANOTHER LOW AROUND 1011 MB IN NORTHERN GEORGIA. ONE COLD FRONT
CONTINUES TO MOVE SOUTHEAST...HAVING RECENTLY CLEARED PITTSBURGH
AND CINCINATTI. SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE IN
ADVANCE OF THIS FRONT AND ARE CURRENTLY PUSHING INTO VIRGINIA FROM
WEST VIRGINIA...AND CONTINUE ADVANCING EAST ACROSS MARYLAND.

THESE CELLS ARE STILL NOTABLY IN ADVANCE OF THE LOW...WHICH WON`T
CROSS THE AREA UNTIL MID-LATE MORNING SATURDAY. THIS MEANS WE WILL
CONTINUE TO SEE CLOUDS AND A THREAT OF SHOWERS THROUGH SATURDAY
MORNING BEFORE DRYING OCCURS IN THE SYSTEM`S WAKE SATURDAY
AFTERNOON. WHILE WE WILL LOSE INTENSITY OVERNIGHT...PARTICULARLY
WITH REGARD TO THUNDER...SHOWERS APPEAR LIKELY TO CONTINUE AS
FORCING WILL CONTINUE TO EXIST WITH THE UPPER LOW AND SURFACE
FRONT UNTIL THEY CROSS THE AREA LATER SATURDAY MORNING.

DRY NORTH WIND 10 TO 15 MPH (WITH 20 MPH GUSTS)
SATURDAY...WITH CLEARING IN THE AFTERNOON. MAX TEMPS 60S N/W OF
I-95 AND 70S NEAR AND S/E OF I-95.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
SFC HIGH BUILDS OVERHEAD FROM THE NW THROUGH SUNDAY MORNING
BEFORE SHIFTING OFF CAPE HATTERAS SUNDAY AFTERNOON. RETURN FLOW
ADVANCES WEST TO EAST WITH MAX TEMPS HIGHER WEST (MID 70S) VS EAST
(UPR 60S TO LOW 70S).

WARMER SUNDAY NIGHT (GENERALLY AROUND 50F) THAN SATURDAY NIGHT
(GENERALLY LOW TO MID 40S) DUE TO SLY FLOW SUNDAY NIGHT.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
HIGH PRESSURE OFFSHORE MONDAY...ALLOWING S/SE LOW-LEVEL FLOW TO
USHER IN WARM/MOIST AIRMASS...WITH T/TD PEAKING IN THE 80S/50S. WEAK
INSTABILITY DEVELOPS IN THE WAA DURING PEAK HEATING...THOUGH POOR
LAPSE RATES AND SLIGHT MID-LEVEL HEIGHT RISES MIGHT PREVENT ANY
SHOWER/STORM DEVELOPMENT. ATTM...CONFIDENCE TOO LOW TO INCLUDE ANY
POPS.

VERY WARM AGAIN TUESDAY AHEAD OF WEAK FRONT SAGGING SOUTH INTO THE
AREA. SHOWERS/T-STORMS POSSIBLE BY AFTERNOON ALONG THE
FRONT...THOUGH ECMWF FAR LESS BULLISH WITH QPF. BEST T-STORM CHANCES
EAST OF THE BLUE RIDGE...WHERE BETTER INSTABILITY IS FORECAST.
OVERALL...PRECIP AMOUNTS APPEAR RELATIVELY LIGHT WITH THIS SYSTEM.

HIGH PRESSURE NUDGES INTO THE AREA BRIEFLY BEHIND THE FRONT LATE
TUESDAY INTO WEDNESDAY...WITH FRONT LIFTING BACK NORTH AS A WARM
FRONT SOMETIME WEDNESDAY INTO THURSDAY. UNSETTLED WEATHER BY END OF
THE WEEK AS LOW PRESSURE MOVES TOWARD OUR AREA...THOUGH CONFIDENCE
IN TIMING/INTENSITY LOW ATTM.

&&

.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDS OVERALL THIS EVENING AS SHOWERS AND ISOLATED
THUNDERSTORMS CROSS THE AREA. MVFR CONDS IN HEAVIEST ACTIVITY.
MVFR CIGS POSSIBLE BEHIND COLD FRONT LATE TONIGHT AND SATURDAY
MORNING WITH CONTINUED SCATTERED RAIN SHOWERS. RETURNING TO VFR
SATURDAY AFTERNOON WITH CLEARING AS HIGH PRESSURE BUILDS IN. WINDS
VEER TO THE N BY SATURDAY MORNING BEHIND THE COLD FRONT. GUSTS UP
TO 20 KT POSSIBLE SATURDAY AFTERNOON.

VFR CONDITIONS EXPECTED SUN NIGHT THROUGH TUE. SHRA/TSRA LIKELY
WITH A COLD FRONTAL PASSAGE TUESDAY.

&&

.MARINE...
LIKELY SUB-SCA TONIGHT IN LULL JUST AHEAD OF FRONT WITHOUT GOOD
MIXING FROM SOLAR INSOLATION. ADDITIONAL ISOLATED THUNDERSTORMS
POSSIBLE THIS EVENING. HOWEVER...RIGHT NOW LOOKS LIKE WE ARE DONE
WITH ANY SMW`S.

N WINDS IN SCA RANGE THROUGH SAT NIGHT. WINDS SUBSIDE SUNDAY AS
HIGH PRESSURE MOVES ACROSS THE REGION.

SMALL CRAFT ADVZY CONDITIONS LIKELY MON-TUE IN STRONG WSW FLOW AND
BEHIND A CDFNT TUE.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EDT SATURDAY FOR ANZ530-
     531-535-536-538>540.
     SMALL CRAFT ADVISORY FROM 6 AM SATURDAY TO 6 AM EDT SUNDAY FOR
     ANZ532>534-537-541>543.

&&

$$
SYNOPSIS...BAJ
NEAR TERM...BAJ/RCM
SHORT TERM...BAJ
LONG TERM...MSE
AVIATION...BAJ/MSE/RCM
MARINE...BAJ/MSE/RCM



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