Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 150103
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
903 PM EDT TUE APR 14 2015

.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL PASS BY TO OUR SOUTH THIS EVENING.
HIGH PRESSURE WILL BUILD IN BEHIND THIS SYSTEM FOR WEDNESDAY INTO
THURSDAY BEFORE MOVING OFF THE COAST LATE IN THE WEEK. A COLD
FRONT WILL PASS THROUGH LATE SATURDAY INTO SUNDAY.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
...UPDATE TO MARINE SECTION BELOW FOR ADJUSTMENT TO SMALL CRAFT
ADVISORY...

MSAS AND SURFACE ANALYSIS INDICATES COLD FRONT AND
ACCOMPANYING WAVES OF LOW PRESSURE HAVE DROPPED INTO THE VA
TIDEWATER AND NC THIS EVENING. RAINFALL IS TRENDING LIGHTER WITH
LESS AERIAL COVERAGE...ALTHOUGH ISOLATED BRIEF HEAVIER RAIN
REMAINS POSSIBLE THIS EVENING. FLOOD WATCH OVER PORTIONS OF THE
HIGHLANDS AND CENTRAL SHENANDOAH VALLEY HAS BEEN CANCELLED.

DURING THE OVERNIGHT HOURS LOW PRESSURE WILL BECOME MORE ORGANIZED
OFFSHORE...AND THE COLD FRONT WILL DROP FURTHER SOUTH...WHILE WEAK
HIGH PRESSURE NOSES INTO THE REGION FROM THE NORTH. A FEW LINGER
LIGHT RAIN SHOWERS REMAIN POSSIBLE...SO AT LEAST SLIGHT CHANCE
POPS REMAIN IN THE FCST. EXPECTING TEMPS TO GRADUALLY FALL INTO
THE 40S...WITH A FEW LOW 50S.

FOR WED...HIGH PRESSURE WILL BUILD TOWARD THE LOWER GREAT
LAKES...WEDGING DOWN THE EASTERN SIDE OF THE APPALACHIANS. A SHORT
WAVE RIDGE ALOFT WILL ALSO TRAVERSE THE AREA. ADJUSTED POPS DOWNWARD
AS THE AIRMASS IS LOOKING FAIRLY DRY. THE ONLY EXCEPTION MAY BE IF
THE LOW LEVEL EASTERLY FLOW IS ABLE TO FORCE SOME LIGHT UPSLOPE
PRECIP IN THE SOUTHERN MOUNTAINS. AMOUNT OF CLEARING IS
QUESTIONABLE...AND THERE MAY ALSO BE A GOOD DEAL OF MID/HIGH CLOUDS.
COMBINED WITH THE CAD SIGNATURE...UNDERCUT TEMP GUIDANCE BY SEVERAL
DEGREES. FORECAST HIGHS RANGE FROM THE UPPER 50S TO MID 60S.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
HIGH PRESSURE BOTH AT THE SURFACE AND ALOFT WILL BUILD OVERHEAD
WEDNESDAY NIGHT. A NORTHERLY FLOW WILL ALLOW FOR SEASONABLY CHILLY
CONDITIONS. MIN TEMPS WILL RANGE FROM THE UPPER 30S AND LOWER 40S
IN NORTHERN MARYLAND TO THE UPPER 40S/NEAR 50 IN DOWNTOWN
WASHINGTON AND BALTIMORE.

THE HIGH ALOFT AND AT THE SURFACE WILL MOVE OFF THE COAST
THURSDAY. AN UPPER-LEVEL DISTURBANCE WILL MOVE IN FROM THE
SOUTHWEST THURSDAY AFTERNOON. HIGH AND MID-LEVEL CLOUDS WILL
INCREASE...BUT MOST AREAS SHOULD BE DRY. THE ONE EXCEPTION WILL BE
ACROSS CENTRAL VIRGINIA INTO THE POTOMAC HIGHLANDS...WHERE A FEW
SHOWERS ARE POSSIBLE ESPECIALLY LATER IN THE AFTERNOON. EVEN
ACROSS THESE AREAS MOST OF THE TIME WILL BE DRY AND PRECIPITATION
WILL BE LIGHT.

THE UPPER-LEVEL DISTURBANCE WILL SWING THROUGH THE AREA THURSDAY
NIGHT AND SOUTHEAST WINDS WILL CONTINUE TO USHER IN MORE MOISTURE
OFF THE ATLANTIC. RAIN IS POSSIBLE AS A RESULT...ESPECIALLY ACROSS
THE SOUTHWESTERN PORTION OF THE CWA WHERE GUIDANCE IS MOST
CONFIDENT AND MOISTURE WILL BE DEEPER. HOWEVER...RAIN MAY
OVERSPREAD THE WASHINGTON AND BALTIMORE METROPOLITAN AREAS AS WELL
AS EASTERN MARYLAND. PRECIPITATION AMOUNTS WILL BE LIGHT. WILL
HAVE TO WATCH FOR LOW PRESSURE THAT WILL DEVELOP OFF THE SOUTHEAST
COAST...BUT AS OF NOW IT APPEARS THAT IT WILL BE TOO FAR TO OUR
SOUTH TO IMPACT OUR WEATHER. IF IT DOES DEVELOP FURTHER
NORTH...THEN A STEADIER RAIN WOULD DEVELOP OVER OUR AREA.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
HIGH PRESSURE WILL REMAIN OFF THE COAST FRIDAY THROUGH SATURDAY. A
COLD FRONT WILL APPROACH THE AREA SATURDAY BEFORE PASSING THROUGH
SATURDAY NIGHT INTO SUNDAY. SHOWERS ARE POSSIBLE DURING THIS TIME.
THE FRONT WILL STALL OUT JUST TO OUR SOUTH EARLY NEXT WEEK AND LOW
PRESSURE MAY DEVELOP ALONG THE FRONT...BRINGING UNSETTLED
CONDITIONS DURING THIS TIME.

&&

.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
LIGHT RAIN REMAINS OVER THE TERMINALS THIS EVENING...BUT AS OF 00Z
TAF ISSUANCE IS LIGHT ENOUGH TO KEEP VFR CIGS/VSBYS. RAIN IS
EXPECTED TO END BY LATE EVENING...ALTHOUGH THERE REMAINS A CHANCE
FOR OCCASIONAL LIGHT RAIN OVERNIGHT. AMENDMENTS POSSIBLE FOR THIS.
LIGHT N-NE WINDS EXPECTED.

VFR CONDITIONS EXPECTED WED. WINDS WILL BE N TO NE AT 10KT OR
LESS.

HIGH PRESSURE OVERHEAD WEDNESDAY NIGHT WILL ALLOW FOR LIGHT WINDS.
THE HIGH WILL MOVE OFF THE COAST THURSDAY AND THURSDAY NIGHT.
SOUTHEAST WINDS ARE EXPECTED. SOUTHERLY WINDS MAY GUST AROUND 20
KNOTS THURSDAY. RAIN MAY OVERSPREAD THE TERMINALS LATE THURSDAY OR
THURSDAY NIGHT. CONFIDENCE IN TIMING IS LOW...BUT IT DOES APPEAR
THAT PRECIPITATION AMOUNTS WILL BE LIGHT. HOWEVER...SUBVFR CIGS
AND VSBYS ARE POSSIBLE...ESPECIALLY THURSDAY NIGHT.

SUBVFR CONDITIONS MAY CONTINUE FRIDAY INTO SATURDAY AS SOUTHERLY
WINDS USHER IN MORE MOISTURE ACROSS THE AREA

&&

.MARINE...
SCA HAS BEEN CANCELLED FOR CHESAPEAKE BAY FROM SANDY POINT TO
NORTH BEACH. WINDS HAVE DROPPED BELOW SCA CRITERIA. MARGINAL
CONDITIONS EXIST FURTHER SOUTH ON THE BAY AND THE LOWER TIDAL
POTOMAC. IT IS POSSIBLE THAT GUSTS IN THESE ZONES MAY DIMINISH TO
15KT OR LESS FOR A WHILE TONIGHT AND THEN RE-STRENGTHEN LATE
TONIGHT AS LOW PRESSURE BECOMES MORE ORGANIZED OVER THE WRN
ATLANTIC.

LIGHT RAIN REMAINS OVER MOST OF THE WATERS...BUT IS EXPECTED TO
GRADUALLY DIMINISH DURING THE EVENING AND OVERNIGHT HRS. BY
WED...EXPECT NORTHERLY WINDS GENERALLY LESS THAN 15 KT.

HIGH PRESSURE OVERHEAD WEDNESDAY NIGHT WILL MOVE OFF THE COAST
THURSDAY THROUGH THURSDAY NIGHT. SOUTHEAST WINDS ARE EXPECTED
DURING THIS TIME. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR
PORTIONS OF THE WATERS THURSDAY. HIGH PRESSURE WILL REMAIN OFF THE
COAST FRIDAY AND A COLD FRONT WILL PASS THROUGH LATE SATURDAY INTO
SUNDAY. UNSETTLED CONDITIONS ARE POSSIBLE DURING THIS TIME.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR ANZ533-534-
     537-541>543.

&&

$$
SYNOPSIS...BJL
NEAR TERM...ADS/KCS
SHORT TERM...BJL
LONG TERM...DFH
AVIATION...BJL/KCS/DFH
MARINE...BJL/ADS/KCS/DFH


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