Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 280103
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
903 PM EDT MON OCT 27 2014

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OFFSHORE THROUGH TUESDAY. A COLD FRONT
WILL PASS THROUGH THE AREA WEDNESDAY AND HIGH PRESSURE WILL RETURN
FOR THURSDAY AND FRIDAY. ANOTHER COLD FRONT WILL PASS THROUGH THE
AREA FRIDAY NIGHT AND CANADIAN HIGH PRESSURE WILL BUILD OVERHEAD
DURING THE WEEKEND.

&&

.NEAR TERM /THROUGH TUESDAY/...
CENTER OF HIGH PRESSURE HAS SHIFTED OFFSHORE. SOUTHERLY FLOW IS IN
PLACE...AND WARM ADVECTION ALOFT IS UNDERWAY. LOW LEVELS ARE STILL
PRETTY DRY...BUT WITH WARM ADVECTION WILL SEE SOME CIRRUS INCREASE
FROM THE WEST LATE TONIGHT. WARM ADVECTION WILL ALSO KEEP IT FROM
GETTING AS CHILLY LAST NIGHT. NO FROST CONCERNS TONIGHT. RE-
POPULATED MINIMA USING A BLEND OF BIAS CORRECTED MET/SREFS WITH AN UPWARD
ADJUSTMENT OF A DEGREE OR TWO IN DOWNTOWN WASHINGTON/BALTIMORE.

WARM ADVECTION CONTINUES TUESDAY. THERE WILL BE MORE CIRRUS...BUT
MUCH OF THE DAY WILL LIKELY BE MOSTLY SUNNY. VERY WARM
TEMPERATURES /FOR LATE OCTOBER/ ARE EXPECTED WITH UPPER 70S TO
LOWER 80S EXPECTED. THIS WILL BE 10 TO 15 DEGREES ABOVE NORMAL
FOR THIS TIME OF THE YEAR.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AN UPPER LEVEL TROUGH WILL APPROACH THE GREAT LAKES TUESDAY NIGHT. A
DEEP SFC LOW WILL BE RETREATING TOWARDS HUDSON BAY WHILE A COLD
FRONT APPROACHES FROM THE OHIO VALLEY. A CONFINED AREA OF
MOISTURE WITH THE COLD FRONT IS EXPECTED TO MOVE INTO THE POTOMAC
HIGHLANDS BY LATE TUESDAY NIGHT. IT WILL MAKE A EASTWARD
PROJECTION ACROSS THE MID-ATLANTIC THROUGH WEDNESDAY MORNING.
SHOWERS ARE EXPECTED ALONG THE FRONT BUT AMTS SHOULD BE LESS THAN
A QUARTER INCH.

THE COLD FRONT WILL MOVE INTO SOUTHERN VA BY WED AFTERNOON. DRIER
AIR WILL MOVE INTO THE MID-ATLANTIC FROM THE NORTHWEST AND CLOUDS
WILL DIMINISH BY EVENING. HIGH PRESSURE WILL APPROACH FROM THE
MIDWEST THURSDAY. A SHORTWAVE TROUGH WILL DROP INTO THE OHIO
VALLEY THURSDAY AND CLOUDS SHOULD INCREASE FROM THE WEST THURSDAY
AFTERNOON.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
UPPER LEVEL TROUGHING WILL AFFECT THE CWA THROUGH SUNDAY. HIGH
PRESSURE RIDGING RETURNING SUNDAY. SHORTWAVE FROM CENTRAL CANADA
SWEEPING INTO NEW ENGLAND BY LATE SATURDAY.

WEAK SURFACE HIGH PRESSURE WILL BUILD IN FROM THE WEST ON THURSDAY.
POLAR COLD FRONT IS EXPECTED TO USHER IN THE COLDEST TEMPERATURES SO
FAR THIS FALL DURING THE WEEKEND. BREEZY CONDITIONS ARE POSSIBLE
AS GRADIENT TIGHTENS BETWEEN HIGH APPROACHING FROM THE WEST AND
LOW CENTER OVER NEW ENDLAND DURING THE LATTER HALF OF THE PERIOD.
ALTHOUGH WENT HIGHER THAN DETERMINISTIC GUIDANCE FOR SATURDAY
TEMPERATURES DO EXPECT WEEKEND TEMPERATURES TO BE COLDER THAN
NORMAL.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE IS OFFSHORE. SOUTHERLY WINDS WILL PREVAIL THROUGH
TUESDAY...INCREASING TO 8 TO 12 KT DURING THE DAYTIME. NO FLIGHT
RESTRICTIONS DURING THE TAF VALID PERIOD...ONLY INCREASING CIRRUS
LATE TONIGHT INTO TUESDAY.

A COLD FRONT WILL APPROACH THE MID-ATLANTIC TUESDAY AND CLOUDS
WILL INCREASE FROM WEST TO EAST TUESDAY NIGHT THROUGH WEDNESDAY.
SHRA ARE POSSIBLE ALONG FRONT. MVFR CONDITIONS POSSIBLE DURING
THIS TIME. HIGH PRESSURE MOVES INTO THE REGION FOR THE END OF
THE WORK WEEK.

&&

.MARINE...
WILL HAVE TO WATCH SOUTHERLY WINDS TONIGHT FOR ENHANCEMENT UP THE
BAY DUE TO CHANNELLING. PREVAILING 10 TO 15 KT IS EXPECTED
OVERNIGHT...BUT ITS NOT OUT OF THE QUESTION THAT A SCA MAY BE
NEEDED AND WILL CONTINUE TO MONITOR OBS. SCA ALREADY IN EFFECT FOR
TUESDAY FOR 20 KT GUSTS.

COLD FRONT IS EXPECTED TO CROSS WEDNESDAY MORNING. A SMALL CRAFT
ADVISORY MAY BE NEEDED FOR PORTIONS OF THE WATERS AHEAD OF THE
FRONT TUESDAY NIGHT...AND AGAIN WITH A PRESSURE SURGE BEHIND THE
FRONT LATE WEDNESDAY NIGHT INTO THURSDAY.

GRADIENT BETWEEN APPROACHING HIGH AND LOW OVER NEW ENGLAND MAY
GENERATE NORTH TO NORTHWEST GUSTS 20 TO 25 KTS SATURDAY AFTERNOON.

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 6 PM EDT TUESDAY FOR ANZ530-
     531-535-536-538-539.
     SMALL CRAFT ADVISORY FROM 10 AM TUESDAY TO 2 AM EDT WEDNESDAY
     FOR ANZ542.
     SMALL CRAFT ADVISORY FROM 6 AM TUESDAY TO 2 AM EDT WEDNESDAY
     FOR ANZ532>534-537-540-541-543.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 6 PM EDT TUESDAY FOR ANZ530-
     531-535-536-538-539.
     SMALL CRAFT ADVISORY FROM 10 AM TUESDAY TO 2 AM EDT WEDNESDAY
     FOR ANZ542.
     SMALL CRAFT ADVISORY FROM 6 AM TUESDAY TO 2 AM EDT WEDNESDAY
     FOR ANZ532>534-537-540-541-543.

&&

$$
SYNOPSIS...BPP/HAS
NEAR TERM...BPP
SHORT TERM...HAS
LONG TERM...CEM
AVIATION...BPP/HAS
MARINE...BPP/HAS/CEM







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