Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 290845
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
345 AM EST SAT NOV 29 2014

.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFFSHORE TODAY. A WARM FRONT IS EXPECTED
TO LIFT TO THE NORTH TONIGHT. A COLD FRONT WILL THEN MOVE THROUGH
THE REGION ON MONDAY WITH HIGH PRESSURE BUILDING OVER NEW ENGLAND
ON TUESDAY.

&&

.NEAR TERM /THROUGH SUNDAY/...
HAVE HAD A FEW SNOW SHOWERS ACROSS WESTERN MD/EASTERN WV
OVERNIGHT...BUT THEY HAVE THUS FAR DISSIPATED AFTER CROSSING THE
BLUE RIDGE WHERE THE AIR IS ALSO DRIER AND PRESUMABLY THERE IS SOME
SUBSIDENCE IN PLACE WITH HIGH PRESSURE CENTERED ALONG THE EASTERN
SEABOARD. SCATTERED SNOW SHOWERS/FLURRIES WILL CONTINUE OVER THE
NEXT FEW HOURS IN THE NORTHWEST CORNER OF THE CWA /WITH LOCALIZED
VISIBILITY RESTRICTIONS AND A COATING OF ACCUMULATION/ BEFORE
DIMINISHING. A FEW FLURRIES COULD EVEN MAKE IT EAST OF THE BLUE
RIDGE INTO MARYLAND BUT NO ACCUMULATION IS EXPECTED HERE.

HIGH PRESSURE MOVES FURTHER OFFSHORE DURING THE DAY TODAY. WARM
ADVECTION REGIME WILL BE UNDERWAY ACROSS THE MID-ATLANTIC. RESULT
WILL BE PLENTY OF CLOUDS AND THE BEGINNING OF TEMPERATURE
MODERATION. WENT A LITTLE BIT ABOVE MOS...USING A BLEND OF BIAS
CORRECTED ADJMAV/SREFS FOR MAXIMA.

WARM ADVECTION CONTINUES TONIGHT...AND A WARM FRONT WILL LIFT NORTH
THROUGH THE CWA. MODERATING TEMPERATURES CONTINUE THROUGH
SUNDAY...WITH MAXIMA ON SUNDAY LIKELY RISING INTO THE 50S POSSIBLY
EVEN HITTING 60 ACROSS THE VIRGINIA PIEDMONT. CLOUDS MAY ALSO SHIFT
MORE NORTHWEST INTO SUNDAY...AND HAVE STRATIFIED THE CWA FROM MOSTLY
CLOUDY NORTHWEST/PARTLY SUNNY SOUTHEAST. NORTHWEST CWA PARTICULARLY
ALONG THE POTOMAC HIGHLANDS WILL ALSO HAVE A CHANCE OF RAIN SHOWERS
ON SUNDAY BUT REST OF THE CWA SHOULD BE DRY.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
ON SUNDAY NIGHT A COLD FRONT WILL EXTEND SOUTHWESTWARD FROM LOW
PRESSURE TRACKING TOWARD LABRADOR. THE FRONT WILL BE LOSING MOMENTUM
AS IT BECOMES MORE PARALLEL TO THE UPPER FLOW. HOWEVER SOME MOISTURE
WILL BE DRAWN NORTHWARD AROUND HIGH PRESSURE OVER THE SOUTHEASTERN
STATES...AND THIS MAY FEED SHOWERS NEAR AND WEST OF THE APPALACHIAN
CREST. TEMPERATURES WILL ONLY FALL INTO THE 40S OVERNIGHT...SO
PRECIPITATION SHOULD BE RAIN. THE FRONT WILL CONTINUE SOUTHWARD ON
MONDAY. CURRENT FORECAST OF FRONTAL TIMING ALLOWS TEMPERATURES TO
WARM BEFORE PASSAGE...MORE SO SOUTH OF US-50 WHERE 60S COULD BE
REALIZED IN THE NORTH CENTRAL VA PIEDMONT. WITH WSW FLOW
ALOFT...MOISTURE EAST OF THE MOUNTAINS WILL BE LIMITED AND POPS ARE
KEPT IN THE 20-30 PERCENT RANGE.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MODEL SPREAD INCREASES MONDAY NIGHT AS THE FRONT STALLS SOUTH OF THE
AREA AND HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES. IT LOOKS LIKE
THE SURFACE FRONT WILL CLEAR THE AREA...USHERING IN DRIER AND COLDER
AIR...BUT THE MID LEVEL FRONT REMAINS NEARBY. A WAVE OF LOW PRESSURE
WILL RIDE ALONG THE FRONT...WITH SOUTHERLY FLOW AND OVERRUNNING
PRECIPITATION DEVELOPING. THE TIMING AND PLACEMENT OF THIS WAVE
REMAINS LOW CONFIDENCE...BUT PTYPE ISSUES COULD COME INTO PLAY WITH
STRONG HIGH PRESSURE OVER NORTHERN NEW ENGLAND IN A FAVORABLE COLD
AIR DAMMING SET UP. OVERALL QPF IS LIGHT...BUT THE MONDAY NIGHT TO
TUESDAY NIGHT TIME FRAME WILL BE A PERIOD TO WATCH CLOSELY.

THE HIGH WILL MOVE FARTHER EAST ON WEDNESDAY...ALLOWING THE SURFACE
WARM FRONT TO LIFT NORTH AND RETURN TEMPERATURES CLOSER TO NORMAL.
NORTHERN BRANCH OF THE JET STREAM REMAINS OVER CANADA WHICH MEANS
THE NEXT LOW PRESSURE SYSTEM TRACKS WELL TO THE NORTH AS WELL...AND
A WEAK MOISTURE STARVED COLD FRONT SEEPS SOUTHWARD AROUND THURSDAY.
LOW POPS CONTINUE THURSDAY AND FRIDAY SINCE THE FRONT MAY AGAIN
LINGER NEAR THE AREA WITH POSSIBLE DISTURBANCES RIDING ALONG
IT...BUT NO STRONG SYSTEMS ARE IN STORE. TEMPERATURES WILL BE NEAR
OR SLIGHTLY BELOW NORMAL IN THE OVERALL ZONAL FLOW PATTERN AND NO
STRONG ADVECTION.

&&

.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
POTENTIAL FOR REDUCED VIS AT MRB THROUGH ABOUT 11Z DUE TO
-SHSN...EXPECTATION IS FOR -SHSN TO REMAIN WEST OF THE HUBS.
OTHERWISE...VFR TODAY/TONIGHT WITH INCREASING SOUTHERLY WINDS
WITH HIGH PRESSURE OFFSHORE.

SW FLOW AOB 10 KTS MONDAY MORNING BECOMES NW GUSTING UP TO 20 KT
FOLLOWING FROPA LATE MONDAY AFTERNOON...DIMINISHING OVERNIGHT.
SUB-VFR CONDITIONS POSSIBLE AT TIMES MONDAY NIGHT THROUGH TUESDAY
NIGHT DUE TO LOW CIGS. LIGHT PRECIPITATION POSSIBLE DURING THIS TIME
PERIOD...SOME OF WHICH MAY BE WINTRY. VFR CONDITIONS RETURN
WEDNESDAY.

&&

.MARINE...
WITH HIGH PRESSURE OFFSHORE...SOUTHERLY WINDS ARE FORECAST TO
INCREASE THROUGH TONIGHT. EVEN WITH WARM ADVECTION...MODELS SHOW SCA
CONDITIONS DEVELOPING LATER TODAY OR THIS EVENING PARTICULARLY UP
THE CHESAPEAKE BAY AND SCA WILL CONTINUE. HAVE ALSO EXTENDED SCA
INTO SUNDAY AS 20 KT WINDS WILL CONTINUE TO BE LIKELY.

SOUTHWEST WINDS WILL BECOME NORTHWEST TO NORTH MONDAY AFTERNOON AND
EVENING AND INCREASE WITH GUSTS TO 25 KT AS A COLD FRONT SINKS
THROUGH THE WATERS. NORTHERLY CHANNELING COULD RESULT IN A
CONTINUATION OF WIND GUSTS TO SMALL CRAFT ADVISORY LEVELS FOR A TIME
TUESDAY OVER PARTS OF THE WATERS. WINDS WILL DIMINISH AND REMAIN
LIGHT AND VARIABLE TUESDAY NIGHT INTO WEDNESDAY AS A WARM FRONT
SLOWLY LIFTS ACROSS THE AREA.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EST SUNDAY FOR
     ANZ530>534-537-539>541-543.
     SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 PM EST THIS EVENING
     FOR ANZ535-536-538-542.

&&

$$
SYNOPSIS...BPP/ADS
NEAR TERM...BPP
SHORT TERM...ADS
LONG TERM...ADS
AVIATION...BPP/ADS
MARINE...BPP/ADS






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