Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 230135
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
935 PM EDT TUE APR 22 2014

.SYNOPSIS...
A COLD FRONT WILL CONTINUE TO MOVE EAST ACROSS THE AREA THIS
EVENING. HIGH PRESSURE THEN BUILDS THROUGH EARLY THURSDAY BEFORE
MOVING OFF THE COAST. A COLD FRONT IS EXPECTED TO PASS THROUGH
THE AREA LATE FRIDAY BEFORE CANADIAN HIGH PRESSURE BUILDS IN LATE
SATURDAY INTO MONDAY.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 01Z...996MB SFC LOW IS CENTERED OVER NRN NEW HAMPSHIRE WITH
AN ATTENDANT COLD FRONT EXTENDING SOUTH DOWN THE HUDSON VALLEY
THEN SW ACROSS THE CENTRAL MID-ATLANTIC. THUNDERSTORMS HAVE MOVED
OFF THE SHORE NEAR BALTIMORE AND WILL PUSH ACROSS THE EASTERN
SHORE THROUGH THE LATE EVENING. JUST A FEW SHOWERS WEST OF THE
FRONT WITH NW FLOW INCREASING. OVERNIGHT GUSTS OF 20 TO 25 MPH CAN
BE EXPECTED...INCREASING TO 30 TO 40 MPH AROUND SUNRISE. MIN TEMPS
LOW TO MID 40S INLAND...UPR 40S URBAN/NEARSHORE.


HIPRES BUILDS IN FROM THE GREAT LAKES ON WED. COLD AIRMASS WILL
BE MODERATED A BIT BY THE HIGH SUN ANGLE. FORECAST UPDATE A BLEND
OF MAV AND MET WHICH CAME OUT A BIT HIGHER THAN THE PREVIOUS. THIS
IS REASONABLE WITH SUNNY SKIES AND DOWNSLOPING FLOW. MAX TEMPS
GENERALLY RANGE FROM THE MID 50S TO MID 60S EXCEPT FOR COOLER
HIGHS IN THE 40S ALONG HIGHER ELEVATIONS RIDGES.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
SFC LOW PRESSURE SHOULD BE MOVING TOWARDS NEWFOUNDLAND WED NIGHT AND
HIGH PRESSURE WILL MOVE INTO THE MID ATLANTIC FROM THE WEST. THE
PRESSURE GRADIENT RESPONSIBLE FOR THE GUSTY WINDS WEDNESDAY WILL
DEPART TO OUR EAST WED EVENING. TEMPS WILL REACH THE LOW 30S WEST OF
THE BLUE RIDGE AS CLEARING AND CALM WINDS WILL ALLOW FOR TEMPS TO
DROP. ELSEWHERE...MID TO UPPER 30S EXPECTED TO AROUND 40 IN THE
METROS.

UPPER LEVEL RIDGING WILL MOVE OVERHEAD THURSDAY RESULTING IN A SUNNY
DAY WITH TEMPS IN THE 60S. A WEAK COLD FRONT ASSOCIATED WITH LOW
PRESSURE ACROSS THE NRN PLAINS WILL APPROACH THE REGION. CLOUDS WILL
INCREASE FROM THE WEST THURSDAY AS HIGH PRESSURE WILL MOVES OFF THE
COAST BY THURSDAY NIGHT. A BRIEF PERIOD OF RETURN FLOW WILL
INCREASE ACROSS THE REGION THURSDAY NIGHT AND FRIDAY. TEMPS WILL
REACH 70-75 DEGREES FRIDAY AFTERNOON. THE WEAK COLD FRONT WILL CROSS
THE APPALACHIANS FRIDAY AFTERNOON AND SHOWERS ARE EXPECTED TO MOVE
AHEAD OF THE FRONT.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AN UPPER-LEVEL TROUGH...ACCOMPANIED BY A SECONDARY COLD FRONT AND
STRONG PRESSURE SURGE/COLD ADVECTION WILL MOVE THROUGH THE AREA TO
BEGIN THE WEEKEND. THE BOUNDARY LOOKS MOISTURE STARVED...SO ANY
ISOLATED SHOWER ACTIVITY WOULD REMAIN CONFINED TO AREAS ALONG THE
MASON-DIXON LINE CLOSEST TO THE FORCING FROM THE SHORTWAVE TROUGH
SATURDAY. THUS SLIGHT CHANCE POPS HAVE BEEN CONFINED TO THESE AREAS.

AT THE MOMENT...THE MEDIUM RANGE GUIDANCE HAS COME INTO BETTER WITH
THE TIMING AND STRENGTH OF THE FRONT. STRONG AND GUSTY WINDS ARE
APPEARING INCREASINGLY LIKELY FOR SATURDAY...ESPECIALLY CONSIDERING
THE STRONGEST WINDS ACCOMPANYING THE PRESSURE SURGE WILL OCCUR
DURING PEAK HEATING WHEN LAPSE RATES ARE STEEPEST AND MIXING DOWN
HIGHER WIND GUSTS WOULD BE EASIEST.

WINDS DIMINISH SATURDAY NIGHT INTO SUNDAY MORNING AS AN AREA OF HIGH
PRESSURE NOSES OVER THE REGION...BUT ITS STAY OVER OUR AREA IS
SHORT-LIVED AS A LARGE AND SLOW-MOVING AREA OF LOW PRESSURE APPROACH
FROM THE WEST BRINGING A RETURN TO UNSETTLED WEATHER EARLY NEXT WEEK.

&&

.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDS THROUGH TAF PERIOD NOW THAT SHOWER AND THUNDERSTORM
ACTIVITY HAS MOVED EAST. NWLY FLOW INCREASES BEHIND THE COLD FRONT
TONIGHT...WITH 30 KT GUSTS THROUGH WEDNESDAY.

GUSTY NW FLOW CONTINUES WED NIGHT INTO THURSDAY. HIGH PRESSURE
MOVES INTO THE REGION LATE THURSDAY BEFORE MOVING OFF THE COAST
AHEAD OF A WEAK COLD FRONT THURSDAY NIGHT. SHOWERS MAY CROSS THE
TERMINALS FRIDAY.

MODERATE CONFIDENCE IN VFR CONDITIONS AND WESTERLY WINDS AROUND 10
KNOTS FRIDAY NIGHT...WITH MODERATE CONFIDENCE IN WINDS INCREASING TO
BETWEEN 15 AND 20 KNOTS WITH GUSTS UP TO 30 KNOTS DURING THE DAY
SATURDAY.

&&

.MARINE...
SCA REMAINS IN EFFECT FOR THE WATERS THRU TNGT WITH NWLY FLOW
INCREASING TO 25 TO 30 KT THROUGH THE OVERNIGHT BEHIND THE COLD
FRONT. A GALE WARNING IS IN EFFECT WEDNESDAY FOR ALL OF THE WATERS
WITH GUSTS TO AROUND 35 KT EXPECTED DURING THE DAY. THE GALE
WARNING MAY BE ABLE TO BE DOWNGRADING SOMETIME DURING THE AFTN AS
THE PRESSURE GRADIENT AND ASSOCIATED WIND FIELD WEAKENS A BIT.

NORTHWEST WINDS WILL CONTINUE ON THE WATERS WEDNESDAY NIGHT AND
THURSDAY WITH AN SCA IN EFFECT FOR ALL WATERS THROUGH THAT TIME.
HIGH PRESSURE MOVES INTO THE REGION LATE THURSDAY AND THURSDAY
NIGHT. SOUTHERLY FLOW WILL INCREASE ACROSS THE WATERS FRIDAY.

A PERIOD OF HIGH-END SMALL CRAFT ARE EXPECTED BEHIND A STRONG BUT
MOISTURE-STARVED COLD FRONT SATURDAY. WINDS DIMINISH THROUGH THE
NIGHT SATURDAY AND LIKELY DROP BELOW SMALL CRAFT LEVELS DURING THE
DAY SUNDAY.

&&

.FIRE WEATHER...
A COLD FRONT WILL CONTINUE TO PASS THROUGH THE AREA THIS EVENING
AND GUSTY NORTHWEST WINDS ARE EXPECTED BEHIND THE COLD FRONT
WEDNESDAY. A DEEP MIXING LAYER WILL ALLOW FOR DRIER AIR TO MIX
DOWN...CAUSING LOW RELATIVE HUMIDITY VALUES DURING THE LATE
MORNING THROUGH THE AFTERNOON. THE COMBINATION OF GUSTY
WINDS...LOW FUEL MOISTURE AND LOW RELATIVE HUMIDITY WILL ENHANCE
THE THREAT FOR THE SPREAD OF WILDFIRES WEDNESDAY. AFTER
COORDINATION WITH STATE OFFICIALS AND SURROUNDING WFOS...A FIRE
WEATHER WATCH WAS ISSUED.

&&

.TIDES/COASTAL FLOODING...
POSITIVE TIDAL ANOMALIES REMAIN STEADY AROUND THREE-QUARTERS OF A
FOOT THIS EVENING. NWLY WITHIN THE NEXT FEW HRS WILL CAUSE ANOMALIES
TO DECREASE TO ABOUT HALF A FOOT BELOW MLLW.

GUSTY NORTHWEST WINDS WILL DEVELOP TONIGHT AND CONTINUE THROUGH
WEDNESDAY. BLOWOUT TIDES ARE EXPECTED WEDNESDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY
     EVENING FOR DCZ001.
MD...FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY
     EVENING FOR MDZ003>007-009>011-013-014-016>018-502.
VA...FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY
     EVENING FOR VAZ025>031-036>040-042-050>057-501-502-504.
WV...FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY
     EVENING FOR WVZ050>053-055-502-504-506.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR ANZ530>543.
     SMALL CRAFT ADVISORY FROM 6 PM WEDNESDAY TO 6 AM EDT THURSDAY
     FOR ANZ530>534-537>543.
     GALE WARNING FROM 6 AM TO 6 PM EDT WEDNESDAY FOR ANZ530>543.
     SMALL CRAFT ADVISORY FROM 6 PM WEDNESDAY TO MIDNIGHT EDT
     WEDNESDAY NIGHT FOR ANZ535-536.

&&

$$
SYNOPSIS...BAJ/JRK
NEAR TERM...BAJ/JRK
SHORT TERM...HAS
LONG TERM...DFH
AVIATION...BAJ/JRK/HAS/DFH
MARINE...BAJ/JRK/HAS/DFH
FIRE WEATHER...
TIDES/COASTAL FLOODING...








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