Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 261731 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 131 PM EDT SUN OCT 26 2014 .SYNOPSIS... HIGH PRESSURE WILL BUILD OVERHEAD THROUGH TONIGHT BEFORE MOVING OFF THE COAST MONDAY AND TUESDAY. A COLD FRONT WILL PASS THROUGH THE AREA WEDNESDAY AND HIGH PRESSURE MAY RETURN FOR THURSDAY INTO FRIDAY. && .NEAR TERM /THROUGH TONIGHT/...
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UPDATE...FROST ADVISORY HAS BEEN ISSUED FOR THE SHENANDOAH VALLEY...VA PIEDMONT...EXTREME NORTHERN VA...EASTERN PANHANDLE OF WV AND NORTH-CENTRAL MD. THE NRN MID-ATLANTIC IS POST FRONTAL AS A DRY COLD FRONT MOVES INTO SOUTHERN VA THIS MORNING. GUSTY NW WINDS WILL INCREASE BY LATE THIS MORNING. LOCATIONS AT HIGHER ELEVATIONS SUCH AS RIDGE LINES HAVE ALREADY BEEN OBSERVING GUSTS UP TO 30 MPH THIS MORNING. MIXING TO ABOUT 5K FEET IS EXPECTED WHICH MAY CAUSE GUSTS AS HIGH AS 40 MPH TO MIX DOWN ACROSS THE POTOMAC HIGHLANDS AND NRN MD BY THIS AFTERNOON. A DRY AIRMASS IS ALSO ACROSS THE REGION AND OBSERVED BY THE 12Z IAD RAOB THIS MORNING WITH A PWAT OF 0.19 INCHES. DEWPTS ARE EXPECTED TO DROP INTO THE 20S AND LOW 30S ACROSS THE AREA WITH THE LOWEST DEWPTS EXPECTED ACROSS THE VA HIGHLANDS...CENTRAL FOOTHILLS AND SHENANDOAH VALLEY TODAY. THE COMBINATION OF LOW HUMIDITIES AND GUSTY WINDS ALONG WITH LOW FUEL MOISTURES WILL ENHANCE THE THREAT OF WILDFIRES...SEE FIRE WX SECTION BELOW. SYNOPTICALLY...UPPER LEVEL TROUGH WITH ALL ITS ENERGY IS ACROSS NEW ENGLAND AND THE NRN ATLANTIC OCEAN. CLEAR SKIES ARE EXPECTED TODAY ACROSS THE MID-ATLANTIC. FCST MAX TEMPS WILL RANGE FROM THE MID TO UPPER 60S IN NRN MD AND THE LOW 70S IN CENTRAL VA AND THE DC/BALT METROS. PREV DISCUSSION... WITH SFC DEWPOINTS FIRMLY HOLDING IN THE 30S OVERNIGHT...TEMPS WILL MAKE A SIMILAR DROP TONIGHT. MANY AREAS WILL DROP WELL INTO THE 40S AND MUCH OF THE PIEDMONT/SHELTERED VLYS WILL REACH THE M-U30S FOR OVERNIGHT LOWS. PATCHY FROST WILL BE POSSIBLE IN AREAS THAT DO REACH THESE LOWER TEMP VALUES AND CAN HAVE WINDS DECOUPLE AFTER A BREEZY DAY. MOST OF THE AREA SHOULD SEE WINDS DROP OFF SHORTLY AFTER SUNSET...BUT A FEW RESIDUAL GUSTS EXPECTED INTO THE EARLY MRNG HRS.
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&& .SHORT TERM /MONDAY THROUGH TUESDAY/... MONDAY WILL BE MUCH LIKE SATURDAY - A PLEASANT TRANSITION DAY W/ HIGH PRESSURE REBOUNDING FROM THE DEEP SOUTH AFTER GETTING PUSHED OUT OF THE AREA TODAY. A CHANGE IN THE WIND FIELD WILL TURN OUR SFC WINDS TO SLY...BRINGING BACK SOME WARMTH AND INCREASING LOW LEVEL MOISTURE. THE HIGHLANDS WILL BENEFIT THE MOST FROM THIS REGIME...W/ TEMPS CLIMBING WELL INTO THE 70S - SOME LOCALES NEAR 80F IN THE SHELTERED APLCN VLYS. A BIT MORE OF A COMPLEX SOLUTION FOR THE PIEDMONT/COASTAL AREAS...W/ TEMPS ALSO CLIMBING INTO THE SEASONAL AVG`S BUT THE COOLER AIR WILL RESIDE OVER EXTREME NERN MD. BIAS-CORRECTED MAV/MEX SEEMED TO HAVE THE BEST HANDLE ON THIS - W/ SOME EURO CONTRIBUTIONS AS WELL. CLOUD-FREE AND DRY FOR THE MONDAY...W/ SOME CIRRUS MOVING IN FROM THE NW LATER IN THE DAY. HIGH PRESSURE WILL MOVE INTO THE ATLANTIC OCEAN MONDAY NIGHT AND TUESDAY WHILE A COLD FRONT APPROACHES FROM THE WEST. A SOUTHERLY FLOW WILL INCREASE BETWEEN THESE SYSTEMS. THIS WILL ALLOW FOR MILDER CONDITIONS MONDAY NIGHT COMPARED TO SUNDAY NIGHT...AND TUESDAY WILL TURN OUT QUITE WARM FOR THIS TIME OF YEAR AS THE SOUTHERLY FLOW STRENGTHENS. MAX TEMPS TUESDAY WILL RANGE FROM THE MID AND UPPER 70S NEAR WASHINGTON AND BALTIMORE...TO THE LOWER 80S IN CENTRAL VIRGINIA. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... THE COLD FRONT WILL SLOWLY PASS THROUGH THE AREA LATE TUESDAY NIGHT AND WEDNESDAY. CLOUDS WILL INCREASE AHEAD OF THIS SYSTEM AND A FEW SHOWERS ARE POSSIBLE DURING THIS TIME. HOWEVER...PRECIPITATION AMOUNTS SHOULD BE LIGHT SINCE LITTLE MOISTURE WILL BE ASSOCIATED WITH THE BOUNDARY. HIGH PRESSURE WILL RETURN FOR WEDNESDAY NIGHT AND THURSDAY...BRINGING A RETURN OF DRY AND SEASONABLY COOL CONDITIONS. AN UPPER-LEVEL TROUGH WILL SWING THROUGH THE AREA FRIDAY INTO SATURDAY. UNCERTAINTY IN THE STRENGTH AND TIMING OF THIS SYSTEM REMAIN HIGH. THERE WILL BE A CHANCE FOR SHOWERS DURING THIS TIME...AND THERE MAY BE ENOUGH COLD AIR FOR SOME SNOW SHOWERS ALONG THE RIDGE TOPS. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... VFR CONDITIONS EXPECTED TODAY AND TONIGHT. NW WINDS WITH GUSTS IN THE 20-30KT RANGE WILL BEGIN AND CONTINUE WELL INTO THE AFTN HRS. BY LATE THIS AFTN/EVE...THE TOP-END GUSTS WILL SUBSIDE BACK TOWARD 15-20KT THEN DROP OFF AFTER SUNSET. HIGH PRESSURE WILL BUILD BACK INTO THE AREA ON MONDAY...ALLOWING SFC WINDS TO SWITCH TO SLY THRU THE DAYTIME HRS AND CLEAR SKIES FOR ALL SITES TODAY INTO MONDAY. VFR CONDITIONS ARE EXPECTED MOST OF THE TIME MONDAY NIGHT THROUGH THURSDAY. GUSTY SOUTHWEST WINDS ARE POSSIBLE TUESDAY AFTERNOON. A COLD FRONT WILL BRING A CHANCE FOR SHOWERS LATE TUESDAY NIGHT AND WEDNESDAY. CIGS/VSBYS MAY APPROACH MVFR LEVELS DURING THIS TIME. && .MARINE... A COLD FRONT PUSHING ACROSS THE AREA WILL EVENTUALLY SPREAD SOLID SCA GUSTS ACROSS THE WATERS IN THE COMING HRS AND CONTINUE THROUGHOUT THE DAY. A FEW NEAR-GALE GUSTS IN THE U20KT RANGE WILL BE POSSIBLE AT ISOLATED LOCALES DURING THIS TIME PERIOD BUT THE OVERWHELMING RANGE WILL BE A GENERAL 20-25KT. HIGH PRESSURE WILL BUILD INTO THE AREA AGAIN STARTING LATER THIS AFTN...SLOWLY DROPPING WINDS BACK DOWN INTO THE 5-10KT AND SWITCH THE FLOW TO SLY HEADING INTO MONDAY. A COLD FRONT WILL APPROACH THE WATERS MONDAY NIGHT AND TUESDAY. SOUTHERLY WINDS WILL INCREASE TUESDAY. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE WATERS TUESDAY INTO TUESDAY NIGHT. THE COLD FRONT WILL PASS THROUGH THE WATERS WEDNESDAY. HAVE CAPPED GUSTS AROUND 15 KNOTS FOR NOW DUE TO THE RELATIVE WEAK PRESSURE GRADIENT. HOWEVER...A PRESSURE SURGE MAY CAUSE WIND GUSTS TO EXCEED SCA CRITERIA WEDNESDAY NIGHT INTO THURSDAY FOR PORTIONS OF THE WATERS. && .FIRE WEATHER... GUSTY WINDS ARE EXPECTED BEHIND A COLD FRONT TODAY. THE GUSTY WINDS ALONG WITH LOW RELATIVE HUMIDITY AND LOW FUEL MOISTURE WILL ENHANCE THE THREAT FOR THE SPREAD OF WILDFIRES LATE THIS MORNING AND AFTERNOON. WILL CONTINUE WITH A SPECIAL WEATHER STATEMENT FOR THE ENHANCED THREAT ACROSS THE CENTRAL SHENANDOAH VALLEY INTO THE POTOMAC HIGHLANDS OF VIRGINIA. THE RELATIVE HUMIDITY WILL BE LOWEST ACROSS THESE AREAS. ELSEWHERE...THE RELATIVE HUMIDITY MAY BE A BIT HIGHER BUT WINDS WILL BE GUSTY. && .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...NONE. MD...FROST ADVISORY FROM 3 AM TO 9 AM EDT MONDAY FOR MDZ003>005. VA...FROST ADVISORY FROM 3 AM TO 9 AM EDT MONDAY FOR VAZ025>031- 036>040-042-050-051-501-502. WV...FROST ADVISORY FROM 3 AM TO 9 AM EDT MONDAY FOR WVZ051>053. MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT MONDAY FOR ANZ530>534-537- 539>541-543. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ535- 536-538-542.
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&& $$ SYNOPSIS...BJL NEAR TERM...HAS/GMS SHORT TERM...BJL/GMS LONG TERM...BJL AVIATION...BJL/GMS MARINE...BJL/GMS FIRE WEATHER...

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