Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 241833 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 233 PM EDT TUE MAR 24 2015 .SYNOPSIS...
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HIGH PRESSURE WILL MOVE OFFSHORE TONIGHT THROUGH WEDNESDAY. A COLD FRONT WILL PASS THROUGH THE AREA LATE THURSDAY INTO THURSDAY NIGHT BEFORE REMAIN OVERHEAD THIS AFTERNOON. THE HIGH WILL MOVE OFF THE COAST WEDNESDAY AND A COLD FRONT IS EXPECTED TO PASS THROUGH LATE THURSDAY INTO THURSDAY NIGHT. CANADIAN HIGH PRESSURE WILL RETURN FOR FRIDAY INTO THE WEEKEND.
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&& .NEAR TERM /THROUGH WEDNESDAY/...
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SURFACE HIGH PRESSURE OVER NEW ENGLAND WILL CONTINUE TO EXTEND SOUTH THROUGH THE MID-ATLANTIC COAST TONIGHT. LOW PRESSURE WILL TRACK THROUGH THE MIDWEST AND INTO THE GREAT LAKES DURING THIS TIME. SUBSIDENCE BEHIND A DEPARTING SHORTWAVE WILL ALLOW FOR CLEARING SKIES LATE THIS AFTERNOON AND EVENING ACROSS MOST OF MARYLAND...THE WASHINGTON AND BALTIMORE METROPOLITAN AREAS...NORTHERN VIRGINIA AND THE EASTERN WEST VIRGINIA PANHANDLE. HOWEVER...CLOUDS WILL LIKELY HANG ON AND EVEN INCREASE ACROSS CENTRAL VIRGINIA INTO THE POTOMAC HIGHLANDS. OVERRUNNING IS EXPECTED AS WARM AND MOIST AIR OVERRIDES THE SURFACE COOL AIR IN PLACE DUE TO THE LOW PRESSURE PASSING BY WELL TO OUR WEST. THE HIGH WILL SLOWLY MOVE OFF THE COAST LATE TONIGHT AND WEDNESDAY. A SOUTHERLY FLOW WILL DEVELOP...CAUSING MORE OVERRUNNING TO TAKE PLACE. THIS WILL RESULT IN PLENTY OF CLOUD COVER ACROSS THE ENTIRE AREA. HOWEVER...PRECIPITATION CHANCES ARE LOWER SINCE THE MAIN FORCING WILL REMAIN WELL TO OUR NORTH AND WEST...CLOSER TO THE TRACK OF THE LOW OVER THE GREAT LAKES. THE BEST CHANCE FOR PRECIPITATION TONIGHT WILL BE ACROSS CENTRAL VIRGINIA INTO THE POTOMAC AND ALLEGHENY HIGHLANDS. EVEN ACROSS THESE AREAS MOST OF THE TIME WILL BE DRY AND PRECIPITATION AMOUNTS WILL BE LIGHT. THERE MAY BE THIN LAYER OF COLD AIR ALONG THE RIDGE TOPS...CAUSING THE THREAT FOR FREEZING RAIN MAINLY FOR ELEVATIONS ABOVE 2500 FEET IN THE BLUE RIDGE MOUNTAINS AND POTOMAC/ALLEGHENY HIGHLANDS. CONFIDENCE IS TOO LOW IN PRECIPITATION OCCURRING FOR AN ADVISORY AT THIS TIME. RAIN CHANCES MAY EXTEND FARTHER NORTH INTO THE SHENANDAOH VALLEY WEDNESDAY. HOWEVER...WITH LITTLE FORCING CONFIDENCE IN PRECIPITATION IS LOW. EVEN IF THERE IS RAIN...IT WILL BE LIGHT AND MOST OF THE TIME WILL TURN OUT DRY. MAX TEMPS WILL REMAIN BELOW CLIMO FOR MOST AREAS DUE TO THE CLOUD COVER.
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&& .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
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HIGH PRESURE WL BE MOVG OFFSHORE WED NGT. IN RETURN FLOW TEMPS WL BE FAIRLY MILD W/ LOWS IN THE 40S. THU LOOKS TO BE WARM...CLDY..AND WET. A CD FNT WL BE APRCHG THE MID ATLC...ALLOWING TEMPS TO CLIMB INTO THE LM70S ACROSS MUCH OF THE AREA. COLDEST TEMPS SHOULD BE IMMEDIATELY ALONG THE BAY. ALTHO THE E CST HAD A COLD WINTER LATE MAR IS NOT TOO ERLY TO BE THINKING ABT PSBL CNVTN. AHD OF THE FNT LO TOPPED CELLS COULD DVLP. THE THEAT FOR RA/ISOLD TSTMS WL CONT THU EVE B4 WANING. FRI WL BE COOLER BUT NOT AS COLD AS THE WKND WL BE - HIGHS STILL XPCTD TO REACH 55-60 W/ BRZY NW WINDS.
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&& .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
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AN UPPER-LEVEL TROUGH WILL SWING THROUGH THE AREA FRIDAY NIGHT INTO SATURDAY BEFORE COLD HIGH PRESSURE BUILDS OVERHEAD SATURDAY NIGHT INTO SUNDAY. A NORTHWEST FLOW AHEAD OF THE HIGH WILL USHER IN UNUSUALLY COLD CONDITIONS FOR THIS TIME OF YEAR. THE HIGH WILL MOVE OFF THE COAST LATER SUNDAY AND MILDER CONDITIONS ARE EXPECTED IN THE AFTERNOON DUE TO A RETURN FLOW...BUT TEMPS WILL LIKELY REMAIN BELOW CLIMO. A COLD FRONT WILL PASS THROUGH THE AREA MONDAY...BRINGING A CHANCE FOR SHOWERS. MILDER CONDITIONS ARE EXPECTED WITH A SOUTHWEST FLOW AHEAD OF THE FRONT. HIGH PRESSURE WILL RETURN FOR THE MIDDLE PORTION OF NEXT WEEK.
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&& .AVIATION /18Z TUESDAY THROUGH SUNDAY/...
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VFR CONDITIONS ARE EXPECTED TONIGHT FOR MOST OF THE TERMINALS. THE ONE EXCEPTION WILL BE KCHO WHERE MVFR CIGS ARE POSSIBLE LATE TONIGHT WARM AND MOIST AIR BEGINS TO OVERRUN THE SURFACE COOL AIR IN PLACE. CLOUDS WILL EXTEND ACROSS THE REST OF THE TERMINALS EARLY WEDNESDAY. MVFR CONDITIONS WILL BECOME MORE WIDESPREAD DURING THE AFTERNOON. ALTHOUGH RAIN CANNOT BE RULED OUT...ESPECIALLY ACROSS KCHO...MOST OF THE TIME WILL TURN OUT DRY ACROSS THE TERMINALS. M CLDY CONDS XPCTD WED NGT...PSBLY IN THE LIFR CAT. SOME IMRVMNT XPCTD THU MRNG...THEN DEGRADING LATE IN THE DAY AND OVRNGT AHD OF A CD FNT. RA XPCTD THU AFTN/OVRNGT W/ ISOLD TSTMS PSBL. CONDS SHOULD BEGIN IMPRVG AS WINDS TURN TO THE NW FRI. VFR CONDITIONS ARE EXPECTED THROUGH THE WEEKEND.
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&& .MARINE...
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HIGH PRESSURE WILL REMAIN OVER THE WATERS TONIGHT BEFORE MOVING OFF TO THE EAST WEDNESDAY. A SOUTHERLY FLOW WILL DEVELOP WEDNESDAY AND WINDS MAY GUST CLOSE TO SCA CRITERIA DURING THE AFTERNOON. HAVE CAPPED GUSTS AROUND 15 KNOTS FOR NOW DUE TO THE RELATIVELY COOLER WATERS. SCA CONDS XPCTD THU AHD OF A CD FNT...W/ ISOLD TSTMS PSBL...THEN TURNING TO THE NW AFTR MDNGT THU W/ WINDS CONTINUING ABV SCA VALUES INTO FRI MRNG. HIGH PRESSURE WILL BUILD OVER THE WATERS FOR THE WEEKEND.
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&& .TIDES/COASTAL FLOODING...
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SOUTHERLY WINDS WILL DEVELOP WEDNESDAY AND THE SOUTHERLY FLOW WILL INCREASE AHEAD OF A COLD FRONT THURSDAY. THE INCREASED SOUTHERLY FLOW WILL CAUSE WATER LEVELS TO ELEVATE...AND TIDAL ANOMALIES MAY BE HIGH ENOUGH FOR MINOR FLOODING NEAR TIMES OF HIGH TIDE THURSDAY INTO THURSDAY NIGHT. THE COLD FRONT WILL PASS THROUGH LATER THURSDAY EVENING AND A NORTHWEST FLOW WILL CAUSE WATER LEVELS TO DECREASE LATE THURSDAY NIGHT INTO FRIDAY.
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&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...BJL NEAR TERM...BJL SHORT TERM...ABW LONG TERM...BJL/IR AVIATION...BJL/IR/ABW MARINE...BJL/IR/ABW TIDES/COASTAL FLOODING...BJL

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