Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 150006 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 806 PM EDT TUE APR 14 2015 .SYNOPSIS... A WAVE OF LOW PRESSURE WILL PASS BY TO OUR SOUTH THIS EVENING. HIGH PRESSURE WILL BUILD IN BEHIND THIS SYSTEM FOR WEDNESDAY INTO THURSDAY BEFORE MOVING OFF THE COAST LATE IN THE WEEK. A COLD FRONT WILL PASS THROUGH LATE SATURDAY INTO SUNDAY. && .NEAR TERM /THROUGH WEDNESDAY/...
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MSAS AND SURFACE ANALYSIS INDICATES COLD FRONT AND ACCOMPANYING WAVES OF LOW PRESSURE HAVE DROPPED INTO THE VA TIDEWATER AND NC THIS EVENING. RAINFALL IS TRENDING LIGHTER WITH LESS AERIAL COVERAGE...ALTHOUGH ISOLATED BRIEF HEAVIER RAIN REMAINS POSSIBLE THIS EVENING. FLOOD WATCH OVER PORTIONS OF THE HIGHLANDS AND CENTRAL SHENANDOAH VALLEY HAS BEEN CANCELLED. DURING THE OVERNIGHT HOURS LOW PRESSURE WILL BECOME MORE ORGANIZED OFFSHORE...AND THE COLD FRONT WILL DROP FURTHER SOUTH...WHILE WEAK HIGH PRESSURE NOSES INTO THE REGION FROM THE NORTH. A FEW LINGER LIGHT RAIN SHOWERS REMAIN POSSIBLE...SO AT LEAST SLIGHT CHANCE POPS REMAIN IN THE FCST. EXPECTING TEMPS TO GRADUALLY FALL INTO THE 40S...WITH A FEW LOW 50S. FOR WED...HIGH PRESSURE WILL BUILD TOWARD THE LOWER GREAT LAKES...WEDGING DOWN THE EASTERN SIDE OF THE APPALACHIANS. A SHORT WAVE RIDGE ALOFT WILL ALSO TRAVERSE THE AREA. ADJUSTED POPS DOWNWARD AS THE AIRMASS IS LOOKING FAIRLY DRY. THE ONLY EXCEPTION MAY BE IF THE LOW LEVEL EASTERLY FLOW IS ABLE TO FORCE SOME LIGHT UPSLOPE PRECIP IN THE SOUTHERN MOUNTAINS. AMOUNT OF CLEARING IS QUESTIONABLE...AND THERE MAY ALSO BE A GOOD DEAL OF MID/HIGH CLOUDS. COMBINED WITH THE CAD SIGNATURE...UNDERCUT TEMP GUIDANCE BY SEVERAL DEGREES. FORECAST HIGHS RANGE FROM THE UPPER 50S TO MID 60S.
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&& .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... HIGH PRESSURE BOTH AT THE SURFACE AND ALOFT WILL BUILD OVERHEAD WEDNESDAY NIGHT. A NORTHERLY FLOW WILL ALLOW FOR SEASONABLY CHILLY CONDITIONS. MIN TEMPS WILL RANGE FROM THE UPPER 30S AND LOWER 40S IN NORTHERN MARYLAND TO THE UPPER 40S/NEAR 50 IN DOWNTOWN WASHINGTON AND BALTIMORE. THE HIGH ALOFT AND AT THE SURFACE WILL MOVE OFF THE COAST THURSDAY. AN UPPER-LEVEL DISTURBANCE WILL MOVE IN FROM THE SOUTHWEST THURSDAY AFTERNOON. HIGH AND MID-LEVEL CLOUDS WILL INCREASE...BUT MOST AREAS SHOULD BE DRY. THE ONE EXCEPTION WILL BE ACROSS CENTRAL VIRGINIA INTO THE POTOMAC HIGHLANDS...WHERE A FEW SHOWERS ARE POSSIBLE ESPECIALLY LATER IN THE AFTERNOON. EVEN ACROSS THESE AREAS MOST OF THE TIME WILL BE DRY AND PRECIPITATION WILL BE LIGHT. THE UPPER-LEVEL DISTURBANCE WILL SWING THROUGH THE AREA THURSDAY NIGHT AND SOUTHEAST WINDS WILL CONTINUE TO USHER IN MORE MOISTURE OFF THE ATLANTIC. RAIN IS POSSIBLE AS A RESULT...ESPECIALLY ACROSS THE SOUTHWESTERN PORTION OF THE CWA WHERE GUIDANCE IS MOST CONFIDENT AND MOISTURE WILL BE DEEPER. HOWEVER...RAIN MAY OVERSPREAD THE WASHINGTON AND BALTIMORE METROPOLITAN AREAS AS WELL AS EASTERN MARYLAND. PRECIPITATION AMOUNTS WILL BE LIGHT. WILL HAVE TO WATCH FOR LOW PRESSURE THAT WILL DEVELOP OFF THE SOUTHEAST COAST...BUT AS OF NOW IT APPEARS THAT IT WILL BE TOO FAR TO OUR SOUTH TO IMPACT OUR WEATHER. IF IT DOES DEVELOP FURTHER NORTH...THEN A STEADIER RAIN WOULD DEVELOP OVER OUR AREA. && .LONG TERM /FRIDAY THROUGH TUESDAY/... HIGH PRESSURE WILL REMAIN OFF THE COAST FRIDAY THROUGH SATURDAY. A COLD FRONT WILL APPROACH THE AREA SATURDAY BEFORE PASSING THROUGH SATURDAY NIGHT INTO SUNDAY. SHOWERS ARE POSSIBLE DURING THIS TIME. THE FRONT WILL STALL OUT JUST TO OUR SOUTH EARLY NEXT WEEK AND LOW PRESSURE MAY DEVELOP ALONG THE FRONT...BRINGING UNSETTLED CONDITIONS DURING THIS TIME. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
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LIGHT RAIN REMAINS OVER THE TERMINALS THIS EVENING...BUT AS OF 00Z TAF ISSUANCE IS LIGHT ENOUGH TO KEEP VFR CIGS/VSBYS. RAIN IS EXPECTED TO END BY LATE EVENING...ALTHOUGH THERE REMAINS A CHANCE FOR OCCASIONAL LIGHT RAIN OVERNIGHT. AMENDMENTS POSSIBLE FOR THIS. LIGHT N-NE WINDS EXPECTED. VFR CONDITIONS EXPECTED WED. WINDS WILL BE N TO NE AT 10KT OR LESS. HIGH PRESSURE OVERHEAD WEDNESDAY NIGHT WILL ALLOW FOR LIGHT WINDS. THE HIGH WILL MOVE OFF THE COAST THURSDAY AND THURSDAY NIGHT. SOUTHEAST WINDS ARE EXPECTED. SOUTHERLY WINDS MAY GUST AROUND 20 KNOTS THURSDAY. RAIN MAY OVERSPREAD THE TERMINALS LATE THURSDAY OR THURSDAY NIGHT. CONFIDENCE IN TIMING IS LOW...BUT IT DOES APPEAR THAT PRECIPITATION AMOUNTS WILL BE LIGHT. HOWEVER...SUBVFR CIGS AND VSBYS ARE POSSIBLE...ESPECIALLY THURSDAY NIGHT. SUBVFR CONDITIONS MAY CONTINUE FRIDAY INTO SATURDAY AS SOUTHERLY WINDS USHER IN MORE MOISTURE ACROSS THE AREA
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&& .MARINE...
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SCA ADVISORY FOR THE TIDAL POTOMAC FROM INDIAN HEAD TO COBB ISLAND WAS ALLOWED TO EXPIRE AT 8 PM. SCA REMAINS OVER THE LOWER TIDAL POTOMAC AND THE MARYLAND CHESAPEAKE BAY SOUTH OF SANDY POINT TONIGHT. GUSTS HAVE BEEN TRENDING LOWER...AND PORTIONS OF THIS ADVISORY MAY BE EXPIRED EARLY. LIGHT RAIN REMAINS OVER MOST OF THE WATERS...BUT IS EXPECTED TO GRADUALLY DIMINISH DURING THE EVENING AND OVERNIGHT HRS. BY WED...EXPECT NORTHERLY WINDS GENERALLY LESS THAN 15 KT. HIGH PRESSURE OVERHEAD WEDNESDAY NIGHT WILL MOVE OFF THE COAST THURSDAY THROUGH THURSDAY NIGHT. SOUTHEAST WINDS ARE EXPECTED DURING THIS TIME. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE WATERS THURSDAY. HIGH PRESSURE WILL REMAIN OFF THE COAST FRIDAY AND A COLD FRONT WILL PASS THROUGH LATE SATURDAY INTO SUNDAY. UNSETTLED CONDITIONS ARE POSSIBLE DURING THIS TIME.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR ANZ532>534- 537-540>543. SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ536.
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&& $$ SYNOPSIS...BJL NEAR TERM...ADS/KCS SHORT TERM...BJL LONG TERM...DFH AVIATION...BJL/ADS/KCS/DFH MARINE...BJL/ADS/KCS/DFH

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