Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 010111 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 911 PM EDT MON AUG 31 2015 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OFFSHORE THROUGH TUESDAY. AN UPPER- LEVEL DISTURBANCE ALONG WITH ITS ASSOCIATED SURFACE TROUGH WILL PASS THROUGH THE REGION WEDNESDAY. WEAK HIGH PRESSURE WILL BUILD OVERHEAD THURSDAY BEFORE A BACKDOOR COLD FRONT MOVES INTO THE AREA LATE FRIDAY INTO THE WEEKEND. && .NEAR TERM /THROUGH TUESDAY/... PRECIP CHANCES HAVE DISSIPATED THIS EVENING. SKIES WILL LIKELY BECOME MOSTLY CLEAR ACROSS THE MAJORITY OF THE AREA...ALTHOUGH SOME CLOUDS COULD LINGER IN THE S/W. WITH WINDS CALM AND ELEVATED DEW POINTS...SOME PATCHY FOG COULD DEVELOP DEPENDENT ON CLOUD COVER. FAVORED AREAS WOULD BE INLAND AND AWAY FROM THE METROS... PARTICULARLY TO THE S/W. LOWS IN THE 60S WITH LOWER 70S ALONG AND EAST OF I-95. BROAD SFC RIDGING REMAINS IN PLACE ON TUESDAY. MID AND UPPER LEVEL RIDGING WILL ALSO BUILD...AND A CLOSED LOW OVER THE OHIO VALLEY WILL REMAIN TO THE WEST. ATMOSPHERE WILL LIKELY BE CAPPED OVER MOST OF THE AREA...SO HAVE LEFT THE SMALL CHANCE OF DIURNAL CONVECTION LIMITED TO THE WESTERN TERRAIN. WITH MOSTLY SUNNY SKIES EAST OF THE MOUNTAINS...HIGHS SHOULD BE ABLE TO NEAR OR EXCEED 90 IN MANY LOCATIONS. HEAT INDICES SHOULD REMAIN BELOW 100 THOUGH SINCE DEW POINTS SHOULD STAY IN THE 60S. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... ANY MOUNTAIN CONVECTION WILL WANE DURING THE EVENING. OTHERWISE CONTINUED MUGGY CONDITIONS ARE EXPECTED AS WEATHER PATTERN CHANGES VERY LITTLE. LOWS COULD EVEN BE A DEGREE OR TWO HIGHER...WITH MORE LOCATIONS IN THE UPPER 60S TO LOWER 70S. PATCHY FOG IS AGAIN A CONCERN AWAY FROM THE COASTAL WATERS AND THE METROS. AN UPPER-LEVEL DISTURBANCE AND ITS ASSOCIATED SURFACE TROUGH WILL PASS THROUGH THE REGION WEDNESDAY INTO WEDNESDAY EVENING. MORE UNUSUALLY WARM AND HUMID CONDITIONS WILL CONTINUE...BUT THERE WILL BE AN INCREASED CHANCE FOR A SHOWER OR THUNDERSTORM. THE BEST CHANCE FOR CONVECTION WILL BE ACROSS THE POTOMAC HIGHLANDS INTO CENTRAL VIRGINIA...CLOSER TO TRACK OF THE UPPER-LEVEL DISTURBANCE. MOST CONVECTION SHOULD DISSIPATE WEDNESDAY EVENING AS THE UPPER- LEVEL DISTURBANCE AND SURFACE TROUGH MOVE OFF TO OUR SOUTH AND EAST. A NORTHWEST FLOW IS EXPECTED BEHIND THE TROUGH...BUT WITH NO TEMPERATURE OR DEWPOINT GRADIENT MORE WARM AND HUMID CONDITIONS ARE EXPECTED. WEAK HIGH PRESSURE WILL BUILD TOWARD THE AREA THURSDAY. A NORTHWEST FLOW WILL CONTINUE...BUT AGAIN MORE HOT AND HUMID CONDITIONS ARE EXPECTED DUE TO SUNSHINE AND A DOWNSLOPING FLOW. AN ISOLATED SHOWER OR THUNDERSTORM MAY POP UP ACROSS THE HIGHER TERRAIN...BUT MOST OF THE TIME WILL BE DRY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... WARM AND HUMID CONDITIONS WILL CONTINUE THURSDAY NIGHT...BUT MOST AREAS WILL TURN OUT DRY. A BACKDOOR COLD FRONT WILL APPROACH THE REGION FRIDAY BEFORE MOVING INTO THE AREA SATURDAY. THE BOUNDARY MAY TRIGGER A FEW SHOWERS AND THUNDERSTORMS. COOLER AND LESS HUMID CONDITIONS ARE POSSIBLE BEHIND THE BOUNDARY LATER THIS WEEKEND. THERE IS STILL SOME UNCERTAINTY THOUGH AS TO HOW FAR SOUTH AND WEST THE BOUNDARY WILL MAKE IT. HIGH PRESS BUILDS IN SUN THROUGH MON BRINGING DRIER CONDITIONS. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... ALL SHOWERS AND THUNDERSTORMS HAVE DISSIPATED. SOME CLEARING LATER TONIGHT SHOULD HELP BR DEVELOP AT MRB/CHO. CONFIDENCE A BIT HIGHER FOR IAD SO INCLUDED MVFR BR IN TAF THERE AS WELL. FOR TUESDAY...STORMS SHOULD REMAIN WEST OF THE TERMINALS. WINDS REMAIN UNDER 10 KT THROUGH THE TAF PERIOD. SOME BR WILL AGAIN BE A CONCERN ON TUESDAY NIGHT. VFR CONDITIONS ARE EXPECTED MOST OF THE TIME WEDNESDAY AND THURSDAY. A POPUP THUNDERSTORM IS POSSIBLE WEDNESDAY AFTERNOON AND EVENING. PATCHY BR MAY BRIEFLY REDUCE VSBYS EARLY WEDNESDAY MORNING AND AGAIN EARLY THURSDAY MORNING. VFR CONDITIONS EXPECTED THU NIGHT. SUB VFR CONDITIONS PSBL DUE TO SHOWERS AND TSTMS ON FRI. && .MARINE... SOUTHWEST FLOW WILL CONTINUE ACROSS THE WATERS THROUGH TONIGHT. A FEW GUSTS FLIRTED WITH 20 KNOTS THIS EVENING SO ISSUED A STATEMENT FOR THE MIDDLE BAY. THIS EXPIRES AT MIDNIGHT AND WIND SHOULD NOT BE ANY CONCERN AFTER THAT POINT. HIGH PRESSURE BECOMES REESTABLISHED BY TUESDAY AND FLOW WILL BE VARIABLE AND UNDER 10 KT. WINDS SHOULD REMAIN BELOW SCA CRITERIA WEDNESDAY AND THURSDAY. A BACKDOOR COLD FRONT WILL PASS THROUGH THE WATERS LATE FRIDAY INTO SATURDAY. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE WATERS DURING THIS TIME. HIGH PRESSURE WILL RETURN FOR EARLY NEXT WEEK. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...BJL NEAR TERM...ADS/RCM SHORT TERM...BJL/RCM LONG TERM...IMR AVIATION...BJL/ADS/IMR/RCM MARINE...BJL/ADS/IMR/RCM

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