Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 160120 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 920 PM EDT TUE JUL 15 2014 .SYNOPSIS... A COLD FRONT WILL CROSS THE AREA TONIGHT. CANADIAN HIGH PRESSURE WILL BUILD OVERHEAD FOR WEDNESDAY THROUGH THURSDAY NIGHT. HIGH PRESSURE WILL MOVE OFF THE COAST FRIDAY THROUGH THE WEEKEND AND A RETURN FLOW WILL USHER IN MORE HUMID CONDITIONS ALONG WITH THE CHANCE FOR SHOWERS AND THUNDERSTORMS. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... AN ACTIVE SEVERE WEATHER DAY IS COMING TO AN END AS SHOWERS AND THUNDERSTORMS MOVE EAST OF INTERSTATE 95. ALL WATCHES HAVE BEEN DROPPED AND SEVERE WEATHER IS NOT EXPECTED TONIGHT. A COLD FRONT WILL CONTINUE TO PUSH EASTWARD TONIGHT AND MUCH DRIER AIR WILL FILL INTO THE MID-ATLANTIC. DEWPTS ACROSS THE POTOMAC HIGHLANDS ARE IN THE 50S WHEREAS THE INTERSTATE 95 CORRIDOR ARE STILL IN THE 70S. SHOWERS AND THUNDERSTORMS WILL CONTINUE TO PUSH EAST THIS EVENING. MARGINAL SHEAR AND INSTABILITY STILL EXIST AHEAD OF THE COLD FRONT BUT THE LOSS OF DAYTIME HEATING WILL ALLOW ACTIVITY TO WEAKEN. ISOLATED AREAS OF HEAVY RAIN ARE POSSIBLE SINCE AIRMASS IS STILL SATURATED. W-NW WINDS WILL MOVE INTO THE REGION OVERNIGHT AND FOG AND CLOUDS WILL DISSIPATE BY WEDNESDAY MORNING. FCST MIN TEMPS WILL RANGE FROM THE UPPER 50S IN THE POTOMAC HIGHLANDS TO THE UPPER 60S TO NEAR 70 IN LOWER SOUTHERN MARYLAND. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... INSTEAD OF SWINGING EWD...THE UPR TROF LIFT NWD WED. THAT WL DELAY THE CLRG SKIES ALONG THE METRO CORRIDOR. HWVR...WL KEEP A FAIRLY OPTIMISTIC FCST AS CAA WL ERODE THE WRN PERIPHERY. NEEDED TO KEEP LOW END POPS E OF I-95 FOR ANY LINGERING SHRA. OTRW SKIES WL BECOME MOSUN/SUNNY BY AFTN IF NOT BEFORE. GDNC IN GOOD AGREEMENT THAT MAXT WL BE IN THE LWR 80S...W/ DEWPTS IN THE 50S. REFRESHING WX INTO WED NGT AS HIPRES BLDS. && .LONG TERM /THURSDAY THROUGH TUESDAY/... DRY HIGH PRESSURE WITH UNSEASONABLY COMFORTABLE TEMPS/HUMIDITY WILL BE IN PLACE FOR THURSDAY. SHORT WAVE AROUND BASE OF UPPER COLD CORE LOW WILL PUSH OVERHEAD AS WELL AND WILL LIKELY RESULT IN SOME AFTERNOON CU WITH INCREASING LOW LEVEL LAPSE RATES. MOISTURE LOOKS TOO LIMITED FOR ANY INSTABILITY SHOWERS AT THIS TIME. MODERATE MOISTURE RETURN ENSUES FRIDAY WITH INCREASING SOUTHERLY LOW LEVEL FETCH. DECENT SHORT WAVE IN SOUTHWEST FLOW ALOFT...AND MARGINAL INSTABILITY /MUCAPES 1000 J/KG WEST OF BLUE RIDGE/ SHOULD TRIGGER SCATTERED MOUNTAIN STORMS ALONG AND WEST OF THE BLUE RIDGE LATE IN THE DAY. LONG WAVE YET RELATIVELY WEAK AND POSITIVELY TILTED UPPER TROUGH PATTERN SETS UP FOR THE WEEKEND AND INTO NEXT WEEK ACROSS THE EASTERN CONUS. THIS TROUGH COUPLED WITH RIDGING OVER THE ATLANTIC RESULTS IN BETTER MOISTURE RETURN TO THE REGION. SHORT WAVE AND WARM FRONT LIFT OVER THE REGION SATURDAY WILL BRING A BETTER CHANCE OF STORMS...ALTHOUGH SHEAR AND CAPE LOOKS REMAIN LOW/MARGINAL AT THIS TIME. CLOSER PROXIMITY TO THE UPPER TROUGH SUNDAY AND INTO NEXT WEEK WILL CREATE UNSETTLED CONDITIONS AND BETTER CHANCES OF CONVECTION. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... MVFR/IFR CONDITIONS WILL PERSIST AT DCA-BWI-MTN AS SHRA AND VCTS MOVE EAST. WINDS WILL BECOME WESTERLY TONIGHT AS A COLD FRONT CROSSES THE REGION. WINDS SHOULD STAY 5-10KTS LIMITING LOW VSBYS FROM FORMING. WED...VFR UNDER BLDG HIPRES. DRY HIGH PRESSURE WILL BUILD INTO THE REGION FOR THURSDAY INTO FRIDAY. HIGH PRESSURE WILL MOVE OFF THE COAST AND A SOUTHEAST FLOW IS EXPECTED FRIDAY THROUGH THE WEEKEND. INCREASED MOISTURE FROM THE SOUTHEAST FLOW WILL BRING THE CHANCE FOR SHOWERS AND THUNDERSTORMS. && .MARINE... WINDS WILL BECOME WESTERLY BEHIND TSRA AND THE COLD FRONT WILL CROSS THE REGION BY WED MORNING. MIXING WILL INCREASE WEDNESDAY AND SCA CONDITIONS ARE EXPECTED WED MORNING. WINDS WILL RELAX BY WEDNESDAY AFTERNOON AS HIGH PRESSURE APPROACHES THE REGION. HIGH PRESSURE OVER THE WATERS THURSDAY WILL MOVE OFF THE COAST FRIDAY THROUGH EARLY NEXT WEEK. A SOUTHERLY FLOW WILL DEVELOP DURING THIS TIME...BUT THE GRADIENT SHOULD BE WEAK ENOUGH TO KEEP WIND SPEEDS BELOW SCA CRITERIA. HOWEVER...INCREASED MOISTURE WILL BRING THE CHANCE FOR SHOWERS AND THUNDERSTORMS FRIDAY THROUGH EARLY NEXT WEEK. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 7 AM TO 2 PM EDT WEDNESDAY FOR ANZ531>534-537-539>541-543. SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ534- 543. && $$ SYNOPSIS...HAS NEAR TERM...HAS SHORT TERM...HTS LONG TERM...AEB AVIATION...BJL/HAS MARINE...BJL/HAS

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