Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 022238 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 638 PM EDT TUE SEP 2 2014 .SYNOPSIS... BERMUDA HIGH WILL PERSIST THIS AFTERNOON AHEAD OF A WEAK COLD FRONT THAT WILL CROSS THE AREA TONIGHT. HIGH PRESSURE WILL THEN BUILD FROM THE MIDWEST THROUGH WEDNESDAY THEN PERSIST OFFSHORE THURSDAY INTO THE WEEKEND. A COLD FRONT WILL ENTER THE REGION IN THE SATURDAY NIGHT TIME FRAME. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT FOR THE WASHINGTON AND BALTIMORE METROPOLITAN AREAS UNTIL 10 PM THIS EVENING. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ALONG A SURFACE TROUGH OVERHEAD. THE HOT AND HUMID CONDITIONS HAS LED TO HIGH AMOUNTS OF INSTABILITY...WITH MLCAPES OVER 2000 J/KG. THE HIGH INSTABILITY ALONG WITH INCREASING SHEAR PROFILES WILL CAUSE THE THREAT FOR SEVERE THUNDERSTORMS THIS EVENING. WILL HAVE TO WATCH ACROSS SOUTHERN MARYLAND AND CENTRAL VIRGINIA. SCATTERED THUNDERSTORMS ARE ALSO EXPECTED ACROSS THESE AREAS...AND INSTABILITY REMAINS HIGH. HOWEVER...SHEAR PROFILES ARE NOT AS STRONG. FARTHER NORTH AND WEST ACROSS THE SHENANDOAH VALLEY AND POTOMAC HIGHLANDS...A SHOWER OR THUNDERSTORM CANNOT BE RULED OUT THIS EVENING BUT THE SEVERE THREAT SHOULD REMAIN OFF TO THE SOUTH AND EAST. COLD FRONT EVENTUALLY CATCHES UP TO THE TROUGH LATER THIS EVENING...MOVING OFFSHORE TONIGHT. CHANCE OF THUNDERSTORMS WILL END BEHIND THE COLD FRONT.
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&& .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... CWA WILL BE POST-FRONTAL ON WEDNESDAY. NORTHWEST WINDS WILL BRING SOME DRYING THROUGH THE CWA...LEADING TO PLENTY OF SUNSHINE AND LOWER HUMIDITY. FRONT LOOKS LIKE IT GETS HUNG UP IN SOUTHERN VIRGINIA AS WEAK HIGH PRESSURE BUILDS IN FROM THE NORTH. HIGH MOVES OFFSHORE ON THURSDAY. MAY SEE ISOLATED SHOWERS AND THUNDERSTORMS DEVELOP UP/NEAR THE BLUE RIDGE BY AFTERNOON. ACTIVITY WOULD LIKELY BE DIURNAL IN NATURE. TROUGH DEVELOPS ON FRIDAY...WITH THE POTENTIAL FOR MORE DIURNAL CONVECTION. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... ANOTHER COLD FRONT APPROACHES FRIDAY NIGHT. QUESTION IS HOW QUICKLY THE FRONT PUSHES THROUGH THE AREA. IT MAY MOVE THROUGH BY SATURDAY NIGHT...BUT ITS POSSIBLE IT DOESN/T CLEAR THE SOUTHEAST PART OF THE CWA UNTIL SUNDAY. HIGH PRESSURE AND DRY AIRMASS WILL BUILD INTO THE AREA MONDAY. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
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A FEW SHOWERS AND THUNDERSTORMS ARE EXPECTED THIS EVENING. SOME THUNDERSTORMS MAY BE SEVERE...ESPECIALLY ACROSS THE NORTHEASTERN TERMINALS INCLUDING KIAD...KDCA...KBWI AND KMTN. LOW LEVEL MOISTURE LINGERS TONIGHT. IF WINDS BECOME CALM...FOG MAY FORM. THIS APPEARS MOST LIKELY AT CHO. EXPECTATION IS FOR ENOUGH WIND TO OCCUR AT OTHER SITES TO INHIBIT FOG FORMATION. VFR EXPECTED WEDNESDAY POST-FRONTAL AND WITH HIGH PRESSURE IN CONTROL. HIGH MOVES OFFSHORE TO END THE WEEK. NEXT COLD FRONT WILL AFFECT THE AREA OVER THE WEEKEND.
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&& .MARINE...
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PRIMARY CONCERN THIS EVENING WILL BE STRONG GUSTY WINDS AND LIGHTNING IN SCATTERED SHOWERS AND THUNDERSTORMS. CHANCE OF THUNDERSTORMS WILL CONTINUE UNTIL A COLD FRONT PASSES TONIGHT. HIGH PRESSURE BUILDS IN FOR WEDNESDAY THEN MOVES OFFSHORE TO END THE WEEK. COLD FRONT MOVES THROUGH OVER THE WEEKEND.
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&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...BPP NEAR TERM...BJL/BPP SHORT TERM...BPP LONG TERM...CEM AVIATION...BJL/CEM/BPP MARINE...BJL/CEM/BPP

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