Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 100748 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 348 AM EDT THU JUL 10 2014 .SYNOPSIS...
-- Changed Discussion --
A TROUGH OF LOW PRESSURE WILL LINGER ACROSS THE MID-ATLANTIC THROUGH THE END OF THE WEEK. WEAK HIGH PRESSURE BUILDS IN OVER THE WEEKEND. A COLD FRONT WILL THEN APPROACH EARLY NEXT WEEK.
-- End Changed Discussion --
&& .NEAR TERM /THROUGH FRIDAY/...
-- Changed Discussion --
AN UPPER LEVEL TROUGH IS LOCATED ACROSS THE GREAT LAKES REGION THIS MORNING WHILE A SFC TROUGH PERSISTS ACROSS THE MID ATLANTIC. A DEWPT GRADIENT EXISTS RANGING FROM THE UPPER 50S IN THE POTOMAC HIGHLANDS TO THE LOW 70S IN SRN MARYLAND. SOUTHWEST FLOW ALOFT WILL CONTINUE TO MOVE ACROSS THE TROUGH AND ISO-SCT SHOWERS WILL BE POSSIBLE THIS MORNING MAINLY ON THE WARM AND HUMID SIDE OF THE TROUGH ACROSS SRN MARYLAND AND SURROUNDING WATERS. CLEARING HAS OCCURRED ACROSS THE POTOMAC HIGHLANDS AND FOG IS EXPECTED TO DEVELOP IN VALLEY LOCATIONS AS DEWPT DEPRESSIONS ARE NEAR ZERO. THE SFC TROUGH WILL MOVE EASTWARD THIS MORNING AS HIGH PRESSURE APPROACHES FROM THE OHIO VALLEY. NRLY WINDS WILL MOVE INTO THE REGION BEFORE BECOMING NE-E BY MIDDAY. THIS WILL LEAD TO A SHORT REPRIEVE OF HUMID CONDITIONS. THE SFC TROUGH WILL STILL BE NEAR THE TIDEWATER REGION LEADING TO ISO-SCT SHOWER ACTIVITY NEAR THE SRN MD AND THE SRN WATERS. THE SFC TROUGH WILL MORPH INTO AN INVERTED TROUGH BETWEEN THE HIGH PRESSURE TO THE NW AND THE BERMUDA HIGH. RETURN FLOW WILL BEGIN DRAWING IN HIGHER DEWPTS THIS AFTERNOON AND EVENING. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS THE REGION THIS AFTERNOON AND EVENING. LIGHT FLOW IN THE BOUNDARY LAYER WILL AIDE IN TERRAIN CIRCULATIONS AS WELL AS SHOWERS AND THUNDERSTORMS FORMING BASED ON THE INVERTED TROUGH AS WELL AS OTHER LOW LEVEL BOUNDARIES ACROSS THE REGION. SHEAR IS VERY WEAK IN THE BOUNDARY LAYER BUT DEEP LAYER SHEAR IS SUFFICIENT ENOUGH FOR STRONG THUNDERSTORMS. DEWPTS RISING THIS AFTERNOON WILL ALSO AIDE IN INSTABILITY. A FEW STORMS WILL BE CAPABLE OF DMG WINDS. FCST MAX TEMPS ARE IN THE MID 80S TODAY. THE UPPER LEVEL TROUGH WILL CROSS THE MID ATLANTIC TONIGHT AND SHOWERS AND THUNDERSTORMS WILL MOVE OFF TO THE EAST BY FRIDAY MORNING. THE TROUGH AXIS IS EXPECTED TO BE LOCATED ACROSS THE MID ATLANTIC FRIDAY AFTERNOON. SHOWERS AND THUNDERSTORMS MAY FORM ALONG THE AXIS.
-- End Changed Discussion --
&& .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
-- Changed Discussion --
ANY CONVECTION FROM FRIDAY AFTERNOON SHOULD DISSIPATE DURING THE EVENING...WITH CLEARING SKIES PROMOTING PATCHY FOG DEVELOPMENT OVERNIGHT. FRONTAL BOUNDARY REMAINS SOUTH OF THE CWA ON SATURDAY...AND IN CONJUNCTION WITH FLAT RIDGING ALOFT MAY HELP TO INHIBIT THUNDERSTORM DEVELOPMENT HOWEVER CAN/T RULE OUT A FEW TERRAIN-INDUCED DIURNAL STORMS AND THIS IS WHERE LOW CHANCE POPS RESIDE.
-- End Changed Discussion --
&& .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
-- Changed Discussion --
FRONTAL BOUNDARY /OR WHAT IS LEFT OF IT/ LOOKS TO LIFT BACK TO THE NORTH AS A WARM FRONT ON SUNDAY. MOISTURE WILL BE BETTER AND WITH SOME AFTERNOON INSTABILITY THERE WILL BE A CHANCE OF THUNDERSTORMS BACK FOR THE ENTIRE CWA. CONVECTIVE CHANCES LIKELY INCREASE FURTHER EARLY NEXT WEEK WITH DEEPER MOISTURE AND DECENT INSTABILITY ALONG WITH LOWER HEIGHTS FROM AN UPPER TROUGH AND ALSO A SURFACE TROUGH ON MONDAY FOLLOWED BY A COLD FRONT ON TUESDAY. THIS COLD FRONT IS EXPECTED TO MOVE THROUGH BY TUESDAY NIGHT...ALLOWING FOR DRIER AIR TO MOVE IN FOR WEDNESDAY.
-- End Changed Discussion --
&& .AVIATION /08Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
FOG WILL DEVELOP THIS MORNING AND MVFR/IFR VSBYS ARE EXPECTED AT CHO-MRB. NRLY WINDS WILL BECOME EASTERLY LATE THIS MORNING AND BECOME SRLY BY AFTERNOON. SHOWERS AND THUNDERSTORMS ARE EXPECTED MAINLY ALONG RIDGELINES THIS AFTERNOON. ACTIVITY WILL MOVE EASTWARD BY FRIDAY MORNING. A UPPER LEVEL TROUGH WILL CROSS OVER THE REGION FRIDAY AND SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AHEAD OF TROUGH AXIS. FRONTAL BOUNDARY REMAINS TO THE SOUTH INTO SATURDAY THEN LIFTS BACK NORTH SUNDAY. COLD FRONT THEN WILL AFFECT THE AREA EARLY NEXT WEEK WITH A CHANCE OF THUNDERSTORMS.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
SRLY FLOW WILL CONTINUE ACROSS THE WATERS THIS MORNING. A BRIEF PERIOD OF NRLY WINDS ARE EXPECTED ACROSS THE WATERS NORTH OF NORTH BEACH AS A SFC TROUGH MOVES SOUTH OF THE REGION. WINDS WILL BECOME SRLY BY AFTERNOON AS A TROUGH FORMS TO THE WEST. SHOWERS AND THUNDERSTORMS ARE POSSIBLE TODAY AND MAY BRING GUSTY WINDS AND LOW VSBYS TO THE WATERS. ACTIVITY MAY PERSIST INTO THE EVENING AND OVERNIGHT HOURS. RELATIVELY WEAK GRADIENT SHOULD PRECLUDE SCA CONDITIONS INTO THE FIRST PART OF THE WEEKEND. WILL HAVE TO WATCH SOUTHERLY FLOW BY SUNDAY AS MARGINAL SCA CONDITIONS MAY BE POSSIBLE UP THE BAY BY EVENING AND POSSIBLY CONTINUING INTO EARLY NEXT WEEK AHEAD OF A COLD FRONT.
-- End Changed Discussion --
&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...HAS/BPP NEAR TERM...HAS SHORT TERM...BPP LONG TERM...BPP AVIATION...HAS/BPP MARINE...HAS/BPP

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.