Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 191833 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 233 PM EDT SAT JUL 19 2014 .SYNOPSIS... HIGH PRESSURE OVER NEW ENGLAND WILL REMAIN ALONG THE EASTERN SEABOARD THROUGH EARLY IN THE WEEK. A COLD FRONT IS EXPECTED TO MOVE INTO THE MID ATLANTIC REGION THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... SURFACE HIGH ALONG THE NORTHEAST COAST CONTINUES TO NOSE DOWN THE MID-ATLANTIC STATES...PROVIDING A LOW LEVEL EASTERLY FLOW ACROSS THE CWA. MEANWHILE...AN UPPER TROUGH REMAINED OVER THE LOWER GREAT LAKES/OHIO VALLEY. VISIBLE SATELLITE IMAGERY HAS SHOWN A FEW BREAKS IN THE CLOUDS THE PAST COUPLE OF HOURS...MAINLY EAST OF THE BLUE RIDGE. BUT BREAKS HAVE TENDED TO FILL IN WITH CU...KEEPING MOSTLY CLOUDY SKIES IN PLACE. MOST OF THE SHOWERS HAVE RESIDED ACROSS THE POTOMAC HIGHLANDS IN THE AREA OF BEST LIFT. THIS WILL LIKELY CONTINUE TO BE THE CASE THROUGH MID AFTERNOON. IT/S POSSIBLE DURING THE LATE AFTERNOON AND EVENING...SHOWERS EXTEND FURTHER EAST...PARTICULARLY THE CENTRAL SHENANDOAH VALLEY/FOOTHILLS AREA. HRRR/WRF-ARW EVEN SUGGEST A FEW SHOWERS MAKE IT INTO THE WASHINGTON METRO AREA...BUT CONTINUE TO PREFER A SREFS/GFS BLEND WHICH KEEPS THIS AREA DRY THROUGH THE NIGHT. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... SURFACE HIGH CONTINUES TO RESIDE ALONG THE EASTERN SEABOARD SUNDAY THROUGH MONDAY. EASTERLY COMPONENT TO THE WIND PERSISTS...THUS EXPECT PLENTY OF CLOUD COVER. EXPECT SHOWERS TO PRIMARILY BE ACROSS THE POTOMAC HIGHLANDS AGAIN FOR SUNDAY...THEN WILL SPREAD POPS FURTHER EAST TOWARD THE BLUE RIDGE MONDAY. A LITTLE BETTER MOISTURE/INSTABILITY MAY ALSO SUPPORT ISOLATED THUNDERSTORMS. UPPER RIDGE BEGINS TO BUILD IN FOR TUESDAY. THIS WILL ALLOW FOR WARMER TEMPERATURES AND ALSO THE RETURN OF SOME SUNSHINE. CAN/T RULE OUT A FEW DIURNAL STORMS EITHER...MAINLY OVER THE HIGHER ELEVATIONS. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... A WEAK DISTURBANCE SHOULD MOVE ACROSS PORTIONS OF THE REGION TUESDAY INTO TUESDAY NIGHT AND BRING A SLIGHT CHANCE OF SHOWERS OR A THUNDERSTORM. A STRONGER PIECE OF ENERGY WILL SLIDE ACROSS THE GREAT LAKES REGION WEDNESDAY...DROPPING SOUTHEASTWARD INTO THE MID ATLANTIC REGION WEDNESDAY NIGHT AND THURSDAY. MORE FREQUENT SHOWERS AND A COUPLE OF STRONGER THUNDERSTORMS MAY DEVELOP. RELATIVELY HIGH CAPE AND LOW TO MODERATE SHEAR COULD LEAD TO DAMAGING WINDS FROM ANY THUNDERSTORM DEVELOPING WITH THE MAIN THREAT BEING MIDDAY THURSDAY THROUGH THURSDAY EVENING. A SURFACE COLD FRONT WILL FINALLY PUSH THROUGH THE REGION THURSDAY NIGHT TO ALLOW FOR A RIDGE OF HIGH PRESSURE TO BUILD IN FROM THE NORTHWEST. HIGH PRESSURE WILL KEEP THE REGION DRIER AND SLIGHTLY COOLER THURSDAY NIGHT THROUGH FRIDAY NIGHT. THIS SAME HIGH WILL MOVE OFFSHORE SATURDAY TO ALLOW FOR DISTURBANCES TO MOVE ACROSS THE OHIO VALLEY AND MID ATLANTIC REGION...INTRODUCING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS ONCE AGAIN. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... EASTERLY FLOW CONTINUES INTO SUNDAY. BKN-OVC MID CLOUDS EXPECTED THROUGH THEN. NAM HINTS THAT SOME LOWER /IFR/MVFR/ CLOUDS COULD AFFECT THE HUBS LATE TONIGHT/EARLY SUNDAY. CONFIDENCE LOW IN THIS SOLUTION AND PREFERRED A GFS APPROACH. SHOWERS POSSIBLE AT CHO/MRB THROUGH THIS EVENING...OTHERWISE MOST OF THE SHOWERS WILL REMAIN WEST OF THE TERMINALS THIS WEEKEND. ANY SHOWERS OR ISOLATED THUNDERSTORMS THAT DEVELOP TUESDAY THROUGH WEDNESDAY COULD BRING MVFR CONDITIONS TO ANY OF THE TERMINALS. THERE IS A BETTER CHANCE OF IFR OR LIFR IN SHOWER AND THUNDERSTORM ACTIVITY WEDNESDAY NIGHT INTO THURSDAY. && .MARINE... EASTERLY FLOW CONTINUES THROUGH THE WEEKEND...BUT WEAK GRADIENT SHOULD KEEP SPEEDS BELOW SCA THRESHOLDS. OUTLOOK...SMALL CRAFT ADVISORIES MAY BE NEEDED WEDNESDAY NIGHT AND THURSDAY AS UPPER LEVEL ENERGY AND ITS ASSOCIATED SURFACE COLD FRONT MOVE TO THE COASTAL WATERS AND EVENTUALLY OFFSHORE. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...BPP/KLW NEAR TERM...BPP SHORT TERM...BPP LONG TERM...KLW AVIATION...BPP/KLW MARINE...BPP/KLW

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