Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 040748 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 348 AM EDT TUE AUG 4 2015 .SYNOPSIS...
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A COLD FRONT WILL CONTINUE TO GRADUALLY SHIFT SOUTHEAST THROUGH THE AREA TODAY. HIGH PRESSURE WILL BUILD INTO THE AREA LATER TONIGHT THROUGH WEDNESDAY. THE BOUNDARY WILL RETURN NORTH AS A WARM FRONT AND STALL OUT OVER THE AREA FOR THURSDAY AND FRIDAY. LOW PRESSURE WILL RIDE ALONG THE BOUNDARY...PASSING THROUGH THE REGION THURSDAY NIGHT AND FRIDAY. HIGH PRESSURE WILL GRADUALLY BUILD IN BEHIND THE LOW NEXT WEEKEND.
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&& .NEAR TERM /THROUGH TONIGHT/...
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A WEAK COLD FRONT HAS MOVED INTO THE AREA EARLY THIS MORNING. INSTABILITY ACTUALLY INCREASED OVERNIGHT DUE TO A THETA-E RIDGE AXIS JUST AHEAD OF THE FRONT. THEREFORE...SHOWERS AND THUNDERSTORMS DID DEVELOP...MAINLY ACROSS EASTERN WEST VIRGINIA INTO NORTHERN MARYLAND. THIS ACTIVITY WILL CONTINUE TO PUSH TO THE EAST-NORTHEAST EARLY THIS MORNING BUT IT SHOULD WEAKEN AS IT MOVES INTO A MORE STABLE ENVIRONMENT. THE COLD FRONT WILL GRADUALLY SLIDE SOUTH AND EAST THROUGH THE AREA TODAY. LITTLE TEMPERATURE GRADIENT IS ASSOCIATED WITH THE BOUNDARY...BUT THERE WILL BE A DEWPOINT GRADIENT. A WESTERLY DOWNSLOPING FLOW BEHIND THE FRONT ALONG WITH SUNSHINE WILL ALLOW FOR HOT CONDITIONS. WITH HIGHER HUMIDITY SOUTH AND EAST OF THE BOUNDARY A FEW SHOWERS AND THUNDERSTORMS ARE EXPECTED TO POP UP THIS AFTERNOON AND EVENING. MODERATE SHEAR PROFILES SUGGEST THAT SOME STORMS CAN BECOME SEVERE. THE BEST CHANCE FOR SEVERE THUNDERSTORMS WILL BE NEAR AND EAST OF INTERSTATE 95 WHERE HUMIDITY WILL BE HIGHER AHEAD OF THE BOUNDARY DURING PEAK HEATING. THE BOUNDARY WILL CONTINUE TO SLIDE SOUTH TONIGHT AND HIGH PRESSURE WILL BUILD OVERHEAD...CAUSING DRY AND COMFORTABLE CONDITIONS.
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&& .SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
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HIGH PRESSURE WILL REMAIN IN CONTROL FOR WEDNESDAY THROUGH WEDNESDAY NIGHT WHILE THE COLD FRONT STALLS TO OUR SOUTH. A WEST TO NORTHWEST FLOW WILL USHER IN DRY AND COOLER CONDITIONS DURING THIS TIME. ALTHOUGH...MAX TEMPS WEDNESDAY WILL STILL BE NEAR CLIMO DUE TO SUNSHINE AND A DOWNSLOPING FLOW. THE BOUNDARY WILL RETURN NORTH AS A WARM FRONT THURSDAY AND IT WILL STALL OUT OVERHEAD LATE IN THE DAY. LOW PRESSURE WILL RIDE ALONG THE BOUNDARY AND APPROACH FROM THE WEST LATE IN THE DAY. CLOUDS WILL INCREASE AND THERE IS A CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS...ESPECIALLY DURING THE AFTERNOON HOURS. TIMING IS STILL A LITTLE UNCERTAIN AS OF NOW DUE TO DIVERGENCE WITH THE GUIDANCE.
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&& .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
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THE WAVE OF LOW PRESSURE WILL PASS THROUGH THE AREA THURSDAY NIGHT INTO FRIDAY...AND ANOTHER ONE MAY RIDE ALONG THE BOUNDARY AND PASS THROUGH LATER FRIDAY INTO SATURDAY. THIS WILL BRING A BETTER CHANCE FOR SHOWERS AND POSSIBLE THUNDERSTORMS. AS THE SECOND WAVE OF LOW PRESSURE DEPARTS...THE BOUNDARY WILL SLIDE TO THE SOUTH AND HIGH PRESSURE MAY RETURN LATER IN THE WEEKEND INTO EARLY NEXT WEEK.
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&& .AVIATION /08Z TUESDAY THROUGH SATURDAY/...
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A FEW THUNDERSTORMS ARE EXPECTED NEAR KMRB UNTIL AROUND 9Z THIS MORNING. ELSEWHERE...CONVECTION SHOULD REMAIN OFF TO THE NORTH AND WEST. A COLD FRONT WILL PASS THROUGH THE TERMINALS TODAY AND A FEW THUNDERSTORMS ARE POSSIBLE DURING THE AFTERNOON AND EVENING HOURS...MAINLY ACROSS THE EASTERN TERMINALS. HIGH PRESSURE WILL BRING VFR CONDITIONS TONIGHT THROUGH WEDNESDAY NIGHT. NORTHWEST WINDS MAY GUST AROUND 15 TO 20 KNOTS WEDNESDAY AFTERNOON. THE COLD FRONT WILL RETURN AS A WARM FRONT FOR THURSDAY THROUGH SATURDAY. WAVES OF LOW PRESSURE WILL RIDE ALONG THE BOUNDARY...INCREASING THE CHANCES FOR SHOWERS AND POSSIBLE THUNDERSTORMS. SUBVFR CONDITIONS ARE LIKELY DURING THIS TIME.
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&& .MARINE...
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SHOWERS AND THUNDERSTORMS EARLY THIS MORNING MAY APPROACH THE NORTHERN CHESAPEAKE BAY...AS OF NOW MOST OF THE ACTIVITY SHOULD REMAIN OFF TO THE NORTH AND WEST. A COLD FRONT WILL PASS THROUGH THE WATERS LATER THIS AFTERNOON AND EVENING. A FEW THUNDERSTORMS ARE POSSIBLE...AND GUSTY WINDS/HAIL ARE POSSIBLE IN THE STRONGER STORMS. HIGH PRESSURE WILL BUILD OVER THE WATERS LATER TONIGHT THROUGH WEDNESDAY NIGHT AS THE BOUNDARY STALLS TO OUR SOUTH. A SMALL CRAFT ADVISORY IS IN EFFECT FOR MIDDLE PORTIONS OF THE BAY AND LOWER TIDAL POTOMAC THROUGH THIS EVENING. WINDS MAY APPROACH ALSO SCA CRITERIA WEDNESDAY. THE BOUNDARY WILL RETURN NORTH AS A WARM FRONT FOR THURSDAY THROUGH SATURDAY AND IT WILL STALL OUT OVERHEAD DURING THIS TIME. WAVES OF LOW PRESSURE WILL RIDE ALONG THE BOUNDARY...INCREASING THE CHANCES FOR SHOWERS AND THUNDERSTORMS.
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&& .TIDES/COASTAL FLOODING...
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A SOUTH TO SOUTHWEST FLOW HAS CAUSED ANOMALIES TO INCREASE TO BETWEEN ONE QUARTER AND ONE HALF FOOT ABOVE NORMAL. HOWEVER...WATER LEVELS ARE EXPECTED TO REMAIN BELOW MINOR FLOODING THRESHOLDS.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR ANZ532-533- 540>542. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ534-537- 543.
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&& $$ SYNOPSIS...BJL NEAR TERM...BJL SHORT TERM...BJL LONG TERM...BJL AVIATION...BJL MARINE...BJL TIDES/COASTAL FLOODING...BJL

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