Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 250014 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 814 PM EDT SUN AUG 24 2014 .SYNOPSIS... HIGH PRESSURE WILL BUILD OVER THE REGION THROUGH WEDNESDAY BEFORE A COLD FRONT PASSES THROUGH THE AREA WEDNESDAY NIGHT INTO THURSDAY. HIGH PRESSURE WILL RETURN FOR LATE IN THE WEEK. && .NEAR TERM /THROUGH MONDAY/...
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HIGH PRESSURE CONTINUES TO BUILD ACROSS THE MID-ATLANTIC FROM THE NORTH THIS EVENING. CLOUD COVER HAS BEEN GRADUALLY RETREATING TO THE WEST...WITH A CLEAR TO SCATTERED CLOUD DECK OVER THE BALTIMORE/WASHINGTON METROS...SRN MD AND THE VA PIEDMONT. SUBSIDENCE FROM THE HIGH IS EXPECTED TO CONTINUE TO ERODE THE EASTERN EDGE OF THE CLOUD DECK THIS EVENING...WITH CLEAR TO PARTLY CLOUDY SKIES EXPECTED OVER THE ENTIRE CWA EXCEPT PORTIONS OF THE HIGHLANDS BY MIDNIGHT. TEMPS ARE EXPECTED TO DROP INTO THE LOW 60S BY MIDNIGHT OVER MOST OF THE CWA...WITH LOW 70S PERSISTING OVER THE BALTIMORE/WASHINGTON URBAN AREAS. HIGH PRESSURE WILL CONTINUE TO DROP INTO THE AREA FROM THE NORTH AND EAST TONIGHT THROUGH MONDAY. DRIER AIR WILL SLOWLY WORK ITS WAY INTO THE AREA. CLOUDS WILL CONTINUE TO DECREASE OVERNIGHT FROM THE LOSS OF DAYTIME HEATING AND ALSO SUBSIDENCE FROM BUILDING HIGH PRESSURE. MIN TEMPS WILL RANGE FROM THE MID TO UPPER 50S ACROSS MOST LOCATIONS TO THE MIDDLE 60S IN DOWNTOWN WASHINGTON AND BALTIMORE. PATCHY FOG IS EXPECTED LATE TONIGHT...MAINLY ACROSS RIVER VALLEYS AND RURAL AREAS. HIGH PRESSURE WILL REMAIN OVERHEAD MONDAY...BRINGING DRY CONDITIONS ALONG WITH SUNSHINE. ANY FOG WILL BURN OFF BY MID- MORNING. MAX TEMPS WILL BE A FEW DEGREES WARMER THAN TODAY DUE TO MORE SUNSHINE...RANGING FROM THE LOWER 70S IN THE MOUNTAINS TO THE LOWER 80S ACROSS MOST OTHER LOCATIONS.
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&& .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... UPPER RIDGE AXIS NUDGES OVERHEAD MONDAY NIGHT INTO TUESDAY MORNING. WITH HIGH PRESSURE AND DRY AIRMASS IN PLACE...GOOD RADIATIONAL COOLING SHOULD MAKE TUESDAY MORNING THE COOLEST OF THE WEEK. SOME RADIATIONAL FOG WILL BE POSSIBLE AS WELL...ALTHOUGH IT SHOULD BE CONFINED TO RIVER VALLEYS. UPPER RIDGE BEGINS TO FLATTEN OUT TUESDAY NIGHT INTO WEDNESDAY WITH LOWER LEVEL WARM AIR ADVECTION AND AXIS OF MOISTURE ADVECTING IN FROM THE WEST. TEMPERATURES AND HUMIDITY WILL BEGIN TO INCREASE WEDNESDAY AS A RESULT. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... UPPER RIDGE DOMINATES ACROSS THE SOUTHEAST CONUS LATE IN THE WEEK AND THROUGH THE WEEKEND AS TROPICAL SYSTEM SWINGS EAST OFFSHORE THE SOUTHEAST COAST. NORTHERN STREAM CANADIAN TROUGH DIVES SOUTHEAST ACROSS THE NORTHEAST CONUS AND PUSHES A SURFACE COLD FRONT THROUGH THE REGION WEDNESDAY NIGHT INTO THURSDAY. SHOULD SEE SOME SHOWERS AND A FEW STORMS WITH THIS FROPA BEFORE COOLER AIR ADVECTS IN FOR FRIDAY. UPPER RIDGE LOOKS TO RE-AMPLIFY ACROSS THE REGION FOR THE WEEKEND AS FRONT RETREATS AS A WARM FRONT SATURDAY. ANOTHER COLD FRONTAL BOUNDARY WILL THEN APPROACH FROM THE NORTHWEST AHEAD OF APPROACHING MID-LEVEL NORTHERN STREAM TROUGH. THIS WILL RESULT IN UNSETTLED CONDITIONS THROUGH THE WEEKEND. && .AVIATION /00Z MONDAY THROUGH FRIDAY/...
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VFR CONDITIONS ARE EXPECTED THROUGH TONIGHT AT MOST TERMINALS. PATCHY BR MAY CAUSE MVFR/IFR VSBYS LATE TONIGHT INTO EARLY MONDAY MORNING...ESPECIALLY FOR KMRB AND KCHO. ANY FOG WILL BURN OFF BY MID-MORNING MONDAY AND VFR CONDITIONS ARE EXPECTED FOR THE REST OF THE DAY. WINDS BECOME LGT/VRB TONIGHT...THEN E-NE FLOW OF LESS THAN 10KT EXPECTED MONDAY. HIGH PRESSURE WILL BE IN PLACE MONDAY NIGHT THROUGH WEDNESDAY. A COLD FRONT WILL BRING THE CHANCE OF SHOWERS AND STORMS AS IT PASSES THROUGH WEDNESDAY NIGHT INTO THURSDAY. A WARM FRONT WILL LIFT NORTH ACROSS THE AREA SATURDAY AND UNSETTLED WEATHER CONDITIONS ARE EXPECTED THROUGH THE WEEKEND.
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&& .MARINE...
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EAST TO NORTHEAST WINDS ARE EXPECTED THROUGH TONIGHT. A SMALL CRAFT ADVISORY IS IN EFFECT THROUGH TONIGHT FOR THE MARYLAND CHESAPEAKE BAY FROM DRUM POINT TO SMITH POINT INCLUDING THE TANGIER SOUND. WIND GUSTS MAY BE SUB-SCA THIS EVENING...BUT ENOUGH OF A PRESSURE GRADIENT SHOULD BE IN PLACE FOR WINDS TO INCREASE AGAIN OVERNIGHT. MODEL SOUNDINGS THIS EVENING CONTINUE TO SUGGEST THIS...SO WILL LEAVE THE SCA IN PLACE. NORTHEAST WINDS WILL CONTINUE MONDAY...BUT WIND SPEEDS SHOULD REMAIN BELOW SCA CRITERIA. HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN MONDAY NIGHT THROUGH WEDNESDAY WITH WINDS REMAINING BELOW SCA LEVELS. A COLD FRONT WILL BRING THE CHANCE OF SHOWERS AND WEDNESDAY NIGHT INTO THURSDAY. A WARM FRONT WILL LIFT NORTH ACROSS THE AREA SATURDAY AND UNSETTLED WEATHER CONDITIONS ARE EXPECTED THROUGH THE WEEKEND.
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&& .TIDES/COASTAL FLOODING...
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A PERSISTENT ONSHORE FLOW HAS CAUSED TIDAL ANOMALIES TO REMAIN AROUND 1 TO 1.25 FEET ABOVE NORMAL. THE FLOW PATTERN WILL NOT CHANGE FOR THE NEXT COUPLE OF TIDE CYCLES...MEANING TIDAL ISSUES WILL LINGER. THE EVENING TIDE WILL BE THE LOWER OF THE TWO ASTRONOMICALLY...BUT WATER LEVELS WILL BE NEAR MINOR FLOODING THRESHOLDS. THERE IS A BETTER CHANCE FOR MINOR FLOODING WITH THE HIGH TIDE LATE TONIGHT INTO MONDAY MORNING SINCE THAT WILL BE THE HIGHER OF THE TWO ASTRONOMICAL NORMS. A COASTAL FLOOD ADVISORY IS IN EFFECT UNTIL MONDAY MORNING FOR THE WESTERN SHORE OF THE MARYLAND CHESAPEAKE BAY FROM ANNE ARUNDEL COUNTY TO ST MARYS...AND FOR THE UPPER TIDAL POTOMAC RIVER NEAR WASHINGTON DC AND ALEXANDRIA. AS FOR BALTIMORE...ANOMALIES OF LESS THAN 1 FOOT WERE NOT ENOUGH FOR MINOR FLOODING EARLY THIS EVENING. CBOFS HAS BEEN FORECASTING AN INCREASE IN ANOMALIES FOR THE MONDAY MORNING HIGH TIDE...BUT IT HAS ALSO HAS BEEN OVERESTIMATING DEPARTURES SUNDAY. A 1.2 FOOT ANOMALY WILL BE NEEDED FOR MINOR FLOODING MONDAY MORNING...WHICH MAY BE DIFFICULT TO ACHIEVE GIVEN A LIGHT WIND REGIME TONIGHT. WILL CONTINUE TO MONITOR. CBOFS INDICATES POTENTIAL TO TOUCH MINOR COASTAL FLOODING FOR POINTS IN CALVERT AND ST. MARYS COUNTIES FOR THE MONDAY AFTERNOON HIGH TIDE. WILL REFRAIN FROM EXTENDING THEIR ADVISORIES AT THIS POINT IN TIME SINCE THE FORECAST IS MARGINAL. LITTLE CHANGE TO THE OVERALL PATTERN THROUGH TUESDAY...SO WERE NOT OUT OF THE WOODS FOR TUE MORNING EITHER.
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&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...COASTAL FLOOD ADVISORY UNTIL 11 AM EDT MONDAY FOR DCZ001. MD...COASTAL FLOOD ADVISORY UNTIL 5 AM EDT MONDAY FOR MDZ017-018. COASTAL FLOOD ADVISORY UNTIL 11 AM EDT MONDAY FOR MDZ014. VA...COASTAL FLOOD ADVISORY UNTIL 11 AM EDT MONDAY FOR VAZ054. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ534-537-543. && $$ SYNOPSIS...BJL NEAR TERM...BJL/KCS SHORT TERM...AEB LONG TERM...AEB AVIATION...BJL/AEB MARINE...BJL/AEB TIDES/COASTAL FLOODING...KCS/BJL

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