Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 271841 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 241 PM EDT SAT JUN 27 2015 .SYNOPSIS... A WARM FRONT WILL CONTINUE LIFTING INTO THE CENTRAL MID-ATLANTIC THROUGH THIS EVENING. A COLD FRONT WILL PASS THROUGH THE AREA TONIGHT AFTER MIDNIGHT. HIGH PRESSURE WILL BE IN PLACE FOR MONDAY WITH WEAK COLD FRONT TUESDAY NIGHT. LOW PRESSURE IS EXPECTED TO CROSS THE REGION FRIDAY. && .NEAR TERM /THROUGH SUNDAY/... TORNADO WATCH FOR SRN MD WITH CURRENT ACTIVITY APPROACHING THE WARM FRONT OVER SERN PORTIONS OF THE CWA. WARM FRONT WILL CONTINUE TO LIFT NORTH AND THAT TORNADO/SEVERE THREAT WILL EXPAND NW WITH THE WARM FRONT. AS OF 18Z...LOW PRESSURE DRIFTING NE OVER OHIO AND THE WARM FRONT FROM SRN MD SAGGING SW TO CNTRL VA. LOW INTENSIFIES AS IT DRIFTS NE THROUGH THIS EVENING...STALLING TONIGHT OVER NERN OH AS THE STORM BECOMES VERTICALLY STACKED. SBCAPE OF 1000 J/KG LIFTING NORTH INTO SRN PORTIONS OF THE CWA NORTH OF THE WARM FRONT. ONLY LIGHT LIGHTNING ACTIVITY SO FAR...BUT ACTIVITY OVER SERN VA WILL MOVE NORTH AND NEW ACTIVITY WILL DEVELOP IN SRN MD THEN INTO CNTRL MD AND N-CNTRL VA. CURRENT THOUGHT IS SEVERE/TORNADO THREAT WILL EXPAND TO EAST SIDE OF BLUE RIDGE. FLASH FLOOD RISK. THE METRO AREAS ARE PARTICULARLY SENSITIVE...SO THE DC METRO WAS INCLUDED FIRST IN A WARNING. SUBSEQUENT WARNINGS WILL BE BASED ON EXCESSIVE RAINFALL THAT IS EXPECTED TO COVER MANY AREAS. COLD FRONT ENTERS THE WEST LATE THIS EVENING AND CROSSES MOST AREAS AFTER MIDNIGHT. MIN TEMPS MID TO UPR 60S INLAND...AROUND 70F NEAR SHORE. WEST WINDS GUSTING 25 TO 30 MPH SUNDAY WITH MAX TEMPS UPR 70S TO LOW 80S. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... WRAP AROUND MOISTURE AROUND DEEP SFC CYCLONE OVER THE NORTHEAST AND CYCLONIC FLOW WILL MAINTAIN BKN SKIES WITH THE RISK OF A FEW SHOWERS MAINLY NORTHERN AND FAR WESTERN AREAS. BREEZY AND MUCH COOLER THAN NORMAL WITH TEMPS STRUGGLING TO HIT 80F. ANY WRAP-AROUND/UPSLOPE RAIN SHOWERS IN THE POTOMAC HIGHLANDS WILL END SUNDAY EVENING AS THE STRONG LOW PRESSURE SYSTEM PULLS AWAY FROM NEW ENGLAND. A MUCH COOLER AND DRIER AIRMASS WILL BE FOUND IN ITS WAKE...WHICH WILL ALLOW TEMPERATURES TO DROP INTO THE 50S EXCEPT IN THE URBAN AREAS AND COASTAL PLAIN. MONDAY WILL BE A DRY DAY AS SHORTWAVE RIDGING QUICKLY SLIDES ACROSS THE AREA. TEMPERATURES WILL REMAIN SLIGHTLY BELOW NORMAL. && .LONG TERM /TUESDAY THROUGH SATURDAY/... NEXT SHORTWAVE TROUGH WILL BE MOVING INTO THE GREAT LAKES MONDAY NIGHT...LEADING TO AT THE VERY LEAST INCREASING CLOUDS. SOME DIFFERENCES ON HOW MUCH PRECIP MAKES IT INTO OUR AREA...BUT HAVE CONFINED POPS WEST OF I-81 OVERNIGHT. WITH THE TROUGH AXIS APPROACHING TUESDAY...EXPECT AT LEAST SCATTERED CONVECTION ACROSS THE AREA. SFC LOW LIFTS NORTH INTO QUEBEC ON WED...WITH THE TRAILING COLD FRONT BECOMING PARALLEL TO THE UPPER FLOW AND STALLING OVER THE MID-ATLANTIC. THIS LEADS TO AN UNSETTLED PATTERN IN WHICH THE DETAILS ARE A BIT MURKY. THE 00Z GFS PUSHES THE FRONT SOUTH BY FRIDAY...WHILE THE ECMWF KEEPS IT NEARBY AND CONTINUES CHANCES FOR CONVECTION. TEMPERATURES ARE EXPECTED TO REMAIN WITHIN SEVERAL DEGREES OF NORMAL THROUGH THE UPCOMING WEEK. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... IFR CIGS/VSBYS FROM RAIN ACROSS THE DC METROS. TSTMS EXPECTED WITH A RISK OF DAMAGING WINDS ACROSS THE AREA PARTICULARLY LATER THIS AFTERNOON AND EVENING. CIGS IMPROVE TO VFR AFTER 06Z SUN AFTER A COLD FRONT SHIFTS WIND WEST. WEST WIND GUSTS 20 TO 25 KT SUNDAY IN VFR CONDS. VFR CONDITIONS EXPECTED SUNDAY NIGHT THROUGH MONDAY NIGHT. SLOW MOVING COLD FRONT APPROACHES TUESDAY AND THEN MAKES LITTLE PROGRESS. THUNDERSTORMS WITH SUB-VFR CONDITIONS WILL BE POSSIBLE TUESDAY...WITH WEDNESDAY/S THUNDERSTORM FORECAST A LITTLE LESS CERTAIN. ALSO SOUTHERLY WINDS MAY GUST ABOVE 20 KT ON TUESDAY. && .MARINE... SELY FLOW CONTINUES TO GUST 25 KT THROUGH THIS EVENING WITH SCA IN PLACE FOR ALL WATERS. HEAVY AND GUSTY THUNDERSTORMS WITH A WATER SPOUT THREAT INTO THE OVERNIGHT AS A WARM FRONT LIFTS ACROSS THE WATERS AND AHEAD OF A COLD FRONT THAT CROSSES LATE TONIGHT. WINDS SHIFT TO WSW TONIGHT (WITH A BRIEF LULL)...THEN BECOME REMAIN GUSTY THROUGH SUN. SCA THROUGH SUN NIGHT. GUSTY WESTERLY WINDS WILL CONTINUE INTO SUNDAY EVENING AND THE SCA WILL LIKELY NEED TO BE EXTENDED. WINDS WILL DIMINISH ON MONDAY AS HIGH PRESSURE QUICKLY PASSES BY. SOUTHERLY FLOW WILL BECOME ESTABLISHED MONDAY NIGHT...AND CHANNELING OVER THE BAY IS POSSIBLE. SCA IS MORE LIKELY ACROSS ALL WATERS ON TUESDAY AHEAD OF A COLD FRONT. SCATTERED THUNDERSTORMS MAY ALSO DEVELOP. WINDS WILL DIMINISH TUESDAY NIGHT INTO WEDNESDAY AS THE LOW PRESSURE CENTER MOVES INTO CANADA. && .TIDES/COASTAL FLOODING... WIDESPREAD MINOR COASTAL FLOODING EXPECTED TONIGHT ON THE PREFERRED HIGH TIDE. SELY FLOW 15 TO 25 KT HAS RAISED WATER DEPARTURES TO AROUND 1.5 FT ON THE BAY AND 2 FT IN THE UPPER TIDAL POTOMAC. WATER LEVELS WILL CONTINUE TO RISE THROUGH THIS EVENING AHEAD OF A COLD FRONT. AFTERNOON HIGH TIDE WILL SEE MINOR COASTAL FLOODING AT THE PARTICULARLY SENSITIVE SITE OF DC/ALEXANDRIA AND ANNAPOLIS WHERE AN ADVISORY IS IN EFFECT. WIDESPREAD MINOR COASTAL FLOODING TONIGHT ON THE PREFERRED HIGH TIDE. CURRENT ADVISORY FOR WRN SHORE OF THE BAY AND DC/ALEXANDRIA FOR THE PREFERRED HIGH TIDE TONIGHT. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...FLASH FLOOD WATCH UNTIL 2 AM EDT SUNDAY FOR DCZ001. COASTAL FLOOD ADVISORY UNTIL 9 AM EDT SUNDAY FOR DCZ001. MD...FLASH FLOOD WATCH UNTIL 2 AM EDT SUNDAY FOR MDZ003>006-011-013- 014-016-501>508. COASTAL FLOOD ADVISORY FROM 8 PM THIS EVENING TO 4 AM EDT SUNDAY FOR MDZ017-018. COASTAL FLOOD ADVISORY FROM 2 AM TO 10 AM EDT SUNDAY FOR MDZ011-508. COASTAL FLOOD ADVISORY UNTIL 7 AM EDT SUNDAY FOR MDZ014. VA...FLASH FLOOD WATCH UNTIL 2 AM EDT SUNDAY FOR VAZ025>031-036>040- 050>056-501>508. COASTAL FLOOD ADVISORY UNTIL 9 AM EDT SUNDAY FOR VAZ054. WV...FLASH FLOOD WATCH UNTIL 2 AM EDT SUNDAY FOR WVZ050>053-055- 501>506. MARINE...FLASH FLOOD WATCH UNTIL 2 AM EDT SUNDAY FOR ANZ535-538. SMALL CRAFT ADVISORY UNTIL 7 AM EDT MONDAY FOR ANZ530>534- 537>543. SMALL CRAFT ADVISORY UNTIL 9 PM EDT SUNDAY FOR ANZ535-536. COASTAL FLOOD ADVISORY UNTIL 9 AM EDT SUNDAY FOR ANZ535. COASTAL FLOOD ADVISORY FROM 8 PM THIS EVENING TO 4 AM EDT SUNDAY FOR ANZ542. COASTAL FLOOD ADVISORY FROM 2 AM TO 10 AM EDT SUNDAY FOR ANZ538. && $$ SYNOPSIS...BAJ NEAR TERM...BAJ SHORT TERM...LFR LONG TERM...ADS/IMR AVIATION...BAJ/ADS/IMR MARINE...BAJ/ADS/IMR TIDES/COASTAL FLOODING...BAJ

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