Area Forecast Discussion
Issued by NWS Sterling, VA

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156 FXUS61 KLWX 100542 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1242 AM EST WED FEB 10 2016 .SYNOPSIS... LOW PRESSURE OVER TORONTO WILL DRIFT EAST TO NEW ENGLAND THROUGH WEDNESDAY NIGHT. HIGH PRESSURE BUILDS OVER THE AREA INTO FRIDAY. A STRONG COLD FRONT SWINGS THROUGH FRIDAY NIGHT AND SATURDAY WITH ARCTIC HIGH PRESSURE BUILDING IN FOR THE WEEKEND. LOW PRESSURE MAY IMPACT THE MID- ATLANTIC MONDAY INTO TUESDAY. && .NEAR TERM /THROUGH TODAY/... CANCELLED WINTER WEATHER ADVISORIES EAST OF THE ALLEGHENY FRONT AS APPRECIABLE SNOW IN REMAINING AREAS DISSIPATED TO FLURRIES. AS OF 9PM...990MB SFC LOW JUST WEST OF TORONTO/YYZ. SYSTEM IS VERTICALLY STACKED/OCCLUDED WITH A SERIES OF SHORTWAVES ROUNDING THROUGH FRIDAY AS THE LOW DRIFTS EAST ACROSS NEW ENGLAND. PVA AHEAD OF UPR TROUGH AXIS HAS ALLOW SOME AREAS OF LIGHT SNOW WITH EMBEDDED POSSIBLY MODERATE SNOW OVER THE ERN WV PANHANDLE THIS EVENING. THIS WILL DRIFT EAST ACROSS THE BALT-WASH METRO AREA THROUGH THE REST OF THE NIGHT. LIKELY POPS FOR LIGHT ADDITIONAL ACCUM...GENERALLY LESS THAN A QUARTER INCH OF NEW SNOWFALL. HOWEVER...THE PRESENCE OF BANDS COULD ALLOW A SMALL AREA TO PICK UP HALF INCH OR SO OVERNIGHT. TEMPERATURES WILL DROP INTO THE 20S FOR MOST OF THE AREA WITH STEEP LAPSE RATES UNDER THE UPR TROUGH...PROMOTING DEVELOPMENT. SIDE NOTE...AREAS OF SNOW THAT HAVE PERSISTED FROM N-CNTRL VA TO SRN MD WILL CONTINUE TO SLIDE EAST AND DISSIPATE THROUGH MIDNIGHT. MARGINAL TEMPS...ABOVE FREEZING HAVE LIMITED ACCUM...BUT AS TEMPS DIP BELOW FREEZING A LOCAL TENTH INCH IS POSSIBLE YET THIS EVENING BEFORE IT ENDS. SHORTWAVE WITH OVERNIGHT ACTIVITY QUICKLY SHIFTS EAST BY SUNRISE. NEXT SHORTWAVE CROSSES WEDNESDAY EVENING WITH PRETROUGH DEVELOPMENT OF FLURRIES POSSIBLE ACROSS THE AREA FROM WEST TO EAST. LOW RISK OF ACCUM...PARTICULARLY SINCE THIS LOOKS TO REACH THE BAY BY SUNSET...BUT WILL HAVE TO CONTINUE TO MONITOR. AGAIN...STEEP LAPSE RATES AND PARTLY SUNNY SKIES WILL PROMOTE SOME SHALLOW CONVECTION. MAX TEMPS WEDNESDAY LOW TO MID 30S WEST OF THE PIEDMONT AND LOW 40S EAST. STEEP LAPSE RATES MEAN ANY PRECIP WOULD FALL AS SNOW. && .SHORT TERM /TONIGHT THROUGH 6 PM THURSDAY/... MID ATLC WL BE UNDER THE INFLUENCE OF A BROAD UPR LVL TROF THRU THIS PD. COOL TEMPS...PSBLY SCT SNSH. HIGHS IN THE 30S...LOWS WED NGT IN THE TEENS FM I-95 TO E OF THE HIGHLANDS. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... SFC HIGH PRESSURE FINALLY MAKES SOME ADVANCEMENT INTO THE AREA THURSDAY NIGHT WITH VERY SUBTLE HEIGHT RISES ALOFT. UPSLOPE SNOW POTENTIAL WILL DIMINISH. HOWEVER CLOSED UPPER LOW WILL REMAIN POSITIONED OVER QUEBEC AND THE NEXT SHORTWAVE WILL APPROACH FRIDAY AFTERNOON WITH AN INCREASING CHANCE OF LIGHT UPSLOPE SNOW SHOWERS. AREAS TO THE EAST WILL BE DRY THOUGH. BELOW NORMAL TEMPS WILL CONTINUE...WITH WIND CHILLS BELOW ZERO POSSIBLE THURSDAY NIGHT IN THE HIGHEST ELEVATIONS. UPPER LEVEL TROUGH CONTINUES OVER OUR REGION FRI NIGHT AND INTO THE WEEKEND... ENHANCING UPSLOPE SNOW SHOWERS. SOME SNOW SHOWERS COULD MAKE IT EAST OF THE BLUE RIDGE. CAA FROM THE NWLY WINDS WILL BE KEEPING THE TEMPS WELL BELOW NORMAL DURING THE WEEKEND AND SLIGHTLY BELOW NORMAL FOR MON AND TUE. SOME ADDITIONAL PRECIP PSBL MON INTO TUE BUT GUIDANCE IS NOT IN GOOD AGREEMENT ATTM. SAT SEEMS TO BE COLDEST DAY OF THIS PERIOD WITH HIGH TEMPS IN THE TEENS AND 20S... AND LOW TEMPS IN THE SINGLE DIGITS AND BELOW ZERO. SAT WILL ALSO HAVE GUSTY WINDS... AS HIGH AS 20 MPH... SO WIND CHILLS WILL BE A CONCERN. HIGH TEMPS WILL BE INCREASING INTO TUE FROM THE 20S TO THE 40S... AND LOW TEMPS WILL BE MAINLY IN THE TEENS INTO THE 20S. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... VFR CONDS WITH NWLY SURGE TO 20 KT CROSSING THE DC METROS ATTM. LIGHT SNOW NEAR KMRB THIS EVENING WILL SPREAD SOUTHEAST ACROSS THE DC METROS AFTER MIDNIGHT AS NOTED IN 00Z TAFS. VFR WED THRU THU AS HIGH PRESSURE BUILDS. GUSTY NWLY FLOW TO 25 KT AT TIMES. FLURRIES POSSIBLE WEDNESDAY AFTERNOON ACROSS DC METROS. VFR EXPECTED THURSDAY NIGHT- FRIDAY UNDER HIGH PRESSURE. STRONG COLD FRONT CROSSES SATURDAY. && .MARINE... SCA IN EFFECT FOR ALL WATERS THROUGH WEDNESDAY NIGHT. NWLY SURGE WITH GUSTS 20 TO 22KT THIS EVENING/THROUGH MIDNIGHT...THEN GUSTING TO 25KT THROUGH THE DAY WEDNESDAY. NWLY GALES POSSIBLY BEGIN WEDNESDAY NIGHT AND ARE LIKELY THURSDAY MORNING. SCA CONDITIONS WILL CONTINUE THURSDAY NIGHT OVER AT LEAST PORTIONS OF THE WATERS BEFORE DIMINISHING SOME INTO FRIDAY AS HIGH PRESSURE BUILDS OVR THE WATERS. SUB SCA CONDITIONS FRI NIGHT... THEN PSBL SCA CONDITIONS ON SAT WITH WIND GUSTS UP TO 20 MPH. && .TIDES/COASTAL FLOODING...
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NWLY FLOW HAS OVERSPREAD THE AREA AND WILL INCREASE THROUGH MIDNIGHT. THIS WILL AIDE IN PUSHING SOME OF THE EXCESS WATER OUT OF THE ESTUARY. HOWEVER...TIDAL ANOMALIES ARE JUST ABOVE TWO FEET...AND UNFORTUNATELY ARENT DROPPING FAST ENOUGH. WITH THE NEW HIGH TIDE ROLLING IN...LEVELS ARE SUFFICIENT TO REACH MINOR THRESHOLDS AT SOLOMONS ISLAND...WITH THE TIME OF HIGH TIDE STILL 2 1/2 HOURS AWAY. HAVE ADDED CALVERT CO BACK INTO THE COASTAL FLOOD ADVY...TO JOIN THE CURRENT ADVY IN ST MARYS CO. BOTH ARE VALID TIL 5AM. AM HOPEFUL THAT DEPARTURE WILL BEGIN TO DROP MORE...SUCH THAT THE ADVY WONT NEED TO BE CARRIED INTO ANNA ARUNDEL CO /OR AFFECT NORTH BEACH. WL BE MAKING THOSE DECISIONS WITHIN THE NEXT CPL OF HOURS.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...NONE. MD...COASTAL FLOOD ADVISORY UNTIL 5 AM EST EARLY THIS MORNING FOR MDZ017-018. WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR MDZ501. VA...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR VAZ503. WV...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR WVZ501- 503-505. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ530>543.
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