Area Forecast Discussion
Issued by NWS Sterling, VA

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065 FXUS61 KLWX 121902 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 202 PM EST FRI FEB 12 2016 .SYNOPSIS...
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A STRONG COLD FRONT WILL CROSS THE REGION TONIGHT WITH ARCTIC HIGH PRESSURE BUILDING IN ITS WAKE FOR THE WEEKEND. LOW PRESSURE WILL IMPACT THE AREA MONDAY AND TUESDAY. A COLD FRONT AND ITS ASSOCIATED COLD FRONT WILL PASS THROUGH THE AREA WEDNESDAY.
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&& .NEAR TERM /THROUGH TONIGHT/...
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A POTENT COLD FRONT OVER THE OHIO VALLEY THIS AFTERNOON WILL PASS THROUGH OUR AREA TONIGHT. SHORTWAVE ENERGY ALONG WITH FORCING FROM THE COLD FRONT SHOULD BE ENOUGH FOR SOME SNOW SHOWERS TO BREAK OUT LATE THIS AFTERNOON FOR LOCATIONS WEST OF THE BLUE RIDGE MOUNTAINS AND THIS EVENING FOR LOCATIONS EAST OF THE BLUE RIDGE MOUNTAINS. SNOWFALL ACCUMULATIONS WILL BE LIGHT...BUT GIVEN THE RECENT COLD CONDITIONS EVEN A LITTLE SNOWFALL ACCUMULATION WILL CAUSE SLIPPERY CONDITIONS ON UNTREATED SURFACES. A WINTER WEATHER ADVISORY IS IN EFFECT FOR THE WASHINGTON AND BALTIMORE METROPOLITAN AREAS THIS EVENING. A WINTER WEATHER ADVISORY IS ALSO IN EFFECT FOR LOCATIONS ALONG AND WEST OF THE ALLEGHENY FRONT THROUGH TONIGHT. STRONG COLD ADVECTION AND AN UPSLOPE COMPONENT TO THE LOW-LEVEL FLOW WILL CAUSE ACCUMULATING SNOW ACROSS THIS AREA. THE COLD FRONT WILL MOVE OFF TO THE EAST LATE TONIGHT WHILE ARCTIC HIGH PRESSURE BUILDS OVER THE MIDWEST AND OHIO VALLEY. STRONG COLD ADVECTION AND PRESSURE RISES WILL CAUSE GUSTY NORTHWEST WINDS. THE COMBINATION OF VERY COLD AIR AND GUSTY WINDS WILL CAUSE WIND CHILL VALUES TO DIP WELL BELOW ZERO OVER THE BLUE RIDGE MOUNTAINS AND POTOMAC HIGHLANDS. ELSEWHERE...WIND CHILL VALUES WILL DROP TO BETWEEN -5 DEGREES AND 5 DEGREES. CYCLONIC CIRCULATION AROUND AN UPPER-LEVEL TROUGH AND STRONG COLD ADVECTION SUGGESTS THAT A FEW SNOW SHOWERS ARE POSSIBLE OVERNIGHT. COVERAGE WOULD BE LOCALIZED...BUT A BRIEF PERIOD OF HEAVIER SNOW MAY COAT THE GROUND IN A FEW SPOTS OVERNIGHT. HAVE ALSO ISSUED FOR NORTHERN AND CENTRAL PORTIONS OF THE CWA. GUSTS AROUND 50 MPH ARE EXPECTED WITH THE PRESSURE SURGE BEHIND THE COLD FRONT AFTER MIDNIGHT.
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&& .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
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ARCTIC HIGH PRESSURE WILL CONTINUE TO BUILD TOWARD THE REGION SATURDAY THROUGH SATURDAY EVENING BEFORE EVENTUALLY BUILDING OVERHEAD LATER SATURDAY NIGHT INTO SUNDAY. VERY COLD CONDITIONS ARE EXPECTED DURING THIS TIME ALONG WITH DANGEROUSLY LOW WIND CHILLS. THE WIND CHILL HEADLINES CONTINUE FOR THE BLUE RIDGE MOUNTAINS AND POTOMAC HIGHLANDS. ADDITIONAL WIND CHILL HEADLINES MAY BE NEEDED LATE SATURDAY NIGHT INTO SUNDAY MORNING FOR NORTHERN AND CENTRAL PORTIONS OF THE CWA. A FEW SNOW SHOWERS ARE POSSIBLE SATURDAY DUE TO STRONG COLD ADVECTION. ANY ACCUMULATION WOULD BE LOCALIZED...BUT A QUICK COATING OF SNOW CANNOT BE RULED OUT. SNOW SHOWERS WILL CONTINUE FOR LOCATIONS ALONG AND WEST OF THE ALLEGHENY FRONT ON SATURDAY...WITH ADDITIONAL ACCUMULATIONS EXPECTED. THE WIND ADVISORY CONTINUES FOR NORTHERN AND CENTRAL AREAS ON SATURDAY AS WELL. WINDS WILL GRADUALLY DIMINISH SATURDAY NIGHT INTO SUNDAY AS THE HIGH BUILDS OVERHEAD. MAX TEMPS SATURDAY WILL RANGE FROM THE SINGLE DIGITS IN THE MOUNTAINS TO THE LOWER AND MIDDLE 20S NEAR WASHINGTON AND BALTIMORE. MIN TEMPS SATURDAY NIGHT WILL RANGE FROM BELOW ZERO IN THE MOUNTAINS TO THE SINGLE DIGITS ACROSS MOST OTHER LOCATIONS. MAX TEMPS SUNDAY WILL RANGE FROM THE TEENS IN THE MOUNTAINS TO THE 20S ACROSS MOST OTHER LOCATIONS. FOR SUNDAY NIGHT...HIGH PRESSURE WILL MOVE OFF TO THE EAST WHILE AN UPPER-LEVEL TROUGH DEVELOPS OVER THE CENTRAL CONUS. SHORTWAVE ENERGY ASSOCIATED WITH THE TROUGH WILL CAUSE LOW PRESSURE TO DEVELOP OVER THE GULF COAST STATES. DESPITE THE LOW BEING FAR AWAY FROM THE AREA...THERE WILL BE PLENTY OF WARM AND MOIST AIR OVERRUNNING THE ARCTIC AIR IN PLACE. THIS WILL RESULT IN PLENTY OF CLOUDS ALONG WITH INCREASING CHANCES OF SNOW...ESPECIALLY AFTER MIDNIGHT.
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&& .LONG TERM /MONDAY THROUGH FRIDAY/...
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THE LOW WILL TRACK ACROSS THE GULF COAST STATES MONDAY WHILE THE HIGH CONTINUES TO SLIDE OFF TO THE EAST. WARM AND MOIST AIR WILL CONTINUE TO OVERRUN THE COLD AIR IN PLACE...RESULTING IN MORE SNOW. THE LOW WILL INTENSIFY AS IT TRACKS UP THE MID-ATLANTIC COAST MONDAY NIGHT INTO TUESDAY. MORE PRECIPITATION IS LIKELY OVER THE AREA. HOWEVER...WARMER AIR WILL CAUSE A CHANGE OVER TO A WINTRY MIX AND PERHAPS EVEN OVER TO ALL RAIN MONDAY NIGHT INTO TUESDAY. DETAILS ARE UNCERTAIN AT THIS TIME DUE TO GUIDANCE DIFFERING ON THE EXACT TRACK AND STRENGTH OF THE LOW. IF THE LOW IS STRONGER IT WILL LIKELY TRACK FARTHER WEST CAUSING WARMER AIR TO MOVE IN QUICKER. THIS WOULD KEEP THE THREAT FOR WINTRY MIX/ICE LOW. HOWEVER...IF THE LOW IS WEAKER IT WILL TRACK FARTHER TO THE SOUTH AND EAST. THIS WOULD KEEP LOW-LEVEL COLD AIR IN PLACE WHICH COULD LEAD TO A PROLONGED PERIOD OF WINTRY MIX/ICE. AS OF NOW...THE FORECAST LEANS SLIGHTLY TOWARD THE LATTER SOLUTION SINCE SCOURING OUT OF THE LOW-LEVEL COLD AIR WILL BE DIFFICULT. BOTTOM LINE...IT IS INCREASINGLY LIKELY THAT THERE WILL BE ACCUMULATING SNOW LATE SUNDAY NIGHT THROUGH MONDAY WITH A CHANGE OVER TO A WINTRY MIX MONDAY NIGHT AND POSSIBLY RAIN LATE MONDAY NIGHT OR DURING THE DAY TUESDAY. SEVERAL INCHES OF SNOW IS POSSIBLE...AND THIS WOULD IMPACT TRAVEL MONDAY AND MONDAY NIGHT...AND POSSIBLY INTO TUESDAY. THE LOW WILL FINALLY MOVE AWAY FROM THE AREA LATER TUESDAY AND DRIER AIR MAY MOVE INTO THE REGION LATE IN THE DAY. HIGH PRESSURE WILL BUILD TOWARD THE AREA DURING THE MIDDLE AND LATTER PORTIONS OF NEXT WEEK...BRINGING SEASONABLE CONDITIONS.
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&& .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
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A POTENT COLD FRONT WILL PASS THROUGH THE TERMINALS THIS EVENING. A FEW SNOW SHOWERS ARE LIKELY ALONG AND AHEAD OF THE FRONT. BRIEF IFR CONDITIONS ARE POSSIBLE IN ANY SNOW SHOWERS THAT DEVELOP. GUSTY NORTHWEST WINDS WILL DEVELOP BEHIND THE COLD FRONT LATE TONIGHT THROUGH SATURDAY. GUSTS 35 TO 40 KNOTS ARE EXPECTED. A COUPLE SNOW SHOWERS CANNOT BE RULED OUT DURING THIS TIME...BUT MUCH OF THE TIME SHOULD BE DRY. HIGH PRESSURE WILL RETURN FOR SATURDAY NIGHT AND SUNDAY...AND WINDS WILL DIMINISH DURING THIS TIME. LOW PRESSURE WILL APPROACH THE TERMINALS SUNDAY NIGHT THROUGH MONDAY NIGHT. SNOW WILL LIKELY BREAK OUT LATE SUNDAY NIGHT INTO MONDAY...BEFORE CHANGING TO A WINTRY MIX MONDAY NIGHT AND POSSIBLY RAIN TUESDAY. IFR CONDITIONS ARE LIKELY DURING THIS TIME. THE LOW WILL FINALLY MOVE AWAY FROM THE AREA LATER TUESDAY INTO WEDNESDAY.
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&& .MARINE...
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POTENT COLD FRONT WILL PASS THROUGH THE WATERS TONIGHT. GUSTY NORTHWEST WINDS WILL DEVELOP BEHIND THE COLD FRONT AFTER MIDNIGHT. A GALE WARNING IS IN EFFECT FOR THE WATERS. THE GUSTY NORTHWEST WINDS WILL CONTINUE THROUGH SATURDAY BEFORE SLOWLY DIMINISHING SATURDAY NIGHT INTO SUNDAY. THE GALE WARNING CONTINUES THROUGH SATURDAY NIGHT AND A SMALL CRAFT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE WATERS SUNDAY. HIGH PRESSURE WILL BUILD OVER THE WATERS LATER SUNDAY BEFORE MOVING OFF THE EAST EARLY NEXT WEEK. LOW PRESSURE WILL LIKELY IMPACT THE WATERS MONDAY NIGHT AND TUESDAY BEFORE MOVING AWAY FROM THE AREA DURING THE MIDDLE PORTION OF NEXT WEEK.
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&& .TIDES/COASTAL FLOODING...
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A STRONG NORTHWEST FLOW WILL CAUSE TIDAL ANOMALIES TO BE AROUND 2 FEET BELOW NORMAL SATURDAY INTO SUNDAY.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR DCZ001. WIND ADVISORY FROM 3 AM TO 6 PM EST SATURDAY FOR DCZ001. MD...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST SUNDAY FOR MDZ502. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR MDZ004>006-011-013-014-016-503>508. WIND ADVISORY FROM 3 AM TO 6 PM EST SATURDAY FOR MDZ003>006- 011-013-014-016>018-503>508. WINTER WEATHER ADVISORY UNTIL 6 PM EST SATURDAY FOR MDZ501. WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 9 AM EST SUNDAY FOR MDZ501. VA...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST SUNDAY FOR VAZ504-507-508. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR VAZ052>056-501-502-505-506. WIND ADVISORY FROM 3 AM TO 6 PM EST SATURDAY FOR VAZ028-031- 052>054-505-506. WINTER WEATHER ADVISORY UNTIL 6 PM EST SATURDAY FOR VAZ503. WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 9 AM EST SUNDAY FOR VAZ503. WV...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST SUNDAY FOR WVZ050-055-502-504-506. WIND ADVISORY FROM 3 AM TO 6 PM EST SATURDAY FOR WVZ051>053. WINTER WEATHER ADVISORY UNTIL 6 PM EST SATURDAY FOR WVZ501-503- 505. WIND CHILL WARNING FROM MIDNIGHT TONIGHT TO 9 AM EST SUNDAY FOR WVZ501-503-505. MARINE...FREEZING SPRAY ADVISORY FROM 3 AM SATURDAY TO 6 AM EST SUNDAY FOR ANZ530>543. GALE WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR ANZ530>543.
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&& $$ SYNOPSIS...BJL NEAR TERM...BJL SHORT TERM...BJL LONG TERM...KLW AVIATION...BJL/KLW MARINE...BJL/KLW TIDES/COASTAL FLOODING...BJL

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