Area Forecast Discussion


065 
FXUS61 KLWX 121902
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
202 PM EST FRI FEB 12 2016
.SYNOPSIS...
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. 
&&
.NEAR TERM /THROUGH TONIGHT/...
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.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
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.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
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.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
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. 
&&
.MARINE...
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. 
&&
.TIDES/COASTAL FLOODING...
A STRONG NORTHWEST FLOW WILL CAUSE TIDAL ANOMALIES TO BE AROUND 2
FEET BELOW NORMAL SATURDAY INTO SUNDAY. 
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
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.
&&
$$
SYNOPSIS...BJL
NEAR TERM...BJL
SHORT TERM...BJL
LONG TERM...KLW
AVIATION...BJL/KLW
MARINE...BJL/KLW
TIDES/COASTAL FLOODING...BJL