105
FXUS61 KLWX 142020
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
320 PM EST SUN DEC 14 2025
SYNOPSIS
BITTERLY COLD CONDITIONS ARE EXPECTED TONIGHT AS ARCTIC HIGH
PRESSURE BUILDS INTO THE REGION. WIND CHILLS WILL FALL INTO THE
SINGLE DIGITS FOR MOST LOCATIONS HEADING INTO MONDAY MORNING
WITH SUBZERO VALUES OVER THE MOUNTAINS. COLD CONDITIONS
CONTINUE THROUGH MONDAY NIGHT WITH GRADUALLY WARMING
TEMPERATURES TUESDAY AND WEDNESDAY. RAIN CHANCES RETURN WITH A
STRONG COLD FRONT LATE WEEK.
NEAR TERM /UNTIL 6 AM MONDAY MORNING/
WEB CAMERAS AND MICROWAVE IMAGERY FROM SEVERAL NOAA POLAR
PASSES CONTINUE TO INDICATE SNOW IS STILL FALLING ACROSS
WESTERN GARRETT AND WESTERN GRANT COUNTIES. THE TREND SHOULD BE
FOR THE SNOW RATES TO DIMINISH AS SUBSIDENCE INVERSION BEGINS TO
STRENGTHEN AND LOW-LEVEL CURVATURE BECOMES MORE ANTICYCLONIC AS
HIGH PRESSURE STARTS BUILDING CLOSER TO THE AREA.
THE MAIN STORY TONIGHT AND MONDAY WILL BE THE BITTER COLD WIND
CHILLS WITH VALUES APPROACHING ZERO AT THE LOWER ELEVATIONS AND
NEGATIVE TEENS ACROSS THE HIGHER ELEVATIONS. COLD WEATHER
ADVISORIES REMAIN IN EFFECT, MAINLY FOR THE HIGHER ELEVATIONS OF
THE ALLEGHENY AND BLUE RIDGE MOUNTAINS INTO MONDAY.
SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/
FOR THE PAST COUPLE OF DAYS, MODELS HAVE BEEN TRYING TO DEVELOP
AN AREA OF VERY LIGHT SNOW ACROSS NORTHERN MD MONDAY AFTERNOON
AS SHORTWAVE ENERGY DROPS SOUTHEASTWARD FROM LK HURON. CLOSE
EXAMINATIONS OF MODEL SOUNDINGS SHOW VERY DRY AIR/LARGE DEWPOINT
DEPRESSIONS BELOW 700 MB ACROSS NORTHERN MD AND SOUTHERN PA.
VERY DOUBTFUL THAT ANYTHING WOULD BE ABLE TO REACH THE GROUND.
VERY COLD MONDAY NIGHT AS HIGH PRESSURE SETTLES IN AND WINDS
BECOME LIGHT. SLOW WARMING TREND BEGINS TUESDAY AS HIGH PRESSURE
SHIFTS OFFSHORE AND WINDS TURN MORE SOUTHERLY WITH TIME.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
TEMPERATURES CONTINUE TO WARM MIDWEEK AS A RESULT OF HIGH PRESSURE
WEAKENING AND PUSHING FURTHER OFF THE EAST COAST. ZONAL FLOW WILL
PREVAIL ALOFT WITH WARM AIR ADVECTION ENSUING OUT OF THE SOUTHWEST
AT THE SURFACE. THIS WILL HELP TEMPERATURES REBOUND BACK TO NORMAL
LEVELS IF NOT ABOVE NORMAL ON BOTH WEDNESDAY AND THURSDAY AFTERNOON.
HIGH TEMPERATURES WEDNESDAY WILL PUSH INTO THE MID TO UPPER 40S WITH
PORTIONS OF THE SHENANDOAH VALLEY AND CENTRAL VA PIEDMONT
REACHING INTO THE MID 50S. MOUNTAIN LOCATIONS WILL THAW OUT AS
WELL WITH HIGHS IN THE UPPER 30S. LOWS WEDNESDAY NIGHT WILL FALL
BACK INTO THE UPPER 20S AND LOW 30S.
DRY CONDITIONS WILL LIKELY PREVAIL THROUGH THURSDAY AFTERNOON WITH
INCREASING CLOUDS AS A POTENT TROUGH AND SURFACE LOW PRESSURE SYSTEM
WORK INTO THE GREAT LAKES REGION. THIS LOW PRESSURE SYSTEM WILL SEND
A SERIES OF WEAK WARM FRONTAL BOUNDARIES THROUGH THE REGION THURSDAY
AFTERNOON AND EVENING WITH A POTENT COLD FRONT SET TO CROSS LATE
THURSDAY NIGHT INTO FRIDAY. TEMPERATURES THURSDAY WILL WARM INTO THE
LOW TO MID 50S WITH UPPER 40S IN THE MOUNTAINS.
WITH THE SERIES OF FRONTS PASSING THROUGH EXPECT INCREASED CLOUD
COVER THROUGHOUT THE DAY AND PERHAPS A SPOTTY SHOWER DURING THE
AFTERNOON. ANY SUBSTANTIAL RAIN AND/OR CONVECTION LOOKS TO HOLD OFF
UNTIL THURSDAY NIGHT INTO EARLY FRIDAY MORNING. SEVERE WEATHER DOES
NOT APPEAR TO BE CONCERN AT THIS TIME, BUT GIVEN THE STRONG WIND
FIELDS ALOFT AND STRONG WARM AIR ADVECTION AT THE SURFACE,
CONVECTIVE ELEMENTS CANNOT BE RULED OUT. AS IT STANDS NOW, THE
HIGHEST WINDS LOOK TO BE CONFINED TO THE MOUNTAINS WITH LOWER GUSTS
OVER THE LOWER ELEVATIONS. RAIN WILL CHANGE TO SNOW OVER THE
MOUNTAINS FRIDAY MORNING WITH UPSLOPE SNOW SHOWERS LINGERING INTO
FRIDAY NIGHT. THIS IS CONCURRENT WITH 12Z ENSEMBLE/DETERMINISTIC
GUIDANCE WHICH CONTINUES TO SHOW OVERLAP ON THE LATE THURSDAY
EVENING INTO EARLY FRIDAY MORNING TIMEFRAME FOR HAZARDOUS WEATHER
CONCERNS.
HIGH PRESSURE WILL BUILD IN FROM THE WEST FRIDAY INTO SATURDAY.
WHILE COOLER, A ZONAL FLOW PATTERN ALOFT WILL REMAIN RESULTING IN
NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES. THE FORECAST HAS A SMALL
CHANCE OF RAIN/SNOW IN THE ALLEGHENIES SATURDAY WITH SOME POTENTIAL
FOR EMBEDDED WEAK SHORTWAVES IN THE ZONAL FLOW TO ROUND OUT THE
WEEKEND.
AVIATION /19Z SUNDAY THROUGH FRIDAY/
BRISK NW WINDS GUSTING UP TO 30 KT ARE EXPECTED THROUGH THIS
EVENING BEFORE DIMINISHING TO 25 KT LATE AND BELOW 15 KT MONDAY.
BKN CIGS 050 WILL SCATTER OUT TONIGHT. LIGHT WINDS MONDAY NIGHT
AND TUESDAY WITH WINDS SHIFTING TO SW AND THEN S.
VFR CONDITIONS ARE EXPECTED WEDNESDAY THROUGH THURSDAY AFTERNOON AS
HIGH PRESSURE SHIFTS OFFSHORE. GUSTY SOUTHERLY WINDS DEVELOP
THURSDAY AFTERNOON AND EVENING AHEAD OF A STRONG COLD FRONT THURSDAY
NIGHT INTO FRIDAY. SUB-VFR CONDITIONS WILL RETURN WITH THE FRONT
THURSDAY NIGHT INTO FRIDAY AS A LINE OF SHOWERS AND PERHAPS AN
EMBEDDED THUNDERSTORM PUSH THROUGH. VFR CONDITIONS RETURN FOR THE
WEEKEND AHEAD.
MARINE
GALE CONDITIONS WILL CONTINUE THROUGH TONIGHT IN BRISK NW WINDS BEFORE
WINDS BEGIN TO DIMINISH MONDAY. SCA CONDITIONS WILL CONTINUE
THROUGH THE DAY MONDAY BEFORE DIMINISHING FURTHER MONDAY NIGHT.
SCA CONDITIONS ARE POSSIBLE AGAIN TUE NIGHT.
ANY RESIDUAL SOUTHERLY CHANNELING SHOULD COME TO AN END WEDNESDAY
MORNING INTO WEDNESDAY AFTERNOON. SUB-SCA LEVEL WINDS RETURN
WEDNESDAY AFTERNOON AND EVENING WITH HIGH PRESSURE NEARBY. SCAS
RETURN LATE WEDNESDAY NIGHT THROUGH THURSDAY NIGHT AS
SOUTH/SOUTHEASTERLY FLOW INCREASES. THIS IS IN ASSOCIATION WITH A
POTENT LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT PUSHING IN FROM
THE OHIO RIVER VALLEY. THE COLD FRONT WILL CROSS THURSDAY NIGHT
BRINGING A BRIEF PERIOD OF GALE CONDITIONS. ADDITIONAL SCAS WILL BE
NEEDED FRIDAY WITH HIGH PRESSURE RETURNING THIS WEEKEND.
TIDES/COASTAL FLOODING
LOW WATER ADVISORIES HAVE BEEN ISSUED FOR THE WATERS SOUTH OF
POOLES ISLAND TO NORTH BEACH WHERE WATER LEVELS AT 1 FT BELOW
MLLW ARE EXPECTED. WATER LEVELS WILL RECOVER SLIGHTLY ON MONDAY
AS NW WINDS DIMINISH.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...GALE WARNING UNTIL 6 PM EST THIS EVENING FOR MDZ008.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 1 PM EST MONDAY
FOR MDZ008.
COLD WEATHER ADVISORY UNTIL 1 AM EST MONDAY FOR MDZ501.
COLD WEATHER ADVISORY UNTIL 10 AM EST MONDAY FOR MDZ509-510.
WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR MDZ509.
WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MDZ510.
VA...COLD WEATHER ADVISORY UNTIL 1 AM EST MONDAY FOR VAZ504-507-508.
COLD WEATHER ADVISORY UNTIL 10 AM EST MONDAY FOR VAZ503.
COLD WEATHER ADVISORY UNTIL 1 AM EST MONDAY FOR VAZ025-026.
WV...COLD WEATHER ADVISORY UNTIL 1 AM EST MONDAY FOR WVZ503-506.
COLD WEATHER ADVISORY UNTIL 10 AM EST MONDAY FOR WVZ501-505.
WINTER STORM WARNING UNTIL 4 PM EST THIS AFTERNOON FOR WVZ501.
MARINE...GALE WARNING UNTIL 6 PM EST THIS EVENING FOR ANZ530-531-535-
536-538-539.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 1 PM EST MONDAY
FOR ANZ530-531-535-536-538-539.
LOW WATER ADVISORY UNTIL 7 AM EST MONDAY FOR ANZ531-532-
538>540.
GALE WARNING UNTIL 6 AM EST MONDAY FOR ANZ532>534-537-540>543.
SMALL CRAFT ADVISORY FROM 6 AM TO 1 PM EST MONDAY FOR
ANZ532>534-537-540>543.
SYNOPSIS...LFR
NEAR TERM...LFR
SHORT TERM...LFR
LONG TERM...EST
AVIATION...LFR/EST
MARINE...LFR/EST
TIDES/COASTAL FLOODING...LFR
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