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000
FXUS61 KLWX 220855
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
355 AM EST MON DEC 22 2014

.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE WILL TRACK UP THE MID-ATLANTIC COAST
TODAY INTO TUESDAY. STRONGER LOW PRESSURE WILL PUSH NORTH ALONG
THE APPALACHIANS ON WEDNESDAY...SENDING A COLD FRONT EASTWARD
WEDNESDAY NIGHT. BREEZY CONDITIONS WILL FOLLOW THE FRONT ON
THURSDAY...THEN HIGH PRESSURE WILL BUILD BACK INTO THE REGION TO
CLOSE OUT THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
CHALLENGING FORECAST EARLY THIS MORNING. CWA IS DRY ATTM...BUT RAIN
HAS ALREADY PUSHED NORTHWARD INTO SOUTHERN VIRGINIA AT 08Z AND WILL
CONTINUE TO SPREAD NORTHWARD THROUGH THE EARLY MORNING HOURS AS LOW
PRESSURE DEVELOPS OFF THE SOUTHEAST COAST. TEMPERATURES ACROSS MUCH
OF THE CWA WERE BELOW FREEZING...AND AS PRECIPITATION MOVES IN FROM
THE SOUTH IT WILL ENCOUNTER THIS SUB-FREEZING AIR.

A PERIOD OF SLEET IS POSSIBLE INITIALLY AS PRECIPITATION BEGINS OVER
THE CWA...BUT PRIMARY P-TYPES TO CONTEND WITH OVER THE NEXT 12-24
HOURS WILL BE FREEZING RAIN OR RAIN DEPENDING ON SURFACE
TEMPERATURES.

CHALLENGES REVOLVE AROUND THE TIMING AND NORTH/NORTHWEST EXTENT OF
PRECIPITATION TODAY AND ALSO HOW QUICKLY TEMPERATURES WILL BE ABLE
TO CLIMB ABOVE FREEZING.

TREND OF THE MODELS HAS BEEN TO SLOW DOWN THE BEGINNING OF PRECIP BY
A LITTLE BIT. HAVE TRENDED THIS WAY...BUT PRECIP SHOULD STILL MAKE
IT INTO THE VIRGINIA FOOTHILLS/PIEDMONT BY SUNRISE. WILL BE
EXPANDING THE FREEZING RAIN ADVISORY A TIER EAST TO THE I-95
CORRIDOR AS LIGHT QPF IS EXPECTED TO FALL WHILE TEMPERATURES ARE
NEAR FREEZING FROM SPOTSYLVANIA UP TO PRINCE WILLIAM COUNTY.
TEMPERATURES IN THESE AREAS SHOULD RISE ABOVE FREEZING BY NOON.

PRECIP IS ALSO LIKELY TO MAKE IT FURTHER NORTH INTO NORTHERN
VIRGINIA DURING THE LATE MORNING/MIDDAY HOURS. SEVERAL SUITES OF
GUIDANCE SUGGEST TEMPERATURES SITTING AROUND THE FREEZING MARK.
THEREFORE HAVE EXPANDED ADVISORY A TIER NORTH AS WELL FOR AREAS OF
FREEZING RAIN WHICH MAY CONTINUE INTO AFTERNOON. HAVE OPTED NOT TO
EXPAND ADVISORY ALL THE WAY TO THE MASON DIXON LINE HOWEVER AS
CONFIDENCE IS QUITE LOW IN PRECIP BEING ABLE TO MAKE IT THAT FAR
NORTH THROUGH MID-AFTERNOON EVEN IF TEMPERATURES ARE COLD ENOUGH TO
SUPPORT FZRA.

FINALLY...EXPIRATION TIME OF EXISTING ADVISORY HAS BEEN EXTENDED
FROM NOON TO 6 PM. AGAIN...SEVERAL SUITES OF GUIDANCE SUGGEST
TEMPERATURES CONTINUING TO BE AT OR JUST BELOW FREEZING FOR AREAS
NEAR/ALONG AND WEST OF THE BLUE RIDGE INTO THE AFTERNOON.

WEAK LOW PRESSURE MOVES UP THE MID-ATLANTIC COAST TONIGHT. HIGHEST
POPS WILL BE CLOSEST TO THE BAY...LOWER IN THE MOUNTAINS. MUCH OF
THE CWA LOOKS WARM ENOUGH FOR PRIMARILY RAIN TONIGHT BUT THERE STILL
MAY BE POCKETS OF SUB-FREEZING AIR WEST OF THE BLUE RIDGE AND ANY
RAIN OR DRIZZLE MAY FREEZE AND ADVISORY MAY NEED TO BE EXTENDED INTO
TONIGHT FOR THOSE AREAS.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
IN THE WAKE OF THE LOW...MID-ATLANTIC REMAINS IN A WEDGE/LIGHT FLOW
REGIME ON TUESDAY THEREFORE CLOUDY SKIES AND THE CHANCE FOR LIGHT
RAIN OR DRIZZLE WILL CONTINUE. TEMPERATURES SHOULD BE WARM ENOUGH
FOR JUST LIQUID PRECIPITATION.

WHILE THERE IS GENERAL SYNOPTIC AGREEMENT IN THE COMPUTER MODELS
THROUGH THE MIDDLE OF THE WEEK...THERE IS STILL QUITE A BIT OF
SPREAD IN THE SMALLER SCALE FEATURES. AMPLIFIED UPPER LEVEL PATTERN
THROUGH THE MIDDLE PORTION OF THE WEEK. TROUGH OVER THE CENTRAL
CONUS WILL LIFT EAST...INDUCING CYCLOGENESIS OVER THE WESTERN GULF
OF MEXICO TUESDAY NIGHT. THIS LOW WILL RIDE UP THE WESTERN SIDE OF
THE APPALACHIANS...REACHING CENTRAL QUEBEC BY THURSDAY.

A STRONG LOW LEVEL JET AHEAD OF THE DEEPENING LOW WILL TRANSPORT
MOISTURE UP THE EASTERN SEABOARD TUESDAY NIGHT...BRINGING INCREASING
CHANCES OF RAIN. TEMPERATURES DROP LITTLE FROM TUESDAYS HIGHS...SO
NO FROZEN PRECIP CONCERNS. WHILE PROBABLY NOT CONTINUOUSLY RAINY
THROUGH THE PERIOD...90-100 POPS ARE WARRANTED...WITH MODERATE RAIN
POSSIBLE AT TIMES. THE NATURE MAY BECOME MORE SHOWERY ON
WEDNESDAY...BUT NOT A COMPELLING REASON TO BREAK THAT OUT AT THIS
TIME. 00Z NAM/MET GUIDANCE MUCH COOLER FOR HIGHS ON
WEDNESDAY...LIKELY DUE TO A MUCH WEAKER SFC LOW THAN THE GLOBAL
MODELS...WHICH ALLOWS THE COLD POOL TO LINGER EAST OF THE MOUNTAINS.
HOWEVER...THE OTHER GUIDANCE OF 60S MAY BE A BIT OVERDONE...EXCEPT
PERHAPS EAST OF I-95. IF THIS OCCURS...WILL ALSO HAVE TO MONITOR FOR
THE POTENTIAL OF STRONG WIND GUSTS IF CONVECTIVE ELEMENTS DEVELOP.

THE COLD FRONT TRAILING THE LOW WILL PUSH THROUGH THURSDAY
NIGHT...BRINGING AN END TO THE PRECIP EXCEPT SOME POSSIBLE UPSLOPE.
HOWEVER WITH THE WARM START...IT WILL TAKE UNTIL LATE IN THE NIGHT
FOR THE TEMPERATURES TO DROP COLD ENOUGH TO SUPPORT ANY SNOW. ALL
TOLD...IMPRESSIVE PWAT VALUES AND A DYNAMIC SYSTEM COULD LEAD TO
STORM TOTAL RAINFALL IN EXCESS OF AN INCH...ESPECIALLY EAST OF THE
MOUNTAINS.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
THURSDAY WILL BE BREEZY BEHIND THE FRONT. ANY UPSLOPE SNOW SHOWERS
SHOULD GRADUALLY COME TO AN END. THERE WILL ONLY BE A GLANCING BLOW
OF CAA...AS HIGH PRESSURE WILL BE BUILDING IN FROM THE SOUTHWEST.
THIS HIGH WILL REMAIN OVER THE SE STATES THROUGH SATURDAY AND
TEMPERATURES ARE EXPECTED TO REMAIN ABOVE NORMAL. THE NEXT CHANCE OF
PRECIP WILL ARRIVE AS THE NEXT TROUGH APPROACHES SATURDAY INTO
SUNDAY. MODEL SOLUTIONS STILL DIFFER QUITE A BIT...SO POPS REMAIN
LOW. THERE WILL BE POTENTIAL FOR TEMPERATURES TO COOL BACK DOWN
BEHIND THIS SYSTEM FOR THE SECOND PART OF THE WEEKEND.

&&

.AVIATION /09Z MONDAY THROUGH FRIDAY/...
PRECIP IS EXPECTED TO SPREAD NORTH TODAY. PERIOD OF LIGHT FREEZING
RAIN/SLEET IS MOST LIKELY AT CHO/IAD. MAY BE TOO WARM AT DCA/BWI FOR
FREEZING RAIN...BUT INITIAL PERIOD OF SLEET CAN/T BE RULED OUT
BEFORE TURNING TO RAIN. MODELS HAVE TRENDED A LITTLE SLOWER WITH
ONSET OF PRECIP AND HAVE FOLLOWED SUIT IN TAFS. EXPECT CONDITIONS TO
DROP INTO MVFR THIS AFTERNOON...THEN LIKELY IFR OR LIFR TONIGHT AND
CONTINUING INTO TUESDAY.

BELOW-VFR CIGS WILL LINGER THROUGH WEDNESDAY NIGHT. VSBY COULD DROP
BELOW VFR IN HEAVIER RAIN/SHOWERS AT TIMES FROM TUESDAY NIGHT
THROUGH WEDNESDAY NIGHT. WINDS WILL SHIFT FROM SOUTHERLY TO WESTERLY
WEDNESDAY NIGHT AND COULD GUST ABOVE 25 KT ON THURSDAY. NO
SIGNIFICANT WEATHER EXPECTED AFTER THURSDAY EVENING.

&&

.MARINE...
WEAK LOW PRESSURE MOVES OFF THE MID-ATLANTIC COAST TONIGHT. MARGINAL
SCA EXPECTED ON THE LOWER PORTIONS OF THE WATERS THIS AFTERNOON
OTHERWISE WINDS BELOW SCA THROUGH TUESDAY.

A STRONG LOW PRESSURE SYSTEM WILL MOVE THROUGH THE REGION BETWEEN
TUESDAY AND WEDNESDAY NIGHT...BRING MODERATE RAIN AT TIMES OVER THE
WATERS. A SCA IS LIKELY WEDNESDAY THROUGH THURSDAY...WITH THE
STRONGEST GUSTS EXPECTED ON THURSDAY. WINDS WILL DIMINISH THURSDAY
NIGHT AS HIGH PRESSURE BUILDS IN.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...FREEZING RAIN ADVISORY UNTIL 6 PM EST THIS EVENING FOR VAZ025-
     026-029-036>040-501-503-504-507-508.
     FREEZING RAIN ADVISORY UNTIL NOON EST TODAY FOR VAZ050>052-055-
     056-502.
     FREEZING RAIN ADVISORY FROM 10 AM THIS MORNING TO 6 PM EST
     THIS EVENING FOR VAZ027-028-030-031-505-506.
WV...FREEZING RAIN ADVISORY UNTIL 6 PM EST THIS EVENING FOR WVZ505-
     506.
     FREEZING RAIN ADVISORY FROM 10 AM THIS MORNING TO 6 PM EST
     THIS EVENING FOR WVZ055.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 6 PM EST THIS
     EVENING FOR ANZ534-537-543.

&&

$$
SYNOPSIS...ADS
NEAR TERM...BPP
SHORT TERM...BPP/ADS
LONG TERM...ADS
AVIATION...ADS/BPP
MARINE...ADS/BPP









000
FXUS61 KLWX 220231 AAA
AFDLWX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
931 PM EST SUN DEC 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE COAST OVERNIGHT...AHEAD OF A WEAK
COASTAL LOW PRESSURE SYSTEM OVER THE SOUTHERN ATLANTIC. THE LOW
WILL TRACK UP THE MID-ATLANTIC COAST MONDAY INTO TUESDAY. A STRONG
COLD FRONT WILL APPROACH THE AREA WEDNESDAY BEFORE PASSING THROUGH
WEDNESDAY NIGHT. BREEZY CONDITIONS ON THURSDAY...THEN HIGH
PRESSURE WILL BUILD BACK INTO THE REGION TO CLOSE OUT THE WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
HIGH TEMPS ACROSS AREA WERE ON PAR W/ AVG VALUES FOR THIS...THE
WINTER SOLSTICE. HOWEVER...AFTER ONLY REACHING THE LOW-MID 40S
EARLIER THIS AFTN MOST AREAS ARE BACK BELOW FREEZING...WELL AHEAD
OF ANY INCOMING PRECIP. CLEAR SKIES AND CALM SFC WINDS EASILY
ALLOWING TEMPS TO DROP DOWN TOWARD CURRENT DEWPOINTS VALUES IN THE
LOWS 20S. SLOW AND STEADY DEVELOPMENT OF A COASTAL LOW PRES SYSTEM
OVER THE SRN ATLC STATES IS THE NEXT FEATURE TO MONITOR...AS DENSE
CLOUD COVER AND LIGHT/SCATTERED SHOWERS ARE EXPECTED TO MOVE UP
THE EASTERN SEABOARD OVERNIGHT.

MANY SMALLER-SCALE ELEMENTS ARE COMING TOGETHER OVER A MUCH LARGER
PICTURE AND WILL CONTINUE TO DO SO WELL INTO THE MIDDLE OF THE
CURRENT WEEK. NEARLY TWO-THIRDS OF THE CONUS WILL BE AFFECTED IN
SOME PART OF THESE ELEMENTS OR A LARGER COMBINATION OVER THE NEXT
FEW DAYS. THIS FIRST PIECE IS THE INITIAL GROUPING OF A SHORTWAVE
OVER THE SRN ATLC COAST AND A TROUGH STILL WELL BACK TO THE WEST.
THE TROUGH WILL FORCE THE ATLC MOISTURE UP THE COAST...THIS FIRST
BATCH AFFECTING OUR AREA MONDAY INTO EARLY TUE - W/ THE MORE
MOISTURE-LADEN SYSTEM MOVING THRU THE REGION ON THU.

SUCH A COMPLEX SYSTEM OF WAVES...TROUGHS...SYNOPTIC FEATURES
INTERACTING W/ EACH OTHER OVER A MULTI-DAY PERIOD CAN SHOW VERY
VARIED DEPICTIONS AMONGST THE GUIDANCE SUITE. HOWEVER...MOST
MEMBERS IN BOTH THE ENSEMBLE AND DETERMINISTIC FIELDS ARE IN
FAIRLY GOOD AGREEMENT EARLY ON W/ THE INCOMING PRECIP. THE NAM
STILL THE COLDER MODEL IN TERMS OF TEMPS/DEWPOINTS BUT IS NOW
COMING INTO BETTER AGREEMENT W/ GFS/EURO ON PRECIP TIMING.

THE I-95 CORRIDOR WHICH IS NORMALLY A DIVIDING LINE OF NEAR-
FREEZING TEMPS W/ INCOMING PRECIP IS NO DIFFERENT FOR THIS
INCOMING WAVE MON MORNING. HOWEVER...HI-RES AND NEAR TERM GUIDANCE
DOES NOT HAVE THE FIRST BATCHES OF LIGHT PRECIP ARRIVING UNTIL
POST-DAWN AND ACTUALLY MORE TOWARD MID-LATE MRNG...ESPECIALLY
FURTHER NORTH. TEMPS WILL STILL BE BORDERLINE FREEZING/SUB-
FREEZING ACROSS THE PIEDMONT/FOOTHILLS - WHERE THE FREEZING RAIN
ADZY IS IN EFFECT - BUT THE I-95 CORRIDOR MAY ONLY SEE A BRIEF
ONSET PERIOD OF A FZRA/SLEET MIX...THEN TEMPS WILL RISE EVEN A
COUPLE MORE DEGREES HEADING INTO THE LATE MRNG/EARLY AFTN.

THE SHEN VLY AND BLUE RIDGE WILL LIKELY BE ON THE WRN/NRN
PERIPHERY OF THE PRECIP BUT WILL BE MOST PRONE TO HOLDING ONTO THE
SUB-FREEZING CONDITIONS WELL INTO THE MRNG HRS AND EVEN THRU THE
AFTN POTENTIALLY. THE AMOUNTS AND POTENTIAL FOR PRECIP WILL BE THE
MAIN QUESTION BUT THERE IS GOOD CONFIDENCE THAT THESE AREAS WILL
HAVE TROUBLE SEEING TEMPS ABOVE FREEZING FOR VERY LONG TMRW.
LINGERING POCKETS OF DRIZZLE AND LIGHT/SCATTERED RAIN WILL BE THE
REASON FOR AN EXPANSION/EXTENSION OF THE ADZY FOR ALL/MOST OF THE
SHEN VLY/POTOMAC HIGHLANDS/BLUE RIDGE.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
LIGHT PRECIPITATION WILL CONTINUE MONDAY NIGHT INTO TUESDAY MORNING.
THE BIG QUESTION WILL BE HOW LONG THE CAD WEDGE WILL REMAIN IN
PLACE. THERE IS STILL POTENTIAL FOR TEMPERATURES TO REMAIN AT OR
BELOW FREEZING MAINLY WEST OF THE BLUE RIDGE LEAVING THE POTENTIAL
FOR LIGHT FREEZING RAIN TO CONTINUE. TO THE EAST OF THE BLUE RIDGE
AND ACROSS THE METRO AREAS...WARMER AIR WILL LIKELY WIN OUT KEEPING
PRECIPITATION IN THE FORM OF RAIN. A BRIEF RESPITE FROM THE
PRECIPITATION IS POSSIBLE TUESDAY AFTERNOON/EVENING BEFORE THE NEXT
ROUND OF RAINFALL MOVES IN FROM THE WEST LATER TUESDAY NIGHT.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
STRONG COLD FRONT CROSSING THE MID ATLANTIC REGION WEDNESDAY INTO
THURSDAY. LIQUID PRECIPITATION SHOULD ACCOMPANY THE FRONT EXCEPT
ALONG THE ALLEGHENY  FRONT WHERE ARRIVAL OF COLDER AIR WILL CAUSE THE
RAIN TO CHANGE OVER TO SNOW BEFORE PRECIPITATION ENDS THURSDAY.

PASSAGE OF SHORTWAVE WILL SUPPORT DEVELOPMENT OF A COASTAL LOW LATE
SATURDAY AND SUNDAY. PRECIPITATION MAY START AS A WINTRY MIX AT
HIGHER ELEVATIONS.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS INTO THE OVERNIGHT...W/ MID CLOUD DECKS INCREASING
TOWARD THE PREDAWN MON. PRECIPITATION WILL OVERSPREAD THE
TERMINALS MONDAY MORNING - MOST LIKELY POST-DAWN - FROM SOUTHWEST
TO NORTHEAST. FREEZING RAIN IS EXPECTED ACROSS KCHO AND POSSIBLY
KMRB AND KIAD FOR A RELATIVELY BRIEF PERIOD...W/ TEMPS HOVER NEAR
FREEZING DURING THE MID-MRNG HRS. FREEZING RAIN MAY MIX WITH
SLEET AND SNOW AT THE ONSET. RAIN IS EXPECTED ACROSS THE REST OF
THE TERMINALS. RAIN MAY MIX WITH SLEET AT THE ONSET. CIGS/VSBYS
WILL DETERIORATE TO MVFR LEVELS MONDAY WITH POSSIBLE IFR LEVELS.

SUB VFR CIGS AND VSBYS EXPECTED MONDAY NIGHT INTO TUESDAY. LIGHT
FREEZING RAIN WILL BE POSSIBLE WEST OF THE BLUE RIDGE WITH RAIN TO
THE EAST. A PRECIPITATION RESPITE MAY OCCUR TUESDAY AFTERNOON BEFORE
RAIN MOVES BACK IN LATER TUESDAY NIGHT. A STRONG COLD FRONT WILL
APPROACH THE TERMINALS WEDNESDAY BEFORE PASSING THROUGH
WEDNESDAY NIGHT. MORE RAIN AND SUBVFR CONDITIONS ARE EXPECTED.

&&

.MARINE...
HIGH PRESSURE WILL REMAIN OVER THE WATERS TONIGHT. LOW PRESSURE
WILL TRACK UP THE MID-ATLANTIC COAST MONDAY. A SMALL CRAFT
ADVISORY IS IN EFFECT FOR THE MIDDLE PORTIONS OF THE BAY AND LOWER
TIDAL POTOMAC RIVER.

WINDS ARE EXPECTED TO REMAIN BELOW SCA CRITERIA MONDAY NIGHT THROUGH
TUESDAY NIGHT. A STRONG COLD FRONT WILL APPROACH THE WATERS
WEDNESDAY BEFORE PASSING THROUGH WEDNESDAY NIGHT. A SMALL CRAFT
ADVISORY WILL LIKELY BE NEEDED FOR THE WATERS WEDNESDAY AND
THURSDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...FREEZING RAIN ADVISORY FROM 6 AM TO NOON EST MONDAY FOR VAZ025-
     026-029-036>040-050-051-501>504-507-508.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 6 PM EST MONDAY FOR ANZ534-
     537-543.

&&

$$
UPDATE...GMS
PREV DISCUSSION...BJL/KRW/CEM








000
FXUS61 KLWX 220231 AAA
AFDLWX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
931 PM EST SUN DEC 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE COAST OVERNIGHT...AHEAD OF A WEAK
COASTAL LOW PRESSURE SYSTEM OVER THE SOUTHERN ATLANTIC. THE LOW
WILL TRACK UP THE MID-ATLANTIC COAST MONDAY INTO TUESDAY. A STRONG
COLD FRONT WILL APPROACH THE AREA WEDNESDAY BEFORE PASSING THROUGH
WEDNESDAY NIGHT. BREEZY CONDITIONS ON THURSDAY...THEN HIGH
PRESSURE WILL BUILD BACK INTO THE REGION TO CLOSE OUT THE WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
HIGH TEMPS ACROSS AREA WERE ON PAR W/ AVG VALUES FOR THIS...THE
WINTER SOLSTICE. HOWEVER...AFTER ONLY REACHING THE LOW-MID 40S
EARLIER THIS AFTN MOST AREAS ARE BACK BELOW FREEZING...WELL AHEAD
OF ANY INCOMING PRECIP. CLEAR SKIES AND CALM SFC WINDS EASILY
ALLOWING TEMPS TO DROP DOWN TOWARD CURRENT DEWPOINTS VALUES IN THE
LOWS 20S. SLOW AND STEADY DEVELOPMENT OF A COASTAL LOW PRES SYSTEM
OVER THE SRN ATLC STATES IS THE NEXT FEATURE TO MONITOR...AS DENSE
CLOUD COVER AND LIGHT/SCATTERED SHOWERS ARE EXPECTED TO MOVE UP
THE EASTERN SEABOARD OVERNIGHT.

MANY SMALLER-SCALE ELEMENTS ARE COMING TOGETHER OVER A MUCH LARGER
PICTURE AND WILL CONTINUE TO DO SO WELL INTO THE MIDDLE OF THE
CURRENT WEEK. NEARLY TWO-THIRDS OF THE CONUS WILL BE AFFECTED IN
SOME PART OF THESE ELEMENTS OR A LARGER COMBINATION OVER THE NEXT
FEW DAYS. THIS FIRST PIECE IS THE INITIAL GROUPING OF A SHORTWAVE
OVER THE SRN ATLC COAST AND A TROUGH STILL WELL BACK TO THE WEST.
THE TROUGH WILL FORCE THE ATLC MOISTURE UP THE COAST...THIS FIRST
BATCH AFFECTING OUR AREA MONDAY INTO EARLY TUE - W/ THE MORE
MOISTURE-LADEN SYSTEM MOVING THRU THE REGION ON THU.

SUCH A COMPLEX SYSTEM OF WAVES...TROUGHS...SYNOPTIC FEATURES
INTERACTING W/ EACH OTHER OVER A MULTI-DAY PERIOD CAN SHOW VERY
VARIED DEPICTIONS AMONGST THE GUIDANCE SUITE. HOWEVER...MOST
MEMBERS IN BOTH THE ENSEMBLE AND DETERMINISTIC FIELDS ARE IN
FAIRLY GOOD AGREEMENT EARLY ON W/ THE INCOMING PRECIP. THE NAM
STILL THE COLDER MODEL IN TERMS OF TEMPS/DEWPOINTS BUT IS NOW
COMING INTO BETTER AGREEMENT W/ GFS/EURO ON PRECIP TIMING.

THE I-95 CORRIDOR WHICH IS NORMALLY A DIVIDING LINE OF NEAR-
FREEZING TEMPS W/ INCOMING PRECIP IS NO DIFFERENT FOR THIS
INCOMING WAVE MON MORNING. HOWEVER...HI-RES AND NEAR TERM GUIDANCE
DOES NOT HAVE THE FIRST BATCHES OF LIGHT PRECIP ARRIVING UNTIL
POST-DAWN AND ACTUALLY MORE TOWARD MID-LATE MRNG...ESPECIALLY
FURTHER NORTH. TEMPS WILL STILL BE BORDERLINE FREEZING/SUB-
FREEZING ACROSS THE PIEDMONT/FOOTHILLS - WHERE THE FREEZING RAIN
ADZY IS IN EFFECT - BUT THE I-95 CORRIDOR MAY ONLY SEE A BRIEF
ONSET PERIOD OF A FZRA/SLEET MIX...THEN TEMPS WILL RISE EVEN A
COUPLE MORE DEGREES HEADING INTO THE LATE MRNG/EARLY AFTN.

THE SHEN VLY AND BLUE RIDGE WILL LIKELY BE ON THE WRN/NRN
PERIPHERY OF THE PRECIP BUT WILL BE MOST PRONE TO HOLDING ONTO THE
SUB-FREEZING CONDITIONS WELL INTO THE MRNG HRS AND EVEN THRU THE
AFTN POTENTIALLY. THE AMOUNTS AND POTENTIAL FOR PRECIP WILL BE THE
MAIN QUESTION BUT THERE IS GOOD CONFIDENCE THAT THESE AREAS WILL
HAVE TROUBLE SEEING TEMPS ABOVE FREEZING FOR VERY LONG TMRW.
LINGERING POCKETS OF DRIZZLE AND LIGHT/SCATTERED RAIN WILL BE THE
REASON FOR AN EXPANSION/EXTENSION OF THE ADZY FOR ALL/MOST OF THE
SHEN VLY/POTOMAC HIGHLANDS/BLUE RIDGE.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
LIGHT PRECIPITATION WILL CONTINUE MONDAY NIGHT INTO TUESDAY MORNING.
THE BIG QUESTION WILL BE HOW LONG THE CAD WEDGE WILL REMAIN IN
PLACE. THERE IS STILL POTENTIAL FOR TEMPERATURES TO REMAIN AT OR
BELOW FREEZING MAINLY WEST OF THE BLUE RIDGE LEAVING THE POTENTIAL
FOR LIGHT FREEZING RAIN TO CONTINUE. TO THE EAST OF THE BLUE RIDGE
AND ACROSS THE METRO AREAS...WARMER AIR WILL LIKELY WIN OUT KEEPING
PRECIPITATION IN THE FORM OF RAIN. A BRIEF RESPITE FROM THE
PRECIPITATION IS POSSIBLE TUESDAY AFTERNOON/EVENING BEFORE THE NEXT
ROUND OF RAINFALL MOVES IN FROM THE WEST LATER TUESDAY NIGHT.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
STRONG COLD FRONT CROSSING THE MID ATLANTIC REGION WEDNESDAY INTO
THURSDAY. LIQUID PRECIPITATION SHOULD ACCOMPANY THE FRONT EXCEPT
ALONG THE ALLEGHENY  FRONT WHERE ARRIVAL OF COLDER AIR WILL CAUSE THE
RAIN TO CHANGE OVER TO SNOW BEFORE PRECIPITATION ENDS THURSDAY.

PASSAGE OF SHORTWAVE WILL SUPPORT DEVELOPMENT OF A COASTAL LOW LATE
SATURDAY AND SUNDAY. PRECIPITATION MAY START AS A WINTRY MIX AT
HIGHER ELEVATIONS.

&&

.AVIATION /01Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS INTO THE OVERNIGHT...W/ MID CLOUD DECKS INCREASING
TOWARD THE PREDAWN MON. PRECIPITATION WILL OVERSPREAD THE
TERMINALS MONDAY MORNING - MOST LIKELY POST-DAWN - FROM SOUTHWEST
TO NORTHEAST. FREEZING RAIN IS EXPECTED ACROSS KCHO AND POSSIBLY
KMRB AND KIAD FOR A RELATIVELY BRIEF PERIOD...W/ TEMPS HOVER NEAR
FREEZING DURING THE MID-MRNG HRS. FREEZING RAIN MAY MIX WITH
SLEET AND SNOW AT THE ONSET. RAIN IS EXPECTED ACROSS THE REST OF
THE TERMINALS. RAIN MAY MIX WITH SLEET AT THE ONSET. CIGS/VSBYS
WILL DETERIORATE TO MVFR LEVELS MONDAY WITH POSSIBLE IFR LEVELS.

SUB VFR CIGS AND VSBYS EXPECTED MONDAY NIGHT INTO TUESDAY. LIGHT
FREEZING RAIN WILL BE POSSIBLE WEST OF THE BLUE RIDGE WITH RAIN TO
THE EAST. A PRECIPITATION RESPITE MAY OCCUR TUESDAY AFTERNOON BEFORE
RAIN MOVES BACK IN LATER TUESDAY NIGHT. A STRONG COLD FRONT WILL
APPROACH THE TERMINALS WEDNESDAY BEFORE PASSING THROUGH
WEDNESDAY NIGHT. MORE RAIN AND SUBVFR CONDITIONS ARE EXPECTED.

&&

.MARINE...
HIGH PRESSURE WILL REMAIN OVER THE WATERS TONIGHT. LOW PRESSURE
WILL TRACK UP THE MID-ATLANTIC COAST MONDAY. A SMALL CRAFT
ADVISORY IS IN EFFECT FOR THE MIDDLE PORTIONS OF THE BAY AND LOWER
TIDAL POTOMAC RIVER.

WINDS ARE EXPECTED TO REMAIN BELOW SCA CRITERIA MONDAY NIGHT THROUGH
TUESDAY NIGHT. A STRONG COLD FRONT WILL APPROACH THE WATERS
WEDNESDAY BEFORE PASSING THROUGH WEDNESDAY NIGHT. A SMALL CRAFT
ADVISORY WILL LIKELY BE NEEDED FOR THE WATERS WEDNESDAY AND
THURSDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...FREEZING RAIN ADVISORY FROM 6 AM TO NOON EST MONDAY FOR VAZ025-
     026-029-036>040-050-051-501>504-507-508.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 6 PM EST MONDAY FOR ANZ534-
     537-543.

&&

$$
UPDATE...GMS
PREV DISCUSSION...BJL/KRW/CEM









000
FXUS61 KLWX 211945
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
245 PM EST SUN DEC 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH TONIGHT. LOW
PRESSURE WILL TRACK UP THE MID-ATLANTIC COAST MONDAY AND TUESDAY.
A STRONG COLD FRONT WILL APPROACH THE AREA WEDNESDAY BEFORE
PASSING THROUGH WEDNESDAY NIGHT. HIGH PRESSURE WILL BUILD OVERHEAD
LATE IN THE WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
HIGH PRESSURE REMAINS OVER THE REGION THIS AFTERNOON AND
SUBSIDENCE BEHIND A SHORTWAVE HAS ALLOWED FOR SUNSHINE. HIGH
PRESSURE WILL BECOME CENTERED OVER NEW ENGLAND TONIGHT AND THE
SURFACE RIDGE AXIS WILL DROP SOUTHWEST THROUGH OUR REGION DURING
THIS TIME.

POTENT LOW PRESSURE WILL TRACK THROUGH THE PLAINS TONIGHT THROUGH
MONDAY. A WARM FRONT WILL EXTEND SOUTHEAST FROM THIS SYSTEM
THROUGH THE TENNESSEE VALLEY INTO THE APPALACHIANS WHERE IT WILL
BECOME A STATIONARY FRONT THAT CONTINUES TO EXTEND THROUGH THE
SOUTHEASTERN CONUS. LOW PRESSURE WILL DEVELOP ALONG THIS BOUNDARY
OFF THE SOUTHEAST COAST TONIGHT AND IT IS EXPECTED TO TRACK UP THE
MID-ATLANTIC COAST MONDAY. THIS SYSTEM WILL BE WEAK AND MOST OF
THE DYNAMICS WILL REMAIN WELL TO OUR WEST...CLOSER TO THE STRONGER
LOW OVER THE PLAINS. HOWEVER...WARM AND MOIST AIR FROM THE GULF OF
MEXICO AND ATLANTIC OCEAN WILL OVERRUN THE COLDER AND DRIER AIR
THAT IS CURRENTLY IN PLACE. THIS WILL CAUSE CLOUDS TO INCREASE
OVERNIGHT AND PRECIPITATION IS EXPECTED TO OVERSPREAD AT LEAST
PORTIONS OF THE AREA MONDAY MORNING INTO MONDAY AFTERNOON.

THERE WILL BE ENOUGH COLD AIR FOR POSSIBLE FROZEN PRECIPITATION
MONDAY...ESPECIALLY NORTH AND WEST OF INTERSTATE 95. THE MAIN
IMPACT FROM FROZEN PRECIPITATION WOULD BE FROM FREEZING
RAIN...ALTHOUGH SNOW AND SLEET MAY MIX WITH
PRECIPITATION...ESPECIALLY AT THE ONSET. HOWEVER...THERE IS STILL
SOME UNCERTAINTY AS TO HOW FAR NORTH AND WEST THE PRECIPITATION
WILL MAKE IT SINCE IT WILL BE RUNNING INTO DRIER AIR. THE HIGHEST
CONFIDENCE FOR PRECIPITATION AND SUBFREEZING TEMPERATURES IS
ACROSS CENTRAL VIRGINIA. A FREEZING RAIN ADVISORY IS IN EFFECT FOR
THESE AREAS MONDAY MORNING. FREEZING RAIN MAY CONTINUE INTO THE
AFTERNOON HOURS AS WELL.

FOR THE WASHINGTON AND BALTIMORE METROPOLITAN
AREAS...CONFIDENCE IS NOT YET HIGH ENOUGH FOR A HEADLINE SINCE
TEMPERATURES WILL BE MARGINAL AND IMPACT FROM FROZEN PRECIPITATION
IS NOT EXPECTED TO OCCUR UNTIL LATER MONDAY MORNING OR AFTERNOON.
PRECIPITATION WILL LIKELY OVERSPREAD THESE AREAS DURING THE MID TO
LATE MORNING HOURS MONDAY AND CONTINUE THROUGH MONDAY AFTERNOON.
FROZEN PRECIPITATION IS POSSIBLE...ESPECIALLY NORTH AND WEST OF
INTERSTATE 95. A FREEZING RAIN ADVISORY MAY BE NEEDED FOR PORTIONS
OF THESE AREAS.

FOR THE POTOMAC HIGHLANDS...NORTHERN MARYLAND AND EASTERN WEST
VIRGINIA. TEMPERATURES WILL BE COLD ENOUGH FOR FROZEN
PRECIPITATION...BUT THE NORTHERN AND WESTERN EXTENT OF THE PRECIP
IS TOO UNCERTAIN AT THIS TIME TO ISSUE AN ADVISORY. ANY IMPACT
FROM FROZEN PRECIPITATION WOULD NOT OCCUR UNTIL MONDAY AFTERNOON.

MAX TEMPS MONDAY WILL RANGE FROM THE UPPER 20S AND LOWER 30S
ACROSS THE ALLEGHENY AND POTOMAC HIGHLANDS...TO THE MIDDLE 30S
NEAR WASHINGTON AND BALTIMORE...TO NEAR 40 IN SOUTHERN MARYLAND.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
LIGHT PRECIPITATION WILL CONTINUE MONDAY NIGHT INTO TUESDAY MORNING.
THE BIG QUESTION WILL BE HOW LONG THE CAD WEDGE WILL REMAIN IN
PLACE. THERE IS STILL POTENTIAL FOR TEMPERATURES TO REMAIN AT OR
BELOW FREEZING MAINLY WEST OF THE BLUE RIDGE LEAVING THE POTENTIAL
FOR LIGHT FREEZING RAIN TO CONTINUE. TO THE EAST OF THE BLUE RIDGE
AND ACROSS THE METRO AREAS...WARMER AIR WILL LIKELY WIN OUT KEEPING
PRECIPITATION IN THE FORM OF RAIN. A BRIEF RESPITE FROM THE
PRECIPITATION IS POSSIBLE TUESDAY AFTERNOON/EVENING BEFORE THE NEXT
ROUND OF RAINFALL MOVES IN FROM THE WEST LATER TUESDAY NIGHT.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
STRONG COLD FRONT CROSSING THE MID ATLANTIC REGION WEDNESDAY INTO
THURSDAY. LIQUID PRECIPITATION SHOULD ACCOMPANY THE FRONT EXCEPT
ALONG THE ALLEGHENY  FRONT WHERE ARRIVAL OF COLDER AIR WILL CAUSE THE
RAIN TO CHANGE OVER TO SNOW BEFORE PRECIPITATION ENDS THURSDAY.

PASSAGE OF SHORTWAVE WILL SUPPORT DEVELOPMENT OF A COASTAL LOW LATE
SATURDAY AND SUNDAY. PRECIPITATION MAY START AS A WINTRY MIX AT
HIGHER ELEVATIONS.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
VFR CONDITIONS THROUGH THIS EVENING. CLOUDS WILL INCREASE
OVERNIGHT AND PRECIPITATION WILL OVERSPREAD THE TERMINALS MONDAY
FROM SOUTHWEST TO NORTHEAST. FREEZING RAIN IS EXPECTED ACROSS KCHO
AND POSSIBLY KMRB AND KIAD. FREEZING RAIN MAY MIX WITH SLEET AND
SNOW AT THE ONSET. RAIN IS EXPECTED ACROSS THE REST OF THE
TERMINALS. RAIN MAY MIX WITH SLEET AT THE ONSET. CIGS/VSBYS WILL
DETERIORATE TO MVFR LEVELS MONDAY WITH POSSIBLE IFR LEVELS.

SUB VFR CIGS AND VSBYS EXPECTED MONDAY NIGHT INTO TUESDAY. LIGHT
FREEZING RAIN WILL BE POSSIBLE WEST OF THE BLUE RIDGE WITH RAIN TO
THE EAST. A PRECIPITATION RESPITE MAY OCCUR TUESDAY AFTERNOON BEFORE
RAIN MOVES BACK IN LATER TUESDAY NIGHT. A STRONG COLD FRONT WILL
APPROACH THE TERMINALS WEDNESDAY BEFORE PASSING THROUGH
WEDNESDAY NIGHT. MORE RAIN AND SUBVFR CONDITIONS ARE EXPECTED.

&&

.MARINE...
HIGH PRESSURE WILL REMAIN OVER THE WATERS TONIGHT. LOW PRESSURE
WILL TRACK UP THE MID-ATLANTIC COAST MONDAY. A SMALL CRAFT
ADVISORY IS IN EFFECT FOR THE MIDDLE PORTIONS OF THE BAY AND LOWER
TIDAL POTOMAC RIVER.

WINDS ARE EXPECTED TO REMAIN BELOW SCA CRITERIA MONDAY NIGHT THROUGH
TUESDAY NIGHT. A STRONG COLD FRONT WILL APPROACH THE WATERS
WEDNESDAY BEFORE PASSING THROUGH WEDNESDAY NIGHT. A SMALL CRAFT
ADVISORY WILL LIKELY BE NEEDED FOR THE WATERS WEDNESDAY AND
THURSDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...FREEZING RAIN ADVISORY FROM 6 AM TO NOON EST MONDAY FOR VAZ025-
     026-029-036>040-050-051-501>504-507-508.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 6 PM EST MONDAY FOR ANZ534-
     537-543.

&&

$$
SYNOPSIS...BJL
NEAR TERM...BJL
SHORT TERM...KRW
LONG TERM...CEM
AVIATION...BJL/KRW
MARINE...BJL/KRW








000
FXUS61 KLWX 211945
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
245 PM EST SUN DEC 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH TONIGHT. LOW
PRESSURE WILL TRACK UP THE MID-ATLANTIC COAST MONDAY AND TUESDAY.
A STRONG COLD FRONT WILL APPROACH THE AREA WEDNESDAY BEFORE
PASSING THROUGH WEDNESDAY NIGHT. HIGH PRESSURE WILL BUILD OVERHEAD
LATE IN THE WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
HIGH PRESSURE REMAINS OVER THE REGION THIS AFTERNOON AND
SUBSIDENCE BEHIND A SHORTWAVE HAS ALLOWED FOR SUNSHINE. HIGH
PRESSURE WILL BECOME CENTERED OVER NEW ENGLAND TONIGHT AND THE
SURFACE RIDGE AXIS WILL DROP SOUTHWEST THROUGH OUR REGION DURING
THIS TIME.

POTENT LOW PRESSURE WILL TRACK THROUGH THE PLAINS TONIGHT THROUGH
MONDAY. A WARM FRONT WILL EXTEND SOUTHEAST FROM THIS SYSTEM
THROUGH THE TENNESSEE VALLEY INTO THE APPALACHIANS WHERE IT WILL
BECOME A STATIONARY FRONT THAT CONTINUES TO EXTEND THROUGH THE
SOUTHEASTERN CONUS. LOW PRESSURE WILL DEVELOP ALONG THIS BOUNDARY
OFF THE SOUTHEAST COAST TONIGHT AND IT IS EXPECTED TO TRACK UP THE
MID-ATLANTIC COAST MONDAY. THIS SYSTEM WILL BE WEAK AND MOST OF
THE DYNAMICS WILL REMAIN WELL TO OUR WEST...CLOSER TO THE STRONGER
LOW OVER THE PLAINS. HOWEVER...WARM AND MOIST AIR FROM THE GULF OF
MEXICO AND ATLANTIC OCEAN WILL OVERRUN THE COLDER AND DRIER AIR
THAT IS CURRENTLY IN PLACE. THIS WILL CAUSE CLOUDS TO INCREASE
OVERNIGHT AND PRECIPITATION IS EXPECTED TO OVERSPREAD AT LEAST
PORTIONS OF THE AREA MONDAY MORNING INTO MONDAY AFTERNOON.

THERE WILL BE ENOUGH COLD AIR FOR POSSIBLE FROZEN PRECIPITATION
MONDAY...ESPECIALLY NORTH AND WEST OF INTERSTATE 95. THE MAIN
IMPACT FROM FROZEN PRECIPITATION WOULD BE FROM FREEZING
RAIN...ALTHOUGH SNOW AND SLEET MAY MIX WITH
PRECIPITATION...ESPECIALLY AT THE ONSET. HOWEVER...THERE IS STILL
SOME UNCERTAINTY AS TO HOW FAR NORTH AND WEST THE PRECIPITATION
WILL MAKE IT SINCE IT WILL BE RUNNING INTO DRIER AIR. THE HIGHEST
CONFIDENCE FOR PRECIPITATION AND SUBFREEZING TEMPERATURES IS
ACROSS CENTRAL VIRGINIA. A FREEZING RAIN ADVISORY IS IN EFFECT FOR
THESE AREAS MONDAY MORNING. FREEZING RAIN MAY CONTINUE INTO THE
AFTERNOON HOURS AS WELL.

FOR THE WASHINGTON AND BALTIMORE METROPOLITAN
AREAS...CONFIDENCE IS NOT YET HIGH ENOUGH FOR A HEADLINE SINCE
TEMPERATURES WILL BE MARGINAL AND IMPACT FROM FROZEN PRECIPITATION
IS NOT EXPECTED TO OCCUR UNTIL LATER MONDAY MORNING OR AFTERNOON.
PRECIPITATION WILL LIKELY OVERSPREAD THESE AREAS DURING THE MID TO
LATE MORNING HOURS MONDAY AND CONTINUE THROUGH MONDAY AFTERNOON.
FROZEN PRECIPITATION IS POSSIBLE...ESPECIALLY NORTH AND WEST OF
INTERSTATE 95. A FREEZING RAIN ADVISORY MAY BE NEEDED FOR PORTIONS
OF THESE AREAS.

FOR THE POTOMAC HIGHLANDS...NORTHERN MARYLAND AND EASTERN WEST
VIRGINIA. TEMPERATURES WILL BE COLD ENOUGH FOR FROZEN
PRECIPITATION...BUT THE NORTHERN AND WESTERN EXTENT OF THE PRECIP
IS TOO UNCERTAIN AT THIS TIME TO ISSUE AN ADVISORY. ANY IMPACT
FROM FROZEN PRECIPITATION WOULD NOT OCCUR UNTIL MONDAY AFTERNOON.

MAX TEMPS MONDAY WILL RANGE FROM THE UPPER 20S AND LOWER 30S
ACROSS THE ALLEGHENY AND POTOMAC HIGHLANDS...TO THE MIDDLE 30S
NEAR WASHINGTON AND BALTIMORE...TO NEAR 40 IN SOUTHERN MARYLAND.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
LIGHT PRECIPITATION WILL CONTINUE MONDAY NIGHT INTO TUESDAY MORNING.
THE BIG QUESTION WILL BE HOW LONG THE CAD WEDGE WILL REMAIN IN
PLACE. THERE IS STILL POTENTIAL FOR TEMPERATURES TO REMAIN AT OR
BELOW FREEZING MAINLY WEST OF THE BLUE RIDGE LEAVING THE POTENTIAL
FOR LIGHT FREEZING RAIN TO CONTINUE. TO THE EAST OF THE BLUE RIDGE
AND ACROSS THE METRO AREAS...WARMER AIR WILL LIKELY WIN OUT KEEPING
PRECIPITATION IN THE FORM OF RAIN. A BRIEF RESPITE FROM THE
PRECIPITATION IS POSSIBLE TUESDAY AFTERNOON/EVENING BEFORE THE NEXT
ROUND OF RAINFALL MOVES IN FROM THE WEST LATER TUESDAY NIGHT.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
STRONG COLD FRONT CROSSING THE MID ATLANTIC REGION WEDNESDAY INTO
THURSDAY. LIQUID PRECIPITATION SHOULD ACCOMPANY THE FRONT EXCEPT
ALONG THE ALLEGHENY  FRONT WHERE ARRIVAL OF COLDER AIR WILL CAUSE THE
RAIN TO CHANGE OVER TO SNOW BEFORE PRECIPITATION ENDS THURSDAY.

PASSAGE OF SHORTWAVE WILL SUPPORT DEVELOPMENT OF A COASTAL LOW LATE
SATURDAY AND SUNDAY. PRECIPITATION MAY START AS A WINTRY MIX AT
HIGHER ELEVATIONS.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
VFR CONDITIONS THROUGH THIS EVENING. CLOUDS WILL INCREASE
OVERNIGHT AND PRECIPITATION WILL OVERSPREAD THE TERMINALS MONDAY
FROM SOUTHWEST TO NORTHEAST. FREEZING RAIN IS EXPECTED ACROSS KCHO
AND POSSIBLY KMRB AND KIAD. FREEZING RAIN MAY MIX WITH SLEET AND
SNOW AT THE ONSET. RAIN IS EXPECTED ACROSS THE REST OF THE
TERMINALS. RAIN MAY MIX WITH SLEET AT THE ONSET. CIGS/VSBYS WILL
DETERIORATE TO MVFR LEVELS MONDAY WITH POSSIBLE IFR LEVELS.

SUB VFR CIGS AND VSBYS EXPECTED MONDAY NIGHT INTO TUESDAY. LIGHT
FREEZING RAIN WILL BE POSSIBLE WEST OF THE BLUE RIDGE WITH RAIN TO
THE EAST. A PRECIPITATION RESPITE MAY OCCUR TUESDAY AFTERNOON BEFORE
RAIN MOVES BACK IN LATER TUESDAY NIGHT. A STRONG COLD FRONT WILL
APPROACH THE TERMINALS WEDNESDAY BEFORE PASSING THROUGH
WEDNESDAY NIGHT. MORE RAIN AND SUBVFR CONDITIONS ARE EXPECTED.

&&

.MARINE...
HIGH PRESSURE WILL REMAIN OVER THE WATERS TONIGHT. LOW PRESSURE
WILL TRACK UP THE MID-ATLANTIC COAST MONDAY. A SMALL CRAFT
ADVISORY IS IN EFFECT FOR THE MIDDLE PORTIONS OF THE BAY AND LOWER
TIDAL POTOMAC RIVER.

WINDS ARE EXPECTED TO REMAIN BELOW SCA CRITERIA MONDAY NIGHT THROUGH
TUESDAY NIGHT. A STRONG COLD FRONT WILL APPROACH THE WATERS
WEDNESDAY BEFORE PASSING THROUGH WEDNESDAY NIGHT. A SMALL CRAFT
ADVISORY WILL LIKELY BE NEEDED FOR THE WATERS WEDNESDAY AND
THURSDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...FREEZING RAIN ADVISORY FROM 6 AM TO NOON EST MONDAY FOR VAZ025-
     026-029-036>040-050-051-501>504-507-508.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 6 PM EST MONDAY FOR ANZ534-
     537-543.

&&

$$
SYNOPSIS...BJL
NEAR TERM...BJL
SHORT TERM...KRW
LONG TERM...CEM
AVIATION...BJL/KRW
MARINE...BJL/KRW









000
FXUS61 KLWX 211945
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
245 PM EST SUN DEC 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH TONIGHT. LOW
PRESSURE WILL TRACK UP THE MID-ATLANTIC COAST MONDAY AND TUESDAY.
A STRONG COLD FRONT WILL APPROACH THE AREA WEDNESDAY BEFORE
PASSING THROUGH WEDNESDAY NIGHT. HIGH PRESSURE WILL BUILD OVERHEAD
LATE IN THE WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
HIGH PRESSURE REMAINS OVER THE REGION THIS AFTERNOON AND
SUBSIDENCE BEHIND A SHORTWAVE HAS ALLOWED FOR SUNSHINE. HIGH
PRESSURE WILL BECOME CENTERED OVER NEW ENGLAND TONIGHT AND THE
SURFACE RIDGE AXIS WILL DROP SOUTHWEST THROUGH OUR REGION DURING
THIS TIME.

POTENT LOW PRESSURE WILL TRACK THROUGH THE PLAINS TONIGHT THROUGH
MONDAY. A WARM FRONT WILL EXTEND SOUTHEAST FROM THIS SYSTEM
THROUGH THE TENNESSEE VALLEY INTO THE APPALACHIANS WHERE IT WILL
BECOME A STATIONARY FRONT THAT CONTINUES TO EXTEND THROUGH THE
SOUTHEASTERN CONUS. LOW PRESSURE WILL DEVELOP ALONG THIS BOUNDARY
OFF THE SOUTHEAST COAST TONIGHT AND IT IS EXPECTED TO TRACK UP THE
MID-ATLANTIC COAST MONDAY. THIS SYSTEM WILL BE WEAK AND MOST OF
THE DYNAMICS WILL REMAIN WELL TO OUR WEST...CLOSER TO THE STRONGER
LOW OVER THE PLAINS. HOWEVER...WARM AND MOIST AIR FROM THE GULF OF
MEXICO AND ATLANTIC OCEAN WILL OVERRUN THE COLDER AND DRIER AIR
THAT IS CURRENTLY IN PLACE. THIS WILL CAUSE CLOUDS TO INCREASE
OVERNIGHT AND PRECIPITATION IS EXPECTED TO OVERSPREAD AT LEAST
PORTIONS OF THE AREA MONDAY MORNING INTO MONDAY AFTERNOON.

THERE WILL BE ENOUGH COLD AIR FOR POSSIBLE FROZEN PRECIPITATION
MONDAY...ESPECIALLY NORTH AND WEST OF INTERSTATE 95. THE MAIN
IMPACT FROM FROZEN PRECIPITATION WOULD BE FROM FREEZING
RAIN...ALTHOUGH SNOW AND SLEET MAY MIX WITH
PRECIPITATION...ESPECIALLY AT THE ONSET. HOWEVER...THERE IS STILL
SOME UNCERTAINTY AS TO HOW FAR NORTH AND WEST THE PRECIPITATION
WILL MAKE IT SINCE IT WILL BE RUNNING INTO DRIER AIR. THE HIGHEST
CONFIDENCE FOR PRECIPITATION AND SUBFREEZING TEMPERATURES IS
ACROSS CENTRAL VIRGINIA. A FREEZING RAIN ADVISORY IS IN EFFECT FOR
THESE AREAS MONDAY MORNING. FREEZING RAIN MAY CONTINUE INTO THE
AFTERNOON HOURS AS WELL.

FOR THE WASHINGTON AND BALTIMORE METROPOLITAN
AREAS...CONFIDENCE IS NOT YET HIGH ENOUGH FOR A HEADLINE SINCE
TEMPERATURES WILL BE MARGINAL AND IMPACT FROM FROZEN PRECIPITATION
IS NOT EXPECTED TO OCCUR UNTIL LATER MONDAY MORNING OR AFTERNOON.
PRECIPITATION WILL LIKELY OVERSPREAD THESE AREAS DURING THE MID TO
LATE MORNING HOURS MONDAY AND CONTINUE THROUGH MONDAY AFTERNOON.
FROZEN PRECIPITATION IS POSSIBLE...ESPECIALLY NORTH AND WEST OF
INTERSTATE 95. A FREEZING RAIN ADVISORY MAY BE NEEDED FOR PORTIONS
OF THESE AREAS.

FOR THE POTOMAC HIGHLANDS...NORTHERN MARYLAND AND EASTERN WEST
VIRGINIA. TEMPERATURES WILL BE COLD ENOUGH FOR FROZEN
PRECIPITATION...BUT THE NORTHERN AND WESTERN EXTENT OF THE PRECIP
IS TOO UNCERTAIN AT THIS TIME TO ISSUE AN ADVISORY. ANY IMPACT
FROM FROZEN PRECIPITATION WOULD NOT OCCUR UNTIL MONDAY AFTERNOON.

MAX TEMPS MONDAY WILL RANGE FROM THE UPPER 20S AND LOWER 30S
ACROSS THE ALLEGHENY AND POTOMAC HIGHLANDS...TO THE MIDDLE 30S
NEAR WASHINGTON AND BALTIMORE...TO NEAR 40 IN SOUTHERN MARYLAND.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
LIGHT PRECIPITATION WILL CONTINUE MONDAY NIGHT INTO TUESDAY MORNING.
THE BIG QUESTION WILL BE HOW LONG THE CAD WEDGE WILL REMAIN IN
PLACE. THERE IS STILL POTENTIAL FOR TEMPERATURES TO REMAIN AT OR
BELOW FREEZING MAINLY WEST OF THE BLUE RIDGE LEAVING THE POTENTIAL
FOR LIGHT FREEZING RAIN TO CONTINUE. TO THE EAST OF THE BLUE RIDGE
AND ACROSS THE METRO AREAS...WARMER AIR WILL LIKELY WIN OUT KEEPING
PRECIPITATION IN THE FORM OF RAIN. A BRIEF RESPITE FROM THE
PRECIPITATION IS POSSIBLE TUESDAY AFTERNOON/EVENING BEFORE THE NEXT
ROUND OF RAINFALL MOVES IN FROM THE WEST LATER TUESDAY NIGHT.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
STRONG COLD FRONT CROSSING THE MID ATLANTIC REGION WEDNESDAY INTO
THURSDAY. LIQUID PRECIPITATION SHOULD ACCOMPANY THE FRONT EXCEPT
ALONG THE ALLEGHENY  FRONT WHERE ARRIVAL OF COLDER AIR WILL CAUSE THE
RAIN TO CHANGE OVER TO SNOW BEFORE PRECIPITATION ENDS THURSDAY.

PASSAGE OF SHORTWAVE WILL SUPPORT DEVELOPMENT OF A COASTAL LOW LATE
SATURDAY AND SUNDAY. PRECIPITATION MAY START AS A WINTRY MIX AT
HIGHER ELEVATIONS.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
VFR CONDITIONS THROUGH THIS EVENING. CLOUDS WILL INCREASE
OVERNIGHT AND PRECIPITATION WILL OVERSPREAD THE TERMINALS MONDAY
FROM SOUTHWEST TO NORTHEAST. FREEZING RAIN IS EXPECTED ACROSS KCHO
AND POSSIBLY KMRB AND KIAD. FREEZING RAIN MAY MIX WITH SLEET AND
SNOW AT THE ONSET. RAIN IS EXPECTED ACROSS THE REST OF THE
TERMINALS. RAIN MAY MIX WITH SLEET AT THE ONSET. CIGS/VSBYS WILL
DETERIORATE TO MVFR LEVELS MONDAY WITH POSSIBLE IFR LEVELS.

SUB VFR CIGS AND VSBYS EXPECTED MONDAY NIGHT INTO TUESDAY. LIGHT
FREEZING RAIN WILL BE POSSIBLE WEST OF THE BLUE RIDGE WITH RAIN TO
THE EAST. A PRECIPITATION RESPITE MAY OCCUR TUESDAY AFTERNOON BEFORE
RAIN MOVES BACK IN LATER TUESDAY NIGHT. A STRONG COLD FRONT WILL
APPROACH THE TERMINALS WEDNESDAY BEFORE PASSING THROUGH
WEDNESDAY NIGHT. MORE RAIN AND SUBVFR CONDITIONS ARE EXPECTED.

&&

.MARINE...
HIGH PRESSURE WILL REMAIN OVER THE WATERS TONIGHT. LOW PRESSURE
WILL TRACK UP THE MID-ATLANTIC COAST MONDAY. A SMALL CRAFT
ADVISORY IS IN EFFECT FOR THE MIDDLE PORTIONS OF THE BAY AND LOWER
TIDAL POTOMAC RIVER.

WINDS ARE EXPECTED TO REMAIN BELOW SCA CRITERIA MONDAY NIGHT THROUGH
TUESDAY NIGHT. A STRONG COLD FRONT WILL APPROACH THE WATERS
WEDNESDAY BEFORE PASSING THROUGH WEDNESDAY NIGHT. A SMALL CRAFT
ADVISORY WILL LIKELY BE NEEDED FOR THE WATERS WEDNESDAY AND
THURSDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...FREEZING RAIN ADVISORY FROM 6 AM TO NOON EST MONDAY FOR VAZ025-
     026-029-036>040-050-051-501>504-507-508.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 6 PM EST MONDAY FOR ANZ534-
     537-543.

&&

$$
SYNOPSIS...BJL
NEAR TERM...BJL
SHORT TERM...KRW
LONG TERM...CEM
AVIATION...BJL/KRW
MARINE...BJL/KRW









000
FXUS61 KLWX 211945
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
245 PM EST SUN DEC 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH TONIGHT. LOW
PRESSURE WILL TRACK UP THE MID-ATLANTIC COAST MONDAY AND TUESDAY.
A STRONG COLD FRONT WILL APPROACH THE AREA WEDNESDAY BEFORE
PASSING THROUGH WEDNESDAY NIGHT. HIGH PRESSURE WILL BUILD OVERHEAD
LATE IN THE WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
HIGH PRESSURE REMAINS OVER THE REGION THIS AFTERNOON AND
SUBSIDENCE BEHIND A SHORTWAVE HAS ALLOWED FOR SUNSHINE. HIGH
PRESSURE WILL BECOME CENTERED OVER NEW ENGLAND TONIGHT AND THE
SURFACE RIDGE AXIS WILL DROP SOUTHWEST THROUGH OUR REGION DURING
THIS TIME.

POTENT LOW PRESSURE WILL TRACK THROUGH THE PLAINS TONIGHT THROUGH
MONDAY. A WARM FRONT WILL EXTEND SOUTHEAST FROM THIS SYSTEM
THROUGH THE TENNESSEE VALLEY INTO THE APPALACHIANS WHERE IT WILL
BECOME A STATIONARY FRONT THAT CONTINUES TO EXTEND THROUGH THE
SOUTHEASTERN CONUS. LOW PRESSURE WILL DEVELOP ALONG THIS BOUNDARY
OFF THE SOUTHEAST COAST TONIGHT AND IT IS EXPECTED TO TRACK UP THE
MID-ATLANTIC COAST MONDAY. THIS SYSTEM WILL BE WEAK AND MOST OF
THE DYNAMICS WILL REMAIN WELL TO OUR WEST...CLOSER TO THE STRONGER
LOW OVER THE PLAINS. HOWEVER...WARM AND MOIST AIR FROM THE GULF OF
MEXICO AND ATLANTIC OCEAN WILL OVERRUN THE COLDER AND DRIER AIR
THAT IS CURRENTLY IN PLACE. THIS WILL CAUSE CLOUDS TO INCREASE
OVERNIGHT AND PRECIPITATION IS EXPECTED TO OVERSPREAD AT LEAST
PORTIONS OF THE AREA MONDAY MORNING INTO MONDAY AFTERNOON.

THERE WILL BE ENOUGH COLD AIR FOR POSSIBLE FROZEN PRECIPITATION
MONDAY...ESPECIALLY NORTH AND WEST OF INTERSTATE 95. THE MAIN
IMPACT FROM FROZEN PRECIPITATION WOULD BE FROM FREEZING
RAIN...ALTHOUGH SNOW AND SLEET MAY MIX WITH
PRECIPITATION...ESPECIALLY AT THE ONSET. HOWEVER...THERE IS STILL
SOME UNCERTAINTY AS TO HOW FAR NORTH AND WEST THE PRECIPITATION
WILL MAKE IT SINCE IT WILL BE RUNNING INTO DRIER AIR. THE HIGHEST
CONFIDENCE FOR PRECIPITATION AND SUBFREEZING TEMPERATURES IS
ACROSS CENTRAL VIRGINIA. A FREEZING RAIN ADVISORY IS IN EFFECT FOR
THESE AREAS MONDAY MORNING. FREEZING RAIN MAY CONTINUE INTO THE
AFTERNOON HOURS AS WELL.

FOR THE WASHINGTON AND BALTIMORE METROPOLITAN
AREAS...CONFIDENCE IS NOT YET HIGH ENOUGH FOR A HEADLINE SINCE
TEMPERATURES WILL BE MARGINAL AND IMPACT FROM FROZEN PRECIPITATION
IS NOT EXPECTED TO OCCUR UNTIL LATER MONDAY MORNING OR AFTERNOON.
PRECIPITATION WILL LIKELY OVERSPREAD THESE AREAS DURING THE MID TO
LATE MORNING HOURS MONDAY AND CONTINUE THROUGH MONDAY AFTERNOON.
FROZEN PRECIPITATION IS POSSIBLE...ESPECIALLY NORTH AND WEST OF
INTERSTATE 95. A FREEZING RAIN ADVISORY MAY BE NEEDED FOR PORTIONS
OF THESE AREAS.

FOR THE POTOMAC HIGHLANDS...NORTHERN MARYLAND AND EASTERN WEST
VIRGINIA. TEMPERATURES WILL BE COLD ENOUGH FOR FROZEN
PRECIPITATION...BUT THE NORTHERN AND WESTERN EXTENT OF THE PRECIP
IS TOO UNCERTAIN AT THIS TIME TO ISSUE AN ADVISORY. ANY IMPACT
FROM FROZEN PRECIPITATION WOULD NOT OCCUR UNTIL MONDAY AFTERNOON.

MAX TEMPS MONDAY WILL RANGE FROM THE UPPER 20S AND LOWER 30S
ACROSS THE ALLEGHENY AND POTOMAC HIGHLANDS...TO THE MIDDLE 30S
NEAR WASHINGTON AND BALTIMORE...TO NEAR 40 IN SOUTHERN MARYLAND.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
LIGHT PRECIPITATION WILL CONTINUE MONDAY NIGHT INTO TUESDAY MORNING.
THE BIG QUESTION WILL BE HOW LONG THE CAD WEDGE WILL REMAIN IN
PLACE. THERE IS STILL POTENTIAL FOR TEMPERATURES TO REMAIN AT OR
BELOW FREEZING MAINLY WEST OF THE BLUE RIDGE LEAVING THE POTENTIAL
FOR LIGHT FREEZING RAIN TO CONTINUE. TO THE EAST OF THE BLUE RIDGE
AND ACROSS THE METRO AREAS...WARMER AIR WILL LIKELY WIN OUT KEEPING
PRECIPITATION IN THE FORM OF RAIN. A BRIEF RESPITE FROM THE
PRECIPITATION IS POSSIBLE TUESDAY AFTERNOON/EVENING BEFORE THE NEXT
ROUND OF RAINFALL MOVES IN FROM THE WEST LATER TUESDAY NIGHT.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
STRONG COLD FRONT CROSSING THE MID ATLANTIC REGION WEDNESDAY INTO
THURSDAY. LIQUID PRECIPITATION SHOULD ACCOMPANY THE FRONT EXCEPT
ALONG THE ALLEGHENY  FRONT WHERE ARRIVAL OF COLDER AIR WILL CAUSE THE
RAIN TO CHANGE OVER TO SNOW BEFORE PRECIPITATION ENDS THURSDAY.

PASSAGE OF SHORTWAVE WILL SUPPORT DEVELOPMENT OF A COASTAL LOW LATE
SATURDAY AND SUNDAY. PRECIPITATION MAY START AS A WINTRY MIX AT
HIGHER ELEVATIONS.

&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
VFR CONDITIONS THROUGH THIS EVENING. CLOUDS WILL INCREASE
OVERNIGHT AND PRECIPITATION WILL OVERSPREAD THE TERMINALS MONDAY
FROM SOUTHWEST TO NORTHEAST. FREEZING RAIN IS EXPECTED ACROSS KCHO
AND POSSIBLY KMRB AND KIAD. FREEZING RAIN MAY MIX WITH SLEET AND
SNOW AT THE ONSET. RAIN IS EXPECTED ACROSS THE REST OF THE
TERMINALS. RAIN MAY MIX WITH SLEET AT THE ONSET. CIGS/VSBYS WILL
DETERIORATE TO MVFR LEVELS MONDAY WITH POSSIBLE IFR LEVELS.

SUB VFR CIGS AND VSBYS EXPECTED MONDAY NIGHT INTO TUESDAY. LIGHT
FREEZING RAIN WILL BE POSSIBLE WEST OF THE BLUE RIDGE WITH RAIN TO
THE EAST. A PRECIPITATION RESPITE MAY OCCUR TUESDAY AFTERNOON BEFORE
RAIN MOVES BACK IN LATER TUESDAY NIGHT. A STRONG COLD FRONT WILL
APPROACH THE TERMINALS WEDNESDAY BEFORE PASSING THROUGH
WEDNESDAY NIGHT. MORE RAIN AND SUBVFR CONDITIONS ARE EXPECTED.

&&

.MARINE...
HIGH PRESSURE WILL REMAIN OVER THE WATERS TONIGHT. LOW PRESSURE
WILL TRACK UP THE MID-ATLANTIC COAST MONDAY. A SMALL CRAFT
ADVISORY IS IN EFFECT FOR THE MIDDLE PORTIONS OF THE BAY AND LOWER
TIDAL POTOMAC RIVER.

WINDS ARE EXPECTED TO REMAIN BELOW SCA CRITERIA MONDAY NIGHT THROUGH
TUESDAY NIGHT. A STRONG COLD FRONT WILL APPROACH THE WATERS
WEDNESDAY BEFORE PASSING THROUGH WEDNESDAY NIGHT. A SMALL CRAFT
ADVISORY WILL LIKELY BE NEEDED FOR THE WATERS WEDNESDAY AND
THURSDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...FREEZING RAIN ADVISORY FROM 6 AM TO NOON EST MONDAY FOR VAZ025-
     026-029-036>040-050-051-501>504-507-508.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 6 PM EST MONDAY FOR ANZ534-
     537-543.

&&

$$
SYNOPSIS...BJL
NEAR TERM...BJL
SHORT TERM...KRW
LONG TERM...CEM
AVIATION...BJL/KRW
MARINE...BJL/KRW








000
FXUS61 KLWX 211443
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
943 AM EST SUN DEC 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN WEDGED INTO THE MID-ATLANTIC THROUGH
EARLY IN THE WEEK. LOW PRESSURE WILL TRACK UP THE MID-ATLANTIC
COAST LATE MONDAY. A STRONG COLD FRONT WILL THEN PASS THROUGH THE
AREA WEDNESDAY NIGHT.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE WINTER SOLSTICE IS AT 603PM EST TODAY...SUNDAY DECEMBER 21 2014.
THE SUN WILL BE AT THE LOWEST ANGLE OF THE YEAR WITH THE LEAST
AMOUNT OF DAYLIGHT.

A SHORTWAVE IS PASSING BY TO OUR NORTH THIS MORNING WHILE SURFACE
HIGH PRESSURE REMAINS OVERHEAD. LOW-LEVEL MOISTURE TRAPPED
UNDERNEATH THE SUBSIDENCE INVERSION HAS CAUSED PLENTY OF CLOUDS.
HOWEVER...SUBSIDENCE BEHIND THE DEPARTING SHORTWAVE SHOULD ALLOW
FOR CLOUDS TO GIVE WAY TO SUNSHINE THIS AFTERNOON. MAX TEMPS WILL
BE NEAR CLIMO...RANGING FROM THE UPPER 20S AND LOWER 30S IN THE
MOUNTAINS TO THE LOWER 40S NEAR WASHINGTON AND BALTIMORE. SHOULD
CLOUDS HANG ON LONGER THAN EXPECTED...TEMPS WILL REMAIN IN THE 30S
FOR THE WASHINGTON AND BALTIMORE METROPOLITAN AREAS.

HIGH PRESSURE WILL BEGIN TO WEDGE AGAINST THE APPALACHIAN REGION
TONIGHT AS AN UPPER LEVEL TROUGH BEGINS TO AMPLIFY ACROSS THE
CENTRAL US. THE JET STREAM ACROSS THE SE US WILL LEAD TO THE
DEVELOPMENT OF LOW PRESSURE OFF THE CAROLINA COAST. MOISTURE
ADVECTION INTO THE MID-ATLANTIC WILL LEAD TO PRECIPITATION MOVING
INTO THE REGION FROM THE SOUTH LATE TONIGHT. WENT WITH THE SREF
MEAN FOR PRECIP PROGRESSION. AT THIS TIME...MOISTURE SHOULD BE
REACHING THE GROUND ACROSS THE CENTRAL FOOTHILLS...SHENANDOAH
VALLEY...PIEDMONT EARLY MONDAY MORNING. HIGH PRESSURE WILL SERVE
AS A SOURCE OF COLD AIR AT THE SFC WITH TEMPS REACHING THE UPPER
20S TO AROUND 30 BY MONDAY MORNING. 850-700MB THICKNESS VALUES
AROUND 1550M UP TO I-66 AND 1000-850MB THICKNESS VALUES AROUND
1310 WOULD RESULT IN FZRA...SLEET MIXTURE EARLY MONDAY MORNING IF
MOISTURE IS AVAILABLE. TEMPS ALONG AND WEST OF THE BLUE RIDGE ARE
EXPECTED TO BE COLDER RESULTING IN A BETTER CHANCE FOR ICE
ACCRETION.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
STILL HAVE SOME UNCERTAINTY REGARDING THE DETAILS OF MONDAY/MONDAY
NIGHT. GENERAL IDEA IS THAT PRECIP WILL SPREAD NORTHWARD THROUGH THE
CWA DURING THE DAY MONDAY...ALTHOUGH THE EXACT NORTH/NORTHWEST
EXTENT REMAINS SOMEWHAT IN QUESTION. ALSO IN QUESTION WILL BE TIMING
THE CHANGES TO THE THERMAL PROFILE THROUGH THE DAY...WHICH WILL
DETERMINE P-TYPE.

PREFER GENERAL IDEA FROM THE SREFS FOR POPS...ALTHOUGH POPS NOT
QUITE AS HIGH FURTHER NORTH TOWARD THE MASON DIXON LINE. LEANED
TOWARD SREFS FOR TEMPERATURE/PROFILE CONSIDERATIONS TOO. THIS
SUGGESTS THAT INITIAL PRECIP MAY BE SLEET OR FREEZING
RAIN...TRENDING TO JUST RAIN THROUGHOUT THE DAY ALTHOUGH WINTRY
PRECIP COULD LINGER LONGER OVER THE POTOMAC HIGHLANDS. HIGHEST
CONFIDENCE FOR ICING RESIDES ACROSS THE LOWER POTOMAC
HIGHLANDS/SHENANDOAH VALLEY/CENTRAL VA FOOTHILLS.

RISK OF FREEZING RAIN COULD CONTINUE OVER THE POTOMAC HIGHLANDS
MONDAY NIGHT ASSUMING THERE IS PRECIPITATION FALLING...BUT THIS IS
UNCERTAIN AS MODELS SUGGEST THE MAIN BATCH OF QPF LIFTS NORTHEAST IN
TANDEM WITH WEAK LOW PRESSURE OFF THE COAST.

WEDGE REMAINS IN PLACE TUESDAY. NOT SURE THERE/S A LOT OF MEASURABLE
PRECIP GOING ON...IT MAY BE MORE DRIZZLE BUT CONTINUE CHANCE POPS
FOR RAIN ACROSS THE CWA WITH GFS SHOWING BROAD LIGHT QPF. AM
EXPECTING ANY PRECIPITATION TO BE IN LIQUID FORM DURING THE DAY
TUESDAY.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
FOCUS THEN SHIFTS TO DEEP UPPER TROUGH/STRONG COLD FRONT OVER THE
MIDWEST/OHIO VALLEY TUESDAY NIGHT. DECENT PLUME OF MOISTURE
OVERRUNNING A WARM FRONT WILL BRING RAIN INTO THE MID-ATLANTIC
TUESDAY NIGHT.

AS LOW LEVEL JET STRENGTHENS ON WEDNESDAY...THIS SHOULD HELP TO PUSH
THE WARM FRONT TO THE NORTH. PW/S MAY INCREASE NEAR 1.5
INCHES...LIKELY LEADING TO PERIODS OF MODERATE RAINFALL ON
WEDNESDAY. INSTABILITY IS FORECAST TO BE WEAK SO NO THUNDER
MENTIONED BUT POTENTIAL EXISTS FOR SOME GUSTY SHOWERS GIVEN WIND
FIELDS OFF THE DECK. DESPITE CLOUDS/RAIN...MAXIMA SHOULD WARM WELL
INTO THE 50S AND POSSIBLY ECLIPSE 60 IN SOME AREAS.

STRONG COLD FRONT MOVES THROUGH WEDNESDAY NIGHT. SHOWERS END FROM
WEST TO EAST...AND COLD ADVECTION/TIGHT PRESSURE GRADIENT WILL BRING
A BLUSTERY AND COOLER DAY THURSDAY /MEX GUIDANCE LIKELY TOO WARM/.
NEXT COLD FRONT APPROACHES FRIDAY NIGHT OR SATURDAY.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS EXPECTED THROUGH TONIGHT. MID LEVEL MOISTURE WILL
CONTINUE TO MOVE EASTWARD ACROSS THE REGION RESULTING IN BKN-OVC
VFR CIGS. CLEARING IS EXPECTED BY THIS AFTERNOON WITH A SCT-BKN 5K
FEET DECK EXPECTED INTO THE EVENING. CLOUDS WILL BUILD IN FROM THE
SOUTH TONIGHT AS LOW PRESSURE DEVELOPS OFF THE EAST COAST.
MVFR/IFR CIGS SHOULD REACH CHO BY MONDAY MORNING. LIGHT NRLY WINDS
EXPECTED DURING THE TAF PERIOD.

PRECIP SPREADS NORTH ON MONDAY...POSSIBLY BEGINNING AS A WINTRY MIX
OF -IP/-ZR BEFORE TRANSITIONING TO -RA. MVFR CONDITIONS LIKELY ON
MONDAY WITH PRECIP...DEGRADING INTO IFR/LIFR MONDAY NIGHT INTO
TUESDAY. RESTRICTIONS CONTINUE INTO WEDNESDAY WITH SHOWERS AND
POSSIBLE LLWS. COLD FRONT MOVES THROUGH WEDNESDAY NIGHT...WITH GUSTY
SURFACE WINDS THURSDAY.

&&

.MARINE...
LIGHT NRLY WINDS EXPECTED ON THE WATERS THROUGH TONIGHT. WINDS
WILL REMAIN LIGHT BUT BECOME EASTERLY LATE TONIGHT AND INTO MONDAY
MORNING. RAIN AND/OR SLEET SHOULD REACH THE SRN WATERS MONDAY
MORNING BEFORE CHANGING TO ALL RAIN THROUGH MONDAY.

SCA CONDITIONS ARE POSSIBLE IN SOUTHERLY FLOW AHEAD OF A COLD FRONT
ON WEDNESDAY...THEN BEHIND THE FRONT FOR WEDNESDAY NIGHT AND
THURSDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...BPP/HAS
NEAR TERM...BJL/HAS
SHORT TERM...BPP
LONG TERM...BPP
AVIATION...BJL/BPP/HAS
MARINE...BJL/BPP/HAS








000
FXUS61 KLWX 211443
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
943 AM EST SUN DEC 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN WEDGED INTO THE MID-ATLANTIC THROUGH
EARLY IN THE WEEK. LOW PRESSURE WILL TRACK UP THE MID-ATLANTIC
COAST LATE MONDAY. A STRONG COLD FRONT WILL THEN PASS THROUGH THE
AREA WEDNESDAY NIGHT.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE WINTER SOLSTICE IS AT 603PM EST TODAY...SUNDAY DECEMBER 21 2014.
THE SUN WILL BE AT THE LOWEST ANGLE OF THE YEAR WITH THE LEAST
AMOUNT OF DAYLIGHT.

A SHORTWAVE IS PASSING BY TO OUR NORTH THIS MORNING WHILE SURFACE
HIGH PRESSURE REMAINS OVERHEAD. LOW-LEVEL MOISTURE TRAPPED
UNDERNEATH THE SUBSIDENCE INVERSION HAS CAUSED PLENTY OF CLOUDS.
HOWEVER...SUBSIDENCE BEHIND THE DEPARTING SHORTWAVE SHOULD ALLOW
FOR CLOUDS TO GIVE WAY TO SUNSHINE THIS AFTERNOON. MAX TEMPS WILL
BE NEAR CLIMO...RANGING FROM THE UPPER 20S AND LOWER 30S IN THE
MOUNTAINS TO THE LOWER 40S NEAR WASHINGTON AND BALTIMORE. SHOULD
CLOUDS HANG ON LONGER THAN EXPECTED...TEMPS WILL REMAIN IN THE 30S
FOR THE WASHINGTON AND BALTIMORE METROPOLITAN AREAS.

HIGH PRESSURE WILL BEGIN TO WEDGE AGAINST THE APPALACHIAN REGION
TONIGHT AS AN UPPER LEVEL TROUGH BEGINS TO AMPLIFY ACROSS THE
CENTRAL US. THE JET STREAM ACROSS THE SE US WILL LEAD TO THE
DEVELOPMENT OF LOW PRESSURE OFF THE CAROLINA COAST. MOISTURE
ADVECTION INTO THE MID-ATLANTIC WILL LEAD TO PRECIPITATION MOVING
INTO THE REGION FROM THE SOUTH LATE TONIGHT. WENT WITH THE SREF
MEAN FOR PRECIP PROGRESSION. AT THIS TIME...MOISTURE SHOULD BE
REACHING THE GROUND ACROSS THE CENTRAL FOOTHILLS...SHENANDOAH
VALLEY...PIEDMONT EARLY MONDAY MORNING. HIGH PRESSURE WILL SERVE
AS A SOURCE OF COLD AIR AT THE SFC WITH TEMPS REACHING THE UPPER
20S TO AROUND 30 BY MONDAY MORNING. 850-700MB THICKNESS VALUES
AROUND 1550M UP TO I-66 AND 1000-850MB THICKNESS VALUES AROUND
1310 WOULD RESULT IN FZRA...SLEET MIXTURE EARLY MONDAY MORNING IF
MOISTURE IS AVAILABLE. TEMPS ALONG AND WEST OF THE BLUE RIDGE ARE
EXPECTED TO BE COLDER RESULTING IN A BETTER CHANCE FOR ICE
ACCRETION.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
STILL HAVE SOME UNCERTAINTY REGARDING THE DETAILS OF MONDAY/MONDAY
NIGHT. GENERAL IDEA IS THAT PRECIP WILL SPREAD NORTHWARD THROUGH THE
CWA DURING THE DAY MONDAY...ALTHOUGH THE EXACT NORTH/NORTHWEST
EXTENT REMAINS SOMEWHAT IN QUESTION. ALSO IN QUESTION WILL BE TIMING
THE CHANGES TO THE THERMAL PROFILE THROUGH THE DAY...WHICH WILL
DETERMINE P-TYPE.

PREFER GENERAL IDEA FROM THE SREFS FOR POPS...ALTHOUGH POPS NOT
QUITE AS HIGH FURTHER NORTH TOWARD THE MASON DIXON LINE. LEANED
TOWARD SREFS FOR TEMPERATURE/PROFILE CONSIDERATIONS TOO. THIS
SUGGESTS THAT INITIAL PRECIP MAY BE SLEET OR FREEZING
RAIN...TRENDING TO JUST RAIN THROUGHOUT THE DAY ALTHOUGH WINTRY
PRECIP COULD LINGER LONGER OVER THE POTOMAC HIGHLANDS. HIGHEST
CONFIDENCE FOR ICING RESIDES ACROSS THE LOWER POTOMAC
HIGHLANDS/SHENANDOAH VALLEY/CENTRAL VA FOOTHILLS.

RISK OF FREEZING RAIN COULD CONTINUE OVER THE POTOMAC HIGHLANDS
MONDAY NIGHT ASSUMING THERE IS PRECIPITATION FALLING...BUT THIS IS
UNCERTAIN AS MODELS SUGGEST THE MAIN BATCH OF QPF LIFTS NORTHEAST IN
TANDEM WITH WEAK LOW PRESSURE OFF THE COAST.

WEDGE REMAINS IN PLACE TUESDAY. NOT SURE THERE/S A LOT OF MEASURABLE
PRECIP GOING ON...IT MAY BE MORE DRIZZLE BUT CONTINUE CHANCE POPS
FOR RAIN ACROSS THE CWA WITH GFS SHOWING BROAD LIGHT QPF. AM
EXPECTING ANY PRECIPITATION TO BE IN LIQUID FORM DURING THE DAY
TUESDAY.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
FOCUS THEN SHIFTS TO DEEP UPPER TROUGH/STRONG COLD FRONT OVER THE
MIDWEST/OHIO VALLEY TUESDAY NIGHT. DECENT PLUME OF MOISTURE
OVERRUNNING A WARM FRONT WILL BRING RAIN INTO THE MID-ATLANTIC
TUESDAY NIGHT.

AS LOW LEVEL JET STRENGTHENS ON WEDNESDAY...THIS SHOULD HELP TO PUSH
THE WARM FRONT TO THE NORTH. PW/S MAY INCREASE NEAR 1.5
INCHES...LIKELY LEADING TO PERIODS OF MODERATE RAINFALL ON
WEDNESDAY. INSTABILITY IS FORECAST TO BE WEAK SO NO THUNDER
MENTIONED BUT POTENTIAL EXISTS FOR SOME GUSTY SHOWERS GIVEN WIND
FIELDS OFF THE DECK. DESPITE CLOUDS/RAIN...MAXIMA SHOULD WARM WELL
INTO THE 50S AND POSSIBLY ECLIPSE 60 IN SOME AREAS.

STRONG COLD FRONT MOVES THROUGH WEDNESDAY NIGHT. SHOWERS END FROM
WEST TO EAST...AND COLD ADVECTION/TIGHT PRESSURE GRADIENT WILL BRING
A BLUSTERY AND COOLER DAY THURSDAY /MEX GUIDANCE LIKELY TOO WARM/.
NEXT COLD FRONT APPROACHES FRIDAY NIGHT OR SATURDAY.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS EXPECTED THROUGH TONIGHT. MID LEVEL MOISTURE WILL
CONTINUE TO MOVE EASTWARD ACROSS THE REGION RESULTING IN BKN-OVC
VFR CIGS. CLEARING IS EXPECTED BY THIS AFTERNOON WITH A SCT-BKN 5K
FEET DECK EXPECTED INTO THE EVENING. CLOUDS WILL BUILD IN FROM THE
SOUTH TONIGHT AS LOW PRESSURE DEVELOPS OFF THE EAST COAST.
MVFR/IFR CIGS SHOULD REACH CHO BY MONDAY MORNING. LIGHT NRLY WINDS
EXPECTED DURING THE TAF PERIOD.

PRECIP SPREADS NORTH ON MONDAY...POSSIBLY BEGINNING AS A WINTRY MIX
OF -IP/-ZR BEFORE TRANSITIONING TO -RA. MVFR CONDITIONS LIKELY ON
MONDAY WITH PRECIP...DEGRADING INTO IFR/LIFR MONDAY NIGHT INTO
TUESDAY. RESTRICTIONS CONTINUE INTO WEDNESDAY WITH SHOWERS AND
POSSIBLE LLWS. COLD FRONT MOVES THROUGH WEDNESDAY NIGHT...WITH GUSTY
SURFACE WINDS THURSDAY.

&&

.MARINE...
LIGHT NRLY WINDS EXPECTED ON THE WATERS THROUGH TONIGHT. WINDS
WILL REMAIN LIGHT BUT BECOME EASTERLY LATE TONIGHT AND INTO MONDAY
MORNING. RAIN AND/OR SLEET SHOULD REACH THE SRN WATERS MONDAY
MORNING BEFORE CHANGING TO ALL RAIN THROUGH MONDAY.

SCA CONDITIONS ARE POSSIBLE IN SOUTHERLY FLOW AHEAD OF A COLD FRONT
ON WEDNESDAY...THEN BEHIND THE FRONT FOR WEDNESDAY NIGHT AND
THURSDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...BPP/HAS
NEAR TERM...BJL/HAS
SHORT TERM...BPP
LONG TERM...BPP
AVIATION...BJL/BPP/HAS
MARINE...BJL/BPP/HAS









000
FXUS61 KLWX 210900
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
400 AM EST SUN DEC 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN WEDGES INTO THE MID-ATLANTIC THROUGH
EARLY IN THE WEEK. LOW PRESSURE WILL TRACK UP THE MID-ATLANTIC
COAST LATE MONDAY. A STRONG COLD FRONT WILL THEN PASS THROUGH THE
AREA WEDNESDAY NIGHT.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE WINTER SOLSTICE IS AT 603PM EST TODAY...SUNDAY DECEMBER 21 2014.
THE SUN WILL BE AT THE LOWEST ANGLE OF THE YEAR WITH THE LEAST
AMOUNT OF DAYLIGHT. SUNSETS WILL START GETTING LATER AFTER TODAY.

A SHORTWAVE TROUGH WILL MOVE ACROSS THE NORTHERN MID-ATLANTIC WHILE
HIGH PRESSURE CONTINUES AT THE SURFACE THIS MORNING. MOISTURE IN THE
MID-LEVELS HAS MOVED NORTHWARD FROM THE SE US OVERNIGHT IN RESPONSE
TO THE JET STREAM ACROSS THE CAROLINAS. BKN-OVC CONDITIONS ARE
EXPECTED THIS MORNING AS THE CLOUD DECK STRETCHES BACK INTO
THE OHIO VALLEY. RIDGING ALOFT WILL LEAD TO LITTLE FORCING TODAY AND
ONCE MID-LEVEL MOISTURE MOVES EASTWARD BY AFTERNOON...THE SUN SHOULD
START TO SHOW ON THE FIRST DAY OF WINTER. HIGH PRESSURE AT THE SFC
WILL LEAD TO LIGHT NORTHERLY WINDS. FCST MAX TEMPS WILL REACH THE
30S IN THE MTNS AND LOW 40S ELSEWHERE. USED MET GUIDANCE SINCE IT
HAS BEEN DOING THE BEST THE LAST FEW DAYS.

HIGH PRESSURE WILL BEGIN TO WEDGE AGAINST THE APPALACHIAN REGION
TONIGHT AS AN UPPER LEVEL TROUGH BEGINS TO AMPLIFY ACROSS THE
CENTRAL US. THE JET STREAM ACROSS THE SE US WILL LEAD TO THE
DEVELOPMENT OF LOW PRESSURE OFF THE CAROLINA COAST. MOISTURE
ADVECTION INTO THE MID-ATLANTIC WILL LEAD TO PRECIPITATION MOVING
INTO THE REGION FROM THE SOUTH LATE TONIGHT. WENT WITH THE SREF MEAN
FOR PRECIP PROGRESSION. AT THIS TIME...MOISTURE SHOULD BE REACHING
THE GROUND ACROSS THE CENTRAL FOOTHILLS...SHENANDOAH
VALLEY...PIEDMONT EARLY MONDAY MORNING. HIGH PRESSURE WILL SERVE AS
A SOURCE OF COLD AIR AT THE SFC WITH TEMPS REACHING THE UPPER 20S TO
AROUND 30 BY MONDAY MORNING. 850-700MB THICKNESS VALUES AROUND 1550M
UP TO I-66 AND 1000-850MB THICKNESS VALUES AROUND 1310 WOULD RESULT
IN FZRA...SLEET MIXTURE EARLY MONDAY MORNING IF MOISTURE IS
AVAILABLE. TEMPS ALONG AND WEST OF THE BLUE RIDGE ARE EXPECTED TO BE
COLDER RESULTING IN A BETTER CHANCE FOR ICE ACCRETION.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
STILL HAVE SOME UNCERTAINTY REGARDING THE DETAILS OF MONDAY/MONDAY
NIGHT. GENERAL IDEA IS THAT PRECIP WILL SPREAD NORTHWARD THROUGH THE
CWA DURING THE DAY MONDAY...ALTHOUGH THE EXACT NORTH/NORTHWEST
EXTENT REMAINS SOMEWHAT IN QUESTION. ALSO IN QUESTION WILL BE TIMING
THE CHANGES TO THE THERMAL PROFILE THROUGH THE DAY...WHICH WILL
DETERMINE P-TYPE.

PREFER GENERAL IDEA FROM THE SREFS FOR POPS...ALTHOUGH POPS NOT
QUITE AS HIGH FURTHER NORTH TOWARD THE MASON DIXON LINE. LEANED
TOWARD SREFS FOR TEMPERATURE/PROFILE CONSIDERATIONS TOO. THIS
SUGGESTS THAT INITIAL PRECIP MAY BE SLEET OR FREEZING
RAIN...TRENDING TO JUST RAIN THROUGHOUT THE DAY ALTHOUGH WINTRY
PRECIP COULD LINGER LONGER OVER THE POTOMAC HIGHLANDS. HIGHEST
CONFIDENCE FOR ICING RESIDES ACROSS THE LOWER POTOMAC
HIGHLANDS/SHENANDOAH VALLEY/CENTRAL VA FOOTHILLS.

RISK OF FREEZING RAIN COULD CONTINUE OVER THE POTOMAC HIGHLANDS
MONDAY NIGHT ASSUMING THERE IS PRECIPITATION FALLING...BUT THIS IS
UNCERTAIN AS MODELS SUGGEST THE MAIN BATCH OF QPF LIFTS NORTHEAST IN
TANDEM WITH WEAK LOW PRESSURE OFF THE COAST.

WEDGE REMAINS IN PLACE TUESDAY. NOT SURE THERE/S A LOT OF MEASURABLE
PRECIP GOING ON...IT MAY BE MORE DRIZZLE BUT CONTINUE CHANCE POPS
FOR RAIN ACROSS THE CWA WITH GFS SHOWING BROAD LIGHT QPF. AM
EXPECTING ANY PRECIPITATION TO BE IN LIQUID FORM DURING THE DAY
TUESDAY.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
FOCUS THEN SHIFTS TO DEEP UPPER TROUGH/STRONG COLD FRONT OVER THE
MIDWEST/OHIO VALLEY TUESDAY NIGHT. DECENT PLUME OF MOISTURE
OVERRUNNING A WARM FRONT WILL BRING RAIN INTO THE MID-ATLANTIC
TUESDAY NIGHT.

AS LOW LEVEL JET STRENGTHENS ON WEDNESDAY...THIS SHOULD HELP TO PUSH
THE WARM FRONT TO THE NORTH. PW/S MAY INCREASE NEAR 1.5
INCHES...LIKELY LEADING TO PERIODS OF MODERATE RAINFALL ON
WEDNESDAY. INSTABILITY IS FORECAST TO BE WEAK SO NO THUNDER
MENTIONED BUT POTENTIAL EXISTS FOR SOME GUSTY SHOWERS GIVEN WIND
FIELDS OFF THE DECK. DESPITE CLOUDS/RAIN...MAXIMA SHOULD WARM WELL
INTO THE 50S AND POSSIBLY ECLIPSE 60 IN SOME AREAS.

STRONG COLD FRONT MOVES THROUGH WEDNESDAY NIGHT. SHOWERS END FROM
WEST TO EAST...AND COLD ADVECTION/TIGHT PRESSURE GRADIENT WILL BRING
A BLUSTERY AND COOLER DAY THURSDAY /MEX GUIDANCE LIKELY TOO WARM/.
NEXT COLD FRONT APPROACHES FRIDAY NIGHT OR SATURDAY.

&&

.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS EXPECTED TODAY AND TONIGHT. MID LEVEL MOISTURE WILL
CONTINUE TO MOVE EASTWARD ACROSS THE REGION RESULTING IN BKN-OVC VFR
CIGS. CLEARING IS EXPECTED BY THIS AFTERNOON WITH A SCT-BKN 5K FEET
DECK EXPECTED INTO THE EVENING. CLOUDS WILL BUILD IN FROM THE SOUTH
TONIGHT AS LOW PRESSURE DEVELOPS OFF THE EAST COAST. MVFR/IFR CIGS
SHOULD REACH CHO BY MONDAY MORNING. LIGHT NRLY WINDS EXPECTED DURING
THE TAF PERIOD.

PRECIP SPREADS NORTH ON MONDAY...POSSIBLY BEGINNING AS A WINTRY MIX
OF -IP/-ZR BEFORE TRANSITIONING TO -RA. MVFR CONDITIONS LIKELY ON
MONDAY WITH PRECIP...DEGRADING INTO IFR/LIFR MONDAY NIGHT INTO
TUESDAY. RESTRICTIONS CONTINUE INTO WEDNESDAY WITH SHOWERS AND
POSSIBLE LLWS. COLD FRONT MOVES THROUGH WEDNESDAY NIGHT...WITH GUSTY
SURFACE WINDS THURSDAY.

&&

.MARINE...
LIGHT NRLY WINDS EXPECTED ON THE WATERS TODAY AND TONIGHT. WINDS
WILL REMAIN LIGHT BUT BECOME EASTERLY LATE TONIGHT AND INTO MONDAY
MORNING. RAIN AND/OR SLEET SHOULD REACH THE SRN WATERS MONDAY
MORNING BEFORE CHANGING TO ALL RAIN THROUGH MONDAY.

SCA CONDITIONS ARE POSSIBLE IN SOUTHERLY FLOW AHEAD OF A COLD FRONT
ON WEDNESDAY...THEN BEHIND THE FRONT FOR WEDNESDAY NIGHT AND
THURSDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...HAS/BPP
NEAR TERM...HAS
SHORT TERM...BPP
LONG TERM...BPP
AVIATION...HAS/BPP
MARINE...HAS/BPP








000
FXUS61 KLWX 210900
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
400 AM EST SUN DEC 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN WEDGES INTO THE MID-ATLANTIC THROUGH
EARLY IN THE WEEK. LOW PRESSURE WILL TRACK UP THE MID-ATLANTIC
COAST LATE MONDAY. A STRONG COLD FRONT WILL THEN PASS THROUGH THE
AREA WEDNESDAY NIGHT.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE WINTER SOLSTICE IS AT 603PM EST TODAY...SUNDAY DECEMBER 21 2014.
THE SUN WILL BE AT THE LOWEST ANGLE OF THE YEAR WITH THE LEAST
AMOUNT OF DAYLIGHT. SUNSETS WILL START GETTING LATER AFTER TODAY.

A SHORTWAVE TROUGH WILL MOVE ACROSS THE NORTHERN MID-ATLANTIC WHILE
HIGH PRESSURE CONTINUES AT THE SURFACE THIS MORNING. MOISTURE IN THE
MID-LEVELS HAS MOVED NORTHWARD FROM THE SE US OVERNIGHT IN RESPONSE
TO THE JET STREAM ACROSS THE CAROLINAS. BKN-OVC CONDITIONS ARE
EXPECTED THIS MORNING AS THE CLOUD DECK STRETCHES BACK INTO
THE OHIO VALLEY. RIDGING ALOFT WILL LEAD TO LITTLE FORCING TODAY AND
ONCE MID-LEVEL MOISTURE MOVES EASTWARD BY AFTERNOON...THE SUN SHOULD
START TO SHOW ON THE FIRST DAY OF WINTER. HIGH PRESSURE AT THE SFC
WILL LEAD TO LIGHT NORTHERLY WINDS. FCST MAX TEMPS WILL REACH THE
30S IN THE MTNS AND LOW 40S ELSEWHERE. USED MET GUIDANCE SINCE IT
HAS BEEN DOING THE BEST THE LAST FEW DAYS.

HIGH PRESSURE WILL BEGIN TO WEDGE AGAINST THE APPALACHIAN REGION
TONIGHT AS AN UPPER LEVEL TROUGH BEGINS TO AMPLIFY ACROSS THE
CENTRAL US. THE JET STREAM ACROSS THE SE US WILL LEAD TO THE
DEVELOPMENT OF LOW PRESSURE OFF THE CAROLINA COAST. MOISTURE
ADVECTION INTO THE MID-ATLANTIC WILL LEAD TO PRECIPITATION MOVING
INTO THE REGION FROM THE SOUTH LATE TONIGHT. WENT WITH THE SREF MEAN
FOR PRECIP PROGRESSION. AT THIS TIME...MOISTURE SHOULD BE REACHING
THE GROUND ACROSS THE CENTRAL FOOTHILLS...SHENANDOAH
VALLEY...PIEDMONT EARLY MONDAY MORNING. HIGH PRESSURE WILL SERVE AS
A SOURCE OF COLD AIR AT THE SFC WITH TEMPS REACHING THE UPPER 20S TO
AROUND 30 BY MONDAY MORNING. 850-700MB THICKNESS VALUES AROUND 1550M
UP TO I-66 AND 1000-850MB THICKNESS VALUES AROUND 1310 WOULD RESULT
IN FZRA...SLEET MIXTURE EARLY MONDAY MORNING IF MOISTURE IS
AVAILABLE. TEMPS ALONG AND WEST OF THE BLUE RIDGE ARE EXPECTED TO BE
COLDER RESULTING IN A BETTER CHANCE FOR ICE ACCRETION.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
STILL HAVE SOME UNCERTAINTY REGARDING THE DETAILS OF MONDAY/MONDAY
NIGHT. GENERAL IDEA IS THAT PRECIP WILL SPREAD NORTHWARD THROUGH THE
CWA DURING THE DAY MONDAY...ALTHOUGH THE EXACT NORTH/NORTHWEST
EXTENT REMAINS SOMEWHAT IN QUESTION. ALSO IN QUESTION WILL BE TIMING
THE CHANGES TO THE THERMAL PROFILE THROUGH THE DAY...WHICH WILL
DETERMINE P-TYPE.

PREFER GENERAL IDEA FROM THE SREFS FOR POPS...ALTHOUGH POPS NOT
QUITE AS HIGH FURTHER NORTH TOWARD THE MASON DIXON LINE. LEANED
TOWARD SREFS FOR TEMPERATURE/PROFILE CONSIDERATIONS TOO. THIS
SUGGESTS THAT INITIAL PRECIP MAY BE SLEET OR FREEZING
RAIN...TRENDING TO JUST RAIN THROUGHOUT THE DAY ALTHOUGH WINTRY
PRECIP COULD LINGER LONGER OVER THE POTOMAC HIGHLANDS. HIGHEST
CONFIDENCE FOR ICING RESIDES ACROSS THE LOWER POTOMAC
HIGHLANDS/SHENANDOAH VALLEY/CENTRAL VA FOOTHILLS.

RISK OF FREEZING RAIN COULD CONTINUE OVER THE POTOMAC HIGHLANDS
MONDAY NIGHT ASSUMING THERE IS PRECIPITATION FALLING...BUT THIS IS
UNCERTAIN AS MODELS SUGGEST THE MAIN BATCH OF QPF LIFTS NORTHEAST IN
TANDEM WITH WEAK LOW PRESSURE OFF THE COAST.

WEDGE REMAINS IN PLACE TUESDAY. NOT SURE THERE/S A LOT OF MEASURABLE
PRECIP GOING ON...IT MAY BE MORE DRIZZLE BUT CONTINUE CHANCE POPS
FOR RAIN ACROSS THE CWA WITH GFS SHOWING BROAD LIGHT QPF. AM
EXPECTING ANY PRECIPITATION TO BE IN LIQUID FORM DURING THE DAY
TUESDAY.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
FOCUS THEN SHIFTS TO DEEP UPPER TROUGH/STRONG COLD FRONT OVER THE
MIDWEST/OHIO VALLEY TUESDAY NIGHT. DECENT PLUME OF MOISTURE
OVERRUNNING A WARM FRONT WILL BRING RAIN INTO THE MID-ATLANTIC
TUESDAY NIGHT.

AS LOW LEVEL JET STRENGTHENS ON WEDNESDAY...THIS SHOULD HELP TO PUSH
THE WARM FRONT TO THE NORTH. PW/S MAY INCREASE NEAR 1.5
INCHES...LIKELY LEADING TO PERIODS OF MODERATE RAINFALL ON
WEDNESDAY. INSTABILITY IS FORECAST TO BE WEAK SO NO THUNDER
MENTIONED BUT POTENTIAL EXISTS FOR SOME GUSTY SHOWERS GIVEN WIND
FIELDS OFF THE DECK. DESPITE CLOUDS/RAIN...MAXIMA SHOULD WARM WELL
INTO THE 50S AND POSSIBLY ECLIPSE 60 IN SOME AREAS.

STRONG COLD FRONT MOVES THROUGH WEDNESDAY NIGHT. SHOWERS END FROM
WEST TO EAST...AND COLD ADVECTION/TIGHT PRESSURE GRADIENT WILL BRING
A BLUSTERY AND COOLER DAY THURSDAY /MEX GUIDANCE LIKELY TOO WARM/.
NEXT COLD FRONT APPROACHES FRIDAY NIGHT OR SATURDAY.

&&

.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS EXPECTED TODAY AND TONIGHT. MID LEVEL MOISTURE WILL
CONTINUE TO MOVE EASTWARD ACROSS THE REGION RESULTING IN BKN-OVC VFR
CIGS. CLEARING IS EXPECTED BY THIS AFTERNOON WITH A SCT-BKN 5K FEET
DECK EXPECTED INTO THE EVENING. CLOUDS WILL BUILD IN FROM THE SOUTH
TONIGHT AS LOW PRESSURE DEVELOPS OFF THE EAST COAST. MVFR/IFR CIGS
SHOULD REACH CHO BY MONDAY MORNING. LIGHT NRLY WINDS EXPECTED DURING
THE TAF PERIOD.

PRECIP SPREADS NORTH ON MONDAY...POSSIBLY BEGINNING AS A WINTRY MIX
OF -IP/-ZR BEFORE TRANSITIONING TO -RA. MVFR CONDITIONS LIKELY ON
MONDAY WITH PRECIP...DEGRADING INTO IFR/LIFR MONDAY NIGHT INTO
TUESDAY. RESTRICTIONS CONTINUE INTO WEDNESDAY WITH SHOWERS AND
POSSIBLE LLWS. COLD FRONT MOVES THROUGH WEDNESDAY NIGHT...WITH GUSTY
SURFACE WINDS THURSDAY.

&&

.MARINE...
LIGHT NRLY WINDS EXPECTED ON THE WATERS TODAY AND TONIGHT. WINDS
WILL REMAIN LIGHT BUT BECOME EASTERLY LATE TONIGHT AND INTO MONDAY
MORNING. RAIN AND/OR SLEET SHOULD REACH THE SRN WATERS MONDAY
MORNING BEFORE CHANGING TO ALL RAIN THROUGH MONDAY.

SCA CONDITIONS ARE POSSIBLE IN SOUTHERLY FLOW AHEAD OF A COLD FRONT
ON WEDNESDAY...THEN BEHIND THE FRONT FOR WEDNESDAY NIGHT AND
THURSDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...HAS/BPP
NEAR TERM...HAS
SHORT TERM...BPP
LONG TERM...BPP
AVIATION...HAS/BPP
MARINE...HAS/BPP









000
FXUS61 KLWX 210900 CCA
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
400 AM EST SUN DEC 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN WEDGED INTO THE MID-ATLANTIC THROUGH
EARLY IN THE WEEK. LOW PRESSURE WILL TRACK UP THE MID-ATLANTIC
COAST LATE MONDAY. A STRONG COLD FRONT WILL THEN PASS THROUGH THE
AREA WEDNESDAY NIGHT.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE WINTER SOLSTICE IS AT 603PM EST TODAY...SUNDAY DECEMBER 21 2014.
THE SUN WILL BE AT THE LOWEST ANGLE OF THE YEAR WITH THE LEAST
AMOUNT OF DAYLIGHT. SUNSETS WILL START GETTING LATER AFTER TODAY.

A SHORTWAVE TROUGH WILL MOVE ACROSS THE NORTHERN MID-ATLANTIC WHILE
HIGH PRESSURE CONTINUES AT THE SURFACE THIS MORNING. MOISTURE IN THE
MID-LEVELS HAS MOVED NORTHWARD FROM THE SE US OVERNIGHT IN RESPONSE
TO THE JET STREAM ACROSS THE CAROLINAS. BKN-OVC CONDITIONS ARE
EXPECTED THIS MORNING AS THE CLOUD DECK STRETCHES BACK INTO
THE OHIO VALLEY. RIDGING ALOFT WILL LEAD TO LITTLE FORCING TODAY AND
ONCE MID-LEVEL MOISTURE MOVES EASTWARD BY AFTERNOON...THE SUN SHOULD
START TO SHOW ON THE FIRST DAY OF WINTER. HIGH PRESSURE AT THE SFC
WILL LEAD TO LIGHT NORTHERLY WINDS. FCST MAX TEMPS WILL REACH THE
30S IN THE MTNS AND LOW 40S ELSEWHERE. USED MET GUIDANCE SINCE IT
HAS BEEN DOING THE BEST THE LAST FEW DAYS.

HIGH PRESSURE WILL BEGIN TO WEDGE AGAINST THE APPALACHIAN REGION
TONIGHT AS AN UPPER LEVEL TROUGH BEGINS TO AMPLIFY ACROSS THE
CENTRAL US. THE JET STREAM ACROSS THE SE US WILL LEAD TO THE
DEVELOPMENT OF LOW PRESSURE OFF THE CAROLINA COAST. MOISTURE
ADVECTION INTO THE MID-ATLANTIC WILL LEAD TO PRECIPITATION MOVING
INTO THE REGION FROM THE SOUTH LATE TONIGHT. WENT WITH THE SREF MEAN
FOR PRECIP PROGRESSION. AT THIS TIME...MOISTURE SHOULD BE REACHING
THE GROUND ACROSS THE CENTRAL FOOTHILLS...SHENANDOAH
VALLEY...PIEDMONT EARLY MONDAY MORNING. HIGH PRESSURE WILL SERVE AS
A SOURCE OF COLD AIR AT THE SFC WITH TEMPS REACHING THE UPPER 20S TO
AROUND 30 BY MONDAY MORNING. 850-700MB THICKNESS VALUES AROUND 1550M
UP TO I-66 AND 1000-850MB THICKNESS VALUES AROUND 1310 WOULD RESULT
IN FZRA...SLEET MIXTURE EARLY MONDAY MORNING IF MOISTURE IS
AVAILABLE. TEMPS ALONG AND WEST OF THE BLUE RIDGE ARE EXPECTED TO BE
COLDER RESULTING IN A BETTER CHANCE FOR ICE ACCRETION.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
STILL HAVE SOME UNCERTAINTY REGARDING THE DETAILS OF MONDAY/MONDAY
NIGHT. GENERAL IDEA IS THAT PRECIP WILL SPREAD NORTHWARD THROUGH THE
CWA DURING THE DAY MONDAY...ALTHOUGH THE EXACT NORTH/NORTHWEST
EXTENT REMAINS SOMEWHAT IN QUESTION. ALSO IN QUESTION WILL BE TIMING
THE CHANGES TO THE THERMAL PROFILE THROUGH THE DAY...WHICH WILL
DETERMINE P-TYPE.

PREFER GENERAL IDEA FROM THE SREFS FOR POPS...ALTHOUGH POPS NOT
QUITE AS HIGH FURTHER NORTH TOWARD THE MASON DIXON LINE. LEANED
TOWARD SREFS FOR TEMPERATURE/PROFILE CONSIDERATIONS TOO. THIS
SUGGESTS THAT INITIAL PRECIP MAY BE SLEET OR FREEZING
RAIN...TRENDING TO JUST RAIN THROUGHOUT THE DAY ALTHOUGH WINTRY
PRECIP COULD LINGER LONGER OVER THE POTOMAC HIGHLANDS. HIGHEST
CONFIDENCE FOR ICING RESIDES ACROSS THE LOWER POTOMAC
HIGHLANDS/SHENANDOAH VALLEY/CENTRAL VA FOOTHILLS.

RISK OF FREEZING RAIN COULD CONTINUE OVER THE POTOMAC HIGHLANDS
MONDAY NIGHT ASSUMING THERE IS PRECIPITATION FALLING...BUT THIS IS
UNCERTAIN AS MODELS SUGGEST THE MAIN BATCH OF QPF LIFTS NORTHEAST IN
TANDEM WITH WEAK LOW PRESSURE OFF THE COAST.

WEDGE REMAINS IN PLACE TUESDAY. NOT SURE THERE/S A LOT OF MEASURABLE
PRECIP GOING ON...IT MAY BE MORE DRIZZLE BUT CONTINUE CHANCE POPS
FOR RAIN ACROSS THE CWA WITH GFS SHOWING BROAD LIGHT QPF. AM
EXPECTING ANY PRECIPITATION TO BE IN LIQUID FORM DURING THE DAY
TUESDAY.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
FOCUS THEN SHIFTS TO DEEP UPPER TROUGH/STRONG COLD FRONT OVER THE
MIDWEST/OHIO VALLEY TUESDAY NIGHT. DECENT PLUME OF MOISTURE
OVERRUNNING A WARM FRONT WILL BRING RAIN INTO THE MID-ATLANTIC
TUESDAY NIGHT.

AS LOW LEVEL JET STRENGTHENS ON WEDNESDAY...THIS SHOULD HELP TO PUSH
THE WARM FRONT TO THE NORTH. PW/S MAY INCREASE NEAR 1.5
INCHES...LIKELY LEADING TO PERIODS OF MODERATE RAINFALL ON
WEDNESDAY. INSTABILITY IS FORECAST TO BE WEAK SO NO THUNDER
MENTIONED BUT POTENTIAL EXISTS FOR SOME GUSTY SHOWERS GIVEN WIND
FIELDS OFF THE DECK. DESPITE CLOUDS/RAIN...MAXIMA SHOULD WARM WELL
INTO THE 50S AND POSSIBLY ECLIPSE 60 IN SOME AREAS.

STRONG COLD FRONT MOVES THROUGH WEDNESDAY NIGHT. SHOWERS END FROM
WEST TO EAST...AND COLD ADVECTION/TIGHT PRESSURE GRADIENT WILL BRING
A BLUSTERY AND COOLER DAY THURSDAY /MEX GUIDANCE LIKELY TOO WARM/.
NEXT COLD FRONT APPROACHES FRIDAY NIGHT OR SATURDAY.

&&

.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS EXPECTED TODAY AND TONIGHT. MID LEVEL MOISTURE WILL
CONTINUE TO MOVE EASTWARD ACROSS THE REGION RESULTING IN BKN-OVC VFR
CIGS. CLEARING IS EXPECTED BY THIS AFTERNOON WITH A SCT-BKN 5K FEET
DECK EXPECTED INTO THE EVENING. CLOUDS WILL BUILD IN FROM THE SOUTH
TONIGHT AS LOW PRESSURE DEVELOPS OFF THE EAST COAST. MVFR/IFR CIGS
SHOULD REACH CHO BY MONDAY MORNING. LIGHT NRLY WINDS EXPECTED DURING
THE TAF PERIOD.

PRECIP SPREADS NORTH ON MONDAY...POSSIBLY BEGINNING AS A WINTRY MIX
OF -IP/-ZR BEFORE TRANSITIONING TO -RA. MVFR CONDITIONS LIKELY ON
MONDAY WITH PRECIP...DEGRADING INTO IFR/LIFR MONDAY NIGHT INTO
TUESDAY. RESTRICTIONS CONTINUE INTO WEDNESDAY WITH SHOWERS AND
POSSIBLE LLWS. COLD FRONT MOVES THROUGH WEDNESDAY NIGHT...WITH GUSTY
SURFACE WINDS THURSDAY.

&&

.MARINE...
LIGHT NRLY WINDS EXPECTED ON THE WATERS TODAY AND TONIGHT. WINDS
WILL REMAIN LIGHT BUT BECOME EASTERLY LATE TONIGHT AND INTO MONDAY
MORNING. RAIN AND/OR SLEET SHOULD REACH THE SRN WATERS MONDAY
MORNING BEFORE CHANGING TO ALL RAIN THROUGH MONDAY.

SCA CONDITIONS ARE POSSIBLE IN SOUTHERLY FLOW AHEAD OF A COLD FRONT
ON WEDNESDAY...THEN BEHIND THE FRONT FOR WEDNESDAY NIGHT AND
THURSDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...HAS/BPP
NEAR TERM...HAS
SHORT TERM...BPP
LONG TERM...BPP
AVIATION...HAS/BPP
MARINE...HAS/BPP











000
FXUS61 KLWX 210140 AAA
AFDLWX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
840 PM EST SAT DEC 20 2014

.SYNOPSIS...
HIGH PRESSURE WILL PERSIST INTO EARLY NEXT WEEK. LOW PRESSURE WILL
TRACK UP THE MID-ATLANTIC COAST LATE MONDAY. A STRONG COLD FRONT
WILL THEN PASS THROUGH THE AREA LATE WEDNESDAY INTO WEDNESDAY
NIGHT.

&&

.NEAR TERM /THROUGH SUNDAY/...
A COUPLE OF MINOR KINKS IN THE UPPER FLOW WILL MAKE THEIR WAY OVER
THE REGION IN THE COMING HRS. THE FIRST UPPER WAVE NOW SLIDING
OVERHEAD...BRINGING ESSENTIALLY A DENSE MID-STRATUS DECK. AT THE
SFC...MANY OB SITES W/ CALM WINDS WHICH WILL CARRY OVER INTO THE
DAYTIME HRS ON SUNDAY. THE OTHER WAVE IS RIGHT ON THE HEELS OF THE
CURRENT ONE...BOTH WILL SLOWLY DISSIPATE HEADING INTO THE
OVERNIGHT PERIOD AS THEY APPROACH THE ATLC COASTLINE.

TEMPS CONTINUE TO HOVER NEAR FREEZING ACROSS THE AREA AND WILL
SLOWLY SLIP DOWN INTO THE 20S OVERNIGHT. DEWPOINTS ALSO STAYING
THE SAME GENERAL RANGE FOR A LONG STRETCH OF TIME...GENERALLY IN
THE L-M20S WHICH WILL KEEP OUR OVERNIGHT LOWS JUST ABOVE THAT BY
THE PREDAWN HRS. SKIES WILL REMAIN CLOUDY/MOSTLY CLOUDY
OVERNIGHT...ALSO KEEPING TEMPS FROM DROPPING MUCH FURTHER W/ THE
INSULATING EFFECT. LEANED TOWARD THE BIAS-CORRECTED VERSION OF MAV
GUIDANCE FOR LOWS.

BEHIND THE UPPER WAVES...ZONAL UPPER FLOW AGAIN ENCOMPASSES THE
UPPER MIDWEST AND BUILDS IN A LARGE AREA OF HIGH PRESSURE. THIS
FEATURE WILL BUILD INTO THE REGION OVER THE COURSE OF THE DAY ON
SUNDAY...ALLOWING FOR MOSTLY CLEAR TO PARTLY CLOUDY SKIES W/ NOT
MUCH ADVECTION OF ANY KIND WE WILL STAY SEASONABLY CHILLY. WINDS
WILL STAY LIGHT AS THE CENTER OF HIGH ROLLS OVERHEAD.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
UPPER TROUGH WILL BEGIN TO AMPLIFY OVER THE EASTERN U.S ON MONDAY.
UPPER LEVEL JET/DYNAMICS SHIFT EAST TO THE COAST WHERE AN AREA OF
LOW PRESSURE IS LIKELY TO DEVELOP OVER THE CAROLINAS AND TRACK
SLOWLY NORTH INTO MONDAY NIGHT. TIMING OF PRECIPITATION IS STILL A
BIT UNCERTAIN WITHIN THE NAM/GFS/EURO SOLUTIONS WITH THE NAM BEING
THE MOST BULLISH AND QUICKEST TO ARRIVE VS THE SLOWER GFS AND EURO.
EITHER WAY...TEMPERATURES WILL BE CRUCIAL WITH COLD HIGH PRESSURE
OVER NEW ENGLAND PROVIDING CAD WEDGE OVER THE MIDDLE ATLANTIC TO
START THE EVENT.

IF PRECIPITATION BEGINS EARLIER IN THE DAY AS PER THE 12Z NAM
THERE COULD BE MORE OF AN ZR/IP THREAT EVEN OVER SOME OF THE
IMMEDIATE SUBURBS NORTH AND WEST OF DC/BWI THE FIRST PART OF
MONDAY. IT IS TYPICAL FOR GUIDANCE TO ERODE THE CAD WEDGE TOO
QUICKLY IN SITUATIONS LIKE THIS. HAVE UNDERCUT TEMPERATURES A FEW
DEGREES FROM INHERITED NUMBERS AND EXPANDED ZR/IP A BIT EAST AS
WELL. MILDER AIR WILL GRADUALLY CHANGE THE ICE TO RAIN EAST OF THE
BLUE RIDGE BUT A LONGER PERIOD OF ZR/IP MAY OCCUR WEST OF THE BLUE
RIDGE IN THE NORMALLY COLDER LOCALES. WILL CONTINUE TO HIGHLIGHT
POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK.

ENOUGH WARMER AIR SHOULD WORK IN AND CHANGE MUCH OF THE PRECIP TO
RAIN MONDAY NIGHT ALTHOUGH THERE COULD STILL BE A FEW POCKETS OF ZR
OVER THE HIGHER ELEVATIONS WITHIN THE HIGHLANDS.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
A WARM FRONT WILL INCH ITS WAY NORTHWARD FROM THE CAROLINAS TO THE
MID ATLANTIC COAST TUESDAY AND TUESDAY NIGHT. SOME STRATIFORM LIGHT
TO MODERATE RAIN WILL PRECEDE THE WARM FRONT AND OVERRUN THE ENTIRE
REGION.

THROUGH THE DAY WEDNESDAY...AS THE WARM FRONT WORKS ITS WAY NORTH OF
THE MASON-DIXON LINE...A POTENT STORM SYSTEM WILL BE PIVOTING
NORTHEASTWARD FROM THE OHIO VALLEY INTO THE EASTERN GREAT LAKES
REGION. ITS ASSOCIATED COLD FRONT WILL TRAIL SOUTHWARD AND POSSIBLY
WORK INTO THE POTOMAC HIGHLANDS AND SHENANDOAH VALLEY BY LATER IN
THE DAY WEDNESDAY. THIS COLD FRONT SHOULD MOVE ACROSS THE DELMARVA
PENINSULA AND THEN OFFSHORE WEDNESDAY NIGHT. PROBABILITY OF RAIN
REMAINS HIGH...NEAR 90 TO 100 PERCENT. THE RAIN EXPECTED LOOKS TO BE
MORE CONVECTIVE IN NATURE AHEAD OF THE COLD FRONT AND POTENT STORM
SYSTEM.

HIGH TEMPERATURES WEDNESDAY WILL BE 15 TO 20 DEGREES ABOVE NORMAL AS
WE ENCOUNTER MOST LOCATIONS REACHING NEAR 60 TO THE LOWER 60S...MAINLY
EAST OF THE BLUE RIDGE MOUNTAINS. WE WILL LEAVE A CHANCE OF RAIN
SHOWERS IN THE FORECAST FOR WEDNESDAY NIGHT CONSIDERING SOME UNCERTAINTY
ON THE TIMING OF COLD FRONTAL PASSAGE. NONETHELESS...COLDER AND DRIER
AIR WILL FILTER INTO THE REGION FROM WEST TO EAST WEDNESDAY
NIGHT...ALLOWING FOR TEMPERATURES TO QUICKLY FALL THROUGH THE 50S
INTO THE 40S.

THERE IS A CHANCE FOR SOME SNOW SHOWERS IN THE HIGHER ELEVATIONS OF
THE POTOMAC HIGHLANDS THURSDAY...PERHAPS ABOVE 2500 FEET. ALTHOUGH
TEMPERATURES WILL BE SOME 10 TO 15 COOLER THAN WEDNESDAY...TEMPERATURES
WILL STILL BE SLIGHTLY ABOVE NORMAL.

DRY CONDITIONS FRIDAY WITH HIGH PRESSURE BUILDING JUST TO OUR SOUTH.
HIGH TEMPERATURES MAY STILL BE SLIGHTLY ABOVE NORMAL WITH A GOOD BIT
OF SUNSHINE.

ANOTHER COLD FRONT COULD BRING A CHANCE FOR RAIN AND SNOW SHOWERS TO
THE REGION FRIDAY NIGHT INTO SATURDAY.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL REMAIN OVER THE TERMINALS THROUGH SUNDAY...BRINGING
VFR CONDITIONS. CLOUDS WILL INCREASE SUNDAY NIGHT AND SUBVFR CONDITIONS
ARE POSSIBLE TOWARD MONDAY MORNING.

CONDITIONS WILL DETERIORATE MONDAY INTO MONDAY NIGHT WITH SUB VFR
CIGS AND VSBYS. PRECIPITATION TYPE IS A BIT UNCERTAIN ALTHOUGH
EXPECTING MOSTLY LIQUID AT KDCA AND KBWI. NORTH AND WEST COULD SEE A
WINTRY MIX OF FREEZING RAIN AND SLEET FOR PART OF MONDAY. ALL RAIN
EXPECTED MONDAY NIGHT.

IFR OR LIFR CONDITIONS ARE POSSIBLE TUESDAY AND TUESDAY NIGHT
WITH LOW CLOUDS AND PERIODS OF RAIN. WINDS LIGHT AND VARIABLE. IFR
OR LIFR CONDITIONS ARE POSSIBLE AGAIN WEDNESDAY WITH NUMEROUS
GUSTY RAIN SHOWERS AHEAD OF A COLD FRONT. WINDS SOUTHEAST TO SOUTH
5 TO 10 KNOTS WEDNESDAY...INCREASING SOUTHWEST WEDNESDAY NIGHT.

&&

.MARINE...
HIGH PRESSURE WILL REMAIN OVER THE WATERS THROUGH SUNDAY NIGHT. NO
MARINE HAZARDS ARE EXPECTED DURING THIS TIME.

WINDS COULD APPROACH SCA CRITERIA LATER MONDAY INTO EARLY TUESDAY AS
LOW PRESSURE APPROACHES FROM THE SOUTH.

NO MARINE HAZARDS TUESDAY AND TUESDAY NIGHT. SMALL CRAFT ADVISORIES
MAY BE NEEDED WEDNESDAY WITH GUSTS TO 20 KNOTS.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
UPDATE...GMS
PREV DISCUSSION...BJL/KRW/KLW









000
FXUS61 KLWX 210140 AAA
AFDLWX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
840 PM EST SAT DEC 20 2014

.SYNOPSIS...
HIGH PRESSURE WILL PERSIST INTO EARLY NEXT WEEK. LOW PRESSURE WILL
TRACK UP THE MID-ATLANTIC COAST LATE MONDAY. A STRONG COLD FRONT
WILL THEN PASS THROUGH THE AREA LATE WEDNESDAY INTO WEDNESDAY
NIGHT.

&&

.NEAR TERM /THROUGH SUNDAY/...
A COUPLE OF MINOR KINKS IN THE UPPER FLOW WILL MAKE THEIR WAY OVER
THE REGION IN THE COMING HRS. THE FIRST UPPER WAVE NOW SLIDING
OVERHEAD...BRINGING ESSENTIALLY A DENSE MID-STRATUS DECK. AT THE
SFC...MANY OB SITES W/ CALM WINDS WHICH WILL CARRY OVER INTO THE
DAYTIME HRS ON SUNDAY. THE OTHER WAVE IS RIGHT ON THE HEELS OF THE
CURRENT ONE...BOTH WILL SLOWLY DISSIPATE HEADING INTO THE
OVERNIGHT PERIOD AS THEY APPROACH THE ATLC COASTLINE.

TEMPS CONTINUE TO HOVER NEAR FREEZING ACROSS THE AREA AND WILL
SLOWLY SLIP DOWN INTO THE 20S OVERNIGHT. DEWPOINTS ALSO STAYING
THE SAME GENERAL RANGE FOR A LONG STRETCH OF TIME...GENERALLY IN
THE L-M20S WHICH WILL KEEP OUR OVERNIGHT LOWS JUST ABOVE THAT BY
THE PREDAWN HRS. SKIES WILL REMAIN CLOUDY/MOSTLY CLOUDY
OVERNIGHT...ALSO KEEPING TEMPS FROM DROPPING MUCH FURTHER W/ THE
INSULATING EFFECT. LEANED TOWARD THE BIAS-CORRECTED VERSION OF MAV
GUIDANCE FOR LOWS.

BEHIND THE UPPER WAVES...ZONAL UPPER FLOW AGAIN ENCOMPASSES THE
UPPER MIDWEST AND BUILDS IN A LARGE AREA OF HIGH PRESSURE. THIS
FEATURE WILL BUILD INTO THE REGION OVER THE COURSE OF THE DAY ON
SUNDAY...ALLOWING FOR MOSTLY CLEAR TO PARTLY CLOUDY SKIES W/ NOT
MUCH ADVECTION OF ANY KIND WE WILL STAY SEASONABLY CHILLY. WINDS
WILL STAY LIGHT AS THE CENTER OF HIGH ROLLS OVERHEAD.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
UPPER TROUGH WILL BEGIN TO AMPLIFY OVER THE EASTERN U.S ON MONDAY.
UPPER LEVEL JET/DYNAMICS SHIFT EAST TO THE COAST WHERE AN AREA OF
LOW PRESSURE IS LIKELY TO DEVELOP OVER THE CAROLINAS AND TRACK
SLOWLY NORTH INTO MONDAY NIGHT. TIMING OF PRECIPITATION IS STILL A
BIT UNCERTAIN WITHIN THE NAM/GFS/EURO SOLUTIONS WITH THE NAM BEING
THE MOST BULLISH AND QUICKEST TO ARRIVE VS THE SLOWER GFS AND EURO.
EITHER WAY...TEMPERATURES WILL BE CRUCIAL WITH COLD HIGH PRESSURE
OVER NEW ENGLAND PROVIDING CAD WEDGE OVER THE MIDDLE ATLANTIC TO
START THE EVENT.

IF PRECIPITATION BEGINS EARLIER IN THE DAY AS PER THE 12Z NAM
THERE COULD BE MORE OF AN ZR/IP THREAT EVEN OVER SOME OF THE
IMMEDIATE SUBURBS NORTH AND WEST OF DC/BWI THE FIRST PART OF
MONDAY. IT IS TYPICAL FOR GUIDANCE TO ERODE THE CAD WEDGE TOO
QUICKLY IN SITUATIONS LIKE THIS. HAVE UNDERCUT TEMPERATURES A FEW
DEGREES FROM INHERITED NUMBERS AND EXPANDED ZR/IP A BIT EAST AS
WELL. MILDER AIR WILL GRADUALLY CHANGE THE ICE TO RAIN EAST OF THE
BLUE RIDGE BUT A LONGER PERIOD OF ZR/IP MAY OCCUR WEST OF THE BLUE
RIDGE IN THE NORMALLY COLDER LOCALES. WILL CONTINUE TO HIGHLIGHT
POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK.

ENOUGH WARMER AIR SHOULD WORK IN AND CHANGE MUCH OF THE PRECIP TO
RAIN MONDAY NIGHT ALTHOUGH THERE COULD STILL BE A FEW POCKETS OF ZR
OVER THE HIGHER ELEVATIONS WITHIN THE HIGHLANDS.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
A WARM FRONT WILL INCH ITS WAY NORTHWARD FROM THE CAROLINAS TO THE
MID ATLANTIC COAST TUESDAY AND TUESDAY NIGHT. SOME STRATIFORM LIGHT
TO MODERATE RAIN WILL PRECEDE THE WARM FRONT AND OVERRUN THE ENTIRE
REGION.

THROUGH THE DAY WEDNESDAY...AS THE WARM FRONT WORKS ITS WAY NORTH OF
THE MASON-DIXON LINE...A POTENT STORM SYSTEM WILL BE PIVOTING
NORTHEASTWARD FROM THE OHIO VALLEY INTO THE EASTERN GREAT LAKES
REGION. ITS ASSOCIATED COLD FRONT WILL TRAIL SOUTHWARD AND POSSIBLY
WORK INTO THE POTOMAC HIGHLANDS AND SHENANDOAH VALLEY BY LATER IN
THE DAY WEDNESDAY. THIS COLD FRONT SHOULD MOVE ACROSS THE DELMARVA
PENINSULA AND THEN OFFSHORE WEDNESDAY NIGHT. PROBABILITY OF RAIN
REMAINS HIGH...NEAR 90 TO 100 PERCENT. THE RAIN EXPECTED LOOKS TO BE
MORE CONVECTIVE IN NATURE AHEAD OF THE COLD FRONT AND POTENT STORM
SYSTEM.

HIGH TEMPERATURES WEDNESDAY WILL BE 15 TO 20 DEGREES ABOVE NORMAL AS
WE ENCOUNTER MOST LOCATIONS REACHING NEAR 60 TO THE LOWER 60S...MAINLY
EAST OF THE BLUE RIDGE MOUNTAINS. WE WILL LEAVE A CHANCE OF RAIN
SHOWERS IN THE FORECAST FOR WEDNESDAY NIGHT CONSIDERING SOME UNCERTAINTY
ON THE TIMING OF COLD FRONTAL PASSAGE. NONETHELESS...COLDER AND DRIER
AIR WILL FILTER INTO THE REGION FROM WEST TO EAST WEDNESDAY
NIGHT...ALLOWING FOR TEMPERATURES TO QUICKLY FALL THROUGH THE 50S
INTO THE 40S.

THERE IS A CHANCE FOR SOME SNOW SHOWERS IN THE HIGHER ELEVATIONS OF
THE POTOMAC HIGHLANDS THURSDAY...PERHAPS ABOVE 2500 FEET. ALTHOUGH
TEMPERATURES WILL BE SOME 10 TO 15 COOLER THAN WEDNESDAY...TEMPERATURES
WILL STILL BE SLIGHTLY ABOVE NORMAL.

DRY CONDITIONS FRIDAY WITH HIGH PRESSURE BUILDING JUST TO OUR SOUTH.
HIGH TEMPERATURES MAY STILL BE SLIGHTLY ABOVE NORMAL WITH A GOOD BIT
OF SUNSHINE.

ANOTHER COLD FRONT COULD BRING A CHANCE FOR RAIN AND SNOW SHOWERS TO
THE REGION FRIDAY NIGHT INTO SATURDAY.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL REMAIN OVER THE TERMINALS THROUGH SUNDAY...BRINGING
VFR CONDITIONS. CLOUDS WILL INCREASE SUNDAY NIGHT AND SUBVFR CONDITIONS
ARE POSSIBLE TOWARD MONDAY MORNING.

CONDITIONS WILL DETERIORATE MONDAY INTO MONDAY NIGHT WITH SUB VFR
CIGS AND VSBYS. PRECIPITATION TYPE IS A BIT UNCERTAIN ALTHOUGH
EXPECTING MOSTLY LIQUID AT KDCA AND KBWI. NORTH AND WEST COULD SEE A
WINTRY MIX OF FREEZING RAIN AND SLEET FOR PART OF MONDAY. ALL RAIN
EXPECTED MONDAY NIGHT.

IFR OR LIFR CONDITIONS ARE POSSIBLE TUESDAY AND TUESDAY NIGHT
WITH LOW CLOUDS AND PERIODS OF RAIN. WINDS LIGHT AND VARIABLE. IFR
OR LIFR CONDITIONS ARE POSSIBLE AGAIN WEDNESDAY WITH NUMEROUS
GUSTY RAIN SHOWERS AHEAD OF A COLD FRONT. WINDS SOUTHEAST TO SOUTH
5 TO 10 KNOTS WEDNESDAY...INCREASING SOUTHWEST WEDNESDAY NIGHT.

&&

.MARINE...
HIGH PRESSURE WILL REMAIN OVER THE WATERS THROUGH SUNDAY NIGHT. NO
MARINE HAZARDS ARE EXPECTED DURING THIS TIME.

WINDS COULD APPROACH SCA CRITERIA LATER MONDAY INTO EARLY TUESDAY AS
LOW PRESSURE APPROACHES FROM THE SOUTH.

NO MARINE HAZARDS TUESDAY AND TUESDAY NIGHT. SMALL CRAFT ADVISORIES
MAY BE NEEDED WEDNESDAY WITH GUSTS TO 20 KNOTS.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
UPDATE...GMS
PREV DISCUSSION...BJL/KRW/KLW








000
FXUS61 KLWX 201932
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
232 PM EST SAT DEC 20 2014

.SYNOPSIS...
HIGH PRESSURE WILL PERSIST THROUGH SUNDAY. LOW PRESSURE WILL
TRACK UP THE MID-ATLANTIC COAST LATE MONDAY. A STRONG COLD FRONT
WILL THEN PASS THROUGH THE AREA LATE WEDNESDAY INTO WEDNESDAY
NIGHT.

&&

.NEAR TERM /THROUGH SUNDAY/...
A SHORTWAVE WILL PASS THROUGH THE REGION THIS AFTERNOON...CAUSING
HIGH AND MID-LEVEL CLOUDS WHILE SURFACE HIGH PRESSURE BUILDS
OVERHEAD. SEASONABLY CHILLY CONDITIONS WILL CONTINUE...BUT THE
DEEP MOISTURE FROM THIS SYSTEM IS EXPECTED TO REMAIN TO OUR SOUTH.
THEREFORE...MOST AREAS WILL TURN OUT DRY. MAX TEMPS WILL RANGE
FROM THE UPPER 20S TO LOWER 30S IN THE MOUNTAINS TO THE UPPER
30S/NEAR 40 IN WASHINGTON AND BALTIMORE.

HIGH PRESSURE WILL REMAIN OVER THE REGION TONIGHT WHILE ANOTHER
UPPER-LEVEL DISTURBANCE PASSES THROUGH THE AREA IN THE WESTERLY
FLOW ALOFT. A BKN DECK OF MID-LEVEL CLOUDS IS EXPECTED...BUT
MOISTURE WILL REMAIN TO OUR SOUTH SO DRY WEATHER IS EXPECTED.
CLOUDS MAY BREAK OUT TOWARD MORNING BEHIND THE DISTURBANCE...AND
WITH HIGH PRESSURE OVERHEAD THIS COULD LEAD RADIATIONAL COOLING.
THEREFORE...MIN TEMPS HAVE BEEN TAKEN DOWN A FEW DEGREES CLOSER TO
THE MAV GUIDANCE. MIN TEMPS WILL RANGE FROM THE LOWER AND MIDDLE
20S ACROSS MOST LOCATIONS TO THE LOWER AND MIDDLE 30S IN DOWNTOWN
WASHINGTON AND BALTIMORE.

HIGH PRESSURE WILL REMAIN OVER THE REGION FOR WEDNESDAY AND AN
UPPER-LEVEL RIDGE WILL BUILD OVERHEAD BEHIND A DEPARTING
DISTURBANCE. THIS WILL ALLOW FOR PLENTY OF SUNSHINE...BUT
SEASONABLY CHILLY CONDITIONS WILL CONTINUE.


&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
UPPER TROUGH WILL BEGIN TO AMPLIFY OVER THE EASTERN U.S ON MONDAY.
UPPER LEVEL JET/DYNAMICS SHIFT EAST TO THE COAST WHERE AN AREA OF
LOW PRESSURE IS LIKELY TO DEVELOP OVER THE CAROLINAS AND TRACK
SLOWLY NORTH INTO MONDAY NIGHT. TIMING OF PRECIPITATION IS STILL A
BIT UNCERTAIN WITHIN THE NAM/GFS/EURO SOLUTIONS WITH THE NAM BEING
THE MOST BULLISH AND QUICKEST TO ARRIVE VS THE SLOWER GFS AND EURO.
EITHER WAY...TEMPERATURES WILL BE CRUCIAL WITH COLD HIGH PRESSURE
OVER NEW ENGLAND PROVIDING CAD WEDGE OVER THE MIDDLE ATLANTIC TO
START THE EVENT. IF PRECIPITATION BEGINS EARLIER IN THE DAY AS PER
THE 12Z NAM THERE COULD BE MORE OF AN ZR/IP THREAT EVEN OVER SOME OF
THE IMMEDIATE SUBURBS NORTH AND WEST OF DC/BWI THE FIRST PART OF
MONDAY. IT IS TYPICAL FOR GUIDANCE TO ERODE THE CAD WEDGE TOO
QUICKLY IN SITUATIONS LIKE THIS. HAVE UNDERCUT TEMPERATURES A FEW
DEGREES FROM INHERITED NUMBERS AND EXPANDED ZR/IP A BIT EAST AS
WELL. MILDER AIR WILL GRADUALLY CHANGE THE ICE TO RAIN EAST OF THE
BLUE RIDGE BUT A LONGER PERIOD OF ZR/IP MAY OCCUR WEST OF THE BLUE
RIDGE IN THE NORMALLY COLDER LOCALES. WILL CONTINUE TO HIGHLIGHT
POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK.

ENOUGH WARMER AIR SHOULD WORK IN AND CHANGE MUCH OF THE PRECIP TO
RAIN MONDAY NIGHT ALTHOUGH THERE COULD STILL BE A FEW POCKETS OF ZR
OVER THE HIGHER ELEVATIONS WITHIN THE HIGHLANDS.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
A WARM FRONT WILL INCH ITS WAY NORTHWARD FROM THE CAROLINAS TO THE
MID ATLANTIC COAST TUESDAY AND TUESDAY NIGHT. SOME STRATIFORM LIGHT
TO MODERATE RAIN WILL PRECEDE THE WARM FRONT AND OVERRUN THE ENTIRE
REGION.

THROUGH THE DAY WEDNESDAY...AS THE WARM FRONT WORKS ITS WAY NORTH OF
THE MASON-DIXON LINE...A POTENT STORM SYSTEM WILL BE PIVOTING
NORTHEASTWARD FROM THE OHIO VALLEY INTO THE EASTERN GREAT LAKES
REGION. ITS ASSOCIATED COLD FRONT WILL TRAIL SOUTHWARD AND POSSIBLY
WORK INTO THE POTOMAC HIGHLANDS AND SHENANDOAH VALLEY BY LATER IN
THE DAY WEDNESDAY. THIS COLD FRONT SHOULD MOVE ACROSS THE DELMARVA
PENINSULA AND THEN OFFSHORE WEDNESDAY NIGHT. PROBABILITY OF RAIN
REMAINS HIGH...NEAR 90 TO 100 PERCENT. THE RAIN EXPECTED LOOKS TO BE
MORE CONVECTIVE IN NATURE AHEAD OF THE COLD FRONT AND POTENT STORM
SYSTEM. HIGH TEMPERATURES WEDNESDAY WILL BE 15 TO 20 DEGREES ABOVE
NORMAL AS WE ENCOUNTER MOST LOCATIONS REACHING NEAR 60 TO THE LOWER
60S...MAINLY EAST OF THE BLUE RIDGE MOUNTAINS. WE WILL LEAVE A
CHANCE OF RAIN SHOWERS IN THE FORECAST FOR WEDNESDAY NIGHT
CONSIDERING SOME UNCERTAINTY ON THE TIMING OF COLD FRONTAL PASSAGE.
NONETHELESS...COLDER AND DRIER AIR WILL FILTER INTO THE REGION FROM
WEST TO EAST WEDNESDAY NIGHT...ALLOWING FOR TEMPERATURES TO QUICKLY FALL
THROUGH THE 50S INTO THE 40S.

THERE IS A CHANCE FOR SOME SNOW SHOWERS IN THE HIGHER ELEVATIONS OF
THE POTOMAC HIGHLANDS THURSDAY...PERHAPS ABOVE 2500 FEET. ALTHOUGH
TEMPERATURES WILL BE SOME 10 TO 15 COOLER THAN
WEDNESDAY...TEMPERATURES WILL STILL BE SLIGHTLY ABOVE NORMAL.

DRY CONDITIONS FRIDAY WITH HIGH PRESSURE BUILDING JUST TO OUR SOUTH.
HIGH TEMPERATURES MAY STILL BE SLIGHTLY ABOVE NORMAL WITH A GOOD BIT
OF SUNSHINE.

ANOTHER COLD FRONT COULD BRING A CHANCE FOR RAIN AND SNOW SHOWERS TO
THE REGION FRIDAY NIGHT INTO SATURDAY.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL REMAIN OVER THE TERMINALS THROUGH
SUNDAY...BRINGING VFR CONDITIONS. CLOUDS WILL INCREASE SUNDAY
NIGHT AND SUBVFR CONDITIONS ARE POSSIBLE TOWARD MONDAY MORNING.

CONDITIONS WILL DETERIORATE MONDAY INTO MONDAY NIGHT WITH SUB VFR
CIGS AND VSBYS. PRECIPITATION TYPE IS A BIT UNCERTAIN ALTHOUGH
EXPECTING MOSTLY LIQUID AT KDCA AND KBWI. NORTH AND WEST COULD SEE A
WINTRY MIX OF FREEZING RAIN AND SLEET FOR PART OF MONDAY. ALL RAIN
EXPECTED MONDAY NIGHT.

IFR OR LIFR CONDITIONS ARE POSSIBLE TUESDAY AND TUESDAY NIGHT
WITH LOW CLOUDS AND PERIODS OF RAIN. WINDS LIGHT AND VARIABLE. IFR
OR LIFR CONDITIONS ARE POSSIBLE AGAIN WEDNESDAY WITH NUMEROUS
GUSTY RAIN SHOWERS AHEAD OF A COLD FRONT. WINDS SOUTHEAST TO SOUTH
5 TO 10 KNOTS WEDNESDAY...INCREASING SOUTHWEST WEDNESDAY NIGHT.

&&

.MARINE...
HIGH PRESSURE WILL REMAIN OVER THE WATERS THROUGH SUNDAY NIGHT. NO
MARINE HAZARDS ARE EXPECTED DURING THIS TIME.

WINDS COULD APPROACH SCA CRITERIA LATER MONDAY INTO EARLY TUESDAY AS
LOW PRESSURE APPROACHES FROM THE SOUTH.

NO MARINE HAZARDS TUESDAY AND TUESDAY NIGHT. SMALL CRAFT ADVISORIES
MAY BE NEEDED WEDNESDAY WITH GUSTS TO 20 KNOTS.
&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...BJL
NEAR TERM...BJL
SHORT TERM...BJL/KRW
LONG TERM...KLW
AVIATION...BJL/KLW/KRW
MARINE...BJL/KLW/KRW









000
FXUS61 KLWX 201932
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
232 PM EST SAT DEC 20 2014

.SYNOPSIS...
HIGH PRESSURE WILL PERSIST THROUGH SUNDAY. LOW PRESSURE WILL
TRACK UP THE MID-ATLANTIC COAST LATE MONDAY. A STRONG COLD FRONT
WILL THEN PASS THROUGH THE AREA LATE WEDNESDAY INTO WEDNESDAY
NIGHT.

&&

.NEAR TERM /THROUGH SUNDAY/...
A SHORTWAVE WILL PASS THROUGH THE REGION THIS AFTERNOON...CAUSING
HIGH AND MID-LEVEL CLOUDS WHILE SURFACE HIGH PRESSURE BUILDS
OVERHEAD. SEASONABLY CHILLY CONDITIONS WILL CONTINUE...BUT THE
DEEP MOISTURE FROM THIS SYSTEM IS EXPECTED TO REMAIN TO OUR SOUTH.
THEREFORE...MOST AREAS WILL TURN OUT DRY. MAX TEMPS WILL RANGE
FROM THE UPPER 20S TO LOWER 30S IN THE MOUNTAINS TO THE UPPER
30S/NEAR 40 IN WASHINGTON AND BALTIMORE.

HIGH PRESSURE WILL REMAIN OVER THE REGION TONIGHT WHILE ANOTHER
UPPER-LEVEL DISTURBANCE PASSES THROUGH THE AREA IN THE WESTERLY
FLOW ALOFT. A BKN DECK OF MID-LEVEL CLOUDS IS EXPECTED...BUT
MOISTURE WILL REMAIN TO OUR SOUTH SO DRY WEATHER IS EXPECTED.
CLOUDS MAY BREAK OUT TOWARD MORNING BEHIND THE DISTURBANCE...AND
WITH HIGH PRESSURE OVERHEAD THIS COULD LEAD RADIATIONAL COOLING.
THEREFORE...MIN TEMPS HAVE BEEN TAKEN DOWN A FEW DEGREES CLOSER TO
THE MAV GUIDANCE. MIN TEMPS WILL RANGE FROM THE LOWER AND MIDDLE
20S ACROSS MOST LOCATIONS TO THE LOWER AND MIDDLE 30S IN DOWNTOWN
WASHINGTON AND BALTIMORE.

HIGH PRESSURE WILL REMAIN OVER THE REGION FOR WEDNESDAY AND AN
UPPER-LEVEL RIDGE WILL BUILD OVERHEAD BEHIND A DEPARTING
DISTURBANCE. THIS WILL ALLOW FOR PLENTY OF SUNSHINE...BUT
SEASONABLY CHILLY CONDITIONS WILL CONTINUE.


&&

.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/...
UPPER TROUGH WILL BEGIN TO AMPLIFY OVER THE EASTERN U.S ON MONDAY.
UPPER LEVEL JET/DYNAMICS SHIFT EAST TO THE COAST WHERE AN AREA OF
LOW PRESSURE IS LIKELY TO DEVELOP OVER THE CAROLINAS AND TRACK
SLOWLY NORTH INTO MONDAY NIGHT. TIMING OF PRECIPITATION IS STILL A
BIT UNCERTAIN WITHIN THE NAM/GFS/EURO SOLUTIONS WITH THE NAM BEING
THE MOST BULLISH AND QUICKEST TO ARRIVE VS THE SLOWER GFS AND EURO.
EITHER WAY...TEMPERATURES WILL BE CRUCIAL WITH COLD HIGH PRESSURE
OVER NEW ENGLAND PROVIDING CAD WEDGE OVER THE MIDDLE ATLANTIC TO
START THE EVENT. IF PRECIPITATION BEGINS EARLIER IN THE DAY AS PER
THE 12Z NAM THERE COULD BE MORE OF AN ZR/IP THREAT EVEN OVER SOME OF
THE IMMEDIATE SUBURBS NORTH AND WEST OF DC/BWI THE FIRST PART OF
MONDAY. IT IS TYPICAL FOR GUIDANCE TO ERODE THE CAD WEDGE TOO
QUICKLY IN SITUATIONS LIKE THIS. HAVE UNDERCUT TEMPERATURES A FEW
DEGREES FROM INHERITED NUMBERS AND EXPANDED ZR/IP A BIT EAST AS
WELL. MILDER AIR WILL GRADUALLY CHANGE THE ICE TO RAIN EAST OF THE
BLUE RIDGE BUT A LONGER PERIOD OF ZR/IP MAY OCCUR WEST OF THE BLUE
RIDGE IN THE NORMALLY COLDER LOCALES. WILL CONTINUE TO HIGHLIGHT
POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK.

ENOUGH WARMER AIR SHOULD WORK IN AND CHANGE MUCH OF THE PRECIP TO
RAIN MONDAY NIGHT ALTHOUGH THERE COULD STILL BE A FEW POCKETS OF ZR
OVER THE HIGHER ELEVATIONS WITHIN THE HIGHLANDS.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
A WARM FRONT WILL INCH ITS WAY NORTHWARD FROM THE CAROLINAS TO THE
MID ATLANTIC COAST TUESDAY AND TUESDAY NIGHT. SOME STRATIFORM LIGHT
TO MODERATE RAIN WILL PRECEDE THE WARM FRONT AND OVERRUN THE ENTIRE
REGION.

THROUGH THE DAY WEDNESDAY...AS THE WARM FRONT WORKS ITS WAY NORTH OF
THE MASON-DIXON LINE...A POTENT STORM SYSTEM WILL BE PIVOTING
NORTHEASTWARD FROM THE OHIO VALLEY INTO THE EASTERN GREAT LAKES
REGION. ITS ASSOCIATED COLD FRONT WILL TRAIL SOUTHWARD AND POSSIBLY
WORK INTO THE POTOMAC HIGHLANDS AND SHENANDOAH VALLEY BY LATER IN
THE DAY WEDNESDAY. THIS COLD FRONT SHOULD MOVE ACROSS THE DELMARVA
PENINSULA AND THEN OFFSHORE WEDNESDAY NIGHT. PROBABILITY OF RAIN
REMAINS HIGH...NEAR 90 TO 100 PERCENT. THE RAIN EXPECTED LOOKS TO BE
MORE CONVECTIVE IN NATURE AHEAD OF THE COLD FRONT AND POTENT STORM
SYSTEM. HIGH TEMPERATURES WEDNESDAY WILL BE 15 TO 20 DEGREES ABOVE
NORMAL AS WE ENCOUNTER MOST LOCATIONS REACHING NEAR 60 TO THE LOWER
60S...MAINLY EAST OF THE BLUE RIDGE MOUNTAINS. WE WILL LEAVE A
CHANCE OF RAIN SHOWERS IN THE FORECAST FOR WEDNESDAY NIGHT
CONSIDERING SOME UNCERTAINTY ON THE TIMING OF COLD FRONTAL PASSAGE.
NONETHELESS...COLDER AND DRIER AIR WILL FILTER INTO THE REGION FROM
WEST TO EAST WEDNESDAY NIGHT...ALLOWING FOR TEMPERATURES TO QUICKLY FALL
THROUGH THE 50S INTO THE 40S.

THERE IS A CHANCE FOR SOME SNOW SHOWERS IN THE HIGHER ELEVATIONS OF
THE POTOMAC HIGHLANDS THURSDAY...PERHAPS ABOVE 2500 FEET. ALTHOUGH
TEMPERATURES WILL BE SOME 10 TO 15 COOLER THAN
WEDNESDAY...TEMPERATURES WILL STILL BE SLIGHTLY ABOVE NORMAL.

DRY CONDITIONS FRIDAY WITH HIGH PRESSURE BUILDING JUST TO OUR SOUTH.
HIGH TEMPERATURES MAY STILL BE SLIGHTLY ABOVE NORMAL WITH A GOOD BIT
OF SUNSHINE.

ANOTHER COLD FRONT COULD BRING A CHANCE FOR RAIN AND SNOW SHOWERS TO
THE REGION FRIDAY NIGHT INTO SATURDAY.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL REMAIN OVER THE TERMINALS THROUGH
SUNDAY...BRINGING VFR CONDITIONS. CLOUDS WILL INCREASE SUNDAY
NIGHT AND SUBVFR CONDITIONS ARE POSSIBLE TOWARD MONDAY MORNING.

CONDITIONS WILL DETERIORATE MONDAY INTO MONDAY NIGHT WITH SUB VFR
CIGS AND VSBYS. PRECIPITATION TYPE IS A BIT UNCERTAIN ALTHOUGH
EXPECTING MOSTLY LIQUID AT KDCA AND KBWI. NORTH AND WEST COULD SEE A
WINTRY MIX OF FREEZING RAIN AND SLEET FOR PART OF MONDAY. ALL RAIN
EXPECTED MONDAY NIGHT.

IFR OR LIFR CONDITIONS ARE POSSIBLE TUESDAY AND TUESDAY NIGHT
WITH LOW CLOUDS AND PERIODS OF RAIN. WINDS LIGHT AND VARIABLE. IFR
OR LIFR CONDITIONS ARE POSSIBLE AGAIN WEDNESDAY WITH NUMEROUS
GUSTY RAIN SHOWERS AHEAD OF A COLD FRONT. WINDS SOUTHEAST TO SOUTH
5 TO 10 KNOTS WEDNESDAY...INCREASING SOUTHWEST WEDNESDAY NIGHT.

&&

.MARINE...
HIGH PRESSURE WILL REMAIN OVER THE WATERS THROUGH SUNDAY NIGHT. NO
MARINE HAZARDS ARE EXPECTED DURING THIS TIME.

WINDS COULD APPROACH SCA CRITERIA LATER MONDAY INTO EARLY TUESDAY AS
LOW PRESSURE APPROACHES FROM THE SOUTH.

NO MARINE HAZARDS TUESDAY AND TUESDAY NIGHT. SMALL CRAFT ADVISORIES
MAY BE NEEDED WEDNESDAY WITH GUSTS TO 20 KNOTS.
&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...BJL
NEAR TERM...BJL
SHORT TERM...BJL/KRW
LONG TERM...KLW
AVIATION...BJL/KLW/KRW
MARINE...BJL/KLW/KRW








000
FXUS61 KLWX 201421
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
921 AM EST SAT DEC 20 2014

.SYNOPSIS...
HIGH PRESSURE WILL PERSIST THROUGH SUNDAY. LOW PRESSURE WILL
TRACK UP THE MID-ATLANTIC COAST LATE MONDAY. A STRONG COLD FRONT
WILL THEN PASS THROUGH THE AREA LATE WEDNESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
A SHORTWAVE WILL PASS THROUGH THE REGION TODAY...CAUSING HIGH AND
MID-LEVEL CLOUDS WHILE SURFACE HIGH PRESSURE BUILDS OVERHEAD.
SEASONABLY CHILLY CONDITIONS WILL CONTINUE...BUT THE DEEP MOISTURE
FROM THIS SYSTEM IS EXPECTED TO REMAIN TO OUR SOUTH.
THEREFORE...MOST AREAS WILL TURN OUT DRY. A FEW FLURRIES OR
PERHAPS A PERIOD OF LIGHT SNOW CANNOT BE RULED OUT ACROSS CENTRAL
VIRGINIA INTO THE POTOMAC HIGHLANDS...BUT LITTLE OR NO SNOW
ACCUMULATION IS EXPECTED.

MULTIPLE ROUNDS OF ENERGY WILL PASS OVER THE MID-ATLANTIC THROUGH
TONIGHT. DUE TO LITTLE FORCING AS THE JET STREAM IS FURTHER
SOUTH...DRY CONDITIONS ARE EXPECTED THROUGH TONIGHT. SUBSIDENCE
BEHIND ANY VORT MAXES MAY LEAD TO SOME CLEARING. FCST MIN TEMPS
SHOULD BE IN THE UPPER 20S TO LOW 30S IN URBAN AREAS. CLEARING MAY
RESULT IN TEMPS DROPPING A FEW MORE DEGREES.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
HIGH PRESSURE EXTENDS FROM NEW ENGLAND DOWN INTO THE MID-ATLANTIC
SUNDAY. MODELS SUGGEST A GOOD DEAL OF SUNSHINE WITH MAXIMA NEAR
CLIMO.

HIGH PRESSURE EDGES A LITTLE EAST SUNDAY NIGHT INTO MONDAY...WITH
PRESSURE PATTERN SIGNALING SOME SEMBLANCE OF A WEDGE. AT THE SAME
TIME...SOUTHERN STREAM SHORTWAVE ENERGY IS ALSO FORECAST TO MOVE
NORTHEAST ON MONDAY.

RESULT WILL BE INCREASING/THICKENING CLOUDS SUNDAY NIGHT BUT THINK
ANY PRECIP WILL REMAIN TO THE SOUTH THROUGH DAYBREAK. TREND OF THE
MODELS IS TO DELAY PRECIP A LITTLE LONGER DURING THE DAY MONDAY.
LEANED TOWARD ECMWF/SREFS FOR TIMING. BUT IF PRECIP ARRIVES EARLY
ENOUGH...MONDAY MORNING MAY SEE A WINTRY MIX OF PRECIP PARTICULARLY
BLUE RIDGE WESTWARD. BULK OF THE PRECIP MONDAY AFTERNOON/EVENING
APPEARS TO BE RAIN BUT A WINTRY MIX INCLUDING POTENTIAL ICING FROM
FREEZING RAIN MAY LINGER ACROSS THE HIGHER ELEVATIONS OF THE POTOMAC
HIGHLANDS INTO MONDAY EVENING.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
SHORTWAVE EXITS LATE MONDAY NIGHT...BUT THE WEDGE REMAINS INTO
TUESDAY AND WITH LOW LEVEL MOISTURE IN PLACE CHANCE OF RAIN OR
DRIZZLE CONTINUES.

ATTENTION THEN TURNS TO A DEEP/STRONG UPPER LEVEL TROUGH SENDING
A COLD FRONT THROUGH LATE WEDNESDAY. DECENT LOW LEVEL JET AND
PLUME OF MOISTURE ARE EXPECTED TO BE TRANSPORTED AHEAD OF THE
FRONT ON WEDNESDAY...LEADING TO SHOWERS. MAXIMA ARE EXPECTED TO
BE WARM FOR THIS TIME OF YEAR AND HAVE TRENDED MAXIMA NEAR 60 EAST
OF THE BLUE RIDGE FOR WEDNESDAY.

DYNAMIC SYSTEM MOVES AWAY WEDNESDAY NIGHT. TIGHT GRADIENT AND COLD
ADVECTION BRING A WINDY AND COOLER CHRISTMAS DAY...ALTHOUGH MAXIMA
MAY ACTUALLY STILL BE A FEW DEGREES ABOVE CLIMO.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS EXPECTED THROUGH TONIGHT. HIGH AND MID-LEVEL CLOUDS
ARE EXPECTED DURING THIS TIME. A FEW FLURRIES CANNOT BE RULED OUT
TODAY...BUT MOST LOCATIONS WILL BE DRY. WINDS WILL BE
LIGHT...GENERALLY AROUND 5 KNOTS OR LESS. HIGH PRESSURE WILL
CONTROL THE WEATHER PATTERN FOR SUNDAY WITH VFR CONDITIONS AND
LIGHT WINDS.

DEVELOPING WEDGE AND AREA OF LOW PRESSURE WILL LIKELY BRING SOME
RAIN AND AT LEAST MVFR CONDITIONS MONDAY. IF PRECIP ARRIVES EARLY
ENOUGH MONDAY MORNING...IT MAY BEGIN AS A MIX.

IFR OR LOWER CONDITIONS ARE THEN EXPECTED MONDAY NIGHT INTO TUESDAY
WITH WEDGE IN PLACE AND AREAS OF RAIN OR DRIZZLE. STRONG COLD FRONT
FOLLOWS LATE WEDNESDAY WITH SHOWERS/POSSIBLY GUSTY WINDS.

&&

.MARINE...
HIGH PRESSURE WILL PERSIST ACROSS THE WATERS TODAY AND TONIGHT. NW
WINDS 5-10KTS ARE EXPECTED ON THE WATERS TODAY AND WEAKEN FURTHER
INTO TONIGHT.

HIGH PRESSURE OVER NEW ENGLAND ON SUNDAY MOVES OFFSHORE EARLY IN THE
WEEK. SCA CONDITIONS ARE POSSIBLE IN SOUTHERLY FLOW AHEAD OF A COLD
FRONT ON WEDNESDAY...THEN BEHIND THE FRONT FOR WEDNESDAY NIGHT AND
THURSDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...BPP/HAS
NEAR TERM...BJL/HAS
SHORT TERM...BPP
LONG TERM...BPP
AVIATION...BJL/BPP/HAS
MARINE...BPP/HAS









000
FXUS61 KLWX 201421
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
921 AM EST SAT DEC 20 2014

.SYNOPSIS...
HIGH PRESSURE WILL PERSIST THROUGH SUNDAY. LOW PRESSURE WILL
TRACK UP THE MID-ATLANTIC COAST LATE MONDAY. A STRONG COLD FRONT
WILL THEN PASS THROUGH THE AREA LATE WEDNESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
A SHORTWAVE WILL PASS THROUGH THE REGION TODAY...CAUSING HIGH AND
MID-LEVEL CLOUDS WHILE SURFACE HIGH PRESSURE BUILDS OVERHEAD.
SEASONABLY CHILLY CONDITIONS WILL CONTINUE...BUT THE DEEP MOISTURE
FROM THIS SYSTEM IS EXPECTED TO REMAIN TO OUR SOUTH.
THEREFORE...MOST AREAS WILL TURN OUT DRY. A FEW FLURRIES OR
PERHAPS A PERIOD OF LIGHT SNOW CANNOT BE RULED OUT ACROSS CENTRAL
VIRGINIA INTO THE POTOMAC HIGHLANDS...BUT LITTLE OR NO SNOW
ACCUMULATION IS EXPECTED.

MULTIPLE ROUNDS OF ENERGY WILL PASS OVER THE MID-ATLANTIC THROUGH
TONIGHT. DUE TO LITTLE FORCING AS THE JET STREAM IS FURTHER
SOUTH...DRY CONDITIONS ARE EXPECTED THROUGH TONIGHT. SUBSIDENCE
BEHIND ANY VORT MAXES MAY LEAD TO SOME CLEARING. FCST MIN TEMPS
SHOULD BE IN THE UPPER 20S TO LOW 30S IN URBAN AREAS. CLEARING MAY
RESULT IN TEMPS DROPPING A FEW MORE DEGREES.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
HIGH PRESSURE EXTENDS FROM NEW ENGLAND DOWN INTO THE MID-ATLANTIC
SUNDAY. MODELS SUGGEST A GOOD DEAL OF SUNSHINE WITH MAXIMA NEAR
CLIMO.

HIGH PRESSURE EDGES A LITTLE EAST SUNDAY NIGHT INTO MONDAY...WITH
PRESSURE PATTERN SIGNALING SOME SEMBLANCE OF A WEDGE. AT THE SAME
TIME...SOUTHERN STREAM SHORTWAVE ENERGY IS ALSO FORECAST TO MOVE
NORTHEAST ON MONDAY.

RESULT WILL BE INCREASING/THICKENING CLOUDS SUNDAY NIGHT BUT THINK
ANY PRECIP WILL REMAIN TO THE SOUTH THROUGH DAYBREAK. TREND OF THE
MODELS IS TO DELAY PRECIP A LITTLE LONGER DURING THE DAY MONDAY.
LEANED TOWARD ECMWF/SREFS FOR TIMING. BUT IF PRECIP ARRIVES EARLY
ENOUGH...MONDAY MORNING MAY SEE A WINTRY MIX OF PRECIP PARTICULARLY
BLUE RIDGE WESTWARD. BULK OF THE PRECIP MONDAY AFTERNOON/EVENING
APPEARS TO BE RAIN BUT A WINTRY MIX INCLUDING POTENTIAL ICING FROM
FREEZING RAIN MAY LINGER ACROSS THE HIGHER ELEVATIONS OF THE POTOMAC
HIGHLANDS INTO MONDAY EVENING.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
SHORTWAVE EXITS LATE MONDAY NIGHT...BUT THE WEDGE REMAINS INTO
TUESDAY AND WITH LOW LEVEL MOISTURE IN PLACE CHANCE OF RAIN OR
DRIZZLE CONTINUES.

ATTENTION THEN TURNS TO A DEEP/STRONG UPPER LEVEL TROUGH SENDING
A COLD FRONT THROUGH LATE WEDNESDAY. DECENT LOW LEVEL JET AND
PLUME OF MOISTURE ARE EXPECTED TO BE TRANSPORTED AHEAD OF THE
FRONT ON WEDNESDAY...LEADING TO SHOWERS. MAXIMA ARE EXPECTED TO
BE WARM FOR THIS TIME OF YEAR AND HAVE TRENDED MAXIMA NEAR 60 EAST
OF THE BLUE RIDGE FOR WEDNESDAY.

DYNAMIC SYSTEM MOVES AWAY WEDNESDAY NIGHT. TIGHT GRADIENT AND COLD
ADVECTION BRING A WINDY AND COOLER CHRISTMAS DAY...ALTHOUGH MAXIMA
MAY ACTUALLY STILL BE A FEW DEGREES ABOVE CLIMO.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS EXPECTED THROUGH TONIGHT. HIGH AND MID-LEVEL CLOUDS
ARE EXPECTED DURING THIS TIME. A FEW FLURRIES CANNOT BE RULED OUT
TODAY...BUT MOST LOCATIONS WILL BE DRY. WINDS WILL BE
LIGHT...GENERALLY AROUND 5 KNOTS OR LESS. HIGH PRESSURE WILL
CONTROL THE WEATHER PATTERN FOR SUNDAY WITH VFR CONDITIONS AND
LIGHT WINDS.

DEVELOPING WEDGE AND AREA OF LOW PRESSURE WILL LIKELY BRING SOME
RAIN AND AT LEAST MVFR CONDITIONS MONDAY. IF PRECIP ARRIVES EARLY
ENOUGH MONDAY MORNING...IT MAY BEGIN AS A MIX.

IFR OR LOWER CONDITIONS ARE THEN EXPECTED MONDAY NIGHT INTO TUESDAY
WITH WEDGE IN PLACE AND AREAS OF RAIN OR DRIZZLE. STRONG COLD FRONT
FOLLOWS LATE WEDNESDAY WITH SHOWERS/POSSIBLY GUSTY WINDS.

&&

.MARINE...
HIGH PRESSURE WILL PERSIST ACROSS THE WATERS TODAY AND TONIGHT. NW
WINDS 5-10KTS ARE EXPECTED ON THE WATERS TODAY AND WEAKEN FURTHER
INTO TONIGHT.

HIGH PRESSURE OVER NEW ENGLAND ON SUNDAY MOVES OFFSHORE EARLY IN THE
WEEK. SCA CONDITIONS ARE POSSIBLE IN SOUTHERLY FLOW AHEAD OF A COLD
FRONT ON WEDNESDAY...THEN BEHIND THE FRONT FOR WEDNESDAY NIGHT AND
THURSDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...BPP/HAS
NEAR TERM...BJL/HAS
SHORT TERM...BPP
LONG TERM...BPP
AVIATION...BJL/BPP/HAS
MARINE...BPP/HAS








000
FXUS61 KLWX 200852
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
352 AM EST SAT DEC 20 2014

.SYNOPSIS...
HIGH PRESSURE WILL PERSIST THROUGH SUNDAY. LOW PRESSURE WILL
TRACK UP THE MID-ATLANTIC COAST LATE MONDAY. A STRONG COLD FRONT
WILL THEN PASS THROUGH THE AREA LATE WEDNESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE MID ATLANTIC IS BETWEEN TWO SHORTWAVE TROUGHS THIS MORNING...ONE
ACROSS NEW YORK AND ANOTHER APPROACHING FROM THE OHIO VALLEY. HIGH
PRESSURE IS CENTERED OVERHEAD AND HAS LED TO CALM AND DRY CONDITIONS
THIS MORNING.

MOISTURE ADVECTION FROM SW FLOW ALOFT WILL CONTINUE AHEAD OF THE
APPROACHING SHORTWAVE TROUGH AND CIRRUS WILL CONTINUE TO MOVE INTO
THE REGION FROM SW TO NE THIS MORNING. PRECIPITATION ACROSS THE SE
US WILL CONTINUE TO MOVE NORTH-NORTHEAST THIS MORNING. THERE IS A
SLIGHT CHANCE OF SNOW TO SKIM THE CENTRAL FOOTHILLS BEFORE NOON
TODAY AS MOISTURE MOVES NORTHWARD. IT IS NOT LIKELY AS SW FLOW ALOFT
IS EXPECTED TO BECOME WESTERLY MIDDAY LIMITING MOISTURE ADVECTION
INTO THE MID-ATLANTIC. MOST IF NOT ALL PRECIPITATION SHOULD STAY SOUTH
OF THE OUTLOOK AREA. CLOUDS AND LOW SUN ANGLE WILL LIMIT HEATING
TODAY AND TEMPS WILL ONLY CLIMB INTO THE UPPER 30S TO AROUND 40
TODAY.

MULTIPLE ROUNDS OF ENERGY WILL PASS OVER THE MID-ATLANTIC THROUGH
TONIGHT. DUE TO LITTLE FORCING AS THE JET STREAM IS FURTHER
SOUTH...DRY CONDITIONS ARE EXPECTED THROUGH TONIGHT. SUBSIDENCE
BEHIND ANY VORT MAXES MAY LEAD TO SOME CLEARING. FCST MIN TEMPS
SHOULD BE IN THE UPPER 20S TO LOW 30S IN URBAN AREAS. CLEARING MAY
RESULT IN TEMPS DROPPING A FEW MORE DEGREES.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
HIGH PRESSURE EXTENDS FROM NEW ENGLAND DOWN INTO THE MID-ATLANTIC
SUNDAY. MODELS SUGGEST A GOOD DEAL OF SUNSHINE WITH MAXIMA NEAR
CLIMO.

HIGH PRESSURE EDGES A LITTLE EAST SUNDAY NIGHT INTO MONDAY...WITH
PRESSURE PATTERN SIGNALING SOME SEMBLANCE OF A WEDGE. AT THE SAME
TIME...SOUTHERN STREAM SHORTWAVE ENERGY IS ALSO FORECAST TO MOVE
NORTHEAST ON MONDAY.

RESULT WILL BE INCREASING/THICKENING CLOUDS SUNDAY NIGHT BUT THINK
ANY PRECIP WILL REMAIN TO THE SOUTH THROUGH DAYBREAK. TREND OF THE
MODELS IS TO DELAY PRECIP A LITTLE LONGER DURING THE DAY MONDAY.
LEANED TOWARD ECMWF/SREFS FOR TIMING. BUT IF PRECIP ARRIVES EARLY
ENOUGH...MONDAY MORNING MAY SEE A WINTRY MIX OF PRECIP PARTICULARLY
BLUE RIDGE WESTWARD. BULK OF THE PRECIP MONDAY AFTERNOON/EVENING
APPEARS TO BE RAIN BUT A WINTRY MIX INCLUDING POTENTIAL ICING FROM
FREEZING RAIN MAY LINGER ACROSS THE HIGHER ELEVATIONS OF THE POTOMAC
HIGHLANDS INTO MONDAY EVENING.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
SHORTWAVE EXITS LATE MONDAY NIGHT...BUT THE WEDGE REMAINS INTO
TUESDAY AND WITH LOW LEVEL MOISTURE IN PLACE CHANCE OF RAIN OR
DRIZZLE CONTINUES.

ATTENTION THEN TURNS TO A DEEP/STRONG UPPER LEVEL TROUGH SENDING
A COLD FRONT THROUGH LATE WEDNESDAY. DECENT LOW LEVEL JET AND
PLUME OF MOISTURE ARE EXPECTED TO BE TRANSPORTED AHEAD OF THE
FRONT ON WEDNESDAY...LEADING TO SHOWERS. MAXIMA ARE EXPECTED TO
BE WARM FOR THIS TIME OF YEAR AND HAVE TRENDED MAXIMA NEAR 60 EAST
OF THE BLUE RIDGE FOR WEDNESDAY.

DYNAMIC SYSTEM MOVES AWAY WEDNESDAY NIGHT. TIGHT GRADIENT AND COLD
ADVECTION BRING A WINDY AND COOLER CHRISTMAS DAY...ALTHOUGH MAXIMA
MAY ACTUALLY STILL BE A FEW DEGREES ABOVE CLIMO.

&&

.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS EXPECTED TODAY AND TONIGHT. CLOUDS WILL INCREASE FROM
SW TO NE ACROSS THE TERMINALS TODAY. MID-HIGH LEVEL CIGS EXPECTED.
-SN IS POSSIBLE BUT NOT LIKELY AT CHO THIS MORNING. NW WINDS
AROUND 5 KTS EXPECTED TODAY AND TONIGHT.

DEVELOPING WEDGE AND AREA OF LOW PRESSURE WILL LIKELY BRING SOME
RAIN AND AT LEAST MVFR CONDITIONS MONDAY. IF PRECIP ARRIVES EARLY
ENOUGH MONDAY MORNING...IT MAY BEGIN AS A MIX.

IFR OR LOWER CONDITIONS ARE THEN EXPECTED MONDAY NIGHT INTO TUESDAY
WITH WEDGE IN PLACE AND AREAS OF RAIN OR DRIZZLE. STRONG COLD FRONT
FOLLOWS LATE WEDNESDAY WITH SHOWERS/POSSIBLY GUSTY WINDS.

&&

.MARINE...
HIGH PRESSURE WILL PERSIST ACROSS THE WATERS TODAY AND TONIGHT. NW
WINDS 5-10KTS ARE EXPECTED ON THE WATERS TODAY AND WEAKEN FURTHER
INTO TONIGHT.

HIGH PRESSURE OVER NEW ENGLAND ON SUNDAY MOVES OFFSHORE EARLY IN THE
WEEK. SCA CONDITIONS ARE POSSIBLE IN SOUTHERLY FLOW AHEAD OF A COLD
FRONT ON WEDNESDAY...THEN BEHIND THE FRONT FOR WEDNESDAY NIGHT AND
THURSDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...BPP/HAS
NEAR TERM...HAS
SHORT TERM...BPP
LONG TERM...BPP
AVIATION...BPP/HAS
MARINE...BPP/HAS








000
FXUS61 KLWX 200852
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
352 AM EST SAT DEC 20 2014

.SYNOPSIS...
HIGH PRESSURE WILL PERSIST THROUGH SUNDAY. LOW PRESSURE WILL
TRACK UP THE MID-ATLANTIC COAST LATE MONDAY. A STRONG COLD FRONT
WILL THEN PASS THROUGH THE AREA LATE WEDNESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE MID ATLANTIC IS BETWEEN TWO SHORTWAVE TROUGHS THIS MORNING...ONE
ACROSS NEW YORK AND ANOTHER APPROACHING FROM THE OHIO VALLEY. HIGH
PRESSURE IS CENTERED OVERHEAD AND HAS LED TO CALM AND DRY CONDITIONS
THIS MORNING.

MOISTURE ADVECTION FROM SW FLOW ALOFT WILL CONTINUE AHEAD OF THE
APPROACHING SHORTWAVE TROUGH AND CIRRUS WILL CONTINUE TO MOVE INTO
THE REGION FROM SW TO NE THIS MORNING. PRECIPITATION ACROSS THE SE
US WILL CONTINUE TO MOVE NORTH-NORTHEAST THIS MORNING. THERE IS A
SLIGHT CHANCE OF SNOW TO SKIM THE CENTRAL FOOTHILLS BEFORE NOON
TODAY AS MOISTURE MOVES NORTHWARD. IT IS NOT LIKELY AS SW FLOW ALOFT
IS EXPECTED TO BECOME WESTERLY MIDDAY LIMITING MOISTURE ADVECTION
INTO THE MID-ATLANTIC. MOST IF NOT ALL PRECIPITATION SHOULD STAY SOUTH
OF THE OUTLOOK AREA. CLOUDS AND LOW SUN ANGLE WILL LIMIT HEATING
TODAY AND TEMPS WILL ONLY CLIMB INTO THE UPPER 30S TO AROUND 40
TODAY.

MULTIPLE ROUNDS OF ENERGY WILL PASS OVER THE MID-ATLANTIC THROUGH
TONIGHT. DUE TO LITTLE FORCING AS THE JET STREAM IS FURTHER
SOUTH...DRY CONDITIONS ARE EXPECTED THROUGH TONIGHT. SUBSIDENCE
BEHIND ANY VORT MAXES MAY LEAD TO SOME CLEARING. FCST MIN TEMPS
SHOULD BE IN THE UPPER 20S TO LOW 30S IN URBAN AREAS. CLEARING MAY
RESULT IN TEMPS DROPPING A FEW MORE DEGREES.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
HIGH PRESSURE EXTENDS FROM NEW ENGLAND DOWN INTO THE MID-ATLANTIC
SUNDAY. MODELS SUGGEST A GOOD DEAL OF SUNSHINE WITH MAXIMA NEAR
CLIMO.

HIGH PRESSURE EDGES A LITTLE EAST SUNDAY NIGHT INTO MONDAY...WITH
PRESSURE PATTERN SIGNALING SOME SEMBLANCE OF A WEDGE. AT THE SAME
TIME...SOUTHERN STREAM SHORTWAVE ENERGY IS ALSO FORECAST TO MOVE
NORTHEAST ON MONDAY.

RESULT WILL BE INCREASING/THICKENING CLOUDS SUNDAY NIGHT BUT THINK
ANY PRECIP WILL REMAIN TO THE SOUTH THROUGH DAYBREAK. TREND OF THE
MODELS IS TO DELAY PRECIP A LITTLE LONGER DURING THE DAY MONDAY.
LEANED TOWARD ECMWF/SREFS FOR TIMING. BUT IF PRECIP ARRIVES EARLY
ENOUGH...MONDAY MORNING MAY SEE A WINTRY MIX OF PRECIP PARTICULARLY
BLUE RIDGE WESTWARD. BULK OF THE PRECIP MONDAY AFTERNOON/EVENING
APPEARS TO BE RAIN BUT A WINTRY MIX INCLUDING POTENTIAL ICING FROM
FREEZING RAIN MAY LINGER ACROSS THE HIGHER ELEVATIONS OF THE POTOMAC
HIGHLANDS INTO MONDAY EVENING.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
SHORTWAVE EXITS LATE MONDAY NIGHT...BUT THE WEDGE REMAINS INTO
TUESDAY AND WITH LOW LEVEL MOISTURE IN PLACE CHANCE OF RAIN OR
DRIZZLE CONTINUES.

ATTENTION THEN TURNS TO A DEEP/STRONG UPPER LEVEL TROUGH SENDING
A COLD FRONT THROUGH LATE WEDNESDAY. DECENT LOW LEVEL JET AND
PLUME OF MOISTURE ARE EXPECTED TO BE TRANSPORTED AHEAD OF THE
FRONT ON WEDNESDAY...LEADING TO SHOWERS. MAXIMA ARE EXPECTED TO
BE WARM FOR THIS TIME OF YEAR AND HAVE TRENDED MAXIMA NEAR 60 EAST
OF THE BLUE RIDGE FOR WEDNESDAY.

DYNAMIC SYSTEM MOVES AWAY WEDNESDAY NIGHT. TIGHT GRADIENT AND COLD
ADVECTION BRING A WINDY AND COOLER CHRISTMAS DAY...ALTHOUGH MAXIMA
MAY ACTUALLY STILL BE A FEW DEGREES ABOVE CLIMO.

&&

.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS EXPECTED TODAY AND TONIGHT. CLOUDS WILL INCREASE FROM
SW TO NE ACROSS THE TERMINALS TODAY. MID-HIGH LEVEL CIGS EXPECTED.
-SN IS POSSIBLE BUT NOT LIKELY AT CHO THIS MORNING. NW WINDS
AROUND 5 KTS EXPECTED TODAY AND TONIGHT.

DEVELOPING WEDGE AND AREA OF LOW PRESSURE WILL LIKELY BRING SOME
RAIN AND AT LEAST MVFR CONDITIONS MONDAY. IF PRECIP ARRIVES EARLY
ENOUGH MONDAY MORNING...IT MAY BEGIN AS A MIX.

IFR OR LOWER CONDITIONS ARE THEN EXPECTED MONDAY NIGHT INTO TUESDAY
WITH WEDGE IN PLACE AND AREAS OF RAIN OR DRIZZLE. STRONG COLD FRONT
FOLLOWS LATE WEDNESDAY WITH SHOWERS/POSSIBLY GUSTY WINDS.

&&

.MARINE...
HIGH PRESSURE WILL PERSIST ACROSS THE WATERS TODAY AND TONIGHT. NW
WINDS 5-10KTS ARE EXPECTED ON THE WATERS TODAY AND WEAKEN FURTHER
INTO TONIGHT.

HIGH PRESSURE OVER NEW ENGLAND ON SUNDAY MOVES OFFSHORE EARLY IN THE
WEEK. SCA CONDITIONS ARE POSSIBLE IN SOUTHERLY FLOW AHEAD OF A COLD
FRONT ON WEDNESDAY...THEN BEHIND THE FRONT FOR WEDNESDAY NIGHT AND
THURSDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...BPP/HAS
NEAR TERM...HAS
SHORT TERM...BPP
LONG TERM...BPP
AVIATION...BPP/HAS
MARINE...BPP/HAS









000
FXUS61 KLWX 200230
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
930 PM EST FRI DEC 19 2014

.SYNOPSIS...
HIGH PRESSURE WILL PERSIST THROUGH SUNDAY. LOW PRESSURE WILL
TRACK UP THE MID-ATLANTIC COAST MONDAY NIGHT. A STRONG COLD FRONT
WILL PASS THROUGH THE AREA WEDNESDAY.

&&

.NEAR TERM /THROUGH SATURDAY/...
AS OF 02Z...1024MB WILL PERSIST OVER THE AREA THROUGH SUNDAY
NIGHT. CLEAR SKIES EAST OF THE ALLEGHENIES INTO LATE TONIGHT
BEFORE STRATUS SPREADS IN FROM THE SOUTHWEST AS AN UPPER-LEVEL
TROUGH APPROACHES FROM THE TENNESSEE VALLEY. TEMPS HAVE CRASHED
INTO THE 20S IN TYPICAL COOL SPOTS ...LOW 30S ELSEWHERE. MINS JUST
A FEW DEGREES LESS AS MIXING PERSISTS WITH 1027MB PRESSURE OVER
THE ERN OH VLY.

THE UPPER-LEVEL DISTURBANCE WILL PASS THROUGH THE REGION SATURDAY.
THIS WILL CAUSE SURFACE LOW PRESSURE TO DEVELOP OFF THE SOUTH
CAROLINA COAST...BUT IT WILL BE TOO FAR TO OUR SOUTH FOR ANY
PRECIPITATION. HOWEVER...MOSTLY CLOUDY SKIES ARE EXPECTED AS HIGH
AND MID-LEVEL CLOUDS PASS THROUGH WITH THE UPPER-LEVEL
DISTURBANCE. SEASONABLY CHILLY CONDITIONS WILL CONTINUE BUT WINDS
WILL BE LIGHT. MAX TEMPS WILL RANGE FROM THE UPPER 20S AND LOWER
30S IN THE ALLEGHENY HIGHLANDS TO THE LOWER AND MIDDLE 40S IN
CENTRAL VIRGINIA.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
LARGE SURFACE HIGH PRESSURE WILL EXTEND FROM SOUTHEASTERN CANADA
THROUGH THE MIDDLE ATLANTIC AND INTO THE SOUTHEASTERN CONUS SATURDAY
NIGHT. A WEAK UPPER TROUGH WILL MOVE THROUGH THE AREA...RESULTING IN
A MID-LEVEL CLOUD DECK OVER THE AREA. GIVEN THE CLOUD
COVER...FAVORED THE WARMER MET GUIDANCE FOR LOW TEMPS.  IT WILL BE A
COLD NIGHT...WITH LOWS IN THE 20S OVER NEARLY ALL OF THE FORECAST
AREA. DOWNTOWN AREAS OF BALTIMORE AND WASHINGTON MAY STAY AT OR JUST
ABOVE FREEZING OVERNIGHT.

THE HIGH WILL BE DIRECTLY OVERHEAD SUNDAY...WITH MOSTLY SUNNY SKIES
AND LIGHT WINDS. SOME DISCREPANCY AMONG MODELS AS TO WHETHER THE
RIDGE AXIS WILL MAKE IT TO THE DELMARVA BY THE AFTERNOON...WHICH
WOULD RESULT IN LIGHT RETURN FLOW ACROSS THE SOUTHERN AND WESTERN
COUNTIES OF THE CWA. HIGH EXPECTED TO BE IN THE MID TO UPPER 40S
ACROSS MOST OF THE CWA...WITH LOW 40S POSSIBLE NEAR THE MASON DIXON
LINE AND IN HIGHER ELEVATIONS.

ONLY GRADUAL EWD MOVEMENT IN THE RIDGE AXIS TOWARDS THE COAST SUNDAY
NIGHT. MODELS HAVE TRENDED SLOWER IN THE DEVELOPMENT OF LOW PRESSURE
ALONG THE SOUTHEAST COAST. REMOVED ALL POPS FROM THE CWA SUNDAY
NIGHT ACCORDINGLY. LOWS WILL BE SIMILAR TO SATURDAY NIGHT...IN THE
20S FOR MOST OF THE CWA AND A FEW SPOTS ABOVE 30 IN METRO
BALTIMORE/WASHINGTON.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
PVA MAX IN SOUTHERN FLOW WILL SUPPORT WIDESPREAD PRECIPITATION
ACROSS REGION MONDAY. ALTHOUGH MOST OF PRECIPITATION LOOKS TO LIQUID
IT APPEARS THAT ENOUGH COLD AIR IS IN PLACE FOR PRECIPITATION BEGIN
AS A WINTRY MIX EARLY MONDAY.

STRONG COLD FRONT SUPPORTED BY UPPER LEVEL CUT-OFF SOUTH OF THE
GREAT LAKES WILL CROSS THE MID ATLANTIC STATES BY WEDNESDAY. RAIN
WILL CHANGE OVER TO SNOW IN AREA AFFECTED BY MUCH COLDER AIR
STREAMING INTO REGION BEHIND THE LOW.

&&

.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
NW FLOW 5-10 KT INTO LATE TONIGHT BEFORE DIMINISHING. HIGH
PRESSURE WILL BUILD OVER THE TERMINALS TONIGHT THROUGH SATURDAY.
VFR CONDITIONS WILL CONTINUE.

HIGH PRESSURE WILL BE DIRECTLY OVERHEAD SATURDAY NIGHT THROUGH
SUNDAY NIGHT. VFR CONDITIONS EXPECTED WITH LIGHT WINDS. LOW
PRESSURE MAY BRING PRECIPITATION AND SUBVFR CONDITIONS MONDAY AND
TUESDAY. A STRONG COLD MAY IMPACT THE TERMINALS WEDNESDAY.

&&

.MARINE...
SCA CANCELLED EARLY FOR GUSTS AROUND 15 KT THIS EVENING...EASING
THROUGH SATURDAY MORNING AS HIGH PRESSURE BUILDS OVERHEAD.

HIGH PRESSURE WILL BE DIRECTLY OVER THE WATERS SATURDAY NIGHT
THROUGH SUNDAY NIGHT. LIGHT NORTHERLY FLOW SATURDAY NIGHT AND
SUNDAY...SHIFTING TO THE E-NE SUNDAY NIGHT. LOW PRESSURE MAY
IMPACT THE WATERS MONDAY INTO TUESDAY BEFORE A STRONG COLD FRONT
PASSES THROUGH WEDNESDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...BAJ/BJL
NEAR TERM...BAJ/BJL
SHORT TERM...KS
LONG TERM...CEM
AVIATION...BAJ/BJL/KS
MARINE...BAJ/BJL/KS







000
FXUS61 KLWX 200230
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
930 PM EST FRI DEC 19 2014

.SYNOPSIS...
HIGH PRESSURE WILL PERSIST THROUGH SUNDAY. LOW PRESSURE WILL
TRACK UP THE MID-ATLANTIC COAST MONDAY NIGHT. A STRONG COLD FRONT
WILL PASS THROUGH THE AREA WEDNESDAY.

&&

.NEAR TERM /THROUGH SATURDAY/...
AS OF 02Z...1024MB WILL PERSIST OVER THE AREA THROUGH SUNDAY
NIGHT. CLEAR SKIES EAST OF THE ALLEGHENIES INTO LATE TONIGHT
BEFORE STRATUS SPREADS IN FROM THE SOUTHWEST AS AN UPPER-LEVEL
TROUGH APPROACHES FROM THE TENNESSEE VALLEY. TEMPS HAVE CRASHED
INTO THE 20S IN TYPICAL COOL SPOTS ...LOW 30S ELSEWHERE. MINS JUST
A FEW DEGREES LESS AS MIXING PERSISTS WITH 1027MB PRESSURE OVER
THE ERN OH VLY.

THE UPPER-LEVEL DISTURBANCE WILL PASS THROUGH THE REGION SATURDAY.
THIS WILL CAUSE SURFACE LOW PRESSURE TO DEVELOP OFF THE SOUTH
CAROLINA COAST...BUT IT WILL BE TOO FAR TO OUR SOUTH FOR ANY
PRECIPITATION. HOWEVER...MOSTLY CLOUDY SKIES ARE EXPECTED AS HIGH
AND MID-LEVEL CLOUDS PASS THROUGH WITH THE UPPER-LEVEL
DISTURBANCE. SEASONABLY CHILLY CONDITIONS WILL CONTINUE BUT WINDS
WILL BE LIGHT. MAX TEMPS WILL RANGE FROM THE UPPER 20S AND LOWER
30S IN THE ALLEGHENY HIGHLANDS TO THE LOWER AND MIDDLE 40S IN
CENTRAL VIRGINIA.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
LARGE SURFACE HIGH PRESSURE WILL EXTEND FROM SOUTHEASTERN CANADA
THROUGH THE MIDDLE ATLANTIC AND INTO THE SOUTHEASTERN CONUS SATURDAY
NIGHT. A WEAK UPPER TROUGH WILL MOVE THROUGH THE AREA...RESULTING IN
A MID-LEVEL CLOUD DECK OVER THE AREA. GIVEN THE CLOUD
COVER...FAVORED THE WARMER MET GUIDANCE FOR LOW TEMPS.  IT WILL BE A
COLD NIGHT...WITH LOWS IN THE 20S OVER NEARLY ALL OF THE FORECAST
AREA. DOWNTOWN AREAS OF BALTIMORE AND WASHINGTON MAY STAY AT OR JUST
ABOVE FREEZING OVERNIGHT.

THE HIGH WILL BE DIRECTLY OVERHEAD SUNDAY...WITH MOSTLY SUNNY SKIES
AND LIGHT WINDS. SOME DISCREPANCY AMONG MODELS AS TO WHETHER THE
RIDGE AXIS WILL MAKE IT TO THE DELMARVA BY THE AFTERNOON...WHICH
WOULD RESULT IN LIGHT RETURN FLOW ACROSS THE SOUTHERN AND WESTERN
COUNTIES OF THE CWA. HIGH EXPECTED TO BE IN THE MID TO UPPER 40S
ACROSS MOST OF THE CWA...WITH LOW 40S POSSIBLE NEAR THE MASON DIXON
LINE AND IN HIGHER ELEVATIONS.

ONLY GRADUAL EWD MOVEMENT IN THE RIDGE AXIS TOWARDS THE COAST SUNDAY
NIGHT. MODELS HAVE TRENDED SLOWER IN THE DEVELOPMENT OF LOW PRESSURE
ALONG THE SOUTHEAST COAST. REMOVED ALL POPS FROM THE CWA SUNDAY
NIGHT ACCORDINGLY. LOWS WILL BE SIMILAR TO SATURDAY NIGHT...IN THE
20S FOR MOST OF THE CWA AND A FEW SPOTS ABOVE 30 IN METRO
BALTIMORE/WASHINGTON.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
PVA MAX IN SOUTHERN FLOW WILL SUPPORT WIDESPREAD PRECIPITATION
ACROSS REGION MONDAY. ALTHOUGH MOST OF PRECIPITATION LOOKS TO LIQUID
IT APPEARS THAT ENOUGH COLD AIR IS IN PLACE FOR PRECIPITATION BEGIN
AS A WINTRY MIX EARLY MONDAY.

STRONG COLD FRONT SUPPORTED BY UPPER LEVEL CUT-OFF SOUTH OF THE
GREAT LAKES WILL CROSS THE MID ATLANTIC STATES BY WEDNESDAY. RAIN
WILL CHANGE OVER TO SNOW IN AREA AFFECTED BY MUCH COLDER AIR
STREAMING INTO REGION BEHIND THE LOW.

&&

.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
NW FLOW 5-10 KT INTO LATE TONIGHT BEFORE DIMINISHING. HIGH
PRESSURE WILL BUILD OVER THE TERMINALS TONIGHT THROUGH SATURDAY.
VFR CONDITIONS WILL CONTINUE.

HIGH PRESSURE WILL BE DIRECTLY OVERHEAD SATURDAY NIGHT THROUGH
SUNDAY NIGHT. VFR CONDITIONS EXPECTED WITH LIGHT WINDS. LOW
PRESSURE MAY BRING PRECIPITATION AND SUBVFR CONDITIONS MONDAY AND
TUESDAY. A STRONG COLD MAY IMPACT THE TERMINALS WEDNESDAY.

&&

.MARINE...
SCA CANCELLED EARLY FOR GUSTS AROUND 15 KT THIS EVENING...EASING
THROUGH SATURDAY MORNING AS HIGH PRESSURE BUILDS OVERHEAD.

HIGH PRESSURE WILL BE DIRECTLY OVER THE WATERS SATURDAY NIGHT
THROUGH SUNDAY NIGHT. LIGHT NORTHERLY FLOW SATURDAY NIGHT AND
SUNDAY...SHIFTING TO THE E-NE SUNDAY NIGHT. LOW PRESSURE MAY
IMPACT THE WATERS MONDAY INTO TUESDAY BEFORE A STRONG COLD FRONT
PASSES THROUGH WEDNESDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...BAJ/BJL
NEAR TERM...BAJ/BJL
SHORT TERM...KS
LONG TERM...CEM
AVIATION...BAJ/BJL/KS
MARINE...BAJ/BJL/KS








000
FXUS61 KLWX 191800
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
100 PM EST FRI DEC 19 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVERHEAD THIS AFTERNOON...THEN PERSIST
THROUGH SUNDAY. LOW PRESSURE WILL TRACK UP THE MID-ATLANTIC COAST
MONDAY THROUGH MONDAY NIGHT. A STRONG COLD FRONT WILL PASS THROUGH
THE AREA WEDNESDAY.

&&

.NEAR TERM /THROUGH SATURDAY/...
SURFACE HIGH PRESSURE WILL CONTINUE TO BUILD TOWARD THE REGION
FROM THE OHIO VALLEY THIS AFTERNOON. A NORTHWEST FLOW AHEAD OF
THE HIGH WILL CAUSE SEASONABLY CHILLY CONDITIONS DURING THIS TIME.

THERE WILL BE JUST ENOUGH MOISTURE UNDERNEATH THE SUBSIDENCE
INVERSION FOR A BKN STRATOCU DECK ACROSS THE NORTHERN AND CENTRAL
PORTIONS OF THE CWA. FURTHER SOUTH ACROSS CENTRAL
VIRGINIA...PLENTY OF SUNSHINE IS EXPECTED DUE TO THE DOWNSLOPING
NORTHWEST FLOW.

HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT. THE STRATO CU DECK
SHOULD BREAK ACROSS MOST AREAS THIS EVENING...BUT HIGH AND MID-
LEVEL CLOUDS WILL INCREASE FROM SOUTHWEST TO NORTHEAST LATER
TONIGHT AS AN UPPER-LEVEL DISTURBANCE APPROACHES FROM THE
TENNESSEE VALLEY. MIN TEMPS WILL RANGE FROM THE LOWER 20S IN THE
MOUNTAINS TO THE LOWER AND MIDDLE 30S IN DOWNTOWN WASHINGTON AND
BALTIMORE.

THE UPPER-LEVEL DISTURBANCE WILL PASS THROUGH THE REGION SATURDAY.
THIS WILL CAUSE SURFACE LOW PRESSURE TO DEVELOP OFF THE SOUTH
CAROLINA COAST...BUT IT WILL BE TOO FAR TO OUR SOUTH FOR ANY
PRECIPITATION. HOWEVER...MOSTLY CLOUDY SKIES ARE EXPECTED AS HIGH
AND MID-LEVEL CLOUDS PASS THROUGH WITH THE UPPER-LEVEL
DISTURBANCE. SEASONABLY CHILLY CONDITIONS WILL CONTINUE BUT WINDS
WILL BE LIGHT. MAX TEMPS WILL RANGE FROM THE UPPER 20S AND LOWER
30S IN THE ALLEGHENY HIGHLANDS TO THE LOWER AND MIDDLE 40S IN
CENTRAL VIRGINIA.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
LARGE SURFACE HIGH PRESSURE WILL EXTEND FROM SOUTHEASTERN CANADA
THROUGH THE MIDDLE ATLANTIC AND INTO THE SOUTHEASTERN CONUS SATURDAY
NIGHT. A WEAK UPPER TROUGH WILL MOVE THROUGH THE AREA...RESULTING IN
A MID-LEVEL CLOUD DECK OVER THE AREA. GIVEN THE CLOUD
COVER...FAVORED THE WARMER MET GUIDANCE FOR LOW TEMPS.  IT WILL BE A
COLD NIGHT...WITH LOWS IN THE 20S OVER NEARLY ALL OF THE FORECAST
AREA. DOWNTOWN AREAS OF BALTIMORE AND WASHINGTON MAY STAY AT OR JUST
ABOVE FREEZING OVERNIGHT.

THE HIGH WILL BE DIRECTLY OVERHEAD SUNDAY...WITH MOSTLY SUNNY SKIES
AND LIGHT WINDS. SOME DISCREPANCY AMONG MODELS AS TO WHETHER THE
RIDGE AXIS WILL MAKE IT TO THE DELMARVA BY THE AFTERNOON...WHICH
WOULD RESULT IN LIGHT RETURN FLOW ACROSS THE SOUTHERN AND WESTERN
COUNTIES OF THE CWA. HIGH EXPECTED TO BE IN THE MID TO UPPER 40S
ACROSS MOST OF THE CWA...WITH LOW 40S POSSIBLE NEAR THE MASON DIXON
LINE AND IN HIGHER ELEVATIONS.

ONLY GRADUAL EWD MOVEMENT IN THE RIDGE AXIS TOWARDS THE COAST SUNDAY
NIGHT. MODELS HAVE TRENDED SLOWER IN THE DEVELOPMENT OF LOW PRESSURE
ALONG THE SOUTHEAST COAST. REMOVED ALL POPS FROM THE CWA SUNDAY
NIGHT ACCORDINGLY. LOWS WILL BE SIMILAR TO SATURDAY NIGHT...IN THE
20S FOR MOST OF THE CWA AND A FEW SPOTS ABOVE 30 IN METRO
BALTIMORE/WASHINGTON.


&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
PVA MAX IN SOUTHERN FLOW WILL SUPPORT WIDESPREAD PRECIPITATION
ACROSS REGION MONDAY. ALTHOUGH MOST OF PRECIPITATION LOOKS TO LIQUID
IT APPEARS THAT ENOUGH COLD AIR IS IN PLACE FOR PRECIPITATION BEGIN
AS A WINTRY MIX EARLY MONDAY.

STRONG COLD FRONT SUPPORTED BY UPPER LEVEL CUT-OFF SOUTH OF THE
GREAT LAKES WILL CROSS THE MID ATLANTIC STATES BY WEDNESDAY. RAIN
WILL CHANGE OVER TO SNOW IN AREA AFFECTED BY MUCH COLDER AIR
STREAMING INTO REGION BEHIND THE LOW.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
A BKN STRATOCU DECK IS EXPECTED ACROSS MOST OF THE TERMINALS
THROUGH THIS AFTERNOON. CIGS SHOULD REMAIN ABOVE 3KFT. NORTHWEST
WINDS WILL GUST AROUND 15 TO 20 KNOTS THROUGH THIS AFTERNOON
BEFORE DIMINISHING AROUND SUNSET. HIGH PRESSURE WILL BUILD OVER
THE TERMINALS TONIGHT THROUGH SATURDAY. VFR CONDITIONS WILL
CONTINUE.

HIGH PRESSURE WILL BE DIRECTLY OVERHEAD SATURDAY NIGHT THROUGH
SUNDAY NIGHT. VFR CONDITIONS EXPECTED WITH LIGHT WINDS. LOW
PRESSURE MAY BRING PRECIPITATION AND SUBVFR CONDITIONS MONDAY AND
TUESDAY. A STRONG COLD MAY IMPACT THE TERMINALS WEDNESDAY.

&&

.MARINE...
NW WINDS WILL CONTINUE TODAY AS HIGH PRESSURE APPROACHES FROM THE
WEST. A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE WATERS DURING
THIS TIME. HIGH PRESSURE WILL BUILD OVER THE TONIGHT THROUGH
SATURDAY. A SMALL CRAFT ADVISORY IS IN EFFECT FOR THIS EVENING
ACROSS THE MARYLAND CHESAPEAKE BAY FROM SANDY POINT TO SMITH POINT
AND THE LOWER TIDAL POTOMAC RIVER FROM COBB ISLAND TO SMITH POINT.

HIGH PRESSURE WILL BE DIRECTLY OVER THE WATERS SATURDAY NIGHT
THROUGH SUNDAY NIGHT. LIGHT NORTHERLY FLOW SATURDAY NIGHT AND
SUNDAY...SHIFTING TO THE E-NE SUNDAY NIGHT. LOW PRESSURE MAY
IMPACT THE WATERS MONDAY INTO TUESDAY BEFORE A STRONG COLD FRONT
PASSES THROUGH WEDNESDAY.



&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR ANZ530-
     531-535-536-538-539-542.
     SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ532>534-
     537-540-541-543.

&&

$$
SYNOPSIS...BJL
NEAR TERM...BJL
SHORT TERM...KS
LONG TERM...CEM
AVIATION...BJL/KS
MARINE...BJL/KS









000
FXUS61 KLWX 191800
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
100 PM EST FRI DEC 19 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVERHEAD THIS AFTERNOON...THEN PERSIST
THROUGH SUNDAY. LOW PRESSURE WILL TRACK UP THE MID-ATLANTIC COAST
MONDAY THROUGH MONDAY NIGHT. A STRONG COLD FRONT WILL PASS THROUGH
THE AREA WEDNESDAY.

&&

.NEAR TERM /THROUGH SATURDAY/...
SURFACE HIGH PRESSURE WILL CONTINUE TO BUILD TOWARD THE REGION
FROM THE OHIO VALLEY THIS AFTERNOON. A NORTHWEST FLOW AHEAD OF
THE HIGH WILL CAUSE SEASONABLY CHILLY CONDITIONS DURING THIS TIME.

THERE WILL BE JUST ENOUGH MOISTURE UNDERNEATH THE SUBSIDENCE
INVERSION FOR A BKN STRATOCU DECK ACROSS THE NORTHERN AND CENTRAL
PORTIONS OF THE CWA. FURTHER SOUTH ACROSS CENTRAL
VIRGINIA...PLENTY OF SUNSHINE IS EXPECTED DUE TO THE DOWNSLOPING
NORTHWEST FLOW.

HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT. THE STRATO CU DECK
SHOULD BREAK ACROSS MOST AREAS THIS EVENING...BUT HIGH AND MID-
LEVEL CLOUDS WILL INCREASE FROM SOUTHWEST TO NORTHEAST LATER
TONIGHT AS AN UPPER-LEVEL DISTURBANCE APPROACHES FROM THE
TENNESSEE VALLEY. MIN TEMPS WILL RANGE FROM THE LOWER 20S IN THE
MOUNTAINS TO THE LOWER AND MIDDLE 30S IN DOWNTOWN WASHINGTON AND
BALTIMORE.

THE UPPER-LEVEL DISTURBANCE WILL PASS THROUGH THE REGION SATURDAY.
THIS WILL CAUSE SURFACE LOW PRESSURE TO DEVELOP OFF THE SOUTH
CAROLINA COAST...BUT IT WILL BE TOO FAR TO OUR SOUTH FOR ANY
PRECIPITATION. HOWEVER...MOSTLY CLOUDY SKIES ARE EXPECTED AS HIGH
AND MID-LEVEL CLOUDS PASS THROUGH WITH THE UPPER-LEVEL
DISTURBANCE. SEASONABLY CHILLY CONDITIONS WILL CONTINUE BUT WINDS
WILL BE LIGHT. MAX TEMPS WILL RANGE FROM THE UPPER 20S AND LOWER
30S IN THE ALLEGHENY HIGHLANDS TO THE LOWER AND MIDDLE 40S IN
CENTRAL VIRGINIA.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
LARGE SURFACE HIGH PRESSURE WILL EXTEND FROM SOUTHEASTERN CANADA
THROUGH THE MIDDLE ATLANTIC AND INTO THE SOUTHEASTERN CONUS SATURDAY
NIGHT. A WEAK UPPER TROUGH WILL MOVE THROUGH THE AREA...RESULTING IN
A MID-LEVEL CLOUD DECK OVER THE AREA. GIVEN THE CLOUD
COVER...FAVORED THE WARMER MET GUIDANCE FOR LOW TEMPS.  IT WILL BE A
COLD NIGHT...WITH LOWS IN THE 20S OVER NEARLY ALL OF THE FORECAST
AREA. DOWNTOWN AREAS OF BALTIMORE AND WASHINGTON MAY STAY AT OR JUST
ABOVE FREEZING OVERNIGHT.

THE HIGH WILL BE DIRECTLY OVERHEAD SUNDAY...WITH MOSTLY SUNNY SKIES
AND LIGHT WINDS. SOME DISCREPANCY AMONG MODELS AS TO WHETHER THE
RIDGE AXIS WILL MAKE IT TO THE DELMARVA BY THE AFTERNOON...WHICH
WOULD RESULT IN LIGHT RETURN FLOW ACROSS THE SOUTHERN AND WESTERN
COUNTIES OF THE CWA. HIGH EXPECTED TO BE IN THE MID TO UPPER 40S
ACROSS MOST OF THE CWA...WITH LOW 40S POSSIBLE NEAR THE MASON DIXON
LINE AND IN HIGHER ELEVATIONS.

ONLY GRADUAL EWD MOVEMENT IN THE RIDGE AXIS TOWARDS THE COAST SUNDAY
NIGHT. MODELS HAVE TRENDED SLOWER IN THE DEVELOPMENT OF LOW PRESSURE
ALONG THE SOUTHEAST COAST. REMOVED ALL POPS FROM THE CWA SUNDAY
NIGHT ACCORDINGLY. LOWS WILL BE SIMILAR TO SATURDAY NIGHT...IN THE
20S FOR MOST OF THE CWA AND A FEW SPOTS ABOVE 30 IN METRO
BALTIMORE/WASHINGTON.


&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
PVA MAX IN SOUTHERN FLOW WILL SUPPORT WIDESPREAD PRECIPITATION
ACROSS REGION MONDAY. ALTHOUGH MOST OF PRECIPITATION LOOKS TO LIQUID
IT APPEARS THAT ENOUGH COLD AIR IS IN PLACE FOR PRECIPITATION BEGIN
AS A WINTRY MIX EARLY MONDAY.

STRONG COLD FRONT SUPPORTED BY UPPER LEVEL CUT-OFF SOUTH OF THE
GREAT LAKES WILL CROSS THE MID ATLANTIC STATES BY WEDNESDAY. RAIN
WILL CHANGE OVER TO SNOW IN AREA AFFECTED BY MUCH COLDER AIR
STREAMING INTO REGION BEHIND THE LOW.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
A BKN STRATOCU DECK IS EXPECTED ACROSS MOST OF THE TERMINALS
THROUGH THIS AFTERNOON. CIGS SHOULD REMAIN ABOVE 3KFT. NORTHWEST
WINDS WILL GUST AROUND 15 TO 20 KNOTS THROUGH THIS AFTERNOON
BEFORE DIMINISHING AROUND SUNSET. HIGH PRESSURE WILL BUILD OVER
THE TERMINALS TONIGHT THROUGH SATURDAY. VFR CONDITIONS WILL
CONTINUE.

HIGH PRESSURE WILL BE DIRECTLY OVERHEAD SATURDAY NIGHT THROUGH
SUNDAY NIGHT. VFR CONDITIONS EXPECTED WITH LIGHT WINDS. LOW
PRESSURE MAY BRING PRECIPITATION AND SUBVFR CONDITIONS MONDAY AND
TUESDAY. A STRONG COLD MAY IMPACT THE TERMINALS WEDNESDAY.

&&

.MARINE...
NW WINDS WILL CONTINUE TODAY AS HIGH PRESSURE APPROACHES FROM THE
WEST. A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE WATERS DURING
THIS TIME. HIGH PRESSURE WILL BUILD OVER THE TONIGHT THROUGH
SATURDAY. A SMALL CRAFT ADVISORY IS IN EFFECT FOR THIS EVENING
ACROSS THE MARYLAND CHESAPEAKE BAY FROM SANDY POINT TO SMITH POINT
AND THE LOWER TIDAL POTOMAC RIVER FROM COBB ISLAND TO SMITH POINT.

HIGH PRESSURE WILL BE DIRECTLY OVER THE WATERS SATURDAY NIGHT
THROUGH SUNDAY NIGHT. LIGHT NORTHERLY FLOW SATURDAY NIGHT AND
SUNDAY...SHIFTING TO THE E-NE SUNDAY NIGHT. LOW PRESSURE MAY
IMPACT THE WATERS MONDAY INTO TUESDAY BEFORE A STRONG COLD FRONT
PASSES THROUGH WEDNESDAY.



&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR ANZ530-
     531-535-536-538-539-542.
     SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ532>534-
     537-540-541-543.

&&

$$
SYNOPSIS...BJL
NEAR TERM...BJL
SHORT TERM...KS
LONG TERM...CEM
AVIATION...BJL/KS
MARINE...BJL/KS








000
FXUS61 KLWX 191518
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1018 AM EST FRI DEC 19 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVERHEAD THIS AFTERNOON...THEN PERSIST
THROUGH SUNDAY. LOW PRESSURE WILL TRACK UP THE MID-ATLANTIC COAST
MONDAY THROUGH MONDAY NIGHT. A STRONG COLD FRONT WILL PASS THROUGH
THE AREA WEDNESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AN UPPER-LEVEL DISTURBANCE WILL CONTINUE TO MOVE AWAY FROM THE
AREA THIS AFTERNOON WHILE SURFACE HIGH PRESSURE BUILDS IN FROM THE
OHIO VALLEY. A NORTHWEST FLOW AHEAD OF THE HIGH WILL CAUSE
SEASONABLY CHILLY CONDITIONS DURING THIS TIME.

A BKN/OVC STRATOCU DECK REMAINS ACROSS THE NORTHERN AND CENTRAL
PORTIONS OF THE CWA THIS MORNING. THIS IS BECAUSE MOISTURE REMAINS
TRAPPED UNDERNEATH THE SUBSIDENCE INVERSION. COLD ADVECTION SHOULD
CAUSE ENOUGH INSTABILITY FOR THE CLOUD DECK TO HANG AROUND...BUT
THERE WILL BE BREAKS OF SUNSHINE THIS AFTERNOON AS DRIER AIR MOVES
IN FROM THE NORTHWEST. FURTHER SOUTH ACROSS CENTRAL
VIRGINIA...PLENTY OF SUNSHINE IS EXPECTED DUE TO THE DOWNSLOPING
NORTHWEST FLOW.

HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT. THE STRATO CU DECK
SHOULD BREAK ACROSS MOST AREAS THIS EVENING...BUT HIGH AND MID-
LEVEL CLOUDS WILL INCREASE FROM SOUTHWEST TO NORTHEAST LATER
TONIGHT AS AN UPPER-LEVEL DISTURBANCE APPROACHES FROM THE
TENNESSEE VALLEY. MIN TEMPS WILL RANGE FROM THE LOWER 20S IN THE
MOUNTAINS TO THE LOWER AND MIDDLE 30S IN DOWNTOWN WASHINGTON AND
BALTIMORE.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY/...
A PAIR OF SHORTWAVES WILL APPROACH ON SATURDAY THEN EXIT OFF THE
COAST SATURDAY NIGHT. NORTHERN STREAM IS MOISTURE STARVED AND WILL
NOT PHASE WITH THE SOUTHERN STREAM ONE. IN ADDITION...QPF ASSOCIATED
WITH THE SOUTHERN STREAM ONE LOOKS MAINLY SOUTH OF THE CWA. LIGHT
PRECIP MAY BRUSH THE SOUTHWEST TIER /HIGHLAND COUNTY TO ALBEMARLE
COUNTY/...OTHERWISE CWA WILL BE DRY WITH SOME CLOUDS. FOLLOWED
BLEND OF SREFS/MAV FOR MAXIMA AND SREFS/MET FOR MINIMA.

HIGH PRESSURE BUILDS NORTH OF THE AREA ON SUNDAY. SHOULD BE SOME
SUNSHINE WITH TEMPERATURES AROUND CLIMO.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
SOMEWHAT OF A WEDGE DEVELOPS SUNDAY NIGHT INTO MONDAY. MEANWHILE...SOUTHERN
STREAM WAVE LEADS TO LOW PRESSURE DEVELOPMENT ALONG/OFF THE
SOUTHEAST COAST. RESULT WILL BE INCREASING CLOUDS SUNDAY NIGHT
THEN THE LIKELIHOOD OF PRECIPITATION MONDAY. MUCH OF THE PRECIP
LOOKS TO BE LIQUID BUT IF IT ARRIVES EARLY ENOUGH MONDAY THEN THE
EVENT MAY BEGIN AS A WINTRY MIX.

THIS WOULD EXIT MONDAY NIGHT BUT MODELS SHOW A SIGNIFICANT TROUGH
AFFECTING THE MID-ATLANTIC THROUGH MID-WEEK. FOLLOWED LATEST WPC
GRIDS WITH FAIRLY HIGH POPS TUESDAY THROUGH WEDNESDAY...P-TYPE
MOSTLY IN THE FORM OF RAIN.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
A BKN STRATOCU DECK IS EXPECTED ACROSS MOST OF THE TERMINALS
THROUGH THIS AFTERNOON. CIGS SHOULD REMAIN ABOVE 3KFT. NORTHWEST
WINDS WILL GUST AROUND 15 TO 20 KNOTS THROUGH THIS AFTERNOON
BEFORE DIMINISHING AROUND SUNSET. HIGH PRESSURE WILL BUILD OVER
THE TERMINALS TONIGHT. VFR CONDITIONS WILL CONTINUE.

VFR EXPECTED THROUGH SUNDAY. POTENTIAL EXISTS FOR FLIGHT
RESTRICTIONS LATE SUNDAY NIGHT INTO MONDAY AS WEDGE SETS UP AND WAVE
OF LOW PRESSURE BRINGS PRECIP.

&&

.MARINE...
NW WINDS WILL CONTINUE TODAY AS HIGH PRESSURE APPROACHES FROM THE
WEST. A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE WATERS DURING
THIS TIME. HIGH PRESSURE MOVES OVERHEAD TONIGHT AND WINDS SHOULD
SUBSIDE BY EVENING.

GENERALLY SUB-SCA CONDITIONS EXPECTED INTO EARLY NEXT WEEK.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
     ANZ530>543.

&&

$$
SYNOPSIS...BPP/HAS
NEAR TERM...BJL/HAS
SHORT TERM...BPP
LONG TERM...BJL/BPP
AVIATION...BJL/BPP/HAS
MARINE...BJL/BPP/HAS








000
FXUS61 KLWX 191518
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1018 AM EST FRI DEC 19 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVERHEAD THIS AFTERNOON...THEN PERSIST
THROUGH SUNDAY. LOW PRESSURE WILL TRACK UP THE MID-ATLANTIC COAST
MONDAY THROUGH MONDAY NIGHT. A STRONG COLD FRONT WILL PASS THROUGH
THE AREA WEDNESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AN UPPER-LEVEL DISTURBANCE WILL CONTINUE TO MOVE AWAY FROM THE
AREA THIS AFTERNOON WHILE SURFACE HIGH PRESSURE BUILDS IN FROM THE
OHIO VALLEY. A NORTHWEST FLOW AHEAD OF THE HIGH WILL CAUSE
SEASONABLY CHILLY CONDITIONS DURING THIS TIME.

A BKN/OVC STRATOCU DECK REMAINS ACROSS THE NORTHERN AND CENTRAL
PORTIONS OF THE CWA THIS MORNING. THIS IS BECAUSE MOISTURE REMAINS
TRAPPED UNDERNEATH THE SUBSIDENCE INVERSION. COLD ADVECTION SHOULD
CAUSE ENOUGH INSTABILITY FOR THE CLOUD DECK TO HANG AROUND...BUT
THERE WILL BE BREAKS OF SUNSHINE THIS AFTERNOON AS DRIER AIR MOVES
IN FROM THE NORTHWEST. FURTHER SOUTH ACROSS CENTRAL
VIRGINIA...PLENTY OF SUNSHINE IS EXPECTED DUE TO THE DOWNSLOPING
NORTHWEST FLOW.

HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT. THE STRATO CU DECK
SHOULD BREAK ACROSS MOST AREAS THIS EVENING...BUT HIGH AND MID-
LEVEL CLOUDS WILL INCREASE FROM SOUTHWEST TO NORTHEAST LATER
TONIGHT AS AN UPPER-LEVEL DISTURBANCE APPROACHES FROM THE
TENNESSEE VALLEY. MIN TEMPS WILL RANGE FROM THE LOWER 20S IN THE
MOUNTAINS TO THE LOWER AND MIDDLE 30S IN DOWNTOWN WASHINGTON AND
BALTIMORE.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY/...
A PAIR OF SHORTWAVES WILL APPROACH ON SATURDAY THEN EXIT OFF THE
COAST SATURDAY NIGHT. NORTHERN STREAM IS MOISTURE STARVED AND WILL
NOT PHASE WITH THE SOUTHERN STREAM ONE. IN ADDITION...QPF ASSOCIATED
WITH THE SOUTHERN STREAM ONE LOOKS MAINLY SOUTH OF THE CWA. LIGHT
PRECIP MAY BRUSH THE SOUTHWEST TIER /HIGHLAND COUNTY TO ALBEMARLE
COUNTY/...OTHERWISE CWA WILL BE DRY WITH SOME CLOUDS. FOLLOWED
BLEND OF SREFS/MAV FOR MAXIMA AND SREFS/MET FOR MINIMA.

HIGH PRESSURE BUILDS NORTH OF THE AREA ON SUNDAY. SHOULD BE SOME
SUNSHINE WITH TEMPERATURES AROUND CLIMO.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
SOMEWHAT OF A WEDGE DEVELOPS SUNDAY NIGHT INTO MONDAY. MEANWHILE...SOUTHERN
STREAM WAVE LEADS TO LOW PRESSURE DEVELOPMENT ALONG/OFF THE
SOUTHEAST COAST. RESULT WILL BE INCREASING CLOUDS SUNDAY NIGHT
THEN THE LIKELIHOOD OF PRECIPITATION MONDAY. MUCH OF THE PRECIP
LOOKS TO BE LIQUID BUT IF IT ARRIVES EARLY ENOUGH MONDAY THEN THE
EVENT MAY BEGIN AS A WINTRY MIX.

THIS WOULD EXIT MONDAY NIGHT BUT MODELS SHOW A SIGNIFICANT TROUGH
AFFECTING THE MID-ATLANTIC THROUGH MID-WEEK. FOLLOWED LATEST WPC
GRIDS WITH FAIRLY HIGH POPS TUESDAY THROUGH WEDNESDAY...P-TYPE
MOSTLY IN THE FORM OF RAIN.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
A BKN STRATOCU DECK IS EXPECTED ACROSS MOST OF THE TERMINALS
THROUGH THIS AFTERNOON. CIGS SHOULD REMAIN ABOVE 3KFT. NORTHWEST
WINDS WILL GUST AROUND 15 TO 20 KNOTS THROUGH THIS AFTERNOON
BEFORE DIMINISHING AROUND SUNSET. HIGH PRESSURE WILL BUILD OVER
THE TERMINALS TONIGHT. VFR CONDITIONS WILL CONTINUE.

VFR EXPECTED THROUGH SUNDAY. POTENTIAL EXISTS FOR FLIGHT
RESTRICTIONS LATE SUNDAY NIGHT INTO MONDAY AS WEDGE SETS UP AND WAVE
OF LOW PRESSURE BRINGS PRECIP.

&&

.MARINE...
NW WINDS WILL CONTINUE TODAY AS HIGH PRESSURE APPROACHES FROM THE
WEST. A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE WATERS DURING
THIS TIME. HIGH PRESSURE MOVES OVERHEAD TONIGHT AND WINDS SHOULD
SUBSIDE BY EVENING.

GENERALLY SUB-SCA CONDITIONS EXPECTED INTO EARLY NEXT WEEK.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
     ANZ530>543.

&&

$$
SYNOPSIS...BPP/HAS
NEAR TERM...BJL/HAS
SHORT TERM...BPP
LONG TERM...BJL/BPP
AVIATION...BJL/BPP/HAS
MARINE...BJL/BPP/HAS









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