Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 251950 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 250 PM EST THU DEC 25 2014 .SYNOPSIS... MILD SOUTHERN HIGH PRESSURE WILL BUILD THROUGH FRIDAY...BEFORE MOVING OFFSHORE ON SATURDAY. A WEAK COLD FRONT WILL PUSH IN FROM THE NORTHWEST SUNDAY. THEN LOW PRESSURE FROM THE DEEP SOUTH WILL RIDE UP ALONG THAT FRONT AND PASS JUST SOUTH OF US MONDAY. COLDER HIGH PRESSURE WILL FOLLOW FOR MID WEEK. && .NEAR TERM /THROUGH FRIDAY/... HIPRES CENTERED OVER TN WL BE ADVCG TWD CWFA TAFTN-TNGT...AND WL BE OVHD FRI. THERES A BIT OF A P-GRAD ACRS MD/VA...BUT WINDS HV BEEN IN THE MEAN MIXED LVL...ARND 25 KT. ALSO HV HAD BKN CLDS IN THERMAL TROF. AS SUBSIDENCE INCREASES LT TDA INTO TNGT...BOTH OF THESE WL DECR. DEWPTS BACK IN NERN KY IN THE LWR 30S ATTM. THATS A HINT OF WHERE RADL COOLING WL TAKE OUR TEMPS TNGT. MOS CONCURS. SINCE SOURCE RGN CONTINENTAL...WENT MUCH CLOSER TO MAV MAXT TMRW. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... TEMPS OVERNIGHT WILL ONLY TOUCH THE FREEZING MARK ACROSS THE SHELTERED VLYS/LOW LANDS OVER THE PIEDMONT/SHEN VLY. HIGHER TERRAIN WILL ACTUALLY HAVE THE WARMEST VALUES IN THE AREA W/ THE ELEVATED INVERSION. CLEAR/CALM CONDITIONS EVEN AS A WEAK UPPER TROUGH PASSES OVERHEAD AND WEAKENS AS IT APPROACHES THE COAST - A PRECURSOR THE NEXT UPPER WAVE. MUCH OF SATURDAY WILL REMAIN CLEAR AND QUIET...W/ ONLY A FEW PASSING CLOUDS AND RELATIVELY WARM CONDITIONS. THE CENTER OF THE HIGH WILL BE DRIFTING OFF THE CAROLINA COAST AND ALLOW FOR TEMPS TO REACH THE M-U50S ACROSS MUCH OF THE REGION. OUR BRIEF REPRIEVE FROM ACTIVE WX WILL BE INTERRUPTED BY LATE SAT NIGHT...AS THE BEGINNINGS OF THE NEXT WAVE OF LOW PRESSURE ARRIVE IN THE FORM OF DENSE MID-UPPER LEVEL CLOUDS. THE ONSLAUGHT OF DENSE CLOUD COVER WILL PREVENT TEMPS FROM DROPPING BACK TOWARD THE FREEZING MARK...UNLIKE THE PREVIOUS COUPLE OF NIGHTS. THIS WILL ALSO BE KEY IN MITIGATING THE POTENTIAL FOR FROZEN PRECIP OVER THE REGION DURING THE INITIAL STAGES OF THE INCOMING SYSTEM. && .LONG TERM /SUNDAY THROUGH THURSDAY/... A COLD FRONT WILL PUSH ACROSS THE REGION SUNDAY BEFORE SLIDING INTO THE CAROLINAS SUNDAY NIGHT. SOME STRATIFORM RAIN WILL ACCOMPANY THE FRONT SUNDAY THROUGH MONDAY. SOME LIGHT SNOW COULD MIX WITH A LITTLE RAIN IN THE POTOMAC HIGHLANDS AND ALONG PORTIONS OF THE MASON-DIXON LINE SUNDAY NIGHT AS COLDER AIR IS EXPECTED TO PUSH INTO THESE AREAS FIRST. WE`LL HANG ONTO A SLIGHT CHANCE OF SOME LIGHT RAIN OR SNOW MONDAY NIGHT...MAINLY ACROSS THE SOUTH...AS THERE IS STILL SOME DEGREE OF UNCERTAINTY OF A LOW DEVELOPING ALONG THE FRONT TO THE SOUTH. THE 00Z EURO TRIES TO FORM A LOW ALONG THE NORTH AND SOUTH CAROLINA BORDER. THE LATEST 12Z GFS WANTS TO FORM A LOW 12 HOURS EARLIER AND ALONG THE VIRGINIA AND NORTH CAROLINA BORDER BEFORE QUICKLY KICKING THE LOW OUT TO SEA. HIGH PRESSURE WILL BUILD INTO THE REGION MONDAY NIGHT AND TUESDAY...THUS PERSISTING WEDNESDAY AND THURSDAY. DRIER AND COOLER AIR WILL MOVE INTO THE REGION...ESCORTED BY THE HIGH. && .AVIATION /20Z THURSDAY THROUGH TUESDAY/... VFR THRU VALID TAF PD. WLY WNDS G25KT TAFTN...RAPIDLY DECRSG TNGT AFTR SUNSET. SHUD HV LTL WND BY MIDNGT...CONTG INTO FRI. WHEN WINDS DO PICK UP AGN...ITLL BE MIDDAY AND THE DIRECTION WL BE SLY. BKN CLDS /CIGS 050-060/ WL ALSO BE DSPTG BY SUNSET. HIGH PRESSURE REMAINS OVERHEAD FOR LATE FRI INTO MUCH OF SAT...W/ CALM WINDS AND SOLID VFR CONDS. MVFR TO IFR CONDITIONS MAY OCCUR WITH LIGHT RAIN SUNDAY INTO SUNDAY NIGHT. WINDS SOUTHWEST SHIFTING NORTH 5 TO 10 KNOTS WITH FRONTAL PASSAGE. MVFR CONDITIONS POSSIBLE MONDAY WITH LINGERING LIGHT RAIN. WINDS NORTHEAST 5 TO 10 KNOTS. && .MARINE... FOR THE MOST PART...WINDS HV STUCK IN SCA LVL AS ANTICIPATED. TPLM2 WAS THE EXCEPTION...BRIEFLY VENTURING INTO GLW. HIPRES BLDG ACRS WATERS FOR THE REST OF THE AFTN INTO TNGT. WNDS WL BE DECRSG FM HERE...DROPPING BLO SCA BY ELY EVNG...AND LESS THAN 10 KT OVNGT. WNDS WL BECOME SLY FRI...STILL ARND 10 KT. LIGHT WINDS OVER THE WATERS TO END THE WEEK W/ ONLY SOME MINOR SLY CHANNELING SAT NIGHT AS A SFC HIGH MOVES OFF THE CAROLINA COAST. && .TIDES/COASTAL FLOODING... TIDAL DEPARTURES DROPPING TO LESS THAN A FOOT...AND WILL CONTINUE TO DECLINE IN WLY WINDS. NO ADDTL ISSUES ANTICIPATED ATTM. && .EQUIPMENT... KLWX 88D WILL REMAIN OUT OF SERVICE UNTIL SATURDAY...WHEN PARTS TO REPAIR WILL ARRIVE. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ530>534-537>543. SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR ANZ535- 536. && $$ SYNOPSIS...HTS NEAR TERM...HTS SHORT TERM...GMS LONG TERM...KLW AVIATION...HTS/GMS/KLW MARINE...HTS/GMS TIDES/COASTAL FLOODING...HTS EQUIPMENT...HTS

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