Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 250243 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 943 PM EST TUE FEB 24 2015 .SYNOPSIS... LOW PRESSURE WILL CONTINUE TO DEVELOP AND MOVE AWAY FROM CAPE HATTERAS TONIGHT. A COLD FRONT WILL PASS THROUGH THE MID- ATLANTIC STATES LATE TONIGHT INTO WEDNESDAY. LOW PRESSURE WILL TRACK ALONG THE CAROLINA COAST WEDNESDAY NIGHT WHILE AN UPPER LEVEL TROUGH CROSSES THE GREAT LAKES. HIGH PRESSURE WILL THEN BUILD THROUGH SATURDAY NIGHT. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... AS OF 02Z...LOW PRESSURE IS WELL EAST OF CAPE HATTERAS WHILE A DEEP TROUGH IS OVER THE GREAT LAKES WITH THE SFC LOW OVER JAMES BAY. AN ASSOCIATED COLD FRONT WILL PUSH EAST ACROSS THE AREA LATE TONIGHT. LIGHT SLY FLOW WILL INCREASE AND TURN WLY WITH THE COLD FRONT. MIN TEMPS GENERALLY MID TO UPR TEENS INLAND WITH LOW 20S URBAN/NEARSHORE PER MAV/MET/SREF BLEND. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... HIGH PRES BUILDS OVER THE NRN MID-ATLANTIC WITH A WLY DOWNSLOPING FLOW. INCREASED MAX TEMPS A DEGREE OR TWO OVER MAV/MET/GMOS GUIDANCE DUE TO COMPRESSION WARMING. MAX TEMPS GENERALLY MID TO UPR 30S WITH LOW 40S ROUGHLY DC AND SOUTH. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... GUIDANCE CONSENSUS CONTINUES TO SUGGEST MID LEVEL CONVERGENCE BETWEEN THE COASTAL LOW WEDNESDAY NIGHT AND THE UPR TROUGH OVER THE GREAT LAKES PRODUCES SNOW ACROSS THE CWA. WENT LIKELY/CATEGORICAL ACROSS THE AREA (EXCEPT FOR CHANCE IN FAR NERN MD). LATE WEDNESDAY NIGHT WITH ACCUM GENERALLY 1 TO 2 INCHES. 00Z GUIDANCE WILL HELP HONE THE MIDNIGHT SHIFT INTO POTENTIAL HEADLINES. AS OF NOW A WINTER WEATHER ADVISORY SEEMS LIKELY FOR SOUTHERN SECTIONS OF THE CWA AND ACROSS THE BALT-WASH METRO WHERE AN INCH AT MORNING RUSH THURSDAY WOULD WARRANT AN ADVISORY. PREVIOUS... 24.12Z MODEL GUIDANCE HAS INCHED NORTHWARD WRT TRACK OF SOUTHERN STREAM LOW PRESSURE MOVING TO A POSITION EAST OF CAPE HATTERAS BY 12Z THURSDAY. OF ADDITIONAL CONCERN IS THE POSSIBILITY OF AN AREA OF LIFT ACROSS THE NORTHWESTERN PERIPHERY WHERE MODELS MAY BE UNDERDOING QPF GENERATION. FOR THIS ISSUANCE HAVE RAISED POPS TO LIKELY FROM HIGHLAND TO ST MARYS COUNTIES...ALTHOUGH THESE MAY ULTIMATELY NEED TO BE RAISED HIGHER AND EXTEND FARTHER NORTH. BRUNT OF STORM STILL STAYS SOUTH OF THE AREA THOUGH...SO ACCUMULATIONS WOULD BE A FEW INCHES AT THE MAX. HOWEVER WITH OVERNIGHT LOWS IN THE TEENS TO LOWER 20S...ROADWAY ACCUMULATIONS WOULD BE POSSIBLE FOR THE MORNING COMMUTE. THE LOW WILL MOVE QUICKLY OFFSHORE THURSDAY BUT STRONG CAA WILL HOLD OFF UNTIL LATER IN THE DAY. HOWEVER TEMPERATURES WILL STILL STRUGGLE TO REACH THE FREEZING MARK. CLOUDY CONDITIONS WILL PERSIST AND SOME FLURRIES OR SNOW SHOWERS COULD DEVELOP...PARTICULARLY IN THE UPSLOPE AREAS. THE EVENING HOURS MAY BE THE MOST FAVORABLE TIME FOR SNOW SHOWERS TO MOVE EAST OF THE DIVIDE AS THE 850MB TROUGH AND MID-LEVEL PVA CROSS THE AREA. LOW TEMPERATURES WILL FALL INTO THE TEENS WITH SINGLE DIGITS NEAR THE PA BORDER AND IN THE HIGHLANDS. DEEP MEAN TROUGH WILL PERSIST OVER THE EASTERN CONUS THROUGH THE PERIOD BUT ABATE SLIGHTLY BY THE MIDDLE OF NEXT WEEK. MEANWHILE...SUBTROPICAL RIDGING WILL BEGIN TO AMPLIFY OVER THE SOUTHEASTERN CONUS. THIS WILL SET THE STAGE FOR A COUPLE OF OVERRUNNING/PERHAPS MIXED P-TYPE EVENTS LATE IN THE WEEKEND INTO EARLY NEXT WEEK AS MODERATING AIRMASS ALOFT MOVES OVER RESIDUAL COLD AIR AT THE SURFACE. THE OVERALL PATTERN WILL BE FOR A TREND IN MODERATING TEMPERATURES THROUGH THE MIDDLE OF NEXT WEEK HOWEVER. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... VFR CONDS XPCTD TNGT/WED. LIGHT SLY FLOW BECOMES NWLY 10 TO 15 KT LATE TONIGHT THROUGH WEDNESDAY BEFORE SHIFTING NORTH. IFR IN SNOW POSSIBLE LATE WED NIGHT-THU MORNING. HIGHEST PROB OF AT KCHO THOUGH DC METROS COULD ALSO SEE ACCUMULATING SNOW. REDUCED CIGS MAY LINGER INTO THU. FLURRIES OR A SNOW SHOWER POSSIBLE REST OF THURSDAY. MAINLY VFR FRI-SAT...THOUGH SOME SUB-VFR POSSIBLE IN ISO -SHSN WRN TERMINAL FRI PM. SLY FLOW AROUND 10 KT BECOMES WLY 10-20 K`S FRI NIGHT-SAT BEHIND COLD FRONT. && .MARINE... SLY CHANNELING HAS GENERALLY ENDED. BRIEF 20 KT GUSTS OCCURRED THIS EVENING OVER CNTRL MD BAY WATERS. MOST OF THESE AREAS ARE QUITE ICE BOUND. COLD FRONT CROSSES LATE TONIGHT WITH NWLY FLOW 10 TO 15 KT WEDNESDAY. LOW PRESSURE WILL PASS OFF CAPE HATTERAS LATE WEDNESDAY NIGHT. THIS WILL BRING THE POSSIBILITY OF LIGHT SNOW. ALSO NORTHERLY WINDS MAY REACH SCA LEVELS FOR PORTIONS OF WEDNESDAY NIGHT INTO THURSDAY MORNING. WINDS ARE MORE MARGINAL THURSDAY NIGHT BUT MAY ULTIMATELY BE GUSTY WITH COLDER AIR RUSHING IN. SCA GUSTS POSSIBLE FRI AFT IN SLY CHANNELING...MORE LIKELY FRI NIGHT-SAT IN WLY PRESSURE SURGE BEHIND FRONT. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ UPDATE...JACKSON PREVIOUS...WOODY!/ADS/DFH

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