Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 240258 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 958 PM EST MON FEB 23 2015 .SYNOPSIS... HIGH PRESSURE OVER IOWA WILL MOVE ONTO THE EAST COAST TUESDAY. A COLD FRONT IS EXPECTED TO PASS THROUGH THE MID ATLANTIC STATES TUESDAY NIGHT INTO WEDNESDAY. LOW PRESSURE WILL TRACK ACROSS GEORGIA WEDNESDAY NIGHT. HIGH PRESSURE WILL RETURN FOR THE LATTER PORTION OF THE WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... ARCTIC HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT...BRINGING DRY AND BITTERLY COLD CONDITIONS. LEANED TOWARD THE COLDER GUIDANCE DUE TO THE POTENTIAL FOR RADIATIONAL COOLING OVERNIGHT AS WINDS BECOME LIGHT AND SKIES REMAIN MOSTLY CLEAR ACROSS MANY LOCATIONS. MIN TEMPS WILL RANGE FROM 5 TO 10 BELOW ZERO OVER THE ALLEGHENY HIGHLANDS TO THE SINGLE DIGITS NEAR WASHINGTON AND BALTIMORE. WILL CONTINUE WITH THE WIND CHILL ADVISORY FOR THE ALLEGHENY HIGHLANDS. WINDS WILL ONLY BE AROUND 5 TO 10 MPH...BUT THE BITTERLY COLD TEMPS WILL BE ENOUGH TO COMBINE WITH THE WINDS FOR WIND CHILLS TO DIP TO NEAR FIFTEEN DEGREES BELOW ZERO. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... COLD PERIOD CONTINUES INTO TUESDAY...THOUGH SHOULD SEE WARMER TEMPS THAN TODAY AS SOUTHERLY FLOW SETS UP WAA AHEAD OF THE NEXT APPROACHING COLD FRONT. NOT ANTICIPATING THE EXTENSION OF THE WIND CHILL ADVISORY TO BE NEEDED. GENERAL CONSENSUS OF THE 00Z MODELS KEEP PCPN TO THE WEST THROUGH 00Z WED...AND AS SUCH WILL RUN WITH A DRY FORECAST. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... LOPRES RAMBLES ACRS SERN CNDA TUE NGT-WED...DROPPING A REINFORCING CDFNT ACRS THE CWFA. BELIEVE THAT FROPA WL OCCUR TUE NGT...MOST LKLY AFTR MIDNGT. CLDS WL INCR WELL AHD OF THE FNT...MAINLY IN THE EVNG HRS. AREA NOT WELL SITUATED WRT JETMAX STRUCTURE OR VORTICIY PTTN TO RECEIVE ADDED LIFT. THEREFORE BELIEVE FNT WL PASS THRU DRY FOR ALL BUT THE MTNS...WHERE UPSLP ENHANCEMENT MAY BE ABLE TO SQUEEZE OUT CHC POPS. DUE TO THIS UNCERTAINTY OF LOW PROBABILITY...HV ACCUM GRIDS BLANK. CAA WL TAKE RESIDENCE ON WED. DOWNSLOPING WL PROVIDE A PD OF PRTL SUNSHINE E OF THE APLCNS...WHILE THE FLOW PTTN WL YIELD CONTD UPSLP SHSN TO THE WRN SLOPES. H8 TEMPS CHG OVER 24 HRS TUE NGT TO WED DAY ON THE ORDER OF 2-3 DEGC. ITS NOT A HUGE CHG...AND SUBSEQUENTLY HV KEPT WINDS ON THE LIGHTER SIDE. WED NGT A BIT TRICKIER AS AN AREA OF LOPRES SHOOTS EWD TO THE S OF THE AREA...PER GFS/NAM. THE CATCH IS THAT THE EURO SEND THE LOW A BIT FURTHER N...CLIPPING SRN CWFA W/ A SWATH OF PCPN. THERMALLY... THIS WOULD BE COLD ENUF FOR SNOW. IF ITS WERE TO HPPN...CHO-EZF ONT HE EDGE...SO ACCUMS WUD BE SMALL. HV ATTEMPTED TO MAINTAIN A PINCH OF CONTINUITY...AND CONFINED A 20 POP ACRS THE FAR S. THIS WL NEED TO BE WATCHED IN CASE LATER GFS/NAM RUNS CARRY LOW MORE LIKE CURRENT ECMWF. OVERALL...TEMP CHGS IN GRIDS NOT THAT SGFNT. STAYED SLGTLY WARMER MIN-T TUE NGT DUE TO INSUALTING BLANKET OF SLY WNDS/CLDS. WHILE CAA NOT INCREDIBLY STRONG WED...DID SHADE ABT A DEGF COOLER TO ACCNT FOR EFFECTS OF CDFNT/CAA. BLENDED GDNC FOR WED NGT MIN-T. END RESULT WL BE CONTINGENT UPON BOTH THE LOW AS WELL AS HOW FAR S ARCTIC AIR CAN PLUNGE ONCE AGN. THURSDAY THROUGH SUNDAY/... ARCTIC HIGH PRESSURE BUILDS INTO THE AREA OVERNIGHT WEDNESDAY..WITH COLD AND DRY WEATHER OVER THE CWA. 00Z ECMWF/GEFS HAVE SIMILAR TRACK FOR NEXT LOW PRESSURE SYSTEM DEVELOPING IN THE GULF ON THURSDAY...WILL NOT INCLUDE ANY POPS AT THIS TIME AS IMPACTS APPEAR TO STAY TO OUR SOUTH THRU THURSDAY. MODELS BEGIN TO DIVERGE SIGNIFICANTLY BEYOND THURSDAY...WITH SOME MODELS MOVING PIECES OF ENERGY TO OUR SOUTH FRIDAY AND AGAIN ON SATURDAY...BRINGING PRECIPITATION TO PARTS OF THE CWA. OTHERS KEEP OUR ENTIRE AREA COMPLETELY DRY. FOR NOW WILL KEEP PREVIOUS FORECAST OF SLIGHT CHANCE POPS GOING LATE FRIDAY NIGHT THROUGH SUNDAY. REGARDLESS...AIR TEMPERATURES WILL BE WELL BELOW NORMAL THROUGH AT LEAST SATURDAY EVENING. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... VFR CONDITIONS ALONG WITH LIGHT WINDS ARE EXPECTED TONIGHT. A STORM SYSTEM WILL TRACK WELL SOUTH OF THE REGION ON TUESDAY. MOISTURE FROM THIS SYSTEM WILL LIKELY PRODUCE MVFR CIGS DURING THE PM HOURS AT KCHO. THERE IS EVEN A SLIGHT CHC OF MINOR PM VIS REDUCTIONS FROM LGT SNOW AT KCHO. ELSEWHERE...MDL SOUNDINGS INDICATE THE LOW LVLS REMAIN DRY ENOUGH TO SUPPORT VFR CONDS THRU TUE EVENING. OUTLOOK WED...MAINLY VFR. WED NGT...WL DEPEND UPON TRACK OF LOPRES PASSING S OF TERMINALS. IF IT STAYS FAR ENUF S...THEN VFR. OTRW...MAY BE MVFR-IFR IN SNW. THU-SAT...LOW CONFIDENCE IN FLGT RESTRICTIONS. && .MARINE... A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE WATERS LATE THIS EVENING. WINDS WILL DIMINISH OVERNIGHT AS HIGH PRESSURE MOVES OVERHEAD. WIND WILL TURN TOWARD THE SOUTH TUESDAY AS HIGH PRESSURE MOVES OFF THE COAST...BUT WIND SPEEDS WILL REMAIN BELOW SCA CRITERIA. CDFNT WL CROSS MARINE AREA LT TUE NGT. IN THE CAA THA ENSUES WED... ENUF MIXING FOR LOW END SCA PSBL. HV SOME GUSTS FCST THAT WUD BARELY TRIGGER SCA/S. CONFIDENCE THEREAFTER WANES. LOPRES WL PASS S OF WATERS WED NGT-THU MRNG...PERHAPS CLOSE ENUF TO IMPACT WATERS. THRU THE END OF THE WEEK THE QSTN WL BE HOW STRONG/QUICKLY ARCTIC HIPRES WL BUILD...AND WHAT TYPE OF P-GRAD WL RESIDE BTWN IT AND THE STORM TRACK TO THE S. THAT IS WHAT WL DICTATE WHEN/WHERE SCA WL BE REQD. WONT CHG CURRENT THINKING THAT WED NGT-THU A PD OF OPPORTUNITY. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...WIND CHILL ADVISORY UNTIL 9 AM EST TUESDAY FOR MDZ501. VA...NONE. WV...WIND CHILL ADVISORY UNTIL 9 AM EST TUESDAY FOR WVZ501-503. MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST TUESDAY FOR ANZ530>543. && $$ SYNOPSIS...BJL NEAR TERM...BJL SHORT TERM...BJL LONG TERM...BJL AVIATION...BJL MARINE...BJL

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