Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 270229 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 929 PM EST MON JAN 26 2015 .SYNOPSIS... LOW PRESSURE OVER SOUTHEASTERN VIRGINIA WILL RAPIDLY INTENSIFY OFFSHORE AND TRACK NORTH. HIGH PRESSURE WILL BUILD OVERHEAD WEDNESDAY BEFORE ANOTHER CLIPPER SYSTEM SWINGS THROUGH THURSDAY INTO THURSDAY NIGHT. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... COASTAL LOW IS RAPIDLY EAST OF THE DELMARVA THIS EVENING...WITH PRESSURES FALLING 7 MB IN THE PAST 6 HOURS PER MSAS ANALYSIS. RADAR BLOSSOMED THIS EVENING AS AN AREA OF CONVERGENCE DEVELOPED IN THE INCREASING NE FLOW AROUND THE SFC LOW...AND THE REMNANT WAVE/FRONT FROM THE CLIPPER LOW...AIDED BY THE OROGRAPHICS OF THE BLUE RIDGE/CATOCTINS. INTENSITY OF THESE SNOW BANDS HAS BEEN VARIED AND LOCALIZED. UNDER THE SMALLER SHOWERS...TOTALS HAVE GENERALLY BEEN LESS THAN AN INCH...BUT DID RECEIVE A REPORT OF 3 INCHES IN FREDERICK CO MD UNDER THE ENHANCED BAND. SYNOPTIC MODELS HAVE DEPICTED THIS IN THE GENERAL SENSE...WITH THE RAP/HRRR GIVING A LITTLE BETTER IDEA OF HOW THIS AREA OF SNOW WILL PIVOT AND WEAKEN OVERNIGHT. IT LOOKS LIKE PEAK SNOW WILL BE THROUGH MIDNIGHT TO 2 AM...WITH A GRADUAL WEAKENING TREND AND SE PIVOT THEREAFTER. ACCUMULATIONS SHOULD CONTINUE THE TREND OF PREVIOUS OBSERVATIONS...COMING IN ONE HALF TO ONE INCH SPURTS. THINK THE WINTER WX ADVISORY GENERALLY COVERS THIS IDEA...BUT WILL MONITOR THE PERSISTENCE OF THE PERSISTENT BAND IN THE NORTH CENTRAL PART OF THE AREA. CENTRAL/SOUTHERN SHENANDOAH VALLEY STILL LOOKS MAINLY DRY...AND ALTHOUGH FLURRIES IN THE CHO AREA...THINK MOST OF THE STEADIER SNOWS STAY EAST. TEMPERATURES ARE NOW BELOW FREEZING IN MANY AREAS...AND ROADS ARE QUICKLY BECOMING SLIPPERY WHERE SNOW FALLS. RESIDUAL MOISTURE UNDERNEATH THE SNOW FROM EARLIER TODAY WHICH FREEZES COULD LEAD TO DECEPTIVELY SLIPPERY CONDITIONS. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... AS THE UPPER TROUGH OVER THE APLCNS WEAKENS AND GETS COMPLETELY ABSORBED INTO THE DEEPENING UPPER LOW OVER THE ATLC COAST....THE SNOW POTENTIAL WILL SHUT DOWN QUICKLY HEADING INTO THE MID MRNG HRS TUE. A LINGERING BAND MAY SET UP OVER THE CHES BAY/DELMARVA THAT COULD INCH OVER INTO THE WRN SHORE MD COUNTIES BUT NOT LIKELY MUCH FURTHER WEST OF THERE. CLOUDS WILL LINGER INTO MIDDAY BUT THEY WILL BE QUICKLY PUSHED TOWARD THE EAST BY A STRENGTHENING NW WINDS... COURTESY OF THE INTENSE LOW WELL OFF TO OUR NORTH AND EAST. TEMPS WILL ONLY BRIEFLY CLIMB ABOVE FREEZING TUE AFTN...BUT WIND CHILLS WILL REMAIN WELL INTO THE 20S/L30S FROM THE GUSTY AND DRIER NW FLOW. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... TIME FLIES - 4 YRS AGO TDA WAS ONE OF THE MOST INTENSE AFTN/EVE`S OF WINTER WX XPRNCD HERE AS HVY SN/IP AT RUSH HR CAUSED THOUSANDS OF CARS TO BE STRANDED ON AREA ROADS. TUE NGT THRU WED NGT LOOKING LK A FAIRLY QUIET PD WXWISE. COLD TEMPS WL BE THE KEY CONCERN - COLD AIR WL BE PUSHED INTO THE MID ATLC AS INTENSE LOW PRES CAUSES BLZRD CONDS IN SRN NEW ENGLAND. HIGH PRES WL BE BLDG INTO THE CWA. LOWS TUE NGT PRIMARILY IN THE MU TEENS...L20S IN THE CITIES... SINGLE DIGITS IN THE MTNS. HIGHS WED IN THE 30S...20S IN THE HIGHLANDS. LOWS WED NGT FAIRLY SIMILAR TO TUE NGT. UPPER LEVEL RIDGING SHOULD MOVE OFF THE MID-ATLANTIC COAST THURSDAY WHILE A SHORTWAVE TROUGH DIGS INTO THE OHIO VALLEY. LOW PRESSURE IS PROGGED TO MOVE AHEAD OF THE TROUGH. SOUTHERLY FLOW AHEAD OF THE SYSTEM SHOULD BRING TEMPS INTO THE UPPER 30S TO LOW 40S ACROSS THE REGION WITH THE EXCEPTION OF NORTHERN PORTIONS OF THE OUTLOOK AREA. SNOW WILL LIKELY MOVE INTO THE HIGHLANDS THURSDAY MORNING AND AS PRECIPITATION MOVES EASTWARD AND TEMPS RISE SNOW MAY TRANSITION TO RAIN. AT THIS TIME ACCUMULATIONS OF LESS THAN AN INCH ARE EXPECTED ACROSS THE OUTLOOK AREA THURSDAY. THE SFC LOW WILL TRACK ACROSS NEW ENGLAND AND A COLD FRONT WILL MOVE ACROSS THE REGION LATE THURSDAY NIGHT. UPSLOPE SNOW SHOWERS WILL CONTINUE ACROSS THE WESTERN SLOPES INTO FRIDAY. HIGH PRESSURE MOVES ACROSS THE REGION FRIDAY AND SATURDAY. ANOTHER SHORTWAVE TROUGH WILL MOVE ACROSS HUDSON BAY THIS WEEKEND AND A COLD FRONT MAY CROSS THE REGION SUNDAY. TEMPERATURES ARE EXPECTED TO BE BELOW NORMAL THROUGH THE LONG TERM. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... BANDS OF SNOW WILL AFFECT THE TERMINALS EXCEPT CHO THROUGH THIS EVENING. IFR VSBYS ARE LIKELY IN THE PERIODS OF HEAVIEST SNOW...AND POSSIBLY BRIEFLY LOWER. CIGS WILL RESIDE EITHER SIDE OF 1000FT IN THE METROS...A BIT HIGHER AT MRB. GUIDANCE VARIES ON WHETHER IFR CIGS STAY LOCKED IN AT CHO OR GRADUALLY LIFT OVERNIGHT...REGARDLESS THEY ARE LEAST LIKELY TO SEE ANY SUSTAINED SNOW OTHER THAN A PASSING SHSN. COVERAGE AND INTENSITY OF SNOW SHOULD BE ON A DIMINISHING TREND AFTER MIDNIGHT...BUT SOME BANDS MAY STILL BACK INTO THE AREA...ESPECIALLY BWI/MTN. CONDITIONS SLOWLY IMPROVE THROUGH THE DAY ON TUESDAY...POSSIBLY REACHING VFR BY MID AFTERNOON. N/NW WINDS WILL INCREASE TONIGHT AND TUESDAY DUE TO THE STRENGTHENING LOW PRESSURE WITH GUSTS OF 20-25 KT LIKELY. VFR CONDS TUE NGT THRU WED NGT. MVFR/IFR CONDITIONS ARE POSSIBLE THURSDAY AS A COLD FRONT CROSSES THE REGION. SN OR RA WILL BE POSSIBLE. && .MARINE... WIDESPREAD SCA CONDS OCCURRING OVER THE WATERS...BUT GUSTS TO GALES ARE STILL POSSIBLE LATER TONIGHT INTO THE OVERNIGHT HRS AS THE COASTAL LOW STRENGTHENS. WINDS WILL REMAIN BREEZY INTO TUE AFTN AS THE LOW CONTINUES TO AFFECT AREAS TO OUR NE...GRADUALLY MOVING AWAY FROM THE AREA LATER IN THE DAY. SCA CONDS WL STILL BE XPRNCD TUE NGT AND WED...FINALLY DIMINISHING WED NGT AS HIGH PRES MOVES OVR THE WATERS. A COLD FRONT WILL MOVE ACROSS THE WATERS FRIDAY AND SCA WILL BE POSSIBLE FOR PORTIONS OF THE WATERS. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...WINTER WEATHER ADVISORY UNTIL 10 AM EST TUESDAY FOR DCZ001. MD...WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR MDZ003-502. WINTER WEATHER ADVISORY UNTIL 10 AM EST TUESDAY FOR MDZ004>006- 011-013-014-016>018-503>508. WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR MDZ501. VA...WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR VAZ028-031- 503-504. WINTER WEATHER ADVISORY UNTIL 10 AM EST TUESDAY FOR VAZ052>057- 505-506. WV...WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR WVZ050>053- 055-502-504>506. WINTER STORM WARNING UNTIL 7 AM EST TUESDAY FOR WVZ501-503. MARINE...SMALL CRAFT ADVISORY FROM 7 AM TUESDAY TO 6 AM EST WEDNESDAY FOR ANZ530>534-537>543. GALE WARNING UNTIL 7 AM EST TUESDAY FOR ANZ530>534-537>543. SMALL CRAFT ADVISORY UNTIL 6 AM EST WEDNESDAY FOR ANZ535-536. && $$ UPDATE...ADS PREVIOUS...GMS/WOODY!/HAS

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