Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 050842 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 342 AM EST THU MAR 5 2015 .SYNOPSIS... A COLD FRONT WILL CONTINUE TO DRIFT SOUTH ACROSS THE REGION THROUGH THIS MORNING WITH PRECIPITATION CONTINUING UNTIL THIS EVENING. HIGH PRESSURE BUILDS OVERHEAD FRIDAY...THEN SETTLES OVER THE SOUTHEASTERN STATES THIS WEEKEND THROUGH THE MIDWEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 3 AM...SFC BOUNDARY HAS SLIPPED TO NEAR THE NC/VA BORDER. HOWEVER...COLDER AIR IS ONLY TRICKLING INTO THE AREA. THERE HAVE BEEN A SOME OBS OF SN IN THE HIGHER ELEVATIONS TO THE NORTHWEST...BUT THERE IS A TEMPORARY LULL IN RADAR THAT MAY TAKE UNTIL CLOSER TO DAYBREAK TO FILL BACK IN AND HAVE BETTER SNOW RATES SPREAD EAST. WX GRIDS WERE ADJUSTED TO SLOW DOWN THE CHANGEOVER...WHICH WILL PUSH SE REACHING THE SE EXTENT OF THE FORECAST AREA BY MID/LATE MORNING. SO JUST BECAUSE CONDITIONS MAY BE JUST WET AT DAYBREAK...CONDITIONS ARE STILL EXPECTED TO DETERIORATE DURING THE MORNING. THERE STILL LOOKS LIKE A GOOD PROB OF A FEW HOURS OF SLEET MIXTURE...ESPECIALLY AS THE TRANSITION ZONE TRAVERSES FARTHER SE. FOR THESE REASONS...IN ADDITION TO A LARGE CHUNK OF SNOW FALLING DURING THE DAYLIGHT HOURS (MARCH SUN ANGLE)...SNOW TOTALS HAVE BEEN TRIMMED BACK BY A FEW INCHES ACROSS A GOOD PART OF THE AREA. NEVERTHELESS...THERE WILL STILL BE GOOD BANDING POTENTIAL. HAVE HEARD REPORTS OF NEARLY A FOOT OF SNOW IN N-CNTL KY (NOT TO DRAW A DIRECT CORRELATION TO THE LOCAL AREA...JUST THE POTENCY OF THE SYSTEM AND THE DEEP MOISTURE TAP). THERE WILL PROBABLY BE A WINDOW OF A FEW HOURS WHERE RATES COULD BE AN INCH PER HOUR OR MORE. THIS WOULD BE EARLY MORNING FOR NW SECTIONS...MIDDAY FOR THE METROS TO CNTL SHEN VALLEY...AFTERNOON FOR CNTL VA TO SRN MD. PINPOINTING BANDING LOCATION AND DURATION WILL ULTIMATELY INFLUENCE SNOW TOTALS SINCE IT WILL REPRESENT THE BEST CHANCE AT ACCUMULATIONS. TEMPERATURES WILL GRADUALLY FALL THROUGH THE DAY. BLENDING IN CURRENT GUIDANCE SUGGESTS THIS FALL WILL BE SLOWER THAN PREVIOUS FORECAST...ANOTHER LIMITING FACTOR TO THE SNOW. THE SNOW WILL QUICKLY WIND DOWN DURING THE MID-LATE AFTERNOON HOURS. BY 6 PM THE SNOW MAY BE LIMITED TO PORTIONS OF SRN MD. SKIES MAY ACTUALLY CLEAR FAIRLY QUICKLY OVERNIGHT AS THE DRY ARCTIC AIRMASS PUSHES IN. SINGLE DIGIT LOWS WILL BE COMMON TONIGHT...WITH TEENS EAST OF I-95 AND POSSIBLY BELOW ZERO IN THE MOUNTAINS. WIND CHILL ADVISORIES MAY BE NEEDED IN THE POTOMAC HIGHLANDS FOR READINGS BELOW -10F. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... HIGH PRESSURE CENTERS OVERHEAD FRIDAY WITH SUNNY AND TRANQUIL CONDITIONS. MAX TEMPS MID TO UPR 20S DUE TO LITTLE MIXING AND FRESH SNOW. HIGH PRESSURE THEN SETTLES OVER THE SOUTHEASTERN STATES FRIDAY NIGHT THROUGH SUNDAY. COLD AGAIN SATURDAY MORNING WITH MINIMA AROUND 10F FOR MANY INTERIOR LOCATIONS...TEENS MORE LIKELY WHERE MIXING PERSISTS. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... BROAD TROUGH CROSSES THE UPR MIDWEST TO THE NRN MID-ATLANTIC MONDAY...THOUGH IT APPEARS CLOUD COVER WOULD BE THE ONLY SENSIBLE WEATHER. OTHERWISE...A WELCOME CALM WEATHER PATTERN WITH A WARMING TREND. A FEW DEGREES WARMER ON MAX TEMPS EACH DAY IN SWLY FLOW...LOW 40S FOR SATURDAY...MID 40S N...MID 50S S MONDAY. 60S POSSIBLE SOUTH OF DC TUESDAY THROUGH THURSDAY. && .AVIATION /09Z THURSDAY THROUGH MONDAY/... MVFR...POSSIBLY VFR AT TIMES...WITH LIGHT RAIN CAN BE EXPECTED THROUGH AT LEAST DAYBREAK AT THE TERMINALS. A CHANGEOVER FROM NW TO SE THROUGH THE MORNING. THERE WILL LIKELY BE A FEW-HOUR PERIOD OF RA/SN/PL BEFORE CHANGING TO ALL SN. CONDITIONS WILL DETERIORATE TO IFR OR LOWER...AND A BAND OF HEAVY SNOW IS POSSIBLE. WILL CONTINUE TO MONITOR AND ADJUST TIMING IN THE TAFS. SN WILL LIGHTEN DURING THE AFTERNOON...WITH CONDITIONS IMPROVING DURING THE EVENING. VFR IS EXPECTED LATER OVERNIGHT. WINDS GENERALLY N OR NW...SOME GUSTS UP TO 20 KT POSSIBLE TODAY. HIGH PRESSURE BUILDS OVERHEAD FRIDAY WITH VFR/TRANQUIL CONDS. COLD AGAIN FRIDAY NIGHT WITH MIN TEMPS IN THE TEENS TO 10F. SWLY FLOW AND MORE HIGH PRESSURE SATURDAY THROUGH THE FIRST HALF OF NEXT WEEK. && .MARINE... SCA CONDITIONS EXPECTED TO DEVELOP TODAY AND PERSIST THROUGH TONIGHT FOR ALL WATERS WITH N/NW WINDS GUSTING 20 TO 25 KT AS COLDER AIR MOVES IN. RAIN WILL CHANGE TO SLEET AND SNOW FROM MID MORNING THROUGH MIDDAY. PRECIP ENDS THIS EVENING BUT WINDS WILL CONTINUE TO GUST TO SCA LEVELS THURSDAY MORNING...WHEN HIGH PRESSURE WILL THEN TAKE CONTROL. SCA CONTINUES FOR SRN MD WATERS FRIDAY MORNING FOR NLY CHANNELING. HIGH PRESSURE BUILDS OVERHEAD FRIDAY AFTERNOON...THEN SETTLES OVER THE SERN STATES THROUGH THE WEEKEND WITH LIGHT SWLY FLOW EXPECTED. && .HYDROLOGY... RAIN IS CHANGING OVER TO WINTRY PRECIPITATION FROM NW TO SE. ADDITIONAL RAIN WILL BE BETWEEN AROUND 1/4 INCH. STREAMS IN NORTH-CENTRAL MARYLAND HAVE RISEN TO NEAR BANKFULL DUE TO RAIN AND ICE EFFECTS. ANY SIGNIFICANT FLOODED WILL BE ADDRESSED. OTHERWISE...TEMPERATURES WILL DROP BELOW FREEZING TODAY AND SNOW WILL OVERSPREAD THE AREA. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...WINTER STORM WARNING UNTIL 9 PM EST THIS EVENING FOR DCZ001. MD...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR MDZ003>006-011-501>508. WINTER STORM WARNING UNTIL 9 PM EST THIS EVENING FOR MDZ013- 014-016-018. WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR MDZ017. VA...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR VAZ025>031-040-501-503>508. WINTER STORM WARNING UNTIL 9 PM EST THIS EVENING FOR VAZ038- 039-050>055-502. WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR VAZ036- 037-056-057. WV...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR WVZ050>053-055-501>506. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ530>532-535- 536-538>542. SMALL CRAFT ADVISORY UNTIL NOON EST FRIDAY FOR ANZ533-534-537- 543. && $$ SYNOPSIS...BAJ/ADS NEAR TERM...ADS SHORT TERM...BAJ LONG TERM...BAJ AVIATION...BAJ/ADS MARINE...BAJ/ADS HYDROLOGY...BAJ

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