Area Forecast Discussion
Issued by NWS Sterling, VA

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122 FXUS61 KLWX 101954 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 254 PM EST WED FEB 10 2016 .SYNOPSIS...
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HIGH PRESSURE WILL BUILD INTO THE MID ATLANTIC THROUGH FRIDAY. A STRONG COLD FRONT WILL CROSS THE REGION FRIDAY NIGHT. ARCTIC HIGH PRESSURE THEN BUILDS IN FOR THE WEEKEND. LOW PRESSURE MAY IMPACT THE AREA MONDAY AND TUESDAY.
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&& .NEAR TERM /TONIGHT/...
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SHORT RANGE MDLS HV BEEN IMPLYING ALL DAY THAT AN AREA OF HIGHER REF (SNSH?) WL DVLP LATE THIS AFTN/ERLY EVE ACROSS LWR SRN MD. THE COMPUTERS HV BEEN ADAMANT ABT PAINTING THIS IN THE SAME LOCATION EVERY RUN HAPPENING AT THE SAME TIME SO HV ADDED LO CHC POPS TO THE FCST FOR THAT AREA. MD CHART ROAD TEMPS FOR THAT AREA ARE IN THE M50S SO IT LOOKS DOUBTFUL THAT ANY SN THAT COULD FALL WOULD FRZ. AFTN SHIFT HAS BEEN BRIEFED ON THIS GIVEN THE SENSITIVITY THAT COMMUTE-TIME SN CAN HV ON THE RGN. IN THE W THE UPSLOPE SN MACHINE RMNS ON...ALTHO AT DOLLY SODS CAM SNFL HAS BEEN WAXING AND WANING. PRSNTLY IT IS SNOWING THERE... AND BLV THE UPSLOPE RGN SN ACTIVITY WL CONT THRU THE NGT. WINT WX ADVSRY RMNS IN EFFECT. THERE IS ALSO A WIND CHILL ADVSRY IN EFFECT FOR HIGHER ELEVS. MAJORITY OF AREA WL SEE LOWS BLO 20 TNGT...AND HIGHER ELEVS WL SEE TEMPS FALL INTO THE SINGLE DIGITS. THIS WL TRANSLATE AT HIGHER ELEVS TO WINDS CHILL BLO NEG 10...SINGLE DIGITS W IF I-95.
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&& .SHORT TERM /THURSDAY THROUGH FRIDAY/...
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CYCLONIC UPR LVL PATTERN OVR THE ERN U.S. WL WKN THU INTO FRI. SKIES SHOULD SEE PLENTY OF SUNSHINE DURG THU BUT TEMPS WL STILL BE COLD - HIGHS PRIMARILY A30S. NO PROBS XPCTD THU NGT W/ HIGH PRES OVR THE AREA. ANOTHER CHILLY NGT ALTHO WINDS WL BE LGT. LOWS IN THE TEENS XPCT SINGLE DIGITS IN THE MTNS. CLDS WL BE ON THE INCRS FRI AHD OF A FNT WHICH WL BE USHERING IN VERY COLD AIR TO THE RGN. SNSH COULD BE PSBL DURG THE AFTN IN THE W. HIGHS IN THE M30S.
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&& .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
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TWO MAIN CONCERNS FOR FRIDAY NIGHT-SATURDAY AS AN ARCTIC COLD FRONT SWINGS THROUGH. THE FIRST IS SNOW SHOWERS. THERE WILL BE AN ENHANCED UPSLOPE COMPONENT AND SEVERAL INCHES OF SNOW WILL BE POSSIBLE. WITH A DEEP MOIST LAYER...SOME SNOW SHOWERS WILL BE ABLE TO MOVE EAST OF THE MOUNTAINS AS WELL BUT ACCUMULATIONS LOOK LIGHT/SCATTERED AT THIS TIME. THE MAIN TIME FRAME FOR THESE WOULD BE FRIDAY NIGHT...BUT THERE COULD BE A RENEWED CHANCE OF AT LEAST FLURRIES ACROSS THE NORTHERN TIER SATURDAY WITH DEEP MIXING AND CONVECTIVE CLOUDS. THE OTHER CONCERN WILL BE INCREASING WINDS AND COLD TEMPS. THE WINDS DO NOT LOOK TO REACH ADVISORY LEVEL AT THIS TIME (PERHAPS CLOSE IN THE HIGH TERRAIN)...ALTHOUGH SOME 30-40 MPH GUSTS CERTAINLY POSSIBLE. HOWEVER...THEY WILL DRIVE WIND CHILL VALUES DOWN. BEHIND THE FRONT...850 MB TEMPS WILL BE BELOW -20C. LOWS FRIDAY NIGHT WILL BE IN THE TEENS AND HIGHS SATURDAY ONLY IN THE TEENS AND 20S. THE WIND CHILLS WILL DROP INTO THE SINGLE DIGITS (BELOW ZERO AT HIGHER ELEVATIONS) WEST AND TEENS EAST AND STAY THERE THROUGH THE DAY SATURDAY. A MAJOR ARCTIC OUTBREAK LOOKS IMMINENT DURING THE SECOND HALF OF THE WEEKEND. A LARGE AREA OF HIGH PRESSURE ORIGINATING FROM DIRECTLY OVER THE NORTH POLE WILL BARREL OVER THE EASTERN HALF OF THE NATION IN THE WAKE OF A COLD FRONT ON SATURDAY. 850 MB TEMPERATURES DROP TO AROUND -25 C OVERNIGHT SATURDAY NIGHT LIKELY PUSHING LOW TEMPS DOWN INTO THE SINGLE DIGITS POSSIBLY EVEN INTO THE CITIES...WITH LOWS BELOW ZERO LIKELY IN THE HIGHER ELEVATIONS. WINDS WILL BE BLOWING AS WELL AS THE COLD AIR RUSHES INTO THE REGION WITH WIND CHILLS WELL BELOW ZERO A GOOD BET AREA WIDE. THE AIRMASS BEGINS TO MODERATE SUNDAY INTO EARLY NEXT WEEK...BUT ARCTIC AIRMASSES OF THIS CALIBER RARELY GO QUIETLY. SUBSEQUENTLY...GUIDANCE UNANIMOUSLY HINTS AT A STORM SYSTEM APPROACHING AS THE COLD AIR RETREATS...BUT DIFFERENCES IN TIMING AND TRACK/STRENGTH MAKE THE ULTIMATE OUTCOME OF POTENTIAL WINTRY WEATHER UNCERTAIN ESPECIALLY EAST OF THE BLUE RIDGE MOUNTAINS. WESTERN PARTS OF THE AREA HAVE THE BEST CHANCE OF AN IMPACTFUL WINTER STORM MONDAY INTO TUESDAY...WITH MORE UNCERTAINTY TOWARDS THE METRO AREAS WHERE THE TIMING OF WARMER AIR MOVING IN WILL BE CRUCIAL TO PTYPE. OF NOTE...THE LARGE ARCTIC HIGH RETREATS TO THE EAST AND SETS UP OVER THE NORTH ATLANTIC...AS OPPOSED TO THE NORTHEAST OVER SOUTHEASTERN NEWFOUNDLAND WHICH WOULD BE THE MOST FAVORABLE FOR LOCKING IN COLDER AIR. THERE IS STILL PLENTY OF TIME FOR CHANGE THOUGH SO THIS SYSTEM BEARS CLOSE MONITORING ESPECIALLY CONSIDERING POTENTIAL PHASING AND PLENTY OF MOISTURE AVAILABLE.
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&& .AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
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CLDS HV INCRSD IN CVRG THIS AFTN BUT STILL ABV VFR AT ALL SITES. THERE IS A CHC THAT SNSH COULD DVLP NEAR DCA IN LATE AFTN/ERLY EVE. NO PROBS XPCTD OVRNGT THRU FRI. VFR WILL PREVAIL FRIDAY NIGHT-SATURDAY...ALTHOUGH THERE COULD BE A BRIEF SNOW SHOWER OR PERIOD OF FLURRIES. WINDS WILL INCREASE MARKEDLY WITH GUSTS TO AROUND 30 KT POSSIBLE LATE FRIDAY NIGHT INTO SATURDAY. GUSTY NWLY/NLY FLOW SAT NGT-SUN 10-20 G 30 KT. VFR LKLY. SUB-VFR PSBL EARLY NEXT WEEK AS LOW PRES APPROACHES. WINDS UNCERTAIN DEPENDING ON TRACK...BUT PREDOMINATELY ELY.
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&& .MARINE...
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LONG TERM SCA IN EFFECT FOR ALL OF THE WATERS. COLD FRONT PASSES FRIDAY NIGHT WITH INCREASING NW WINDS. WILL CONTINUE TO FORECAST POTENTIAL GALES FOR SATURDAY...ESPECIALLY ON THE OPEN BAY. GALES ARE LIKELY SATURDAY NIGHT INTO SUNDAY MORNING AS STRONG HIGH PRESSURE SURGES INTO THE AREA. FREEZING SPRAY IS LIKELY AS WELL GIVEN THE ROBUSTLY COLD AIRMASS THE WINDS WILL BE USHERING IN. WINDS WILL GRADUALLY DIMINISH BY SUNDAY NIGHT...BEFORE LOW PRESSURE APPROACHES THE WATERS FROM THE SOUTHWEST EARLY NEXT WEEK.
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&& .TIDES/COASTAL FLOODING...
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WATER LVLS HV DROPPED IN WNW FLOW.
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&& CLIMATE... BITTERLY COLD AIR WILL MOVE OVER THE AREA OVER THE WEEKEND. THE BRUNT OF THE COLD WILL BE SATURDAY NIGHT INTO SUNDAY. BELOW ARE RECORD COLD TEMPERATURES FOR FEBRUARY 14TH. DCA RECORD LOW: 4 (SET IN 1905) RECORD LOW MAX: 17 (SET IN 1916) BWI RECORD LOW: -2 (SET IN 1979) RECORD LOW MAX: 18 (SET IN 1916) IAD RECORD LOW: -5 (SET IN 1979) RECORD LOW MAX: 24 (SET IN 1979) .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...NONE. MD...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST THURSDAY FOR MDZ501. WINTER WEATHER ADVISORY UNTIL 6 PM EST THURSDAY FOR MDZ501. VA...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST THURSDAY FOR VAZ503-504-507-508. WINTER WEATHER ADVISORY UNTIL 6 PM EST THURSDAY FOR VAZ503. WV...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST THURSDAY FOR WVZ501-503-505-506. WINTER WEATHER ADVISORY UNTIL 6 PM EST THURSDAY FOR WVZ501-503- 505. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ530>534- 537>543. SMALL CRAFT ADVISORY UNTIL 8 PM EST THURSDAY FOR ANZ535-536.
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