Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 121511 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1011 AM EST FRI FEB 12 2016 .SYNOPSIS... HIGH PRESSURE BUILDS IN ACROSS THE REGION TODAY. A STRONG COLD FRONT WILL CROSS THE REGION TONIGHT WITH ARCTIC HIGH PRESSURE BUILDING IN ITS WAKE FOR THE WEEKEND. LOW PRESSURE WILL IMPACT THE AREA MONDAY AND TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A POTENT COLD FRONT WILL MOVE THROUGH THE MIDWEST INTO THE OHIO VALLEY TODAY. HIGH AND MID-LEVEL CLOUDS WILL CONTINUE TO THICKEN OVERHEAD AHEAD OF THE SHORTWAVE ENERGY ASSOCIATED WITH THE COLD FRONT. THE SHORTWAVE ENERGY WILL MOVE INTO THE AREA LATE THIS AFTERNOON FROM THE WEST. THIS ENERGY WILL COMBINE WITH FORCING ALONG AND AHEAD OF THE COLD FRONT FOR SNOW SHOWERS TO BREAK OUT ACROSS THE WESTERN PORTION OF THE CWA. MAX TEMPS WILL BE WELL BELOW CLIMO...RANGING FROM THE TEENS AND 20S IN THE MOUNTAINS TO THE LOWER 30S IN WASHINGTON AND BALTIMORE. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... CFP TNGT...BRINGING A HOST OF POTL HAZARDS. ISSUES ARE WINDS... SNOW... AND WIND CHILL. SNOW...PARAMETERS LOOKING FAVORABLE FOR A BRIEF PERIOD OF SNOW COINCIDENT W/ THE FNT TNGT. SCALE OF THREAT LKLY FINER THAN GDNC...SO AM ABV MOS. ACCUMS WUD BE UNDER AN INCH...AND WUD BE ONT HE ERN SHORE BEFORE MIDNGT. IN THE MTNS...THE TRAJ FVRBL FOR UPSLP TNGT-SAT...AND THE DRY AMS WUD LEAD TO A HIGH SNOW RATIO. THIS WL ACCUM SVRL INCHES. HWVR...AM JUST UNDER ADVY CRITERIA...WHICH IS SOMEWHAT FITTING SINCE SNOW GROWTH ZONE LOW...AND NOT INTERSECTING THE BEST LIFT. WINDS...ATMOS WL BE WELL MIXED IN STRONG CAA POST-FRONT. MDL SNDGS SUGGEST 30-SOMETHING KT GUSTS. WUDNT RULE OUT A FEW 40 KTS. CONFIDENCE NOT QUITE THERE FOR WIND ADVYS. ADMITTEDLY ITS CLOSE FOR THE MTNS. TEMPS...CONTINING TEMP FCSTS ON THE LOW END OF GDNC...BOTH MIN-T TNGT AND MAXT SAT. WIND CHILLS...COMBINE THE PREV TWO BULLETS...AND WIND CHILLS WL DEFINITELY BE A FACTOR. BEST CHC AT ADVY IN THE MTNS. IT FALLS ABT 5- 10 DEGF SHORT ELSW. PROJECTING ONWARD THOUGH...THE MTNS ALMOST THREATEN WIND CHILL WARNING CRITERIA...SPCLY SAT NGT INTO SUN. ELSW...FCST VALUES FLIRT W/ ADVY CRITERIA SAT NGT-SUN. MINDFUL THAT WE/RE SVRL CYCLES OUT...AND NOTHING SEEMS SLAM-DUNK OTHER THAN WIND CHILL ADVYS IN THE MTNS...WUD RATHER NOT MAKE FIRM WRNG/ADVY DECISION YET. COGNIZANT OF THE THREAT THO...WL BE ISSUING WIND CHILL WATCHES FOR THE MTNS...WHERE VALUES ARE THE LOWEST. OTHER COUNTIES WL BE CARRIED IN THE HWO. HOPEFULLY...LATER SHIFTS WL BE ABLE TO MAKE BETTER-INFORMED DECISIONS. BY SUN...THE RDG WL BE OVERHEAD...AND THE ONLY HAZARD LEFT WL BE COLD TEMPS. MAY HV PCPN RETURNING LT SUN NGT AHD OF NXT SYSTEM. HV CHCS TO COVER. MORE IN LONG TERM DSCN. && .LONG TERM /MONDAY THROUGH THURSDAY/... ARCTIC HIGH PRESSURE WILL BE RETREATING QUICKLY ON MON WITH MOISTURE ADVANCING QUICKLY NORTHWARD AHEAD OF A SRN STREAM SYSTEM FOR A POTENTIAL BIG MESS MON-TUE WITH HEAVY PRECIP AMOUNTS. POTENTIAL FOR 6+ INCHES OF SNOW APPEARS TO BE MAINLY CONFINED TO THE POTOMAC HIGHLANDS WITH SIGNIFICANT ICING FROM THERE TO THE ROUTE 15 CORRIDOR AND LIGHT WINTRY PRECIP TO MOSTLY RAIN EAST OF THERE. THERE IS GENERAL CONSENSUS BETWEEN MODELS TO BRING SFC TEMPS ABV FREEZING EVERYWHERE BY 18Z TUE WITH 50S POSSIBLE OVER EASTERN AREAS AS H85 TEMPS CLIMB ABV 5C AS STRONG SRLY WINDS DEVELOP. IN ADDITION TO WINTRY PRECIP CONCERNS...LATEST 00Z ECMWF INDICATES HEAVY PRECIP AMOUNTS UP TO 3.5 INCHES WATER EQUIVALENT WHICH COULD LEAD TO FLOODING ISSUES. WARMER TEMPS...RUNOFF AND SNOWMELT COULD LEAD TO ICE JAM FLOODING PROBLEMS ESPECIALLY AFTER THIS WEEKEND`S FRIGID AIR MASS. BY MID WEEK...SRN STREAM SYSTEM MERGES/PHASES WITH A NRN STREAM DISTURBANCE OVER THE NORTHEAST WITH SYSTEM INTENSIFYING RAPIDLY LEADING TO STRONG NW FLOW AND DRYING CONDITIONS. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... VFR CONDITIONS WITH MID-LEVEL CLOUDS TODAY. CDFNT COMING THIS EVNG...PERHAPS ACCOMPANIED BY A FEW SHSN. AREAL CVRG/CONFIDENCE IN A PT FCST THE CONCERN. THUS...THESE DO NOT APPEAR IN TAFS ATTM. WUD HV BREIF IFR IF AIRFIELD AFFECTED. WINDS BECOME NW AND PICK UP POST-FRONT...WITH SOME GUSTS IN THE MID 30S AFTR MIDNGT TNGT THRU SAT AFTN. HIPRES BLDS SAT NGT-SUN. WINDS GRDLY DIMINISHING. NO OTHER RESTRICTIONS ANTICIPATED. SIG WINTER STORM TO IMPACT THE REGION MON-TUE WITH HEAVY WINTRY PRECIP MON-MON NIGHT ALONG AND WEST OF THE BLUE RIDGE ESPECIALLY AT KCHO...KIAD AND KMRB BEFORE IT TURNS TO ALL RAIN TUE AFTERNOON. IFR CONDITIONS LIKELY MON-TUE. && .MARINE... NO MARINE HEADLINES ANTICIPATED THROUGH THIS AFTERNOON. CDFNT COMING TNGT...PRODUCING NW WINDS W/ 30-40KT GUSTS. THREAT WUD LKLY BEGIN ARND/JUST AFTR MIDNGT. FOR SIMPLICITY...HV RAISED GLW TNGT...AND CARRIED IT THRU SAT NGT. SCA LKLY ON SUN... WHICH CAN BE ADDRESSED LATER. SMALL CRAFT CONDITIONS LIKELY MUCH OF NEXT WEEK. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...WIND CHILL WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR MDZ501-502. VA...WIND CHILL WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR VAZ503-504. WV...WIND CHILL WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR WVZ501>506. MARINE...FREEZING SPRAY ADVISORY FROM 3 AM SATURDAY TO 6 AM EST SUNDAY FOR ANZ530>543. GALE WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR ANZ530>543. && $$ SYNOPSIS...HTS NEAR TERM...BJL/HTS SHORT TERM...HTS LONG TERM...LFR AVIATION...BJL/LFR/HTS MARINE...BJL/LFR/HTS

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