Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 251906 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 206 PM EST WED FEB 25 2015 .SYNOPSIS... WEAK HIGH PRESSURE OVER THE REGION TODAY WILL GIVE WAY TO AN AREA OF LOW PRESSURE TONIGHT THAT WILL TRACK FROM THE GULF COAST TO OFF THE OUTER BANKS BY EARLY THURSDAY. THIS SYSTEM WILL BRING ANOTHER ROUND OF SNOWFALL FOR MUCH OF THE REGION...WITH THE HIGHEST AMOUNTS EXPECTED OVER THE SOUTHERN COUNTIES INTO NORTH CAROLINA. HIGH PRESSURE WITH MORE COLD AIR WILL FOLLOW BEHIND THIS SYSTEM FOR LATE IN THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 200 PM EST WEDNESDAY... FOR THE REMAINDER OF THE AFTERNOON...THE BIGGEST ADJUSTMENT TO THE FORECAST HAS BEEN MILDER TEMPERATURES ACROSS MAINLY EASTERN PARTS OF THE AREA. HAVE ADJUSTED UPWARD MOST HIGH TEMPERATURES BY 2 OR 3 DEGREES. HAVE ALSO MADE ADJUSTMENTS TO THE WINTER HEADLINES FOR TONIGHT AND TOMORROW. BUCKINGHAM...APPOMATTOX...AND CAMPBELL COUNTIES HAVE BEEN ADDED TO THE WINTER STORM WARNING THAT EXPIRES AT 1PM THURSDAY. BATH...ALLEGHANY VA...AND MONROE WV COUNTIES HAVE BEEN ADDED TO THE WINTER WEATHER ADVISORY THAT EXPIRES AT 9AM THURSDAY. A MINOR INCREASE IN THE FORECAST SNOW TOTALS FOR ALL LOCATIONS GENERATED ENOUGH TOTAL SNOWFALL TO WARRANT THESE ADJUSTMENTS TO THE HEADLINES. AS OF 950 AM EST WEDNESDAY... LIMITED ADJUSTMENTS HAVE BEEN MADE TO THE FORECAST THROUGH THE EARLY AFTERNOON HOURS. WE ARE STILL EXPECTING A GRADUAL INCREASE IN CLOUD COVER FROM SOUTHWEST TO NORTHEAST IN ADVANCE OF THE APPROACHING WEATHER SYSTEM. SOME ADJUSTMENTS HAVE BEEN MADE FOR LATE THIS AFTERNOON AND THE EARLY EVENING REGARDING THE TIMING OF RAIN/SNOW INTO THE REGION. HAVE SLOWED THE PROGRESSION OF SNOW INTO THE REGION BY ABOUT TWO HOURS...BUT THE OVERALL GENERAL PATTERN WILL REMAIN THE SAME. A VERY RAPID SPREAD ACROSS THE AREA IS EXPECTED AFTER ONSET THROUGH THE VERY EARLY MORNING HOURS OF THURSDAY. THIS SLOWER TIMING WILL NOT IMPACT SNOW TOTALS A WHOLE LOT. MAYBE AREAS NEAR THE NC/VA BORDER WILL AVERAGE AROUND AN INCH LESS SNOWFALL TONIGHT BECAUSE OF THE TIMING AND BECAUSE OF A BIT MORE RAIN INITIALLY OVER PARTS OF NORTH CENTRAL NORTH CAROLINA. AS OF 230 AM EST WEDNESDAY... UPPER LOW COMING OUT OF THE SW WILL QUICKLY LEAD TO SURFACE LOW PRESSURE DEVELOPMENT ALONG THE GULF COAST BY THIS AFTERNOON WITH THIS SYSTEM ROCKETING NE TO SOUTH OF ILM AFTER MIDNIGHT AND OFF THE OUTER BANKS EARLY THURSDAY. AHEAD OF THIS SYSTEM...WILL SEE A PERIOD OF WEAK SUBSIDENCE AS SURFACE HIGH PRESSURE SLIDES OVERHEAD TODAY AND OFFSHORE THIS EVENING. THIS SHOULD ALLOW FOR A BRIEF WINDOW OF WARM ADVECTION THIS AFTERNOON WITH SOME INITIAL COLD ADVECTION LOW CLOUDS WESTERN MOUNTAINS TO INIT...AND THEN A STEADY INCREASE IN MID/HIGH CLOUDS FROM THE SW LATER IN THE DAY. THUS EXPECTING MORE SUNSHINE EARLY WITH INCREASING CLOUDS THIS AFTERNOON BUT STILL DRY. GRADUAL INCREASE IN WEAK RETURN FLOW SHOULD GIVE DEWPOINTS AND TEMPS A SLIGHT UPWARD BOOST AHEAD OF THE STORM SYSTEM TO THE SW. THEREFORE BOUNCED HIGHS A BIT FARTHER INTO THE LOW/MID 40S SOUTH-EAST WHILE KEEPING MOST OF THE WEST IN THE 30S. CONCERN TONIGHT AGAIN TURNS TO SNOWFALL AND EXACTLY HOW FAR NORTH THE DEEPER MOISTURE SHIELD TO THE NW OF THE SURFACE LOW MAKES IT BEFORE ZIPPING OFFSHORE AROUND DAYBREAK THURSDAY. MODELS REMAIN CONSISTENT IN EXPANDING SOME ISENTROPIC LIFT QPF NORTH TO AROUND THE VA/NC BORDER THIS EVENING AS THE SURFACE LOW TURNS THE BEND ACROSS THE SE STATES BEFORE LIFTING IT NORTHWARD IN CONJUNCTION WITH THE DEFORMATION ZONE...AND UNDER THE DAMPENING 5H VORT THAT LOOKS TO PASS OVERHEAD LATE. THIS BRINGS A PERIOD OF STRONGER UPPER DIFFLUENCE OVERTOP WEAK SOUTHEAST FLOW TO MOST OF THE AREA AROUND MIDNIGHT...FOLLOWED BY AN EAST-WEST AXIS OF LIFT BACK TO ALONG THE BLUE RIDGE-SE OVERNIGHT AS ATLANTIC MOISTURE LINKS IN. MAY SEE PRECIP BEGIN AS RAIN SE GIVEN THE WARMER AFTERNOON BEFORE QUICKLY COOLING BACK AS RATES INCREASE THIS EVENING. QUESTIONS REMAIN WITH POSSIBLE ROBBERY OF MOISTURE TO THE SOUTH VIA CONVECTION NEAR THE COAST AND SPEED OF MOVEMENT THAT MAY LIMIT TOTALS SIMILAR TO THE LATEST FAST GFS. FOR NOW BASED ON TRENDS OF PAST EVENTS BEING FARTHER NORTH...LEANED A BIT MORE TOWARD THE LATEST EURO/NAM BUT A BIT LESS ON QPF THAN THE SREF GIVEN SOME DOWNWARD/EASTWARD TRENDS IN GUIDANCE FROM 00Z. THIS GIVEN SLIGHTLY HIGHER RATIOS WOULD PUT THE HEAVIEST SNOWFALL INITIALLY ACROSS THE NW NC MOUNTAINS WHERE AIDED BY WEAK UPSLOPE...THEN IN A SWATH ALONG THE VA/NC BORDER NEAR THE HIGHER QPF TOTALS OFF MOST GUIDANCE. STILL LOTS OF QUESTIONS IN HOW FAR NORTH/WEST TO GO WITH WARNING CRITERIA BUT DID UPGRADE THE REST OF THE COUNTIES IN THE WATCH TO A WARNING FOR 3-6 INCHES EXCLUDING THE MOUNTAIN EMPIRE REGION WHERE MAY BE CUTOFF A BIT FROM BETTER INFLOW UNDER THE EASTERLY COMPONENT. DID INCLUDE AN ADVISORY FOR THAT REGION AND POINTS EAST ALONG THE ROUTE 460 CORRIDOR FOR 1-4 INCHES WITH HIGHEST SOUTHERN SECTIONS AND LOWEST UP NORTH. THIS WILL ALLOW FOR ADDED UPGRADES IF NEEDED DURING THE DAY PENDING LATER RUNS. SOME LIGHT SNOW LIKELY TO THE NW IN THE VIRGINIA HIGHLANDS AND SE WEST VA BUT THINKING AN INCH OR TWO AND BELOW CRITERIA BUT PERHAPS AN IMPACT ISSUE IN THE MORNING SO INCLUDED MENTION IN THE HWO. OTRW WENT FASTER WITH POPS ARRIVING IN THE SW EARLY ON GIVEN THE FAST FLOW ALOFT...AND THEN QUICKLY INCREASING TO CAT/LIKELY COVERAGE OVERNIGHT. OVERALL LOW TEMPS MAINLY IN THE 20S MAKING FOR A BIT WETTER SNOW THIS TIME AROUND. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM EST WEDNESDAY... LOW PRESSURE OFF THE NORTH CAROLINA COAST THURSDAY MORNING WILL LIFT NORTHEAST THURSDAY AFTERNOON INTO THURSDAY NIGHT. AN UPPER VORT COMBINED WITH THE DEFORMATION ZONE WILL CONTINUE SNOWS THURSDAY MORNING ASSOCIATED WITH THE COASTAL LOW PRESSURE. 500MB TROF WILL SLIDE EAST THURSDAY INTO FRIDAY. SEVERAL SHORTWAVES WILL ROTATE AROUND THE UPPER TROF. MEANWHILE...A 1040 MB HIGH PRESSURE CENTER WILL BUILD SOUTHEAST OUT OF THE MIDWEST. UPSLOPE SNOW SHOWERS AND SNOW FLURRIES WILL DEVELOP ACROSS THE MOUNTAINS THURSDAY AFTERNOON INTO THURSDAY NIGHT. HIGH TEMPERATURES ON THURSDAY WILL RANGE FROM THE MID 20S IN THE MOUNTAINS TO THE MID 30S IN THE PIEDMONT. LOW TEMPERATURES THURSDAY NIGHT WILL BE COLD WITH READINGS FROM THE TEENS IN THE WEST TO THE LOWER 20S IN THE EAST. ON FRIDAY MORNING...A FEW SNOW SHOWERS MAY LINGER ACROSS SOUTHEAST WEST VIRGINIA INTO THE NORTH CAROLINA HIGHLANDS AS ANOTHER SHOT OF ARCTIC HIGH PRESSURE BUILDS EAST FROM THE MIDWEST...PUSHING TOWARD THE APPALACHIANS. WINDS WILL GRADUALLY SHIFT TO NORTHEAST AND INCREASE THE FETCH OF COLD AIR FROM THE NORTH INTO OUR AREA. HIGH TEMPERATURES FRIDAY AFTERNOON WILL VARY FROM THE UPPER TEENS IN THE NORTHWEST MOUNTAINS TO THE LOW TO MID 30S IN THE PIEDMONT. HIGH PRESSURE WILL BUILD EAST ACROSS PENNSYLVANIA FRIDAY EVENING INTO FRIDAY NIGHT. IT WILL BE VERY COLD FRIDAY NIGHT WITH STRONG RADIATIONAL COOLING ASSOCIATED WITH MOSTLY CLEAR SKIES AND LIGHT WINDS. LOW TEMPERATURES FRIDAY NIGHT WILL RANGE FROM NEAR ZERO ACROSS SOUTHEAST WEST VIRGINIA...TO THE UPPER TEENS ACROSS THE SOUTHSIDE. WIND CHILLS WILL BE BELOW ZERO IN NORTHWEST GREENBRIER VALLEY OF WEST VIRGINIA AND ALLEGHENY HIGHLANDS OF VIRGINIA. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 355 PM EST TUESDAY... FOR SATURDAY...HIGH PRESSURE WEDGED AGAINST THE EASTERN FACE OF THE APPALACHIANS WILL MAINTAIN CHILLY TEMPERATURES AREAWIDE...WITH AFTERNOON HIGHS RANGING FROM THE UPPER 20S NORTH TO THE MID 30S SOUTH. CLOUD COVER WILL INCREASE DURING THE EVENING HOWEVER...AS OUR NEXT UPPER LEVEL DISTURBANCE APPROACHES FROM THE WEST...SO EXPECT SATURDAY NIGHT LOWS TO HOLD IN THE TEENS AND LOW 20S. THE CHANCE FOR SNOW WILL INCREASE TOWARD DAWN SUNDAY AS A WEAK LOW PRESSURE SYSTEM PASSES UP THE ATLANTIC COAST...POTENTIALLY SPREADING PRECIPITATION AS FAR WEST AS THE NEW RIVER VALLEY. WITH COLD HIGH PRESSURE STILL IN PLACE ACROSS THE MID ATLANTIC...BELIEVE THE WEATHER MODELS ARE CALLING FOR TEMPERATURES THAT ARE FAR TOO WARM... AND THEREFORE WENT WITH HIGHS THAT ARE SEVERAL DEGREES COOLER. AS SUCH...DO NOT HAVE MUCH CONFIDENCE IN WHAT TYPE OF PRECIPITATION TO EXPECT...IF ANY. WILL JUST CONTINUE TO WATCH THE EVOLUTION OF THIS SYSTEM OVER THE NEXT DAY OR TWO. WITH THE PASSAGE OF THE COASTAL LOW PRESSURE SYSTEM...WINDS ACROSS OUR AREA WILL SHIFT WESTERLY AND DOWNSLOPE...WHICH WILL ALLOW FOR WARMER TEMPERATURES ON MONDAY. EARLY INDICATIONS ARE THAT HIGH TEMPERATURES NEXT MONDAY WILL BE THE WARMEST IN OVER A WEEK...WITH AFTERNOON TEMPERATURES RANGING FROM THE UPPER 40S ACROSS THE MOUNTAINS...TO THE MID 50S ACROSS THE SOUTHSIDE. RAIN CHANCES WILL INCREASE DURING THE AFTERNOON AS ANOTHER COLD FRONT APPROACHES FROM THE WEST. && .AVIATION /19Z WEDNESDAY THROUGH MONDAY/... AS OF 1240 PM EST WEDNESDAY... VFR CONDITIONS WILL CONTINUE TO PREVAIL ACROSS THE REGION THE REMAINDER OF THE AFTERNOON. STARTING AROUND 00Z/7PM...MVFR CIGS AND VSBYS ASSOCIATED WITH A BROAD AREA OF SNOW WILL OVERSPREAD THE AREA. ANTICIPATE FLIGHT CATEGORIES CONTINUE FALLING INTO THE LIFR/IFR LEVELS BY 06Z/1AM ACROSS MOST OF THE REGION. CONDITIONS SLOWLY IMPROVE AFTER SUNRISE THURSDAY SO THAT MOST LOCATION WILL HAVE IMPROVED TO MVFR CIGS AND VFR VSBYS BY 18Z. MVFR CIGS WILL PERSIST ALONG THE WESTERN SLOPES ESPCLY AROUND KBLF A WHILE LONGER BEFORE ALL LOCATIONS BECOME VFR UNDER INCREASING MID/HIGH CLOUDS BY THIS AFTERNOON. GUSTY WEST WINDS SHOULD ALSO WEAKEN AND BACK TO SW BEFORE BECOMING LIGHT/VARIABLE LATER IN THE DAY. YET ANOTHER CLIPPER MAY CROSS THE AREA THURSDAY NIGHT INTO FRIDAY RETURNING THE WESTERN AREAS TO MVFR IN SPOTTY SNOW SHOWERS. COLD HIGH PRESSURE BUILDS IN BEHIND THIS SYSTEM FRIDAY NIGHT INTO SATURDAY WITH A RETURN TO VFR EXPECTED ACROSS THE REGION. DEVELOPING LOW PRESSURE OVER THE SOUTHERN PLAINS BY SUNDAY MAY COMBINE WITH A WARM FRONT OVER THE OHIO VALLEY TO SPILL SOME MVFR CIGS INTO THE AREA INCLUDING SOME SPOTTY RAIN INTO THE MOUNTAIN BY SUNDAY AFTERNOON INTO MONDAY. OTHERWISE VFR EAST OF THE MOUNTAINS WHERE THE RESIDUAL WEDGE OF HIGH PRESSURE WILL REMAIN. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST THURSDAY FOR VAZ007-009>014-018>020-022>024. WINTER STORM WARNING FROM 7 PM THIS EVENING TO 9 AM EST THURSDAY FOR VAZ015>017-032. WINTER STORM WARNING FROM 7 PM THIS EVENING TO 1 PM EST THURSDAY FOR VAZ033-043>047-058-059. WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 PM EST THURSDAY FOR VAZ034-035. NC...WINTER STORM WARNING FROM 7 PM THIS EVENING TO 9 AM EST THURSDAY FOR NCZ001>004-018>020. WINTER STORM WARNING FROM 7 PM THIS EVENING TO 1 PM EST THURSDAY FOR NCZ005-006. WV...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 9 AM EST THURSDAY FOR WVZ044. && $$ SYNOPSIS...JH/PC NEAR TERM...DS/JH SHORT TERM...KK LONG TERM...NF AVIATION...DS/JH/KK/WP

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