Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 140924 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 424 AM EST SUN FEB 14 2016 .SYNOPSIS... COLD HIGH PRESSURE MOVES EAST AND OFF THE MID ATLANTIC COAST BY TONIGHT. A WARM FRONTAL BOUNDARY WORKS TOWARD THE TENNESSEE VALLEY BY THIS EVENING WITH SNOW MOVING INTO THE MOUNTAINS. BY MONDAY...LOW PRESSURE WORKS FROM THE LOWER MISSISSIPPI VALLEY TO THE SOUTHERN APPALACHIANS. WITH COLD AIR IN PLACE EXPECT SNOW CHANGING TO A WINTRY MIX MONDAY INTO MONDAY NIGHT. THIS SYSTEM MOVES EAST BY TUESDAY AFTERNOON. && .NEAR TERM /THROUGH TONIGHT/... AS OF 400 AM EST SUNDAY... WIND CHILL ADVISORY CANCELLED EARLY AS WINDS HAVE DROPPED FOR MOST OF THE AREA TO BELOW 5 MPH. ONLY AREAS WITH NEAR WIND CHILL ADVISORY LEVELS ARE ELEVATIONS ABOVE 3500 FT LIKE HOT SPRINGS...SO MAJORITY OF THE AREA WILL STAY WARMER...THAN -5F THROUGH THE MORNING. NOW OUR EYES FOCUS ON THE WINTER STORM THREAT TAKING SHAPE OVER THE MIDDLE PART OF THE COUNTRY EARLY THIS MORNING. MODELS SHOW DECENT AGREEMENT IN BRINGING LIGHT SNOW TOWARD THE MOUNTAIN EMPIRE OF SW VA INTO NW NC BY LATE AFTERNOON...THEN SHIFTING IN BANDS EAST ACROSS THE NEW RIVER VALLEY INTO THE PIEDMONT. AIRMASS WILL STAY VERY COLD WITH THERMAL PROFILE STAYING BELOW ZERO THROUGH 12Z MONDAY. HENCE WILL SEE SNOW THROUGH TONIGHT. QUESTION REMAINS ON HOW ANY MESOSCALE BANDS WILL LINE UP. MODELS FAVOR A MTN EMPIRE TO ALLEGHANY HIGHLAND CORRIDOR FOR HEAVIER SNOW BAND POTENTIAL BY MIDNIGHT TONIGHT. SMALLER BAND SHOULD SLIDE EAST TO THE PIEDMONT THROUGH THE NIGHT. THIS ARCTIC AIRMASS IN PLACE SHOULD START THE SNOW TO LIQUID RATIOS PRETTY HIGH IN THE 20:1 RANGE...DROPPING TOWARD 15:1 BY 12Z MONDAY. SNOWFALL TOTALS LATE THIS AFTERNOON THROUGH TONIGHT WILL RANGE FROM 6 TO 10 INCHES WEST OF THE BLUE RIDGE TO 2 TO 5 INCHES EAST. WE HAVE GONE WITH A WINTER STORM WARNING TO ACCOUNT FOR SNOW IN THE WEST...WITH MIX OF SNOW/SLEET AND FREEZING RAIN IN THE EAST. MORE DETAILS ON THE WINTRY MIX PART OF THE STORM WILL BE MENTIONED IN THE SHORT TERM DISCUSSION BELOW. LOOK FOR INCREASING CLOUDS TODAY WITH HIGHS IN THE LOWER TO MID 20S WEST TO UPPER 20S EAST. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 259 PM EST SATURDAY... MODELS SEEM TO BE COMING MORE IN LINE WITH A SIMILAR SCENARIO AS DEPICTED BY THE EARLIER EC IN THE LAST FEW DAYS AND SUPPORTED BY THE LATEST GFS/NAM WITH THE UPCOMING SYSTEM FOR EARLY NEXT WEEK. THIS WILL RESULT IN A NORTHERN STREAM SHORTWAVE DIVING SOUTHEAST TOWARD THE REGION SUNDAY NIGHT BEFORE STRONGER ADDED SOUTHERN STREAM ENERGY ROUNDS THE DEVELOPING MEAN TROF TO THE WEST MONDAY/MONDAY NIGHT. THIS SPELLS AN AXIS OF OVERRUNNING MOISTURE JETTING TO THE SOUTHEAST WITH THE INITIAL WAVE SUNDAY NIGHT ALLOWING A BAND OF SNOW TO DEVELOP OVER THE WEST BY EVENING BEFORE SPREADING EAST. HOWEVER QUESTIONS INITIALLY WITH LOW PWAT MOISTURE OVER TOP THE VERY DRY ARCTIC AIR AND HOW LONG IT MIGHT TAKE TO REACH THE SURFACE. NAM REMAINS THE FASTEST AND STRONGEST WITH A CSI TYPE BAND SETUP ALONG/NORTH OF ROUTE 460 OVER THE WEST WHILE THE GFS QUITE DRY AND THE EC IN BETWEEN. SINCE DEGREE OF LIFT RATHER IMPRESSIVE THINK PRECIP WILL BREAK THROUGH THE DRY AIR FASTER MOUNTAINS WITH EFFICIENT SNOWFALL POSSIBLE ONCE THINGS GET GOING. THIS SUPPORTED BY A GOOD SWATH OF 2-5 INCHES WEST OF THE BLUE RIDGE BY EARLY MONDAY OFF THE 12Z EURO WITH AN INCH OR TWO OUT EAST. THUS STEADILY INCREASING POPS OVERNIGHT REACHING CATEGORICAL AFTER MIDNIGHT MOST SECTIONS. TEMPS MOSTLY IN THE TEENS TO LOW 20S BUT LIKELY RISING SOME ESPCLY EAST LATE. UNCERTAINTY IN PTYPE/QPF REMAIN BIG ISSUES MOVING FORWARD MONDAY INTO MONDAY NIGHT AS THE BEST INITIAL LOBE OF LIFT SLIDES NORTH AND THE UPPER SYSTEM SHARPENS TO THE SW WITH THE MAIN SURFACE LOW. THIS WILL ALLOW THE 85H JET TO RAMP UP TO AROUND 50 KTS WITH VERY STRONG WARM ADVECTION ALOFT TAKING SHAPE OVER THE SHALLOW COLD AIR. THIS CREATES A STRONG WARM NOSE SITUATION DEVELOPING FROM SOUTH TO NORTH BY MONDAY AFTERNOON WITH GUIDANCE BASICALLY TAKING THE 0C LINE NORTH/WEST OF MOST OF THE CWA BY MONDAY NIGHT. ALTHOUGH APPEARS GUIDANCE MAY BE TOO FAST IN WARMING THINGS GIVEN THE COLD AIRMASS IN PLACE...LATEST ENSEMBLES QUITE SIMILAR WITH THE WARM NOSE. AHEAD OF THIS APPEARS STEADY SNOW MAY TAPER SOME AS DEPTH OF MOISTURE ALOFT BRIEFLY DECREASES WITH THE FIRST BAND OF LIFT AND BEST UVV REDEVELOPS TO THE SOUTH AND WEST. ONCE THE HEAVIER PRECIP PUSHES BACK IN LATER MONDAY...EXPECT MORE OF THE SLEET VARIETY WEST AND FREEZING RAIN EAST...BUT IFFY GIVEN THE POSSIBLE DEGREE OF BOUNDARY LAYER COLD AIR REMAINING GIVEN SNOW COVER AND INSITU NATURE OF A WEAK WEDGE OFF GUIDANCE. SURFACE LOW AND AXIS OF DEEP MOISTURE AHEAD OF THE UPPER TROF WILL SLIDE THROUGH THE REGION ALMOST IN FRONTAL FASHION MONDAY NIGHT WHEN THE HIGHER QPF APPEARS LIKELY. PROFILES SUGGEST A LOT OF THIS TO BE RAIN WITH MORE FREEZING RAIN NE SECTIONS AND POCKETS ALONG THE BLUE RIDGE INCLUDING DEEPER VALLEYS. THIS COULD CREATE QUITE A ICING ISSUE OVERNIGHT IF SURFACE TEMPS REMAIN TOO COLD. HOWEVER DOES APPEAR A GOOD AMOUNT OF ICE POSSIBLE BLUE RIDGE AND POINTS NORTH BEFORE WARMER AIR FINALLY WINS OUT TUESDAY MORNING WHEN THE MAJORITY OF THE PRECIP EXITS. TEMPS TO REMAIN TRICKY WITH VALUES TRYING TO RISE OUT OF THE 20S MONDAY BUT LIKELY TOUGH OVER THE WEST GIVEN SNOW PACK. TEMPS MONDAY NIGHT LOOK TO RISE A BIT MORE AS DEPTH OF THE WARM AIR INCREASES BUT WHAT SIDE OF FREEZING WILL THEY BE ON WHEN THE HEAVIER PRECIP CROSSES STILL IFFY. THUS GIVEN ALL OF THIS...POSTING A WINTER STORM WATCH FOR ALL OF THE AREA STARTING BY SUNDAY EVENING AND CONTINUING THROUGH MIDDAY TUESDAY. THIS INCLUDES SNOWFALL OF 4-8+ INCHES MOUNTAINS...3-6 ROA-LYH AND 2-5 SOUTHERN SECTIONS PENDING DEGREE OF SLEET. ALSO A TENTH OR TWO OF ICE MOUNTAINS TO A QUARTER INCH OR MORE BLUE RIDGE AND POINTS NE. SHOULD SEE A BRIEF PERIOD OF SUBSIDENCE TUESDAY AFTERNOON SIMILAR TO THE FASTER NAM WITH LEFTOVER POPS MAINLY WESTERN SLOPES AND LOW RAIN CHANCES OUT EAST. DO EXPECT SOME TEMP RECOVERY UNDER WARMING ALOFT SO PUSHED HIGHS TOWARD 40 WEST AND 45-50 EAST. ANOTHER CLIPPER AREA OF LOW PRESSURE WILL BE TRACKING IN ON THE HEELS OF THIS SYSTEM WITH THE SURFACE LOW NOW EXPECTED TO TRACK WELL NORTH OF THE AREA TUESDAY NIGHT WITH RAIN/SNOW SHOWER POPS MAINLY WEST UNDER THE PASSING COLD FRONT. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 1230 PM EST SATURDAY... NEXT CLIPPER WILL BE PASSING TO THE NORTH EARLY WEDNESDAY ALLOWING A TRAILING COLD FRONT TO CROSS THE REGION WITH ANOTHER WEAKER SHOT OF COLD ADVECTION AND DECENT NW FLOW UPSLOPE INTO WEDNESDAY NIGHT. HOWEVER COLD AIR IS MORE OF THE MODIFIED CANADIAN FLAVOR SO NOT LOOKING AT ANY BITTER COLD DESPITE GUSTY WINDS. MOST POPS CONFINED TO THE WESTERN THIRD WITH DOWNSLOPE DRYING OUT EAST WEDNESDAY INTO WEDNESDAY NIGHT. HIGHS STILL CHILLY BUT MOSTLY 30S TO LOW 40S WEST AND PERHAPS NEAR 50 PIEDMONT CHILLY HIGH PRESSURE BUILDS OVERHEAD AND TO THE NORTH EARLY THURSDAY RESULTING IN A COLD BUT DRY START WITH LOWS 20S TO A FEW TEENS VALLEYS. SHORTWAVE RIDGING BUILDS IN LATER THURSDAY AND LINGERS INTO FRIDAY BEFORE THE NEXT TROUGH AND ASSOCIATED COLD FRONT ARRIVE FOR DAY 7. WITH GRADUAL WARMING ALOFT ON THURSDAY SHOULD SEE TEMPS RETURN TO MORE SEASONAL LEVELS UNDER SUNSHINE BEFORE MUCH WARMER AIR SURGES IN FRIDAY INTO SATURDAY AHEAD OF THE FRONT. THIS SHOULD FINALLY PUSH HIGHS INTO THE 40S AND 50S UNDER INCREASING RETURN SW FLOW FRIDAY...AND POSSIBLY 50S TO NEAR 60 PIEDMONT SATURDAY DESPITE MORE CLOUDS AND PERHAPS A FEW MOUNTAIN RAIN SHOWERS. && .AVIATION /10Z SUNDAY THROUGH THURSDAY/... AS OF 1201 AM EST SUNDAY... VFR ANTICIPATED THROUGH LATE SUNDAY AFTERNOON WITH HIGH CLOUDS BECOMING MID DECK BY 12Z THEN LOW END VFR BY 18-22Z. WARM FRONT AND SNOW WILL MOVE INTO THE WESTERN AREAS BY 22Z...AND SHIFT EAST BY THE END OF THIS TAF PERIOD. LOOK FOR VSBYS/CIGS TO DROP TO MVFR AND LOWER ESPECIALLY WEST OF THE BLUE RIDGE BY 06Z. WINDS LIGHT OR FROM THE NW SWING TO THE EAST AND SOUTHEAST SUNDAY AFTERNOON...SOME GUSTS OVER BLF TO 20KTS AFTER 00Z MON. EXTENDED DISCUSSION... WINTER STORM IS EXPECTED TO IMPACT THE AREA WITH WINTRY PRECIPITATION INTO TUESDAY. CONFIDENCE IS HIGH THAT POOR FLYING CONDITIONS WILL EXIST FROM SUNDAY NIGHT THROUGH TUESDAY. THIS WINTER STORM WILL PRODUCE A VARIETY OF WINTRY PRECIPITATION...STARTING AS SNOW SUNDAY NIGHT...THEN TRANSITIONING TO SLEET AND FREEZING RAIN MONDAY. AFTER THE EARLY WEEK WINTER STORM...THERE IS ANOTHER CLIPPER SYSTEM THAT MAY IMPACT THE AREA FOR MID WEEK...POSSIBLY RESULTING IN THE CONTINUATION OF POOR FLYING CONDITIONS THROUGH WEDNESDAY. HIGH PRESSURE BUILDS IN THURSDAY WITH VFR RETURNING. && .CLIMATE... COLDEST AIR OF THE SEASON HAS SETTLED OVER THE MID ATLANTIC REGION. SEVERAL RECORD LOW MAX TEMPERATURES AND LOW TEMPERATURES ARE POSSIBLE. BELOW ARE THE CURRENT RECORDS FOR SUNDAY 2/14. LOOKS LIKE BLF TIED A RECORD LOW FOR 2/13. SUNDAY 02/14/2016 SITE MINT YEAR LOMAX YEAR KBLF 5 1971 16 1960 KDAN 15 1986 32 1986 KLYH 4 1899 24 1905 KROA 10 1943 26 1986 KRNK -2 1969 24 1986 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO NOON EST TUESDAY FOR VAZ007-009>020-022>024-032>035-043>047-058- 059. NC...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO NOON EST TUESDAY FOR NCZ001>006-018>020. WV...WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO NOON EST TUESDAY FOR WVZ042>044-507-508. && $$ SYNOPSIS...JH/WP NEAR TERM...WP SHORT TERM...JH LONG TERM...JH AVIATION...PM/WP CLIMATE...CF

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