Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 140855 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 455 AM EDT MON APR 14 2014 .SYNOPSIS...
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LOW PRESSURE WAS OVER ILLINOIS WITH A COLD FRONT TRAILING FROM THE LOW INTO TEXAS. THIS FRONT WILL MOVE EAST TODAY AND TONIGHT AND WILL CROSS THE MID ATLANTIC REGION ON TUESDAY. BEHIND THE FRONT HIGH PRESSURE WILL BUILD IN FOR WEDNESDAY THROUGH FRIDAY.
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&& .NEAR TERM /THROUGH TONIGHT/...
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AS OF 415 AM EDT MONDAY... WATER VAPOR LOOP SHOWED A WELL DEFINED SHORT WAVE CROSSING THROUGH THE TENNESSE VALLEY. THICK CLOUD COVER WAS ALREADY SPREADING INTO THE COUNTY WARNING AREA FROM THE WEST. SHORT RANGE MODELS INCLUDING THE LATEST RUC/WRF AND HRRR BRING THE PRECIPITATION ASSOCIATED WITH THIS WAVE INTO THE WESTERN COUNTY WARNING AREA BETWEEN 15Z/11AM AND 18Z/2PM. WITH ALL THE CLOUD COVER DO NOT EXPECT MUCH INSTABILITY. BUFKIT OFF THE NAM AND GFS SHOWED LOW CAPE VALUES TODAY. HELD PROBABILITY OF THUNDER TO SLIGHT CHANCE. DO EXPECT ISOLATED TO SCATTERED SHOWERS AHEAD OF THE TENNESSEE VALLEY SHORT WAVE...WITH THE BETTER AREAL COVERAGE IN THE MOUNTAINS THROUGH NOON. HIGH TODAY WILL STILL BE ABOVE NORMAL BUT ONLY A SMALL RISE FROM THE CURRENT MILD TEMPERATURES. MUCH BETTER SYNOPTIC SCALE LIFT AFTER 00Z/8PM THIS EVENING. AS THE COLD FRONT APPROACHES LATE TONIGHT...SURFACE AND LOW LEVEL WINDS BACK...ADDING THE SOUTHEAST UPSLOPE COMPONENT TO THE STRONG FORCING. LARGEST PRECIPITATION AMOUNTS WILL BE AFTER MIDNIGHT. FRONT DOES NOT REACH THE FAR WESTERN PART OF THE FORECAST AREA BEFORE 12Z/8AM. STAYED CLOSER TO THE WARMER GUIDANCE FOR OVERNIGHT LOWS. THE LOW LEVEL JET INCREASES OVERNIGHT. HIGHER ELEVATIONS MAY HAVE GUSTS OF 25 TO 30 MPH.
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&& .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
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AS OF 400 AM EDT MONDAY... A STRONG COLD FRONT WILL MAKE ITS WAY ACROSS THE FORECAST AREA BEGINNING TUESDAY MORNING...AND THEREFORE WILL HAVE SEVERAL THINGS TO KEEP AN EYE. MODELS CONTINUE TO INDICATE A SOUTHWESTERLY 55KT LOW LEVEL JET DEVELOPING AHEAD OF THE FRONT. INSTABILITY AHEAD OF THE FRONT WILL BE MARGINAL...RESULTING IN MAINLY HEAVY SHOWER ACTIVITY WITH ONLY ISOLATED THUNDER AS THE FRONT PASSES. HOWEVER...WITH THE JET BLOWING JUST OFF THE SURFACE OVER THE MOUNTAINS...WOULD NOT BE SURPRISED TO SEE SOME OF THE MORE INTENSE SHOWER ACTIVITY DRAW THE STRONGER WINDS DOWN TO THE GROUND LEVEL. HIGH PRESSURE WILL BUILD IN QUICKLY AFTER THE COLD FRONT PASSES... RESULTING IN A ROUGHLY 10MB PRESSURE GRADIENT ACROSS THE FORECAST AREA FROM MID AFTERNOON THROUGH ALMOST MIDNIGHT. EXPECT STRONG NORTHWEST WINDS WITH 40 TO 50 MPH GUSTS ACROSS THE MOUNTAINS...WITH THE STRONGEST GUSTS FOUND ALONG THE BLUE RIDGE PARKWAY SOUTH OF ROANOKE. THESE GUSTS...WHEN COMBINED WITH PROLONGED RAINFALL...WILL LIKELY BE ENOUGH TO BRING DOWN A FEW TREES...AND RESULT IN LOCALIZED POWER OUTAGES. RAINFALL WILL BE WIDESPREAD AND HEAVY AT TIMES...WITH A STORM TOTAL AMOUNT OF OVER AN INCH FOR THE ENTIRE FORECAST AREA...WITH AROUND 2 INCHES EXPECTED ALONG THE BLUE RIDGE. MAY SEE LOCALIZED MINOR FLOODING ISSUES DEVELOP WHERE BANDS OF HEAVY RAIN PASS REPEATEDLY OVER THE SAME LOCATIONS. RAINFALL MAY ALSO PUSH SOME RIVERS TO BANKFULL OR MINOR FLOOD LATER IN THE WEEK. FOR THE FIRST FEW HOURS AFTER FRONTAL PASSAGE...TEMPERATURES WILL PLUMMET AT A RATE OF 6 TO 9 DEGREES PER HOUR. EXPECT TEMPERATURES TO APPROACH FREEZING FROM SOUTHEAST WEST VIRGINIA THROUGH THE NORTH CAROLINA MOUNTAINS BY EARLY EVENING...ALLOWING RAIN SHOWERS TO CHANGE OVER TO SNOW. WHILE WARM GROUND TEMPERATURES WILL CAUSE SNOW TO MELT ON CONTACT ACROSS MANY AREAS...MAY SEE UP TO A HALF INCH OF SNOW ACCUMULATE ALONG OUR MORE PROMINENT WEST FACING SLOPES BEFORE SNOW SHOWERS END OFF SHORTLY AFTER MIDNIGHT WEDNESDAY. NEXT WE GET TO DEAL WITH SUB FREEZING TEMPERATURES AREAWIDE BY SUNRISE WEDNESDAY. EXPECT OVERNIGHT LOWS TO RANGE FROM THE MID 20S ACROSS SOUTHEAST WEST VIRGINIA TO THE LOW 30S ACROSS THE SOUTHSIDE. PRECAUTIONS SHOULD BE TAKEN TO PROTECT ANY PLANTS THAT MAY BE KILLED BY FREEZING TEMPERATURES. HIGH PRESSURE WILL PASS FROM THE GREAT LAKES TO NEW ENGLAND ON WEDNESDAY...AND WILL BUILD SOUTHWARD ALONG THE EASTERN FACE OF THE APPALACHIANS. THE NORTHEASTERLY WIND FLOW AROUND THE HIGH WILL KEEP COOL CONDITIONS IN PLACE HEADING INTO THE SECOND HALF OF THE WORKWEEK...WITH FREEZING TEMPERATURES LIKELY AGAIN WEDNESDAY NIGHT. A GRADUAL WARM UP WILL TAKE PLACE THURSDAY AS WINDS ALOFT BEGIN TO SHIFT SOUTHWESTERLY AGAIN.
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&& .LONG TERM /FRIDAY THROUGH SUNDAY/...
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AS OF 200 PM EDT SATURDAY... EXPECT HIGH PRESSURE TO REMAIN IN CONTROL OF THE WEATHER PATTERN FOR FRIDAY. A COLD FRONT WILL APPROACH FROM THE WEST FRIDAY NIGHT INTO SATURDAY. GENERALLY FOLLOWED WPCGUIDE FOR POPS. STILL LOOKS LIKE THE BEST CHANCE FOR WIDESPREAD RAIN WILL OCCUR ON FRIDAY NIGHT INTO SATURDAY. LEANED TOWARDS THE ECENS MEAN WITH HANDLING THE SOUTHERN STREAM SYSTEM AND ITS MOISTURE. TEMPERATURES MODERATE TOWARD NEXT WEEKEND CLOSER TO NORMAL.
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&& .AVIATION /08Z MONDAY THROUGH FRIDAY/... AS OF 130 AM EDT MONDAY... CEILINGS WILL GRADUALLY LOWER THIS MORNING. MVFR CLOUDS WILL FORM ALONG THE BLUE RIDGE AND IN THE FOOTHILLS BEFORE 12Z. THERE IS A LOW POSSIBILITY THAT CEILINGS WILL EVEN DROP TO IFR AT KBCB BEFORE 12Z. MODELS BRING THE SHORT WAVE ENTERING THE TENNESSEE VALLEY ACROSS THE REGION MAINLY BETWEEN 15Z/11AM AND 21Z/5PM. WITH ALL THE CLOUD COVER DURING THE DAY...THERE WILL BE ONLY A LIMITED THREAT OF ANY THUNDER. MODERATE CONFIDENCE THAT VISIBILITIES WILL REMAIN VFR AND NOT LOWER AS THE SHOWERS MOVE THROUGH. THE STRONG COLD FRONT WILL ARRIVE IN THE MOUNTAINS BY 12Z/8AM TUESDAY. WILL HOLD OFF ADDING ANOTHER PERIOD OF RAINFALL IN UNTIL AFTER THE END OF THE 06Z TAFS. LOOKS WET TUESDAY THRU TUESDAY NIGHT. STRONG GUSTY NW WINDS ARE LIKELY BEHIND THE FRONT TUESDAY AFTERNOON AND NIGHT. DRIER AIR WORKS IN BEHIND THE SYSTEM FOR WEDNESDAY ALTHOUGH RESIDUAL MOISTURE AND COLD AIR ALOFT MAY ACT TO KEEP MVFR CIGS OVER THE MOUNTAINS ON TUESDAY NIGHT. VFR THEN EXPECTED THURSDAY WITH HIGH PRESSURE RIDGING IN FROM OFF NEW ENGLAND BETWEEN THE EXITING FRONT OFFSHORE AND THE NEXT COLD FRONT TO THE NW. NEXT COLD FRONT APPROACHES FROM THE WEST FRIDAY BUT APPEARS SLOW ENOUGH TO MAINTAIN VFR DURING THE DAY FOR NOW. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS SHORT TERM...NF LONG TERM...KK AVIATION...AMS/JH

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