Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 230103 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 903 PM EDT WED APR 22 2015 .SYNOPSIS... A COLD FRONT WILL MOVE SOUTHEAST OF THE REGION TONIGHT FOLLOWED BY MUCH COOLER AIR OVERNIGHT INTO EARLY THURSDAY. FOR THURSDAY AND FRIDAY...THE COMBINATION OF A DEEP UPPER LOW IN THE NORTHEAST U.S. AND COOL HIGH PRESSURE JUST WEST OF THE MOUNTAINS WILL KEEP BREEZY...CHILLY CONDITIONS ACROSS THE REGION. BY THE WEEKEND...ANOTHER UPPER-LEVEL DISTURBANCE WILL BRING THE NEXT CHANCE OF SHOWERS TO THE REGION ALONG WITH CONTINUED COOL TEMPERATURES. && .NEAR TERM /THROUGH THURSDAY/... AS OF 845 PM EDT WEDNESDAY... COLD FRONT CONTINUES TO SAG SOUTH/SE THROUGH THE REGION AND SHOULD EXIT TO THE SOUTH AFTER MIDNIGHT. MOST LINGERING SHRA HAVE DRIED UP DESPITE STEEP LAPSES SEEN IN EVENING SOUNDINGS AS LOW LEVEL MOISTURE ABOUT NIL WITHIN THE DEEP WESTERLY MIXED ENVIRONMENT FROM THIS AFTERNOON. HOWEVER CANT TOTALLY RULE OUT A BAND OR TWO OF LIGHT SHOWERS FAR NW AS THE AXIS OF THE SHORTWAVE TROUGH PASSES AND ENHANCES UPSLOPE IN ASSOCIATION WITH THE LEADING EDGE OF THE DEEPER 85H COLD ADVECTION. OTRW MOST GUIDANCE SHOWING CONTINUED DRYING OVERNIGHT WITH HIGH PRESSURE GRADUALLY NOSING IN FROM THE WEST. THUS BASICALLY RUNNING WITHOUT ANY ADDED POPS FOR NOW WITH SKIES BECOMING MOSTLY CLEAR OUTSIDE OF THE UPSLOPE FAR NW WHERE SOME LOW CLOUDS MAY LINGER. WINDS HAVE DROPPED WELL BELOW ADVISORY LEVELS AS EARLIER DEEP MIXING HAS WEAKENED WITH LOSS OF HEATING. STILL APPEARS MAY GET A REBOUND IN SPEEDS LATE ONCE THE DEEPER COLD AIR ARRIVES SO KEEPING SOME HIGHER GUSTS AROUND ESPCLY WESTERN RIDGES THROUGH DAYBREAK. COLD AIR WILL DRIVE TEMPS DOWN CLOSE TO OR PERHAPS SLIGHTLY BELOW FREEZING ACROSS THE HIGHEST ELEVATIONS OF SE WEST VA/VA HIGHLANDS AS WELL AS A FEW DEEPER VALLEYS ELSEWHERE ACROSS THE WEST. HOWEVER SINCE SPOTTY AND COLDEST ON THE PEAKS WITH SOME WIND PERSISTING...WONT HOIST ANY HEADLINES FOR A POSSIBLE BRIEF FREEZE. DID INCLUDE MORE 30S MOUNTAINS AND OVERALL 38-45 OUT EAST WHERE BREEZES SHOULD BE LIGHTER BUT OVERALL TOO WARM/DRY FOR FROST. UPDATE AS OF 700 PM EDT WEDNESDAY... QUICK UPDATE TO LET THE GOING WIND ADVISORY EXPIRE GIVEN SOME DROP OFF IN GUSTS DURING THE PAST HOUR. SHOULD ALSO SEE DEEP MIXING FADE WITH LOSS OF HEATING AS WELL WITH MOST GUIDANCE SHOWING A QUICK REDUCTION IN FORECAST SURFACE WINDS AFTER SUNSET. HOWEVER SECONDARY SURGE MAY COME VERY LATE TONIGHT AS THE COLDER AIR AT 85H ARRIVES BUT APPEARS THESE SPEEDS WILL STAY BELOW ADVISORY LEVELS. ALSO LOWERED POPS ACROSS THE REGION WITH LITTLE COVERAGE CURRENTLY ALONG THE FRONT NEARING THE BLUE RIDGE AND ONLY FAINT INSTABILITY WITHIN A DRY AIRMASS TO HELP DRIVE ANY CONVECTION BEFORE LOSS OF INSOLATION. APPEARS SHOULD BE ABLE TO GO WITHOUT ANY POPS SHORTLY AFTER DARK IF TRENDS CONTINUE. FEW OTHER CHANGES FOR NOW. PREVIOUS DISCUSSION AS OF 230 PM EDT WEDNESDAY... A COLD FRONT WILL TRACK ACROSS THE REGION THIS EVENING. WINDY CONDITIONS AHEAD OF THE FRONT WILL CONTINUE TO BRING WARM AIR INTO THE REGION. HOWEVER...THIS WARM AIR IS HAVING TROUBLE WITH MOISTURE WITH SURFACE DEW POINTS REMAINING IN THE 30S THIS AFTERNOON ACROSS THE MAJORITY OF THE AREA. AS SHOWERS ADVANCE EAST INTO THE REGION...DEW POINTS ARE COMING UP INTO THE 40S...BUT ALSO COOLING TEMPERATURES. WITH ALL THIS IN MIND...STORMS ARE LOOKING ANEMIC AND SEVERE THREAT IS LOW. AREAS SOUTH OF HWY 460...ESPECIALLY EAST OF THE BLUE RIDGE...HAS WARMED INTO THE LOWER TO MID 70S THIS AFTERNOON. EVEN THOUGH DEW POINTS ARE STILL LOW...IF THE WIND COULD RELAX...SOUTHSIDE MAY SEE SOME STRONG STORMS...POSSIBLY ISOLATED SEVERE LATE IN THE DAY. THE COLD FRONT MOVES OVER THE COASTAL PIEDMONT THIS EVENING WITH COOLER DRIER AIR TO FOLLOW. TEMPERATURES DROP INTO THE 30S ACROSS THE MOUNTAINS WITH SOME DEEPER MOUNTAINS VALLEYS INTO THE LOWER 30S. A PUBLIC INFORMATION STATEMENT WAS ISSUED THIS AFTERNOON TO START THE GROWING SEASON FOR NWS BLACKSBURG COUNTY WARNING AREA. IF FROST OR A HARD FREEZE IS EXPECTED...FROST ADVISORIES OR FREEZE WARNINGS WILL BE ISSUED. SINCE A PRESSURE GRADIENT WILL REMAIN OVER THE AREA TONIGHT...CONTINUED BREEZY AND GUSTY CONDITIONS WILL DETER FROST FROM FORMING...THEREFORE NO HEADLINES WILL BE ISSUED WITH THIS FORECAST PACKAGE. ANOTHER SHORT WAVE PASSES OVER THE AREA THURSDAY. WITH DRY CONDITIONS...THE WINDS WILL ONCE AGAIN BECOME BREEZY AND GUSTY TOMORROW BUT NOT AS STRONG AS TODAY. TEMPERATURES THURSDAY AFTERNOON WILL RUN 5F-10F COLDER THAN NORMAL. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... AS OF 300 PM EDT WEDNESDAY... IT WILL BE A COLD THURSDAY NIGHT WITH OVERNIGHT LOW TEMPERATURES RANGING FROM THE UPPER 20S IN THE NORTHWEST MOUNTAINS TO THE MID 30S IN THE PIEDMONT. NORTHWEST WINDS WILL REMAIN QUITE GUSTY ESPECIALLY ACROSS THE HIGHER TERRAIN. WILL INCLUDE THE MENTION OF PATCHY FROST ACROSS THE NORTHWEST PORTION OF FORECAST AREA WHERE TEMPERATURES ARE THE COLDEST. IF WINDS RELAX ENOUGH IN THE PIEDMONT AND TEMPERATURES DROP TO LOWER MOS VALUES...ISOLATED FROST MAY BE POSSIBLE OUT EAST. BECAUSE OF AREAL COVERAGE WILL HOLD OFF ON ANY FROST ADVISORIES AT THIS TIME AND MENTION THE POTENTIAL IN THE HWO. HIGH PRESSURE WILL TRAVEL SOUTHEAST ACROSS THE APPALACHIANS FRIDAY. WITH THE UPPER LOW SHIFTING OVER THE CANADIAN MARITIMES AND WEAK UPPER LEVEL RIDGING APPROACHING FROM THE MISSISSIPPI VALLEY...HIGH TEMPERATURES FRIDAY AFTERNOON WITH INCREASING HIGH CLOUDS WILL VARY FROM AROUND 50 DEGREES IN THE NORTHWEST TO THE MID 60S IN THE PIEDMONT. BY LATE FRIDAY NIGHT...WIND SHIFT EASTERLY...DRAWING COOLER AIR AND MOISTURE OFF THE ATLANTIC OCEAN. LOW TEMPERATURES FRIDAY NIGHT WILL GENERALLY BE IN THE MID 30S IN THE MOUNTAINS TO THE MID 40S IN THE PIEDMONT. DECREASED POPS AND SLOWED THE ARRIVAL OF THE ISOLATED TO SCATTERED SHOWERS IN THE WEST FRIDAY NIGHT...WITH A SLOWER TIMING OF LOW PRESSURE SYSTEM ADVANCING EAST ACROSS THE CENTRAL PLAINS. RAIN WILL OVERSPREAD OUR AREA BY SATURDAY AFTERNOON OR EARLY EVENING. THE TIMING OF THE RAIN IS A LITTLE FASTER ON GFS COMPARED TO ECMWF. WITH FLOW OFF THE ATLANTIC AND WIDESPREAD CLOUD COVER AND RAIN...HELD ON TO HIGH TEMPERATURES COOLER THAN MOS HOLDING IN THE 50S AREAWIDE. COOL TEMPERATURES AND STABILITY OFFERED BY THE HIGH TO OUR EAST LIMITS THE POTENTIAL FOR THUNDERSTORMS. PTYPE BECOMES SHOWERS LATE SATURDAY NIGHT AS THE LOW PRESSURE SYSTEM PASSES EAST OF THE APPALACHIANS...MOVING OFFSHORE ON SUNDAY. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 300 PM EDT WEDNESDAY... THE NORTH-ATLANTIC OSCILLATION IS PROGGED TO BE IN A NEGATIVE PHASE ...WHICH TRANSLATES TO BELOW-NORMAL HEIGHTS OVER THE EAST. A WAVY BACK DOOR COLD FRONT WILL REMAIN ACROSS THE REGION SUNDAY...BRINGING COOLER AIR INTO THE AREA FOR THE AFTERNOON INTO MONDAY. A STRONGER SURFACE WAVE OF LOW PRESSURE TRACKS ACROSS THE TENNESSEE VALLEY TO THE CAROLINA TUESDAY INTO WEDNESDAY. THIS WAVE WILL HAVE MORE MOISTURE AND DYNAMICS TO BRING SOME HEAVY RAIN AND STRONG STORMS TO THE REGION. TEMPERATURES THROUGH THE PERIOD WILL REMAIN COOLER THAN NORMAL WITH READINGS MAINLY FROM THE UPPER 50S TO THE LOWER 60S ACROSS THE MOUNTAINS TO THE MID TO UPPER 60S IN THE EAST. && .AVIATION /01Z THURSDAY THROUGH MONDAY/... AS OF 710 PM EDT WEDNESDAY... COLD FRONT NOW ALONG THE BLUE RIDGE WILL SLIDE SOUTHEAST AND AWAY FROM THE AREA OVERNIGHT. CONTINUED DRY ADVECTION BEHIND THE FRONT WILL MAKE FOR OVERALL VFR CONDITIONS OVERNIGHT THROUGH THURSDAY. HOWEVER THE LINGERING PRESSURE GRADIENT COMBINED WITH COOL ADVECTION WILL ACT TO KEEP WEST/NW WINDS GUSTY AT TIMES OVERNIGHT WITH THEN ANOTHER SURGE BY THURSDAY AFTERNOON UNDER CHANNELED ENERGY ALOFT UNDER THE BROAD UPPER TROUGH. SPEEDS SHOULD BE SOMEWHAT LESS THAN THOSE SEEN WEDNESDAY BUT STILL SOME GUSTS TOPPING 30-35 KTS MOUNTAINS...AND 25 KTS OUT EAST THURSDAY AFTERNOON. SURFACE HIGH WILL BUILD A BIT CLOSER THURSDAY NIGHT AND ABOUT OVERHEAD ON FRIDAY ALLOWING FOR LIGHTER WINDS AND CONTINUED VFR CONDITIONS. EXTENDED AVIATION DISCUSSION... OVERRUNNING CLOUDS WORK INTO THE AREA FRIDAY AHEAD OF A WARM FRONT FRIDAY NIGHT. BY SATURDAY...MOISTURE APPEARS ENOUGH TO ALLOW FOR PERIODS OF RAIN AND MVFR WITH BEST FORCING ACROSS THE CAROLINAS. COMPLEX LOW PRESSURE TO THE WEST WILL THEN PUSH THROUGH THE REGION SATURDAY NIGHT INTO SUNDAY BEFORE EXITING OFFSHORE SUNDAY NIGHT. THIS WILL LIKELY KEEP SUB-VFR CONDITIONS IN LOW CLOUDS AND LINGERING RAINFALL INTO SUNDAY NIGHT. FLYING CONDITIONS SHOULD START TO IMPROVE SOME BY MONDAY AS THE LOW PULLS FARTHER OFFSHORE AND WEAK HIGH PRESSURE BUILDS IN FROM THE NW. HOWEVER CONTINUED CYCLONIC FLOW LIKELY TO KEEP MORE MVFR CIGS OVER THE MOUNTAINS WITH IMPROVEMENT TO VFR ACROSS THE EAST ON MONDAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/RAB NEAR TERM...JH/RCS SHORT TERM...KK LONG TERM...KK AVIATION...JH/RCS

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