Area Forecast Discussion
Issued by NWS Blacksburg, VA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KRNK 241948 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 348 PM EDT THU JUL 24 2014 .SYNOPSIS...
-- Changed Discussion --
A COLD FRONT WILL DROP SOUTHEAST OF THE AREA OVERNIGHT WITH HIGH PRESSURE BUILDING IN ON FRIDAY. A DEVELOPING TROUGH OVER THE MIDWEST WILL ALLOW SEVERAL UPPER DISTURBANCES TO POSSIBLY AFFECT THE AREA OVER THE WEEKEND FOLLOWED BY A STRONG COLD FRONT LATER MONDAY.
-- End Changed Discussion --
&& .NEAR TERM /THROUGH FRIDAY/...
-- Changed Discussion --
AS OF 330 PM EDT THURSDAY... SCATTERED TO NUMEROUS STORMS STILL ONGOING LATE THIS AFTERNOON FROM THE WV BORDER WELL OUT INTO THE PIEDMONT. ACTIVITY IS IN ASSOCIATION WITH A SLOW-MOVING COLD FRONT ANALYZED ACROSS THE NORTHERN SECTIONS OF THE CWA AND A SHORT-WAVE CROSSING THE MOUNTAINS. THE FRONT AND SHORT-WAVE ARE FORECAST TO MOVE EAST TONIGHT TAKING THE PRECIPITATION WITH IT. IN THE MEANTIME...A MODEST SEVERE WEATHER THREAT WILL CONTINUE FOR SEVERAL MORE HOURS ESPECIALLY EAST OF THE BLUE RIDGE WHERE WARMER AND MORE UNSTABLE AIR IS LOCATED ALONG AND AHEAD OF THE BOUNDARY. NICKEL SIZE HAIL REPORTS HAVE COME IN FROM SEVERAL OF THE STRONGER CELLS THIS AFTERNOON. IN ADDITION...PWATS 1.5 TO 1.8 INCHES IN THAT SAME AREA WILL ALLOW FOR POCKETS OF HEAVY RAINFALL WITH SOME LOCAL RUNOFF ISSUES POSSIBLE. SEVERAL CELLS HAVE ALREADY DROPPED 2 INCHES OF RAIN IN ABOUT ONE HOUR BUT MOST OF THE ACTIVITY CONTINUES TO TRACK TOWARD THE EAST AT 15 TO 20 MPH WHICH SHOULD PREVENT MORE SERIOUS WATER ISSUES. SKIES WILL BE SLOW TO CLEAR TONIGHT BUT DEPENDING ON HOW FAST THEY DO COULD SEE AREAS OF DENSE FOG TOWARD MORNING...ADDED PATCHY DENSE FOG TO GRIDS AFTER 06Z. FRIDAY LOOKS LIKE A DRY DAY WITH LOWER HUMIDITY AS DEWPOINTS DROP BACK INTO THE UPPER 50S NW AND L/M 60S FAR SE. HIGH TEMPS WILL BE FAIRLY CLOSE TO MID-JULY NORMALS..RANGING FROM UPPER 70S NW TO M/U 80S SE.
-- End Changed Discussion --
&& .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
-- Changed Discussion --
AS OF 330 PM EDT THURSDAY... MAINLY DRY AND SEASONAL WEATHER EXPECTED FRIDAY NIGHT INTO AT LEAST SATURDAY MORNING AS WEAK SURFACE HIGH PRESSURE LINGERS OVER AREA...THEN DRIFTS EAST AND OFFSHORE BY SATURDAY AFTERNOON. WEAK DISTURBANCE AND ASSOCIATED WARM MOIST ADVECTION IN NORTHERN STREAM FORECAST TO MOVE EAST THROUGH THE UPPER GREAT LAKES INTO NEW ENGLAND SATURDAY AFTERNOON INTO SATURDAY EVENING MAY BE CLOSE ENOUGH TO BLACKSBURG FORECAST AREA TO SUPPORT DEVELOPMENT OF WIDELY SCATTERED SHOWERS/THUNDERSTORMS MAINLY NORTH OF I64. HOWEVER... BETTER THREAT FOR EXPANDING AREA OF PRECIPITATION WILL LIKELY BEGIN TOWARD DAYBREAK SUNDAY CONTINUING INTO SUNDAY NIGHT AS MUCH MORE FORMIDABLE SHORT WAVE TROF IN ITS WAKE HELPS TO AMPLIFY WHAT WILL BECOME AN UNUSUALLY STRONG LONG WAVE TROF OVER THE UPPER GREAT LAKES BY/DURING THE LONG TERM PERIOD. STRONG WARM MOIST ADVECTION AND INCREASINGLY FAVORABLE JET DYNAMICS ASSOCIATED WITH THIS SECOND SHORT WAVE SHOULD SUPPORT THE DEVELOPMENT OF A MORE ORGANIZED CONVECTIVE EVENT...ESPECIALLY DURING THE TIME OF PEAK HEATING ON SUNDAY AFTERNOON INTO SUNDAY NIGHT. SOUTHWEST TO WESTERLY WINDS WOULD IMPLY MOST FAVORABLE AREA FOR SHOWERS/STORMS WOULD BE ACROSS THE WESTERN FLANKS OF THE APPALACHIANS...WITH A LOWER THREAT EAST OF THE BLUE RIDGE...MINIMIZED ACROSS SOUTHSIDE VA INTO NORTH CENTRAL NC DUE TO NEGATIVE INFLUENCE OF DOWNSLOPING...DISPLACEMENT FROM BETTER DYNAMICS...AND PREFRONTAL STORMS THAT MAY ARRIVE WELL AFTER TIME OF BEST HEATING ON SUNDAY. REGARDLESS...SOUTHWESTERLY WINDS IN ADVANCE OF THIS SYSTEM SHOULD HELP TO ADVECT SOME VERY WARM AIR BACK INTO THE REGION...WITH HIGHS OVER THE WEEKEND RANGING FROM THE 70S ACROSS THE HIGHEST ELEVATIONS...TO 90F OR A BIT ABOVE ACROSS MUCH OF THE PIEDMONT.
-- End Changed Discussion --
&& .LONG TERM /MONDAY THROUGH THURSDAY/...
-- Changed Discussion --
AS OF 330 PM EDT THURSDAY... LONG TERM PERIOD WILL BE CHARACTERIZED BY UNUSUALLY DEEP LONG WAVE TROF THAT WILL REMAIN CENTERED OVER THE UPPER GREAT LAKES THROUGHOUT MUCH OF NEXT WEEK AS SERIES OF SHORT WAVE TROFS HELP TO AMPLIFY THIS FEATURE. COLD FRONT EXPECTED TO MOVE INTO AND THROUGH THE MOUNTAINS MONDAY MORNING...LIKELY PRECEDED AND ACCOMPANIED BY SCATTERED SHOWERS/THUNDERSTORMS...POSSIBLY LINGERING INTO THE EVENING AS COOLER AIR ALOFT AND UPSLOPE INCREASES ACROSS THE WESTERN FLANKS OF THE APPALACHIANS. WITH EARLIER ARRIVAL OF FRONT...AND ASSOCIATED CLOUDS/THREAT OF PRECIPITATION...DAYTIME HIGHS MAY BE HARD PRESSED TO REACH THE 70S ACROSS SOME OF THE HIGHER ELEVATIONS...ESPECIALLY IN WESTERN GREENBRIER COUNTY WV. EAST OF THE BLUE RIDGE...FRONT NOT LIKELY TO CLEAR THE PIEDMONT COUNTIES UNTIL MID TO LATE AFTERNOON ON MONDAY. INCREASING SOUTHWEST TO WESTERLY WINDS AND ASSOCIATED COMPRESSIONAL HEATING...AND BETTER PREFRONTAL INSOLATION MAY HELP DRIVE TEMPERATURES WELL UP INTO THE 80S BEFORE LEVELING OFF WITH ARRIVAL OF SCATTERED FRONTAL CLOUDS/SHOWERS. MUCH OF THE REST OF THE LONG TERM FORECAST APPEARS TO WARRANT MOSTLY DRY AND COOL CONDITIONS AS SURFACE RIDGE OF HIGH PRESSURE NOSES INTO AND THEN OVER BLACKSBURG FORECAST AREA. MOST AREAS WILL REMAIN 5-10F BELOW NORMAL THROUGH THE PERIOD. MANY MOUNTAIN VALLEYS...ALONG WITH THE HIGHEST RIDGES WILL LIKELY EXPERIENCE AT LEAST A COUPLE OF NIGHTS WHERE TEMPERATURES FALL INTO THE 40S. APPROACH OF ANOTHER SHORT WAVE TROF RIDING AROUND THE BASE OF THE UPPER TROF MAY HELP BACK LOW LEVEL FLOW SUFFICIENTLY ON THURSDAY TO WARRANT A LOW CHANCE THREAT FOR SOME SHOWERS ACROSS THE SOUTHWESTERN MOUNTAIN ON THURSDAY...BUT PRECIPITATION AMOUNTS FROM THIS DISTURBANCE...IF ANY...APPEAR TO BE SCANT AT BEST.
-- End Changed Discussion --
&& .AVIATION /20Z THURSDAY THROUGH TUESDAY/... AS OF 135 PM EDT THURSDAY... FAIRLY WIDESPREAD CONVECTION AFFECTING ALL MOUNTAIN TAF SITES EARLY THIS AFTERNOON WITH VCTS OT TEMPO COVERAGE. CONVECTION MOVING EAST AT 10-15 MPH BUT CONDITIONS WILL BE HIGHLY VARIABLE OVER THE NEXT SEVERAL HOURS. SHOULD EXIT THE MOUNTAINS BY 22-23Z AND DAN/LYH BY 00-01Z. FOG LIKELY TO BE AN ISSUE AT MOST SITES OVERNIGHT DEPENDING ON LOCAL RAINFALL AND SPEED OF DRY AIR ARRIVAL. THINK LWB/BCB WILL HAVE DENSE FOG BEFORE SUNRISE FOR A FEW HOURS AND REDUCED VSBYS AT OTHER SITES POSSIBLE. EXTENDED AVIATION DISCUSSION... AIRMASS WILL DRY OUT BEHIND THE FRONT GOING INTO FRIDAY- SATURDAY. VFR FRI- SAT OUTSIDE OF ANY VALLEY FOG AT KLWB/KBCB EACH MORNING. ANOTHER FRONT AND ASSOCIATED UPPER IMPULSES COULD BRING A GOOD THREAT OF STORMS IN THE SUN-MON TIME FRAME. DURING THIS TIME MAINLY VFR...EXCEPT IN TSRA AND FOR ANY LATE NIGHT FOG. && .HYDROLOGY...
-- Changed Discussion --
U.S. DROUGHT MONITOR ISSUED THIS MORNING AND VALID THROUGH 12Z TUESDAY JULY 22 SHOWED EXPANSION OF THE EXISTING ABNORMALLY DRY CONDITIONS INTO MOST OF OUR SE WV COUNTIES AND FAR WESTERN VA...MAINLY THE UPPER JAMES RIVER BASIN. 30-DAY RAINFALL DEFICITS IN MUCH OF THIS AREA ARE RUNNING 2 TO 3 INCHES OR ONLY 25 TO 50 PERCENT OF NORMAL AND 60-DAY RAINFALL NUMBERS NOT MUCH BETTER. JULY IS CLIMATOLOGICALLY THE WETTEST MONTH IN OUR CWA WITH AN AVERAGE RANGING FROM 4 TO 5 INCHES.
-- End Changed Discussion --
&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PC NEAR TERM...PC SHORT TERM...WERT LONG TERM...WERT AVIATION...PC/WP HYDROLOGY...PC

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.