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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KRNK 020523 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 123 AM EDT SUN AUG 2 2015 .SYNOPSIS... HIGH PRESSURE WILL BUILD EAST ACROSS THE REGION OVERNIGHT AND REMAIN IN PLACE SUNDAY INTO SUNDAY NIGHT. AN UPPER DISTURBANCE PASSES ACROSS THE GREAT LAKES MONDAY FOLLOWED BY A COLD FRONT THAT WILL DROP SOUTH INTO THE AREA TUESDAY...THEN STALL OVER OR NEAR THE AREA BY WEDNESDAY. && .NEAR TERM /THROUGH TODAY/...
-- Changed Discussion --
AS OF 113 AM EDT SUNDAY... FORECAST REMAINS ON TRACK...THOUGH A FEW MORE HIGHER CLOUDS TRACKING ACROSS KY/WV SHOULD STREAK OVER US DURING THE MORNING. SHOULD NOT SEE ANY IMPACT ON TEMPS WHICH WERE RUNNING A FEW DEGREES COOLER THAN FORECAST...SO ADJUSTED DOWN SOME INTO THE MORNING. STILL LOOKING AT UPPER 40S/LOWER 50S DEEPER HIGHER VALLEYS IN THE WEST...LIKE BURKES GARDEN WITH MOST LOCATIONS IN THE MID 50S TO LOWER 60S. PREVIOUS FORECAST DISCUSSION... AS OF 1030 PM SATURDAY... FORECAST REMAINS ON TRACK. MADE SOME MINOR MODIFICATIONS TO MIN TEMPS AND HOURLY TEMPS AS SOME OF THE MORE URBAN AREAS APPEARED A LITTLE TO COOL FOR MIN TEMPS GIVEN THE WARM TEMPS OF THIS AFTERNOON AND SLOW DECLINE RATE AT THE CURRENT HOUR. OTHERWISE...NO CHANGES WERE NEEDED AT THIS TIME. AS OF 200 PM EDT SATURDAY... WEAK SURFACE TROUGH CROSSING THE BLUE RIDGE THIS AFTERNOON WILL BRING A REINFORCING SHOT OF DRIER/COOLER AIR OVERNIGHT AS HIGH PRESSURE BUILDS EAST AND SETTLES ABOUT OVERHEAD THE WESTERN MOUNTAINS BY DAWN SUNDAY. THIS SHOULD ALLOW ANY RESIDUAL CU TO FADE WITH LOSS OF HEATING AS DRIER AIR ADVECTS IN WHILE ALSO HELPING WINDS DIMINISH THIS EVENING...BUT PERHAPS NOT ON THE RIDGES UNTIL AFTER MIDNIGHT. THIS ALONG WITH EVEN COOLER AIR AT 85H THAN SEEN BEFORE LIKELY TO MAKE FOR GREAT RADIATIONAL COOLING WEST LATE WITH A LIGHT NORTH/NE BREEZE LINGERING OUT EAST IN SPOTS. LATEST MOS SIMILAR TO PREVIOUS WITH MAINLY LOW/MID 60S EAST AND COOL 50S TO AROUND 60 WEST. HOWEVER A FEW UPPER 40S POSSIBLE DEEPEST WESTERN VALLEYS PENDING ANY LATE NIGHT RIVER FOG AND RESIDUAL WESTERN SLOPE STRATO-CU THAT MAY LINGER. SURFACE HIGH WILL BE OVERHEAD FOR MUCH OF SUNDAY ALLOWING FOR ANOTHER WARM BUT DRY DAY WITH OVERALL LOW HUMIDITY UNDER MAINLY SUNNY SKIES. A WEAK MID LEVEL WAVE RIDING THROUGH THE BASE OF THE 5H TROUGH COULD PRODUCE SOME LOW CLOUDS NW EARLY BEFORE MIXING OUT. ALSO MAY SEE JUST ENOUGH RETURN SW FLOW AS THE HIGH SLIDES EAST LATE TO PROMPT A BIT MORE CU OVER SW SECTIONS BUT WITHOUT ANY POP MENTION FOR NOW GIVEN DRYNESS. SHOULD BE ANOTHER LARGE DIURNAL SWING TO TEMPS AS 850 MB VALUES START TO REBOUND WHILE HIGHS AIDED BY HEATING OF DRY AIR AND WEAK EASTERN DOWNSLOPE. THIS SIMILAR TO THE PAST COUPLE OF DAYS SO STAYING CLOSE TO PERSISTENCE WITH MOSTLY 80S MOUNTAINS AND UPPER 80S/LOW 90S EAST.
-- End Changed Discussion --
&& .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... AS OF 325 PM EDT SATURDAY... BROAD UPPER TROF EXPECTED TO LINGER FROM THE HUDSON BAY AREA SOUTH INTO THE GREAT LAKES REGION THROUGH MUCH OF THE SHORT TERM PERIOD AS A SERIES OF SHORT WAVE TROFS HELP TO SLOWLY AMPLIFY AND DEEPEN FEATURE. MOST OF THE ENERGY AND MOISTURE ASSOCIATED WITH THESE WAVES WILL REMAIN SUFFICIENTLY NORTH OF THE BLACKSBURG FORECAST AREA TO MAINTAIN A MAINLY DRY FORECAST FOR MOST AREAS...BUT INFLUENCE OF THE MOST SUBSTANTIAL OF THE WAVES PIVOTING EAST THROUGH THE UPPER AND LOWER GREAT LAKES LATE MONDAY INTO MONDAY NIGHT...ALONG WITH ATTENDANT COOL FRONT...STILL WARRANTS SUFFICIENT CONFIDENCE TO MAINTAIN A REFLECTION OF AN INCREASE IN CLOUDS AND A THREAT FOR WIDELY SCATTERED LATE DAY AND NIGHTTIME SHOWERS/THUNDERSHOWERS INTO UPSLOPE AREAS OF THE WESTERN BLUE RIDGE NORTH INTO THE ALLEGHANY HIGHLANDS. DESPITE SOME MODEL DEPICTIONS...WESTERLY LOW LEVEL FLOW AND RELATIVE DRY LOWER TROPOSPHERE AHEAD OF THE WAVE SHOULD LIMIT ANY POTENTIAL FOR SPILL-OVER INTO DOWNSLOPE AREAS EAST OF THE BLUE RIDGE ON MONDAY NIGHT. SOUTHWEST TO WESTERLY PRE-FRONTAL WINDS EXPECTED TO ALLOW 850 MILLIBAR TEMPERATURES TO CLIMB BACK INTO THE +22-23C RANGE IN MOST AREAS...DRIVING TEMPERATURES INTO THE 90S ACROSS MUCH OF THE PIEDMONT ON MONDAY AFTERNOON. HOWEVER...UNLIKE PAST SEVERAL WEEKS...DEW POINTS STILL EXPECTED TO BE RELATIVELY LACKLUSTER... MAINLY IN 60S...AS OPPOSED TO MORE OPPRESSIVE 70S EXPERIENCED EARLIER. AS SHORT WAVE TROF LIFTS NORTHEAST AND AWAY FROM THE BLACKSBURG FORECAST AREA ON TUESDAY...DECAYING COOL FRONT LIKELY TO STALL OVER OR NEAR THE VA/NC STATE LINE AS UPPER FLOW REVERTS TO MORE OF A ZONAL CONFIGURATION. PROXIMITY OF OLD FRONT...AND SOME LOW LEVEL POOLING OF MOISTURE IN REGION OF CONFLUENCE MAY BE SUFFICIENT TO SPARK ISOLATED TO WIDELY SCATTERED LATE AFTERNOON AND EVENING SHOWERS OR THUNDERSHOWERS JUST ABOUT ANYWHERE IN THE FORECAST AREA...MOST NOTABLY IN THE MOUNTAINS WHERE DIFFERENTIAL HEATING AND LOCALIZED UPSLOPING WILL AID IN VERTICAL DEVELOPMENT... ALTHOUGH MOST AREAS STILL LIKELY TO REMAIN PRECIPITATION FREE. SOME WEAK POST-FRONTAL COOL ADVECTION AND CLOUDS MAY HELP TO LOWER DAYTIME HIGHS IN THE MOUNTAINS A DEGREE OR TWO FROM THOSE EXPERIENCED ON MONDAY...BUT CONTINUED GOOD INSOLATION AND NEGLIGIBLE PUSH OF COOLER AIR INTO SOUTHSIDE VA AND NORTH CENTRAL NC SHOULD ENSURE ANOTHER DAY OF AFTERNOON HIGHS IN THE 90S IN THOSE AREAS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 325 PM EDT SATURDAY... EAST-WEST BAROCLINIC ZONE EXPECTED TO BECOME ESTABLISHED OVER OR NEAR THE FORECAST AREA THROUGH MUCH OF THE LONG-TERM PERIOD AS ADDITIONAL UPSTREAM SHORT WAVES AND/OR MESOSCALE VORTICITY CENTERS FROM DECAYING OLD MIDWEST CONVECTIVE COMPLEXES PROVIDE SUFFICIENT ENERGY/SUPPORT TO MAINTAIN THREAT FOR DAILY SCATTERED CONVECTION. STRENGTH AND MOVEMENT/POSITIONING OF EACH WAVE IN MAINLY ZONAL UPPER FLOW WILL INFLUENCE DAILY POSITION OF DECAYING FRONTAL BOUNDARY...EXTENT OF CLOUD COVER...AND EXTENT OF WARM OR COOL ADVECTION DEPENDING ON POSITION RELATIVE TO FRONT. HIGHEST THREAT FOR PRECIPITATION AT THE PRESENT TIME APPEARS TO COME ON WEDNESDAY INTO WEDNESDAY NIGHT...AND AGAIN ON FRIDAY WHEN TWO OF THE MORE NOTABLE UPSTREAM WAVES ARRIVE...AND THIS REFLECTED ACCORDINGLY IN GRIDS FOR THESE TIMEFRAMES. OTHERWISE...A LOWER AND MORE GENERALIZED THREAT FOR DAILY PRECIPITATION WILL BE MAINTAINED INTO SATURDAY UNTIL REGIONAL/MESOSCALE FEATURES BECOME BETTER RESOLVED. && .AVIATION /05Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
AS OF 120 AM EDT SUNDAY... FORECAST FOR TERMINALS IS EXPECTED TO STAY VFR THIS PERIOD. EXCEPTION WILL BE A FEW PERIOD OF MVFR/IFR FOG AT LWB/BCB THIS MORNING BETWEEN 09-12Z. NO WINDS TO SPEAK OF AND EXPECT JUST SOME HIGHER LEVEL CLOUDS TODAY...WITH A POTENTIAL FOR SCT CU/SC IN THE MTNS BY LATE AFTERNOON/EVENING. EXTENDED AVIATION FORECAST... AS OF 1230 PM EDT SATURDAY... MOSTLY VFR OUTSIDE OF ANY CONVECTION THROUGH THE PERIOD. A FRONT WILL SET UP IN THE MID ATLANTIC WHICH COULD BRING A FEW SHRA/TSRA BY TUESDAY...WITH PERHAPS A BIT MORE COVERAGE LATER WEDNESDAY AT THIS POINT. THUS THE THREAT OF SUB-VFR REMAINS LOW UNTIL AROUND MIDWEEK...EXCEPT FOR THE TYPICAL FOG POTENTIAL AT KLWB/KBCB EACH MORNING BETWEEN 09-13Z.
-- End Changed Discussion --
&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH/WP NEAR TERM...JH/RAB/WP SHORT TERM...WERT LONG TERM...WERT AVIATION...DS/JH/WP

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