Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 010513 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 113 AM EDT SAT AUG 1 2015 .SYNOPSIS... HIGH PRESSURE WILL BUILD EAST INTO THE MID ATLANTIC REGION TONIGHT. THIS HIGH CENTER WILL STAY OVER MOST OF REGION THIS WEEKEND. A COUPLE OF UPPER DISTURBANCES MAY BRING A FEW SPOTTY SHOWERS TO THE MOUNTAINS LATE SATURDAY OR SUNDAY...BUT THE MAJORITY OF OUR AREA WILL STAY DRY. && .NEAR TERM /THROUGH TODAY/... AS OF 100 AM EDT SATURDAY... A MOONLIT NIGHT FOR MOST OF THE REGION. A FEW LOWER CLOUDS TO SKIRT ACROSS THE SKIES OF THE GREENBRIER MOUNTAINS INTO THE ALLEGHANYS OF VIRGINIA. PATCHY FOG TO FORM IN THE RIVER VALLEYS OF THE WEST BY DAWN. LEANED TOWARDS THE COOLER MOS COOP GUIDANCE FOR LOW TEMPERATURES TONIGHT. LOW TEMPERATURES TONIGHT INTO SATURDAY MORNING WILL RANGE FROM AROUND 50 DEGREES IN THE COLDEST DEEPER VALLEYS TO THE LOWER 60S IN THE PIEDMONT. HIGH PRESSURE WILL BRING LOWER HUMIDITY AGAIN SATURDAY. ABUNDANT SUNSHINE AND LIGHT DOWNSLOPE WIND FLOW WILL WARM HIGH TEMPERATURES SATURDAY INTO THE UPPER 70S IN THE NORTHWEST MOUNTAINS TO THE LOWER 90S. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... AS OF 335 PM EDT FRIDAY... BROAD UPPER TROF WILL REMAIN ANCHORED FROM THE JAMES BAY AREA SOUTH INTO THE UPPER AND LOWER GREAT LAKES SATURDAY NIGHT INTO MONDAY MORNING...WITH WEAK SURFACE HIGH PRESSURE SYSTEM LINGERING OVER THE MID APPALACHIAN REGION. THIS SETUP WILL ENSURE A CONTINUATION OF DRY WEATHER AND RELATIVELY LOW DEW POINTS THAT WILL SUPPORT EFFICIENT DAYTIME HEATING...WITH GOOD RADIATIONAL COOLING AT NIGHT...RESULTING IN MARKED DIURNAL TEMPERATURE SWINGS OF AROUND 30F. BY MONDAY AFTERNOON INTO MONDAY NIGHT...APPROACH AND EVENTUAL PASSAGE OF AN UPSTREAM SHORTWAVE TROF DIVING SOUTHEAST THROUGH/OUT OF THE UPPER GREAT LAKES WILL BRING AN INCREASE IN CLOUDS ALONG WITH A THREAT FOR WIDELY SCATTERED SHOWERS/THUNDERSHOWERS INTO UPSLOPE AREAS OF THE WESTERN BLUE RIDGE NORTH INTO THE ALLEGHANY HIGHLANDS. HOWEVER...WESTERLY LOW LEVEL FLOW AHEAD OF THE WAVE SHOULD PREVENT ANY POTENTIAL FOR SPILL-OVER INTO DOWNSLOPE AREAS EAST OF THE BLUE RIDGE. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 335 PM EDT FRIDAY... ENERGY ASSOCIATED WITH GREAT LAKES TROF EXPECTED TO BE NORTHEAST OF THE BLACKSBURG FORECAST AREA BY DAYBREAK TUESDAY. ATTENDANT COOL FRONT WILL LIKELY SLOW AND THEN STALL OVER/NEAR THE MID APPALACHIAN AND MID ATLANTIC REGION LATER TUESDAY INTO TUESDAY NIGHT AS TROF SPOKE LIFTS NORTHEAST AND AWAY FROM AREA AND AS UPPER FLOW IN ITS WAKE GRADUALLY FLATTENS TO MORE OF A ZONAL CONFIGURATION. EAST-WEST BAROCLINIC ZONE WILL THEN BECOME ESTABLISHED OVER THE FORECAST AREA FOR THE REST OF THE LONG-TERM PERIOD...WITH ADDITIONAL UPSTREAM SHORT WAVES AND/OR MESOSCALE VORTICITY CENTERS FROM DECAYING OLD MIDWEST CONVECTIVE COMPLEXES PROVIDING SUFFICIENT ENERGY/SUPPORT TO MAINTAIN THREAT FOR SCATTERED CONVECTION THROUGH THE PERIOD. GRADUALLY RISING DEW POINTS WILL SLOWLY COMPRESS THE DIURNAL TEMPERATURE CURVE BACK TO AROUND 20F AS SULTRY AIRMASS SLOWLY REESTABLISHES ITSELF OVER THE AREA. EXPECT OVERNIGHT LOWS DURING THE PERIOD TO RANGE FROM THE 60S IN THE MOUNTAINS TO AROUND 70 IN THE PIEDMONT...WITH HIGHS RANGING FROM MAINLY 80S IN THE MOUNTAINS TO LOWER-MID 90S ACROSS THE PIEDMONT. && .AVIATION /05Z SATURDAY THROUGH WEDNESDAY/... AS OF 109 AM EDT SATURDAY... VFR CONDITIONS EXPECTED FOR MOST AREAS THROUGH THE TAF PERIOD. THE EXCEPTION WILL BE SOME BRIEF...EARLY MORNING PATCHY RIVER OR MOUNTAIN VALLEY FOG AT LWB/BCB. ANY THAT DOES DEVELOP WILL QUICKLY MIX OUT BY 13Z/9AM SATURDAY. HIGH CONFIDENCE IN CEILINGS...VISIBILITIES AND WINDS DURING THE TAF PERIOD. EXTENDED AVIATION FORECAST... MAINLY VFR THROUGH THE PERIOD. A FRONT WILL SET UP IN THE MID ATLANTIC WHICH COULD BRING A FEW SHRA/TSRA MON-WED BUT THREAT OF SUB VFR IS LOW...EXCEPT FOR THE TYPICAL FOG THREAT AT KLWB/KBCB EACH MORNING BETWEEN 09-13Z. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...KK/WP NEAR TERM...AMS/KK/WP SHORT TERM...WERT LONG TERM...WERT AVIATION...DS/KK/WP

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