Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 281751 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 151 PM EDT THU APR 28 2016 .SYNOPSIS... LOW PRESSURE WILL MOVE EAST TODAY THROUGH FRIDAY WITH THE FRONT CROSSING THROUGH OUR AREA ON FRIDAY MORNING. ANOTHER LOW WILL MOVE ACROSS THE REGION ON SUNDAY AND MONDAY. && .NEAR TERM /THROUGH TONIGHT/...
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AS OF 130 PM EDT THURSDAY... NOT MUCH CHANGE TO THE MODELS AS CONTINUE TO SEE TREND OF DEVELOPING SHOWERS AND STORMS ALONG WEDGE FRONT AND JUST WEST FROM THE ALLEGHANYS AND SE WV SOUTH INTO THE NC MTNS. EARLY THIS AFTERNOON SHOWERS HAD SLOWLY FORMED FROM HSP-NEAR LWB TO BKW. VIS SATELLITE SHOWING WEAK VERTICAL DEVELOPMENT IN THE CU FIELD OVER SW VA/NW NC. WEAK VORT LOBE APPEARS TO MOVE FROM KY/INDIANA AT 1 PM TO THE CENTRAL VA AREA BY 00Z. AS THIS APPROACHES WILL SEE BETTER DEVELOPMENT...THOUGH THE STRONG WESTERLY FLOW ALOFT MAY INHIBIT GOOD VERTICAL DEVELOPMENT. AS SUCH STORMS MAY BE ISOLATED. THOSE STORMS THAT CAN OVERCOME THE SHEAR ALOFT WILL HAVE THE WIND ENERGY AVAILABLE TO AT LEAST BECOME STRONG TO SEVERE. THE STORM PREDICTION CENTER CONTINUES TO MENTION SLIGHT RISK OF SEVERE STORMS FROM SRN WV TO SW VA INTO NW NC THIS AFTERNOON. PREVIOUS MID MORNING DISCUSSION... FORECAST THIS MORNING SHOWING LESS THREAT OF SHOWERS AS WE ARE BETWEEN AREAS OF STRONG CONVERGENCE. AIRMASS WORKED OVER SOME...BUT SUNSHINE BREAKING OUT ACROSS THE MOUNTAINS WILL HEAT THE AIRMASS UP AND LEAD TO OVERALL INCREASING INSTABILITY BY THIS AFTERNOON. LATEST MODELS...MAINLY THE RAP13 AND HRRR FAVOR MORE DEVELOPMENT IN THE MOUNTAINS OF WEST VIRGINIA BY MIDDAY...THEN SURGING EAST TO THE BLUE RIDGE AND PIEDMONTS AFTER 1PM. THEREFORE...HAVE LOWERED CHANCES OF SHOWERS THIS MORNING...BUT KEPT HIGH CHANCE TO LOW LIKELYS THIS AFTERNOON. THE LOW CLOUDS ARE HANGING TOUGH AT THE MOMENT FROM ROANOKE TO LYNCHBURG AND DANVILLE...BUT RETREATING WEDGE UNDER INCREASING WESTERLY FLOW ALOFT AND STRONG SUNSHINE WILL OCCUR BY MID AFTERNOON. WENT WARMER BASED ON MORE SUNSHINE FOR A FEW HOURS THIS MORNING TIL EARLY AFTERNOON. THE STORM PREDICTION CENTER CONTINUES TO HIGHLIGHT THE SOUTHSIDE VIRGINIA INTO THE NORTHWEST NC PIEDMONT FOR A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON. MODELS SHOWING SBCAPES OF 1000-1500 J/KG HERE...WITH ANOTHER HIGHER ZONE OF 1000 J/KG OVER WEST VIRGINIA. OUTSIDE THE SLIGHT RISK...THE REST OF THE FORECAST AREA REMAINS IN A MARGINAL RISK. STILL THINK OUR NORTHEAST COUNTY WARNING AREA FROM THE SOUTHERN SHENANDOAH VALLEY TO LYNCHBURG NORTH WILL BE STABLE LONGER TO KEEP THREAT OF SEVERE LOW...THEREFORE NO CHANGES TO BE MADE TO THE HAZARDOUS WEATHER OUTLOOK. A COMPLEX LOW PRESSURE SYSTEM FROM THE MID MISSISSIPPI VALLEY TO THE MID ATLANTIC REGION WILL MOVE EAST THROUGH TONIGHT. BY FRIDAY MORNING LOW PRESSURE WILL BE OVER PENNSYLVANIA WITH A COLD FRONT TRAILING DOWN THE SOUTHERN APPALACHIANS. AREAL COVERAGE OF SHOWERS AND THUNDERSTORMS WILL DIMINISH LATE TONIGHT.
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&& .SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/... AS OF 340 AM EDT THURSDAY... THE MAIN FRONTAL BOUNDARY WILL HAVE PUSHED TO OUR SOUTH ON FRIDAY BUT AN INVERTED TROF WILL BE LINGERING OVER THE APPALACHIANS AND THIS LOOKS TO KEEP A CHANCE OF SHOWERS MAINLY FOR THE FAR NORTH AND EAST THROUGHOUT THE DAY. AS THIS TROF ERODES HIGH PRESSURE OVER CENTRAL CANADA WILL BUILD DOWN INTO THE EASTERN UNITED STATES AND WEDGE DOWN THE EASTERN SEABOARD. THIS WILL BRING COOLER...SLIGHTLY BELOW NORMAL TEMPERATURES AND A SLIGHT CHANCE OF SPRINKLES/DRIZZLE TO THE AREA FRIDAY NIGHT INTO SATURDAY. BY LATE SATURDAY A DEVELOPING LOW OVER THE MIDWEST WILL START TO MOVE IN OUR DIRECTION AND PUSH THE OLD FRONTAL BOUNDARY BACK INTO THE AREA FORM THE SOUTH AS A WARM FRONT. THIS WILL GENERATE A GOOD AMOUNT OF ISENTROPIC LIFT OVER THE HIGH PRESSURE WEDGE AND BRING WIDESPREAD PRECIPITATION TO THE REGION SATURDAY NIGHT THROUGH THE END OF THE WEEKEND. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 325 PM EDT WEDNESDAY... WEAK HIGH PRESSURE ACROSS THE MID ATLANTIC REGION AND INTO THE CAROLINAS WILL LIKELY STAY IN THE AREA INTO MONDAY MORNING. A DISTURBANCE MOVING FROM THE MID WEST INTO THE SOUTHERN OHIO VALLEY WILL PUSH A WARM FRONT OVER THIS WEDGE OF COOL AIR. WARM MOIST AIR AND ISENTROPIC LIFT WILL KEEP A HIGH CHANCE FOR RAIN AND LOW CLOUDS IN THE REGION THROUGH AT LEAST MONDAY MORNING. A STRONG NORTHERN STREAM TROUGH IS FORECASTED TO KICK THIS WEDGE AND RAIN EAST AND OFF SHORE MONDAY AFTERNOON. THIS TROUGH MAY HANG OVER THE REGION INTO TUESDAY...HOWEVER ONLY FAIR WEATHER CUMULUS CLOUDS ARE EXPECTED. HIGH PRESSURE BUILDS IN TUESDAY NIGHT AND MAY KEEP THE AREA DRY THROUGH WEDNESDAY. SOME MODELS ARE BRINGING A DISTURBANCE ACROSS THE SOUTHEASTERN US WEDNESDAY OR THURSDAY...WHICH WILL KEEP OUR DRY SPELL BRIEF. MONDAY TEMPERATURES COULD REBOUND BACK TO SEASONAL LEVELS WITH NEAR 70F WEST AND MID 70S EAST. NEAR NORMAL TEMPERATURES ARE POSSIBLE FOR THE REMINDER OF THE PERIOD. WEDNESDAY`S TEMPERATURES MAY TREND COOLER BASED ON THE DISTURBANCE TRACKING ACROSS THE SOUTHEASTERN US. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/...
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AS OF 135 PM EDT THURSDAY... LOW CLOUDS WITH WEDGE FROM DAN/LYH SHOULD LIFT TO VFR CIGS BY 21Z AT DAN...BUT NOT CONFIDENT LYH WILL...SO KEPT THEM MVFR THEN IFR AFTER 00Z THIS EVENING. SHRA/TSRA COVERAGE WILL BE MAINLY SCATTERED...SO NOT PUTTING PREDOMINANT IN THE TAFS YET. LWB SEEING SOME CLOSE BY AS OF 130 PM EDT. SHOULD SEE THE FRONTAL BOUNDARY AND LOW PRESSURE SYSTEM MOVE WEST TO EAST THIS EVENING. THE THREAT OF SHOWERS WILL SUBSIDE BY LATE EVENING...THEN CONCERN SHIFTS BACK TO LOW CIGS AND/OR FOG. WEDGE MAY HANG THRU FRIDAY MORNING AT LYH/DAN...SO EXPECT AT LEAST IFR TO LOW END MVFR CIGS HERE TONIGHT INTO FRIDAY MORNING. FOG WILL BE LIMITED BUT SHOULD STAY BETWEEN 3-6SM. FURTHER WEST THE SFC FLOW WILL BECOME MORE SW TO TO NW AND THINK ROA/BCB WILL BE MAINLY VFR THOUGH SOME MVFR FOG POSSIBLE. BLF SHOULD BE DRY ENOUGH TO KEEP TO VFR CONDITIONS BUT THINK LWB WILL SEE FOG AND/OR LOW CLOUDS SO LEANED TOWARD IFR CIGS FOR NOW. CONFIDENCE IS FAIRLY LOW IN PLACEMENT OF STORMS THIS AFTERNOON AND CIGS/VSBYS OVERNIGHT....BUT MEDIUM OTHERWISE. EXTENDED AVIATION DISCUSSION... BY FRIDAY AFTERNOON...DRIER AIR AND VFR RETURN AND CONTINUE INTO SATURDAY. MORE WIDESPREAD SHOWERS WITH MVFR INCLUDING LOCALLY IFR CONDITIONS RETURN LATE SATURDAY NIGHT AND PERSIST INTO MONDAY AS LOW PRESSURE TRACKS UP THE RESIDUAL STALLED FRONT RESULTING IN WIDESPREAD RAINFALL...AND SUB VFR CONDITIONS. FRONT WILL BE SOUTHEAST OF US TUESDAY SO MAY SEE VFR AGAIN.
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&& .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS/WP NEAR TERM...AMS/WP SHORT TERM...MBS LONG TERM...RCS AVIATION...AMS/JH/WP

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