Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 232313 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 713 PM EDT SAT MAY 23 2015 .SYNOPSIS... HIGH PRESSURE BOTH SURFACE AND ALOFT WILL SLIDE EAST THROUGH THE WEEKEND WHILE MAINTAINING CONTROL OF THE AREA WEATHER INTO MONDAY. THIS WILL BRING A WARMING TREND WITH HEAT AND HUMIDITY ON THE INCREASE THROUGHOUT THE HOLIDAY WEEKEND...WITH JUST AN OUTSIDE CHANCE FOR A LATE DAY SHOWER OR THUNDERSTORM WEST OF THE BLUE RIDGE BY MONDAY OR TUESDAY. AS THE HIGH MOVES FURTHER TO THE EAST...OUR CHANCES FOR SHOWERS WILL BE ON THE INCREASE FOR THE MIDDLE OF NEXT WEEK. && .NEAR TERM /THROUGH SUNDAY/... AS OF 250 PM EDT SATURDAY... AFTERNOON VISIBLE SATELLITE IMAGES SHOW A VERY PLEASANT SATURDAY UNDERWAY ACROSS THE AREA WITH OROGRAPHIC EFFECTS GENERATING SOME CUMULUS CLOUDS ALONG AND WEST OF THE BLUE RIDGE...TOPPED BY SOME MID/HIGH CLOUDS MAKING THEIR WAY IN FROM THE WEST AS THEY SPILL OVER THE UPPER RIDGE. THE CU WILL DISSIPATE EARLY THIS EVENING BUT THE MID/HIGH DEBRIS CLOUDS WILL REMAIN OVER THE REGION TONIGHT. WITH HIGH PRESSURE TO OUR EAST CONTINUING TO BRING LIGHT WINDS TO THE AREA...THIS SHOULD BE A DECENT SET UP FOR RADIATIONAL COOLING TONIGHT. IT DOES NOT LOOK QUITE AS COOL AS LAST NIGHT WITH DEW POINTS EXPECTED TO BE A FEW DEGREES HIGHER. EXPECT READINGS IN THE MID/UPPER 40S EAST OF THE RIDGE WITH LOWER 40S IN THE NORMALLY COLDER VALLEYS...TO UPPER 40S/LOW 50S EAST. FOG FORMATION WAS CONFINED TO ISOLATED PATCHES ALONG PORTIONS OF THE NEW RIVER AND DO NOT EXPECT COVERAGE TO BE MUCH MORE WIDESPREAD TONIGHT. SUNDAY LOOKS TO BE A CARBON COPY OF TODAY...DOES ANYONE KNOW WHAT A CARBON COPY IS THESE DAYS?...WITH TEMPERATURES TRENDING UP A FEW DEGREES. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... AS OF 250 PM EDT SATURDAY... WITH AN AMPLIFYING UPPER RIDGE BUILDING OVER THE EASTERN U.S. FOR THE REMAINDER OF THE HOLIDAY WEEKEND...WEATHER CONDITIONS SHOULD BE EXCELLENT FOR THOSE PARTICIPATING IN OUTDOOR ACTIVITIES. THE MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT WITH HEIGHTS ALOFT BUILDING THROUGH MONDAY...BEFORE THE AXIS OF THE UPPER LEVEL RIDGE SHIFTS EAST FOR TUESDAY. THIS SHOULD RESULT IN WARMING TEMPERATURES EACH DAY DURING THIS PERIOD AND INCREASING HUMIDITY LEVELS. INCREASED HIGHS ONLY A DEGREE OR TWO MONDAY WITH SURGING 1000-850MB THICKNESSES. CANNOT RULE OUT AN ISOLATED SHOWER/STORM IN NW NC/FAR SW VA MONDAY AFTERNOON AS HIGHER THETA-E AIR ADVECTS INTO THIS REGION AND LOCAL TERRAIN CONVERGENCE. ALTHOUGH IF THE SLOWER ECMWF VERIFIES...THE ENTIRE FORECAST AREA WILL AGAIN BE VOID OF PRECIPITATION. FOR NOW...WILL ONLY KEEP A SLIGHT CHANCE FOR AN AFTERNOON SHOWER/STORM IN NW NC/FAR SW VA. PRECIP CHANCES INCREASE IN THE MOUNTAINS TUESDAY AS WEAK UPPER LEVEL ENERGY MOVES INTO THE REGION ON THE FAR EASTERN FRINGE OF THE CENTRAL U.S. UPPER LEVEL SYSTEM. A DEEP SOUTH/SOUTHWEST FLOW WILL HELP PUSH PWATS IN EXCESS OF 1.5 INCHES BY TUESDAY HELPING TO INCREASE THE COVERAGE OF PRECIPITATION IN THE MOUNTAINS. INCREASING CLOUDS MONDAY NIGHT/TUESDAY SHOULD KEEP HIGHS ON TUESDAY SIMILAR TO MONDAY...BUT IN THE EAST...CONTINUED TO GO A DEGREE OR TWO ABOVE GUIDANCE VALUES FOR HIGHS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 330 PM EDT FRIDAY... A SUMMER-LIKE PATTERN WILL PREVAIL THROUGH THE LONG TERM PERIOD...WITH ABOVE NORMAL TEMPS EXPECTED AND DAILY CHANCES OF SHOWERS AND STORMS MOSTLY DIURNALLY DRIVEN. GEFS ENSEMBLES SHOW PWATS THROUGH MOST OF THE LONG TERM PERIOD WILL BE 1-2 STANDARD DEVIATIONS ABV NORMAL. ALOFT...LONG RANGE MODELS TAKE A CENTRAL U.S. UPPER LEVEL SYSTEM AND WEAKEN IT AS IT MOVES INTO THE EASTERN U.S. RIDGE. THIS WILL HELP DRAG A WEAK BOUNDARY INTO OUR AREA WEDNESDAY WHICH WILL HELP INCREASE COVERAGE OF PRECIPITATION. IN TERMS OF SENSIBLE WEATHER SCATTERED DIURNALLY DRIVEN SHOWER AND STORMS WILL BE POSSIBLE EACH DAY...WITH THE BEST CHANCES EAST OF THE BLUE RIDGE LATE WEDNESDAY NIGHT INTO FRIDAY AS A WEAK SFC BOUNDARY TRIES TO MOVE THROUGH THE AREA. WARMEST TEMPERATURES ARE FORECAST LATE IN THE LONG TERM PERIOD...AS A NOSE OF 16+C 850MB TEMPS NOSES INTO OUR AREA. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... AS OF 645 PM EDT SATURDAY... EXPECTING OVERALL VFR CONDITIONS TO PREVAIL TONIGHT INTO SUNDAY WITH LIGHT WINDS OVERNIGHT TURNING MORE SOUTHERLY AT 5-12 KTS SUNDAY AFTERNOON. SHEARED WEAK MID LEVEL WAVE CROSSING THE REGION MAY SPREAD A FEW BANDS OF CU/AC ACROSS WESTERN LOCATIONS THIS EVENING... WITH SOME RESIDUAL MID DECK POSSIBLE FROM TIME TO TIME AT KBCB/KROA/KBLF SUNDAY MORNING. HOWEVER WILL ONLY KEEP SCATTERED VFR CU FOR NOW WITH PERIODS OF BROKEN MID DECK MOUNTAINS GIVEN DRYNESS AND LACK OF UPSTREAM CLOUDINESS THIS EVENING. RADIATIONAL COOLING COULD AGAIN LEAD TO SOME LATE NIGHT RIVER VALLEY FOG BUT GIVEN SUCH A DRY/MIXED ENVIRONMENT FROM THIS AFTERNOON APPEARS ANY FOG QUITE ISOLATED IF AT ALL AGAIN TONIGHT. MAY LEAVE IN A BRIEF TEMPO GROUP AT KLWB FOR PATCHY FOG LATER OTHERWISE LEAVING OUT MENTION ELSEWHERE. A BIT MORE CU POSSIBLE ACROSS THE REGION SUNDAY AS MOISTURE SLOWLY RETURNS...BUT OVERALL MOSTLY SCATTERED AT THIS POINT WITH PERHAPS THE RIDGES SEEING SOME BROKEN CIGS IN THE AFTERNOON. EXTENDED AVIATION DISCUSSION... VFR CONDITIONS EXPECTED TO PERSIST INTO EARLY NEXT WEEK AS HIGH PRESSURE GRADUALLY MOVES OFFSHORE. SOUTHWEST WINDS IN RETURN FLOW AROUND THE HIGH WILL RESULT IN SOME INCREASE IN MOISTURE BY MONDAY. THIS MAY BRING A GRADUAL INCREASE IN MOUNTAIN AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS...ESPECIALLY BY LATER TUESDAY...WHEN PERIODS OF MVFR COULD OCCUR MAINLY BLUE RIDGE WEST. WEAK TROUGH DRIFTS INTO THE REGION WEDNESDAY BEFORE SLIDING EAST OF THE BLUE RIDGE LATER THURSDAY. THIS SHOULD BRING THE BEST CHANCES OF SEEING MORE WIDESPREAD AFTERNOON/EVENING SUB-VFR IN SHOWERS/STORMS WEDNESDAY FOLLOWED BY MORE ISOLATED NATURE COVERAGE ACROSS THE EAST ON THURSDAY. OTHERWISE...MAINLY VFR CONDITIONS EXPECTED OUTSIDE OF ANY LATE DAY CONVECTION FOR MUCH OF THE WEEK. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...JH NEAR TERM...MBS SHORT TERM...PH LONG TERM...PH AVIATION...JH/MBS

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