Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 301751 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 151 PM EDT SAT AUG 30 2014 .SYNOPSIS... A FRONT WILL MOVE NORTH AND DISSIPATE OVER THE MID ATLANTIC REGION BY SUNDAY. A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE GREAT LAKES TONIGHT AND SUNDAY WITH A COLD FRONT TRAILING FROM THE UPPER MISSISSIPPI VALLEY TO THE CENTRAL PLAINS BY SUNDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 110 PM EDT SATURDAY... RADAR SCOPE REMAINS CLEAR. CU BUILDING SOME ACROSS THE MOUNTAINS THIS AFTERNOON BUT NOT MUCH VERTICAL STRUCTURE AS OF 1 PM. HIGH RES MODELS CONTINUE TO PAINT ISOLATED SHRA/STORM FORMATION OVER THE BLUE RIDGE MAINLY NORTH OF ROANOKE THIS AFTERNOON AND INTO THE ALLEGHANY HIGHLANDS. MADE SOME MINOR TWEAKS TO LOCATION OF ANY CONVECTION BUT STILL NOT SEEING ANYTHING MORE THAN ISOLATED COVERAGE. THERE IS ALSO BETTER DEEP MOISTURE CONVERGENCE IN THE NC MTNS...SO CANNOT RULE OUT SOME TSRA HEADING TOWARD BEECH MTN AND BLOWING ROCK LATER THIS AFTERNOON. OTHERWISE...A SCT/BKN CU FIELD THIS AFTERNOON WITH TEMPS WARMING INTO THE 80S...POSSIBLY AROUND 90 TOWARD RICHLANDS IN FAR SW VA AND AROUND SOUTH BOSTON IN THE SOUTHEAST. PREVIOUS VALID DISCUSSION... UPPER RIDGE AXIS IS JUST OFF THE SOUTHEAST COAST BY TONIGHT. BROAD SOUTHWEST FLOW FROM THE LOWER MISSISSIPPI VALLEY TO THE EASTERN GREAT LAKES TONIGHT. THE SHORT WAVE COMING OUT OF THE NORTHERN GULF AND THE BEST Q-V FORCING ALONG THE APPROACHING COLD FRONT WILL STILL BE WEST OF THE FORECAST AREA BY SUNDAY MORNING. MID AND HIGH CLOUDS WILL COVER THE WESTERN COUNTY WARNING AREA OVERNIGHT...THEN INCREASING PROBABILITY OF PRECIPITATION IN THE FAR WEST. WITH THE INCREASING CLOUDS AND SINCE THE FORECAST AREA WILL BE WELL WITHIN THE WARM SECTOR TONIGHT...NOT MUCH DROP IN TEMPERATURES IS EXPECTED. USED THE WARMER GUIDANCE FOR OVERNIGHT LOWS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 310 AM EDT SATURDAY... A STUBBORN UPPER LEVEL RIDGE WILL HUG THE SOUTHEASTERN COAST LONGER THAN PREVIOUSLY EXPECTED. FROM A MODEL STAND POINT...THIS UPPER RIDGE IS ALSO FARTHER INLAND...WHICH WILL LOWER THE CHANCE OF SHOWERS AND THUNDERSTORMS AS THE SHORT WAVE TRACK IS PUSHED WESTWARD. THE LATEST 00Z MODELS TRACKS A TROPICAL SHORT WAVE ON THE OUTER RINGS OF THE RIDGE ACROSS EASTERN TENNESSEE AND CENTRAL KENTUCKY SUNDAY MORNING...THEN OVER THE OHIO VALLEY IN THE AFTERNOON. AS THIS SHORT WAVE MOVES OVER THE OHIO VALLEY IN THE AFTERNOON...MID LEVEL CAPPING WEAKENS ALLOWING STORMS TO GENERATE ALONG OUT FLOW BOUNDARIES AND IN MODEST INSTABILITIES. WITH THE STRONGEST LOW LEVEL JET REMAINING OVER THE TENNESSEE AND OHIO VALLEYS...DISORGANIZED PULSE-LIKE STORMS ARE EXPECTED OVER THE MOUNTAINS IN THE AFTERNOON AND MAY DRIFT EAST OF THE BLUE RIDGE IN THE EVENING...IF THE RIDGE DOES JOG TO THE SOUTHEAST. THERE WILL ALSO BE A LEE TROUGH OVER THE PIEDMONT THAT MAY HELP FIRE STORMS EAST OF THE BLUE RIDGE DURING THE LATE AFTERNOON AND EVENING HOURS. CAN NOT RULE OUT THE CHANCE FOR A FEW STORMS TO BECOME SEVERE WHERE THE CAP IS THE WEAKEST...MOUNTAIN EMPIRE TO THE BLUEFIELD RICHLANDS AREA. SINCE THE MODELS HAVE MOVED ORGANIZED CONVECTION TO THE WEST...LOWERED POPS ESPECIALLY IN THE EAST. SINCE THE CHANCES OF SHOWERS IS LOWER AND SCATTERED IN NATURE...INCREASE TEMPERATURES ACROSS THE MOUNTAINS INTO THE MID 80S AND U80S-L90S EAST OF THE BLUE RIDGE. ON MONDAY...MODELS ONCE AGAIN DRIFT UPPER LEVEL RIDGE TO THE SOUTH...PLACING THE OUTER RINGS ACROSS THE FORECAST AREA. A WEAK SHORT WAVE IS EXPECTED TO TRACK ALONG THE SOUTHERN APPALACHIANS BRING A CHANCE FOR SHOWERS AND THUNDERSTORMS TO THE AREA MONDAY. ONCE THIS SHORT WAVES TRACKS NORTH OF THE AREA...POSSIBLY BY EARLY AFTERNOON...SURFACE HIGH PRESSURE WILL BUILD ACROSS THE REGION MONDAY NIGHT. WITH THE AREA REMAINING IN A MUGGY AIR MASS...PATCHY DENSE FOG IS LIKELY FOR MOUNTAIN VALLEYS. IF SHOWERS ARE PRIMARILY DURING THE MORNING...MONDAY AFTERNOON TEMPERATURES WILL WARM INTO THE MID 80S IN THE WEST TO U80S-L90S EAST OF THE BLUE RIDGE. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 330 PM FRIDAY... FLAT UPPER RIDGE IS EXPECTED TO DOMINATE OUR MID-WEEK WEATHER PATTERN ACROSS THE CENTRAL APPALACHIAN AND MID-ATLANTIC REGION. THIS SHOULD MAINTAIN SUMMER-LIKE TEMPERATURES THROUGH THE ENTIRE PERIOD WITH HIGHS NEAR 90F IN THE PIEDMONT AND MID-80S IN THE MOUNTAINS ALONG WITH NIGHT-TIME LOWS IN THE 60S TO LOW 70S. COULD END UP BEING ONE OF THE WARMEST WEEKS OF THE SUMMER EVEN AS THE SO-CALLED METEOROLOGICAL SUMMER ENDS ON AUGUST 31. PRECIPITATION WILL ALSO GENERALLY BE OF SUMMER-LIKE CHARACTER WITH DIURNALLY DRIVEN CONVECTION PROVIDING THE BEST CHANCES FOR RAINFALL. WEDNESDAY AFTERNOON LOOKS LIKE THE MOST PROMISING DAY FOR STORMS AS WEAK FRONTAL BOUNDARY PUSHES ACROSS THE CWA. THURSDAY AND FRIDAY LIKELY TO BE DRIER ALTHOUGH WIDELY SCATTERED SHOWERS STILL POSSIBLE. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... AS OF 130 PM EDT SATURDAY... AUTOMATED OBS SHOWING MORE CLOUD COVER THAN REALITY PER SAT/WEB CAMS. MAINLY SCT FIELD OF CU THIS AFTERNOON...AT TIMES BKN. NOT REALLY SEEING ANY TAF SITE THREATENED BY SUB VFR OR CONVECTION. BEST CHANCE OF ANY SHRA/TSRA WOULD BE NEAR ROA/LWB...BUT GIVEN LACK OF VERTICAL STRUCTURE WILL NOT HIGHLIGHT ANY IN THE TAFS. TONIGHT...MODELS SHOWING THE UPPER SHORTWAVE THAT IS OVER THE LOWER MS VALLEY THIS AFTERNOON...TO MOVE INTO THE OHIO VALLEY OVERNIGHT. WILL NOT REALLY SEE ANY GOOD THREAT OF SHOWERS UNTIL SUNDAY MORNING AFTER 12Z WEST OF A LWB/BLF LINE...AND ADDED VCSH AT BLF BY 14Z. OVERALL WILL SEE VFR THOUGH SOME FOG AND/OR LOW CLOUDS COULD FORM NEAR DAN/LWB/ROA/BCB LATE...BUT CONFIDENCE OVERALL IS LOW. EXTENDED DISCUSSION... SUNDAY AN AREA OF LOW PRESSURE WILL HEAD EASTWARD THROUGH THE SOUTHERN QUEBEC. ITS ASSOCIATED COLD FRONT WILL SWEEP THROUGH THE REGION BRINGING A GENEROUS COVERAGE OF SHOWERS AND SOME STORMS. SUB-VFR CONDITIONS ARE EXPECTED TO ACCOMPANY THE SYSTEM AND PRECIPITATION. ANOTHER COLD FRONT IS EXPECTED TO PRODUCE SIMILAR CONDITIONS TUESDAY INTO WEDNESDAY. HOWEVER...MODEL GUIDANCE FOR THIS ONE OFFERS PRECIPITATION IN A MORE SCATTERED DISTRIBUTION. AS SUCH...THE MAGNITUDE OF SUB-VFR CONDITIONS MAY BE LESS. && .EQUIPMENT... AS OF 730 AM EDT FRIDAY ... THE VISIBILITY SENSOR AT KDAN...DANVILLE REGIONAL AIRPORT...WILL BE OUT OF SERVICE UNTIL FURTHER NOTICE. A PART HAS BEEN BACK-ORDERED. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS/WP SHORT TERM...RCS LONG TERM...PC AVIATION...AMS/WP EQUIPMENT...AMS

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