Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 092349 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 749 PM EDT WED JUL 9 2014 .SYNOPSIS... A SLOW MOVING COOL FRONT WILL SLIDE SOUTHEAST INTO NORTH CAROLINA STALLING OVERNIGHT. WEAK HIGH PRESSURE WILL FOLLOW THE FRONT FOR THURSDAY INTO SATURDAY. A MUCH STRONGER COLD FRONT WILL BE PASSING THROUGH THE REGION NEXT MONDAY AND TUESDAY. && .NEAR TERM /THROUGH THURSDAY/... AS OF 710 PM EDT WEDNESDAY... MAIN LINE OF SHOWERS/TSRA LOCATED FROM CHARLOTTE COUNTY VA SOUTH INTO CASWELL COUNTY NC. ISOLATED COVERAGE TO THE WEST. MODIFIED POPS/FORECAST TO KEEP HIGHER POPS IN THE EAST THIS EVENING THEN LITTLE OR SLIGHT CHANCE POPS WEST. NO OTHER CHANGES TO THE FORECAST AT THIS TIME. PREVIOUS VALID DISCUSSION... OVERNIGHT DRIER AIR AS SEEN ON THE WATER VAPOR LOOP WILL PUSH INTO THE REGION AS THE LEADING WEAK COLD FRONT DRIFTS SOUTH INTO NORTH CAROLINA AND STALLS. MODELS CONTINUED TO SHOW A LOW ALONG THE FRONT LATE TONIGHT THAT PUSHES THE DEEPER MOISTURE BACK INTO THE FORECAST AREA AFTER MIDNIGHT. HAVE A LULL IN THE PRECIPITATION... ESPECIALLY IN THE NORTHWEST HALF OF THE FORECAST AREA THIS EVENING...THEN BRING BETTER PROBABILITIES BACK IN BY MORNING. TEMPERATURES WILL DEPEND ON CLOUD COVER. WITH LITTLE DROP IN DEW POINTS TONIGHT MINIMUM TEMPERATURES WILL REMAIN MILD. IF CLEARING DOES OCCUR...MAY BE ADDING FOG BACK INTO THE FORECAST IN LOCATIONS THAT HAD RAIN THIS AFTERNOON. CLOUDS AND SHOWERS WILL ALSO LIMIT RISE IN TEMPERATURES...ESPECIALLY ACROSS THE SOUTH AND EAST ON THURSDAY. STAYED CLOSER TO COOLER SIDE OF GUIDANCE FOR MAXIMUM TEMPERATURES. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... AS OF 300 PM EDT WEDNESDAY... EXPECT AN AREA OF PRECIPITATION TO BE COVERING THE SOUTHEAST PORTION OF THE BLACKSBURG CWA AT THE START OF THE SHORT TERM PERIOD...WITH GOOD LOW LEVEL MOISTURE CONVERGENCE ALONG A SFC BOUNDARY IN THIS AREA. THIS REGION WILL ALSO FALL UNDER THE RIGHT REAR QUAD OF AN UPPER LEVEL AND GOOD UPPER LEVEL DIVERGENCE.THIS AREA OF PRECIP WILL GRADUALLY WANE DURING THE OVERNIGHT HOURS. FOR FRIDAY...THE UPPER LEVEL TROF AXIS WEAKENS AND SHIFTS SLIGHT EAST...PLACING THE BEST UPPER LEVEL SUPPORT EAST OF THE BLACKSBURG FORECAST AREA. STILL EXPECT WIDELY SCATTERED SHOWERS AND STORMS IN THIS AREA WITH WEAK CONVERGENCE ALONG THE DYING BOUNDARY. A SECOND AREA FOR PRECIP DEVELOPMENT WILL BE POSSIBLE IN THE MOUNTAINS...WITH AN UPSLOPE FLOW AND A SFC BOUNDARY FORECAST BY THE GFS/NAM/SREF/ECMWF NEAR THE VA/WV BORDER. AS THE DEEPEST MOISTURE AND BEST UPPER LEVEL SUPPORT SHIFT EAST...THE COVERAGE OF PRECIPITATION FRIDAY SHOULD BE LESS...AS WELL AS THE AMOUNT OF CLOUD COVER. GENERALLY FOLLOWED THE GFS MOS GUIDANCE FOR HIGHS WITH HAS PERFORMED THE BEST IN OUR AREA OVER THE PAST FEW DAYS. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... AS OF 245 PM EDT WEDNESDAY... AS SFC HIGH PRESSURE SHIFTS EAST ON SATURDAY...THE LOW LEVEL FLOW BECOMES EAST/SOUTHEAST BRINGING WEAK UPSLOPE FLOW. AT THIS POINT...THE DEEPEST MOISTURE WILL BE SOUTH AND EAST OF OUR AREA...BUT ENOUGH LOW LEVEL CONVERGENCE SHOULD SPARK ISOLATED/WIDELY SCATTERED SHOWERS/STORMS ACROSS THE SOUTHERN BLUE RIDGE. BY SUNDAY AND MONDAY...A LOW LEVEL THETA-E AXIS SURGES INTO OUR AREA WHICH WILL INCREASE COVERAGE OF DIURNALLY DRIVEN SHOWERS AND STORMS. BUT SIMILAR TO WHAT WE HAVE EXPERIENCED RECENTLY...A DEEP WEST/SOUTHWEST FLOW SHOULD KEEP THE CONVECTION SCATTERED. TOWARD THE END OF THE LONG TERM PERIOD THE MEDIUM RANGE MODELS CONTINUE TO FORECAST A BROAD UPPER TROF AND AN ASSOCIATED CUT OFF LOW OVER THE NORTHERN GREAT LAKES BY TUESDAY. THIS FEATURE HELPS DRIVE A COLD FRONT THROUGH OUR AREA ON TUESDAY. THERE ARE STILL DIFFERENCES WITH REGARD TO THE TIMING OF THIS FRONT...WITH THE 06Z GFS FASTER THAN THE 00Z ECMWF. USING A BLEND OF THESE SOLUTIONS...WILL CONTINUE TO CARRY A CHANCE OF SHOWERS/STORMS ON TUESDAY. TEMPERATURES SHOULD CLIMB IN ADVANCE OF THE FRONT TO NEAR OR SLIGHTLY ABOVE NORMAL...BEFORE FALLING BELOW NORMAL TUESDAY NIGHT INTO WEDNESDAY WHEN DRIER AIR ARRIVES. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... AS OF 745 PM EDT WEDNESDAY... COMMS ISSUES REMAIN AT KDAN DESPITE AN INTERMITTENT RETURN OF OBSERVATION DATA. AMD NOT SKED CONTINUED IN THE TAF. TSRA IN THE DANVILLE AREA ATTM WILL BE EXITING BETWEEN 00Z-01Z. OTHERWISE MOST LOCATIONS ARE GOING TO BE RAINFREE THIS EVENING WITH VFR CONDITIONS. FOG SHOULD BECOME AN ISSUE AT TIMES OVERNIGHT ESPECIALLY WHERE IT RAINED...WHICH WILL BE ALL SITES. ATTM...THE FOG WILL ALSO BE DEPENDENT ON CLOUDS. THINK ENOUGH BREAKS TO ALLOW FOG FORMATION. WILL GO MAINLY MVFR/IFR LATE TONIGHT. FOG WILL BREAK UP AROUND 13-14Z. MODELS KEEPING THE THREAT OF SHRA/TSRA AROUND OVER THE SOUTHEAST CWA THURSDAY...SO HAVE VCTS AT ROA/LYH/DAN...BUT NOTHING AT BCB/LWB/BLF. EXPECT VFR OUTSIDE OF ANY STORMS. EXTENDED AVIATION... A LOWER PROBABILITY OF PRECIPITATION IS EXPECTED ACROSS THE AREA ON FRIDAY AND SATURDAY AS WEAK HIGH PRESSURE SLIDES IN FROM THE NORTH. MOISTURE AND MORE WIDESPREAD SHRA/TSRA LIKELY TO RETURN FOR THE END OF THE WEEKEND AS THE FRONT RETURNS NORTH RESULTING IN PERIODS OF MVFR CONDITIONS. OTRW PATCHY FOG RESULTING IN LOCAL MVFR TO IFR CONDITIONS LIKELY DURING THE LATE NIGHTS AND EARLY MORNINGS ESPCLY VALLEY LOCATIONS AND WHERE EARLIER AFTERNOON RAINFALL OCCURRED. && .EQUIPMENT... AS OF 400 PM EDT WEDNESDAY... COMMUNICATIONS OUTAGE CONTINUES WITH KDAN ASOS NOT TRANSMITTING. THE FAA IS AWARE OF THE OUTAGE AND WILL BE WORKING ON IT...BUT NO ESTIMATED TIME OF WHEN IT WILL BE WORKING AGAIN. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS/WP SHORT TERM...PH LONG TERM...AMS/PH/WERT AVIATION...AMS/JH/WP EQUIPMENT...WP

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