Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 060505 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 105 AM EDT WED MAY 6 2015 .SYNOPSIS... HIGH PRESSURE WILL REMAIN ACROSS THE SOUTHEAST U.S. THROUGH AT LEAST THURSDAY. A BACKDOOR COLD FRONT WILL MOVE INTO THE AREA ON WEDNESDAY...AND THEN STALL ACROSS THE WESTERN HALF OF THE REGION ON THURSDAY. A SLOW MOVING AREA OF LOW PRESSURE WILL IMPACT THE SOUTHEASTERN SEABOARD OF THE U.S. BUT CONFIDENCE IN HOW MUCH OR HOW LITTLE INFLUENCE THE SYSTEM WILL HAVE ON OUR AREA HEADING INTO THE WEEKEND IS STILL QUESTIONABLE. && .NEAR TERM /THROUGH TODAY/... AS OF 1135 PM EDT TUESDAY... VERY SLOW TO DIE OFF CONVECTION LINGERS FROM APPOMATTOX COURT HOUSE EAST TO FARMVILLE. THE MODELS AND MESO ANALYSIS SUGGEST THE ACTIVITY WILL BE GONE BY MIDNIGHT-1AM...WITH SKIES TAKING ON MORE OF CLEAR/PC SCENARIO. TEMP/DEWPOINT SPREAD IS STILL PRETTY HIGH ATTM...BUT THINK WITH THE SHOWERS TODAY AT LEAST WILL SEE PATCHY FOG IN THOSE PLACES...MAYBE MORE NEAR LYH AND IN THE NEW AND GREENBRIER VALLEYS. LOWS STILL LOOK ON TRACK WITH MOSTLY 50S...THOUGH SOME VALLEYS IN THE MTNS COULD DROP TO THE UPPER 40S. PREVIOUS VALID DISCUSSION FROM 4 PM... TEMPERATURES SOME 5 TO 10 DEGREE MILDER ARE EXPECTED TONIGHT THANKS TO HIGHER DEW POINT VALUES. LOWS WILL BE IN THE 50S OVER MUCH OF THE AREA. ON WEDNESDAY...A BACKDOOR COLD FRONT HAS BEEN PROMISED TO MOVE INTO THE AREA BY THE AFTERNOON THE PAST SEVERAL MODEL RUNS...AND A SIMILAR SCENARIO IS OFFERED AGAIN ON THE 12Z/8AM RUN. THIS FEATURE WILL ADD UPON THE DIURNAL INFLUENCE WE HAVE BEEN COUNTING ON FOR ACTIVITY THE PAST COUPLE OF DAYS. THE FRONT SHOULD HELP FIRE CONVECTION A LITTLE SOONER...WITH GREATER COVERAGE...ESPECIALLY IN THE NORTH AND WEST...AND CONTINUE BETTER COVERAGE INTO THE LATE AFTERNOON. THE FRONT WILL ACT MORE AS A LOW LEVEL BOUNDARY RATHER THAN A TRUE COLD FRONT AS TEMPERATURES TOMORROW WILL BE COMPARABLE OR EVEN SLIGHTLY WARMER THAN THOSE OF TODAY. LOOK FOR HIGHS OF THE UPPER 70S TO NEAR 80 IN THE MOUNTAINS TO THE LOW TO MID 80S ACROSS THE PIEDMONT. && .SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/... AS OF 330 PM EDT TUESDAY... SHOWER AND THUNDERSTORM ACTIVITY WILL GRADUALLY DIMINISH AFTER SUNSET WEDNESDAY EVENING...AND IS EXPECTED TO FIZZLE OUT COMPLETELY BY MIDNIGHT. THE INCREASE OF LOW LEVEL MOISTURE OFF THE ATLANTIC... COUPLED WILL PARTLY CLOUDY SKIES THROUGH THE NIGHT...WILL HELP HOLD OVERNIGHT LOWS IN THE UPPER 50S/LOW 60S AREAWIDE. ANOTHER ROUND OF SPOTTY DAYTIME-HEATING DRIVEN SHOWERS...WITH A FEW THUNDERSTORMS...WILL REDEVELOP ON THURSDAY AFTERNOON...AGAIN MAINLY ACROSS THE MOUNTAINS. WITH UPPER LEVEL RIDGING STILL IN PLACE ACROSS OUR AREA...INSTABILITY DOES NOT APPEAR TO BE AS HIGH AS EXPECTED FOR WEDNESDAY...BUT STILL CANNOT RULE OUT AN OCCASIONAL STRONG THUNDERSTORM. AFTERNOON HIGH TEMPERATURES WILL REACH INTO THE MID/UPPER 70S WEST...AND THE LOW 80S EAST...WHILE THURSDAY NIGHT LOWS WILL FALL INTO THE MID/UPPER 50S. WEATHER FORECAST MODELS ARE IN GENERAL AGREEMENT THAT A WAVE OF LOW PRESSURE WILL LIFT NORTH FROM THE CARIBBEAN...AND APPROACH THE CAROLINA COAST THURSDAY NIGHT. WHILE THE LOW WILL NOT DIRECTLY MOVE INTO OUR AREA...IT DOES APPEAR THAT IT WILL APPROACH CLOSE ENOUGH TO PUSH A SIGNIFICANT AMOUNT OF TROPICAL MOISTURE ACROSS THE MID ATLANTIC. AS SUCH...MAY SEE SHOWER AND THUNDERSTORM ACTIVITY MORE CONCENTRATED ACROSS THE PIEDMONT FRIDAY AFTERNOON AS TROPICAL MOISTURE MOVES ACROSS THE AREA. UPPER LEVEL WINDS DIRECTING THE MOVEMENT OF THE LOW ARE EXPECTED TO BE LIGHT...AND WOULD NOT BE SURPRISED TO SEE FLUCTUATIONS IN THE TRACK OF THIS SYSTEM OVER THE NEXT FEW MODELS RUNS. WILL CONTINUE TO MONITOR THE TRACK OF THE LOW CLOSELY...AS AN INLAND TRACK WILL LIKELY PUSH LARGE AMOUNTS OF TROPICAL MOISTURE ACROSS OUR AREA FOR THE WEEKEND. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 345 PM EDT TUESDAY... UPPER LEVEL RIDGING ACROSS THE SOUTHEAST AND MID ATLANTIC IS EXPECTED TO MOVE LITTLE THROUGH THE WEEKEND INTO THE BEGINNING OF THE NEXT WORKWEEK. AS SUCH...EXPECT THE TREND OF SUMMERLIKE WEATHER TO CONTINUE. THE MAIN CONCERN THROUGH THE PERIOD REMAINS THE TRACK OF A LOW APPROACHING THE CAROLINA COAST...POTENTIALLY PUSHING A PLUME OF TROPICAL MOISTURE ACROSS OUR AREA WHICH DAYTIME-HEATING DRIVEN SHOWERS AND THUNDERSTORMS MAY FEED OFF OF. THE THREAT FOR ANY SEVERE THUNDERSTORMS REMAIN ISOLATED DURING THIS TIME...HOWEVER ABUNDANT MOISTURE AND LIGHT UPPER LEVEL WINDS INDICATE A THREAT FOR SLOW MOVING CELLS CAPABLE OF PRODUCING LOCALLY HEAVY RAIN. SHOULD THE LOW REMAIN OFFSHORE...FURTHER AWAY FROM OUR AREA...THE HEAVY RAIN THREAT WILL BE REDUCED. WEATHER FORECAST MODELS ARE STILL TRYING TO GET A HANDLE ON WHAT TRACK THE LOW WILL TAKE...SO THE SITUATION WILL BE MONITORED CLOSELY OVER THE NEXT FEW DAYS. RAINFALL AND INCREASED CLOUD COVER ALSO HAS THE POTENTIAL TO AFFECT DAYTIME TEMPERATURES...AND THEREFORE AFTERNOON HIGHS ALSO REMAIN SOMEWHAT IN QUESTION. WITH THIS AFTERNOON`S FORECAST PACKAGE...HAVE AFTERNOON HIGHS RANGING FROM THE MID/UPPER 70S WEST TO THE LOW 80S EAST EACH DAY...WHILE OVERNIGHT LOWS WILL BE IN THE UPPER 50S AND LOW 60S. INCREASED RAINFALL HAS THE POTENTIAL TO KEEP AFTERNOON HIGHS A FEW DEGREES LOWER ON SATURDAY HOWEVER. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 1245 AM EDT WEDNESDAY... OVERALL VFR TO PREVAIL OVERNIGHT WITH PATCHY FOG DEVELOPMENT LIKELY TO COMMENCE AFTER 08Z/4AM ESPCLY IN THE VALLEYS AND OUT EAST WHERE AIDED BY FADING SHOWERS ATTM. HOWEVER DEGREE OF RESIDUAL MID DECK LIKELY TO PLAY INTO WHETHER OR NOT COVERAGE BECOMES MORE WIDESPREAD AND/OR SPOTS DROP INTO LOW END MVFR/IFR BY DAYBREAK. FOR NOW WILL KEEP SIMILAR TO BEFORE WITH SOME ADDED FOG ALONG THE KLYH-KDAN CORRIDOR AND A LITTLE LESS OUT WEST PER CLOUDS AND WIDER TEMP/DEWPOINT SPREADS. THINK KLWB COULD FALL INTO A PERIOD OF IFR RIGHT AT SUNRISE BUT MOSTLY SHALLOW NATURE FOR THE MOST PART. OTRW KEEPING ALL OTHER SPOTS AT MVFR OR BETTER UNDER TEMPO GROUPS FOR PATCHY FOG COVERAGE AT THIS POINT. CONVECTION SHOULD BE A BIT MORE WIDESPREAD ACROSS THE NORTH/WEST WEDNESDAY AFTERNOON AHEAD OF A WEAK BACKDOOR COLD FRONT AND AIDED BY LIGHT SE FLOW INCLUDING DIFFERENTIAL HEATING. MODELS SUGGEST BEST COVERAGE AROUND KLWB TO INIT AND IN A RIBBON ALONG THE BLUE RIDGE. HOWEVER ORGANIZATION STILL LOOKS TO BE RATHER SCATTERED UNTIL PERHAPS LATE IN THE DAY WHEN CLUSTERS/BANDS MERGE. THUS WILL KEEP MOST CONVECTION OUT OF THE PREVAILING GROUPS BUT INCLUDE MORE OF A VCTS FLAVOR MOUNTAINS FOR A BIT MORE THUNDER PER DECENT INSTABILITY AND MORE FORCING THAN TUESDAY. KEPT SHRA/TSRA OUT OF ALL EASTERN SITES WITH GUIDANCE SHOWING MOST FOCUS OVER THE WEST BUT COULD SEE SOME COVERAGE EVENTUALLY WORK OFF THE MOUNTAINS TOWARD KLYH LATE IN THE DAY. CONVECTION MAY LINGER WELL INTO THE EVENING WHILE POSSIBLY WORKING INTO EASTERN SECTIONS BEFORE FADING BUT TOO IFFY TO INCLUDE VCSH/VCTS MENTION THERE FOR NOW. OTHERWISE SHOULD SEE COVERAGE END WEST BEFORE MIDNIGHT AND LIKELY GIVE WAY TO ANOTHER ROUND OF FOG/STRATUS LATE AT MOST LOCATIONS. A BACKDOOR COLD FRONT WILL IMPACT THE AREA THURSDAY WITH ADDED AFTERNOON SHOWERS AND STORMS MAINLY OVER THE FAR WESTERN SECTIONS. SUB- VFR CONDITIONS WILL BE ASSOCIATED UNDER THE CORES OF THE STRONGEST CELLS...AND THEN DURING THE LATE NIGHT AND EARLY MORNING HOURS WITH LIGHT FOG IN THE VALLEYS. CONFIDENCE IN FORECAST PARAMETERS FRIDAY THROUGH SUNDAY IS LOW TO MODERATE. MODEL GUIDANCE IS HIGHLY VARIABLE IN REGARDS TO THE IMPACT A SLOW MOVING AREA OF UPPER LEVEL LOW PRESSURE ACROSS THE SOUTHEAST U.S. WILL HAVE ON THE REGION. SOME GUIDANCE HAS THE LOW CENTERED STILL OFF THE SOUTH CAROLINA COAST ON SATURDAY INTO SUNDAY...WHILE OTHERS HAVE IT ALONG THE NORTH CAROLINA...SOUTH CAROLINA STATE LINE IN A MORE OR LESS LOOPING SCENARIO. THE FORMER SOLUTION...AND OTHERS LIKE IT...POSE LIMITED IF ANY INFLUENCE ON OUR REGION. THE LATTER AS A WETTER...WINDIER...AND ONE MORE SUBJECT TO SUB-VFR CONDITIONS FOR THE MAJORITY OF THE AREA. THE CONSENSUS SCENARIO STILL HAS DAYTIME...MOUNTAIN FOCUSED ISOLATED TO SCATTERED SHOWERS AND STORMS DEVELOPING ACROSS THE REGION...WITH MAINLY VFR CONDITIONS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...DS NEAR TERM...DS/WP SHORT TERM...NF LONG TERM...NF AVIATION...DS/JH/WP

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