Area Forecast Discussion
Issued by NWS Blacksburg, VA

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000 FXUS61 KRNK 281003 AFDRNK AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG VA 603 AM EDT THU MAY 28 2015 .SYNOPSIS... HIGH PRESSURE IS CENTERED OFF THE SOUTHEAST ATLANTIC COAST AND WILL MAINTAIN A BROAD SOUTHERLY FLOW OF MOISTURE INTO THE REGION THROUGH THE REMAINDER OF THIS WEEK...A PATTERN THAT WILL FEATURE WARM/HUMID SUMMERLIKE CONDITIONS. IN ADDITION TO THE HEAT/HUMIDITY... THERE WILL BE A DAILY THREAT OF SCATTERED SHOWERS/STORMS. FOR TODAY THE STORM POTENTIAL WILL BE MOST PRONOUNCED ALONG A WEAK COLD FRONT THAT WILL BE APPROACHING THE AREA FROM THE NORTHWEST. ADDITIONAL SHOWERS/STORMS WILL ACCOMPANY AN UPPER LEVEL DISTURBANCE THAT WILL BE MOVING NORTHEAST THROUGH THE TENNESSEE VALLEY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 530 AM EDT THURSDAY... A WEAK COLD FRONT EXTENDS FROM WESTERN NEW YORK INTO THE OHIO VALLEY. THIS FRONT WILL MOVE SOUTHEAST INTO THE VA/WV HIGHLANDS TODAY BEFORE DISSIPATING OVER THE REGION TONIGHT. IN ADDITION TO THE FRONT...AN UPPER LEVEL DISTURBANCE WILL BE MOVING NORTHEAST THROUGH THE TENNESSEE VALLEY...AND WILL INTERACT WITH THE APPROACHING SURFACE FRONT TO PROVIDE LIFT FOR SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING. BEST COVERAGE OF SHOWERS/STORMS TODAY WILL BE ACROSS THE MOUNTAINS WEST OF THE BLUE RIDGE. STEERING WINDS ARE WEAK...SFC-20KFT MEAN FLOW OF 10KTS OR LESS. THIS SUGGESTS ANY ACTIVITY THAT DEVELOPS TODAY WILL BE SLOW MOVING AND WILL PROLONG THE HEAVIER SHOWERS ONCE THEY DEVELOP. BOTH THE HIGH RES-WRF AND HRRR INDICATE THAT SHOWERS WILL BEGIN TO DEVELOP OVER OUR MTNS AROUND MID-DAY...BECOMING MOST PRONOUNCED BETWEEN 20Z/3PM AND SUNSET 01Z/9PM. THE OVERALL THREAT FOR WIDESPREAD HAZARDOUS WEATHER IS LOW...HOWEVER WITH PRESENCE OF THE UPPER LEVEL DISTURBANCE...CAN`T RULE OUT SOME PULSE SEVERE STORMS THIS AFTERNOON. MODEL FORECAST CAPE OF 2500 J/KG COUPLED WITH FORECAST DCAPE OF 1000 MAY BE ENOUGH FOR SOME ISOLATED MICROBURSTS. TEMPERATURES TODAY WILL BE SUMMER-LIKE WITH HIGHS IN THE 80S...COMPLIMENTED BY DEWPOINTS IN THE U50S-LOWER 60S. && .SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/... AS OF 500 AM EDT THURSDAY... UPPER LEVEL RIDGING WILL REMAIN IN PLACE ALONG THE EAST COAST ON FRIDAY...BUT WILL SLOWLY BREAK DOWN DURING THE WEEKEND...GIVING WAY TO A FLATTENING...MORE ZONAL PATTERN AS AN UPPER LEVEL TROUGH SHIFTS ACROSS EASTERN CANADA. THE PASSAGE OF THIS TROUGH WILL PUSH A COLD FRONT SOUTHWARD...WHERE IT WILL ENTER OUR AREA SUNDAY AFTERNOON BEFORE STALLING. FOR FRIDAY AND SATURDAY...SPOTTY SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS THE MOUNTAINS EARLY BOTH AFTERNOONS...WITH COVERAGE PEAKING DURING EARLY EVENING. CONVECTION WILL WEAKEN AND FADE AROUND SUNSET WITH LOSS OF HEATING...BUT STILL EXPECT LIGHT SHOWER TO TWO TO FLOAT ACROSS THE AREA OVERNIGHT. MAY SEE ONE OR TWO STORMS BECOME STRONG...BUT THE BIGGER CONCERN IS LIGHT UPPER LEVEL WINDS/SLOW CELL MOVEMENT...WHICH MAY RESULT IN LOCALLY HEAVY RAIN IF CELLS STALL OR TRAIN. AFTERNOON HIGHS WILL RANGE FROM THE UPPER 70S AND LOW 80S ACROSS THE MOUNTAINS...TO THE MID 80S ACROSS THE PIEDMONT. OVERNIGHT LOWS WILL FALL INTO THE LOW/MID 60S. EXPECT GREATER COVERAGE OF SHOWERS AND THUNDERSTORMS ON SUNDAY AS THE COLD FRONT APPROACHES. WHILE THE UPPER LEVEL DYNAMICS STILL APPEAR TO BE MARGINAL...INCREASED CONVERGENCE IN THE LOW LEVELS SHOULD BE ENOUGH TO SUPPORT A SLIGHTLY BETTER CHANCE OF STRONG STORMS DURING THE AFTERNOON AND EVENING...PERHAPS WITH A FEW STORMS BECOMING SEVERE. THE COLD FRONT WILL ENTER THE INTERSTATE 64 CORRIDOR BY EARLY EVENING...AND EVENTUALLY STALL SOMEWHERE ACROSS OUR AREA FOR THE REMAINDER OF THE NIGHT...PROVIDING THE FOCUS FOR SPOTTY SHOWERS INTO MONDAY MORNING. INCREASED CLOUDS WILL MAKE FOR SLIGHTLY COOLER TEMPERATURES ACROSS THE MOUNTAINS...WITH HIGHS IN THE MID/UPPER 70S...WHILE THE PIEDMONT WILL REACH THE UPPER 80S. LOWS WILL BE IN THE UPPER 50S NEAR INTERSTATE 64...AND HOLD IN THE MID 60S FURTHER SOUTH. && .LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 500 AM EDT THURSDAY... BY MONDAY...THE UPPER PATTERN WILL HAVE ESTABLISHED A SPLIT FLOW REGIME ACROSS THE NORTHERN TIER OF STATES AS A CLOSED LOW DEVELOPS OVER THE LOWER MISSISSIPPI VALLEY AND SLOWLY SINKS SOUTHWARD THROUGH THE MIDDLE OF NEXT WEEK. SOME RIDGING WILL ALSO BE TAKING PLACE OVER THE MID ATLANTIC REGION AND SET UP A SLUGGISH BLOCKY PATTERN. AT THE SURFACE...HIGH PRESSURE PASSING EAST ACROSS THE GREAT LAKES WILL SPREAD ACROSS THE NORTHEAST AND WEDGE DOWN THE EASTERN SEABOARD...GIVE THE COLD FRONT A RENEWED PUSH THROUGH OUR AREA. THE HIGH WILL BRING COOLER/NEAR NORMAL TEMPERATURES TO THE REGION. HOWEVER...THE PATTERN WILL KEEP US MOIST WITH DEEP SOUTHEASTERLY FLOW AND EXPECT ENOUGH FORCING BETWEEN OROGRAPHIC UPSLOPE AND DIURNAL EFFECTS TO KEEP SOME SHOWER ACTIVITY...AND POSSIBLY A THUNDERSTORM...IN THE FORECAST THROUGH THE PERIOD. && .AVIATION /10Z THURSDAY THROUGH MONDAY/... AS OF 200 AM EDT THURSDAY... PATCHY FOG THIS MORNING...OTHERWISE VFR ANTICIPATED THROUGH FIRST HALF OF THE DAY THURSDAY. DAYTIME HEATING...IN ADDITION TO SOME LIFT FROM APPROACHING FRONT OVER THE OHIO VALLEY AND VORTICITY ASSOCIATED WITH CONVECTIVE DEBRIS MOVING NORTH FROM THE SOUTHERN APPALACHIANS...SHOULD RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS DURING THE MID/LATE AFTERNOON AND EVENING. MESOSCALE MODELS FOCUS THE GREATEST COVERAGE BETWEEN 20Z/3PM AND 01Z/9PM...AND MAINLY ACROSS THE MOUNTAINS ALONG AND WEST OF THE BLUE RIDGE. MEAN WINDS FROM SFC-20KFT ARE FCST TO BE LESS THAN 10 KTS...SO SHOWERS/STORMS THAT DEVELOP SHOULD BE SLOW MOVING. SURFACE WINDS THROUGH THE TAF VALID PERIOD WILL BE LIGHT AND VARIABLE...SPEEDS MOSTLY 7KTS OR LESS. EXTENDED AVIATION DISCUSSION... THROUGH THE UPCOMING WEEKEND...A MOIST UNSTABLE AIR MASS WILL REMAIN IN PLACE ACROSS THE REGION WITH ONLY WEAK FORCING. THIS WILL RESULT IN MAINLY SLOW MOVING DIURNALLY DRIVE DEEP CONVECTION DURING THE AFTERNOON AND EVENING HOURS FOLLOWED BY STABLE CONDITIONS AT NIGHT. A FRONTAL SYSTEM WILL APPROACH FROM THE NORTH DURING THE WEEKEND...BUT WILL LIKELY REMAIN WELL NORTH OF THE FORECAST AREA THROUGH SUNDAY. THUS...NO CHANGE IN AIR MASS IS EXPECTED THROUGH THE PERIOD. WITH MOIST/STABLE CONDITIONS AT NIGHT...PATCHY LATE NIGHT/EARLY MORNING LOW CLOUDS/FOG AND ASSOCIATED IFR-LIFR CIGS/VSBYS WILL BE POSSIBLE EACH MORNING...BUT LIMITED TO A FEW HOURS BEFORE DAYBREAK AND QUICKLY BURNING OFF AFTER SUNRISE. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PM NEAR TERM...PM SHORT TERM...NF LONG TERM...MBS/NF AVIATION...PM

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