300  
FXUS61 KRNK 042256  
AFDRNK  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BLACKSBURG VA  
656 PM EDT SAT JUL 4 2020  
   
SYNOPSIS
 
 
A WEAK COLD FRONT WILL MOVE SOUTH THROUGH THE MID-ATLANTIC REGION  
TONIGHT INTO SUNDAY AND STALL ACROSS THE VIRGINIA PIEDMONT. THIS  
WILL BRING A CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS THROUGH  
EARLY NEXT WEEK.  
 

 
   
NEAR TERM /THROUGH SUNDAY/
 
 
AS OF 645 PM EDT SATURDAY...  
 
CONVECTION IS ISOLATED ACROSS THE FORECAST AREA LATE THIS  
AFTERNOON, MOST FIRING UP ALONG OUTFLOW BOUNDARIES AND POCKETS  
OF MOISTURE CONVERGENCE AND HIGHER CAPES. SHOULD SEE A GRADUAL  
WEAKENING TREND THIS EVENING, BUT CAP WEAKENS, SO NOT SEEING A  
COMPLETELY RAINFREE RADAR INTO LATE TONIGHT, BUT MOST WILL BE  
DRY/MUGGY.  
 
PREVIOUS AFTERNOON DISCUSSION...  
 
A COLD FRONT HAS STALLED JUST NORTH OF DC AND ALONG THE NE VA  
COAST THIS AFTERNOON. SINCE THIS SYSTEM HAS NO JET SUPPORT AND  
LACKING STRONG CONVECTION, IT WILL HAVE A TOUGH TIME MOVING  
SOUTH ESPECIALLY INTO 90F TEMPERATURES TODAY. AS WE COOL  
OVERNIGHT, THIS FRONT IS EXPECTED TO ADVANCE SOUTH AND WEST,  
STALLING IN THE VICINITY OF A LINE FROM CHARLOTTESVILLE (KCHO)  
TO DANVILLE (KDAN) BY SUNRISE.  
 
MORNING SOUNDINGS SHOWING A FAIRLY STRONG CAP AROUND 9-11 KFT  
ACROSS THE MOUNTAINS AND 11-13 KFT OVER THE PIEDMONT. JUST LIKE  
YESTERDAY, DIURNAL HEATING AND AMPLE MOISTURE UNDER THIS HIGH  
INVERSION WILL ALLOW FOR CUMULUS CLOUDS TO FORM THROUGH THE  
AFTERNOON AND EARLY EVENING. INVERSION MAY BE LOW ENOUGH TO  
DETER THUNDERSTORMS THIS AFTERNOON, BUT WITH A HIGHER INVERSION  
THAN YESTERDAY, WE MAY SEE MORE AREAL COVERAGE OF SHOWERS. IF AN  
AREA HAS A WEAKENING INVERSION, A STRONG TO SEVERE PULSE STORM  
IS NOT OUT OF THE QUESTION. THE CENTRAL PIEDMONT OF VIRGINIA  
(LYNCHBURG AREA) WOULD BE THE AREA WITH THE WEAKEST INVERSION AS  
IT IS CLOSER TO THE FRONT. WITH DRY AIR ALOFT, DAMAGING WIND  
GUSTS WILL BE A THREAT. HOWEVER, THE THREAT FOR STRONG TO SEVERE  
STORMS IS VERY LOW. SHOWERS WILL WANE THIS EVENING, BUT COULD  
LINGER LONGER INTO THE EVENING WITH A VERY WARM ENVIRONMENT AND  
THE COLD FRONT EDGES CLOSER TO THE AREA.  
 
SUNDAY COVERAGE OF STORMS WILL DEFINITELY BE GREATER WITH THE  
COLD FRONT IN THE VICINITY. THE CHANCES FOR THUNDERSTORMS WILL  
ALSO BE HIGHER WITH A WEAKER CAPPING INVERSION AND CONTINUED  
WARM AND HUMID CONDITIONS. THE CHANCES FOR A STRONG TO SEVERE  
PULSE STORMS WILL ALSO BE HIGHER WITH DAMAGING WIND GUSTS BEING  
THE PRIMARY THREAT AND LARGE HAIL A SECONDARY THREAT. THE FRONT  
IS EXPECTED TO STALL IN OR NEAR THE AREA, THEREFORE STORMS COULD  
LINGER THROUGH THE NIGHT.  
 
HIGHS TODAY WILL RANGE IN THE MID TO UPPER 80S ACROSS THE  
MOUNTAINS TO MID 90S EAST OF THE BLUE RIDGE. SLIGHTLY LOWER  
HEIGHTS TOMORROW WILL RESULT IN COOLER TEMPERATURES, BUT STILL  
LOOKING AT A WARM AND HUMID DAY WITH HIGHS IN THE 80S WEST OF  
THE BLUE RIDGE TO LOW 90S EAST. SUNDAY'S DEWPOINTS WILL RANGE  
FROM THE MID 60S TO LOWER 70S.  
 

 
   
SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/
 
 
AS OF 200 PM EDT SATURDAY...  
 
SOUTHERLY WINDFLOW WILL BECOME BETTER ESTABLISHED ON MONDAY,  
ALLOWING DEEPER MOISTURE TO FLOW INTO THE MID-ATLANTIC AND  
CENTRAL APPALACHIANS REGION. THIS WILL SUPPORT GRADUALLY  
INCREASING COVERAGE OF AFTERNOON SHOWERS AND THUNDERSTORMS EACH  
DAY AS THE WORKWEEK PROGRESSES. COVERAGE IS EXPECTED TO REMAIN  
WIDELY SCATTERED ON MONDAY AS THE MID-ATLANTIC REMAINS UNDER THE  
INFLUENCE OF WEAK RIDGING EXTENDING FROM ACROSS THE SOUTHEAST  
STATES. CONVECTION IS EXPECTED TO BE OF THE HIT-AND-MISS  
VARIETY, STARTING OFF ALONG THE RIDGELINES DURING LATE MORNING,  
BEFORE EXPANDING EAST ACROSS THE PIEDMONT BY MID AFTERNOON.  
GIVEN THE INSTABILITY DERIVED FROM STRONG AFTERNOON HEATING,  
THERE IS POTENTIAL FOR A FEW STORMS TO BECOME SEVERE, PACKING  
LOCALLY DAMAGING WINDS, AS WELL AS HEAVY DOWNPOURS.  
 
THIS PATTERN WILL REPEAT ON TUESDAY, THOUGH WITH GREATER  
COVERAGE OF RAINFALL EXPECTED MORE SO SOUTH OF HIGHWAY 460 AS A  
BROAD BUT WEAK UPPER LEVEL TROUGH DRIFTS EASTWARD ACROSS THE  
LOWER MISSISSIPPI VALLEY.  
 
WEATHER FORECAST MODELS ARE STILL TRYING TO RESOLVE HOW MUCH  
IMPACT THE UPPER LEVEL TROUGH/DEVELOPING ASSOCIATED SURFACE LOW  
PRESSURE WILL HAVE ON OUR WEATHER PATTERN FROM MID-WEEK ONWARD,  
WHICH IS TYPICAL OF WEAK SYSTEMS THAT DRIFT SLOWLY. WHILE LARGE  
AREAS OF HEAVY RAIN ARE NOT EXPECTED, CAN STILL SEE LOCALIZED  
AREAS OF HEAVY RAIN DEVELOPING GIVEN PRECIPITABLE WATER VALUES  
WILL BE AROUND 2 INCHES - AN INDICATOR OF A VERY MOIST  
ATMOSPHERE - IN A PATTERN THAT CAN SUPPORT STORMS TRAINING OVER  
THE SAME LOCATIONS. AS FOR TEMPERATURES WEDNESDAY, UNDERCUT  
MODEL GUIDANCE FOR AFTERNOON HIGHS BY 2-3 DEGREES BASED ON  
WIDESPREAD CLOUD COVER AND SOUTHEASTERLY WINDFLOW OFF THE  
ATLANTIC.  
 

 
   
LONG TERM /WEDNESDAY THROUGH SATURDAY/
 
 
AS OF 200 PM EDT SATURDAY...  
 
AN UPPER LEVEL TROUGH AND ASSOCIATED SURFACE LOW PRESSURE  
DEVELOPING ALONG THE COASTAL CAROLINAS WILL MAINTAIN DEEP  
MOISTURE ACROSS THE MID-ATLANTIC ON THURSDAY AND FRIDAY,  
PROMOTING SCATTERED SHOWERS AND THUNDERSTORMS EACH DAY. SOME OF  
THIS ACTIVITY MAY PRODUCE LOCALLY HEAVY RAIN. WITH THE SURFACE  
LOW LIFTING GRADUALLY NORTHWARD, WINDS WILL SHIFT MORE EAST TO  
NORTHEASTERLY, MAINTAINING A FLOW OF COOL ATLANTIC AIR THAT WILL  
KEEP AFTERNOON TEMPERATURES BELOW NORMAL FOR EARLY JULY, THOUGH  
AT THIS TIME IT'S STILL HARD TO PINPOINT BY HOW MUCH.  
 
BY SATURDAY, WINDS ACROSS OUR AREA WILL SHIFT WEST-  
NORTHWESTERLY AS THE LOW EXITS TOWARD NEW ENGLAND. THE RETURN OF  
DOWNSLOPING WINDS WILL RESULT IN WARMER AFTERNOON TEMPERATURES  
AND A DECREASE IN RAINFALL COVERAGE, THOUGH A FEW SHOWERS AND  
THUNDERSTORMS ARE STILL POSSIBLE IN THE RESIDUAL MOISTURE.  
 

 
   
AVIATION /00Z SUNDAY THROUGH THURSDAY/
 
 
AS OF 650 PM EDT SATURDAY...  
 
CONVECTION AT THE START OF THE TAF PERIOD WILL BE ISOLATED AND  
MAY SEE SOME SHOWERS IN VICINITY OF LYH/PERHAPS LWB. OVERALL  
WILL AMEND AS NECESSARY AS COVERAGE IS WIDELY SCATTERED.  
 
OTHERWISE, VFR THROUGH THE PERIOD, THOUGH SOME FOG AT LWB  
POSSIBLE LATE TONIGHT.  
 
A COLD FRONT ENTERS THE PIEDMONT TONIGHT AND STALLS. THIS WILL  
BE THE FOCUS FOR MORE SHOWERS AND THUNDERSTORMS ON SUNDAY  
AFTERNOON, BUT AGAIN COVERAGE SEEMS WIDELY SCATTERED SO NO  
PINPOINTING TIMING OF WHEN/IF AIRPORTS GET IMPACTED.  
 
EXTENDED AVIATION DISCUSSION...  
 
THE THREAT FOR SCATTERED AFTERNOON AND EVENING THUNDERSTORMS  
CONTINUES INTO NEXT WEEK AS MOISTURE AND INSTABILITY BECOME  
MORE WIDESPREAD.  
 

 
   
RNK WATCHES/WARNINGS/ADVISORIES
 
 
VA...NONE.  
NC...NONE.  
WV...NONE.  
 

 
 

 
SYNOPSIS...RCS  
NEAR TERM...RCS/WP  
SHORT TERM...NF  
LONG TERM...NF/VFJ  
AVIATION...RCS/WP  
 
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