031  
FXUS61 KRNK 311820  
AFDRNK  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BLACKSBURG VA  
220 PM EDT SUN MAY 31 2020  
   
SYNOPSIS
 
 
HIGH PRESSURE CONTINUES TO DOMINATE THE FORECAST THROUGH MONDAY.  
A WEAK COLD FRONT WILL DRIFT INTO THE REGION FROM THE NORTH BY  
TUESDAY THEN LINGER OR STALL NEAR THE NORTH CAROLINA...VIRGINIA  
BORDER THROUGH MIDWEEK AS STRONG HIGH PRESSURE BUILDS ACROSS THE  
MIDWEST. DRY AND MILD CONDITIONS THROUGH MONDAY WILL GIVE WAY  
TO SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS DURING THE  
LATER HALF OF THE WEEK ALONG WITH INCREASINGLY WARM AND HUMID  
CONDITIONS.  
 

 
   
NEAR TERM /THROUGH MONDAY/
 
 
AS OF 130 PM EDT SUNDAY...  
 
HIGH PRESSURE CONTINUES TO DOMINATE THE FORECAST BRINGING MOSTLY  
SUNNY, DRY, AND WARM WEATHER. SINCE ABOUT 14Z A CUMULUS DECK HAS  
BEEN BUILDING ACROSS A MAJORITY OF THE CWA. NOTHING FURTHER IS  
EXPECTED TO DEVELOP WITH SUCH DRY AIR IN PLACE AND NO DRIVING FORCE  
TO PUSH UPDRAFTS BEYOND THE LCL.  
 
BASED ON HOW FAST TEMPERATURES HAVE WARMED THROUGH THE AM, MOST  
AREAS BESIDES ELEVATION ABOVE 3500 FEET WERE BUMPED UP A DEGREE FOR  
LIKELY A SLIGHTLY WARMER AFTERNOON THAN ORIGINALLY FORECAST. DESPITE  
THE DRY AIR IN PLACE, SUCH SATURATED SOIL CONDITIONS MEAN THAT ANY  
REAL SURFACE HEATING IS GOING TO BE LIMITED SOME FROM LATENT HEAT  
RESTRICTIONS.  
 
TONIGHT, LOOKING AT HOW LOWS PERFORMED LAST NIGHT, I AM RUNNING  
SLIGHTLY WARMER THAN ORIGINALLY THOUGHT. AREAS WHERE UPPER LEVEL  
CLOUDS WEREN'T PRESENT WERE ~2 DEGREES ABOVE FORECAST. THIS IS AGAIN  
LIKELY DUE TO THE AMPLE SOIL MOISTURE FIGHTING EFFECTIVE COOLING  
DESPITE THE DRY AIRMASS IN PLACE.  
 
LOOKING AHEAD TO TOMORROW, IT LOOKS TO BE A NEAR REPEAT FROM TODAY.  
HIGH PRESSURE TO OUR NORTHWEST WILL BE SLOWLY SLIPPING EASTWARD.  
OVERALL, THE MAIN CHANGE IN WEATHER WILL BE SLIGHTLY LOWER WINDS AND  
MORE WESTERLY FLOW FOR THE WESTERN SLOPES BY THE AFTERNOON.  
 

 
   
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/
 
 
AS OF 155 PM EDT SUNDAY...  
 
THE WEEK WILL START ON A QUIET AND COOL NOTE AS A LARGE AREA OF  
CANADIAN HIGH PRESSURE DRIFTS SLOWLY SOUTHEAST FROM THE OHIO  
VALLEY ACROSS THE REGION AND OFF THE MID-ATLANTIC COAST BY  
TUESDAY. UNSEASONABLY COOL MORNING TEMPERATURES IN THE 40S CAN  
BE EXPECTED TUESDAY MORNING, BUT THAT SHOULD BE THE END OF THE  
COOL AND DRY WEATHER FOR SOMETIME TO COME. AS THE SURFACE HIGH  
MOVES OFF SHORE AND AN UPPER RIDGE BUILDS TO OUR WEST, 850MB  
TEMPERATURES WILL WARM FROM THE SINGLE DIGITS EARLY IN THE WEEK  
WELL INTO THE POSITIVE TEENS, WITH EVEN A POCKET OF +20 FLIRTING  
WITH THE REGION AS WE PROGRESS INTO MID AND LATE WEEK. HUMIDITY  
LEVELS WILL ALSO BEGIN TO COME UP THROUGH THE PERIOD.  
 
TUESDAY AT THIS POINT APPEARS TO REMAIN DRY WITH HIGH PRESSURE  
ALOFT JUST TO THE WEST. A FRONTAL SYSTEM DRIVEN BY A SHORT WAVE  
RIDING AROUND THE NORTHERN PERIPHERY OF THE UPPER RIDGE THROUGH  
THE GREAT LAKES AND INTO PA/NY, WILL SAG SOUTHWARD TO NEAR THE  
MD/WV/VA BORDER LATE TUESDAY. FOR NOW, MODELS HAVE HELD OFF ON  
BRINGING ANY ASSOCIATION CONVECTION FURTHER SOUTH THAN THIS AREA  
AS IT DISSIPATES TRYING TO MOVE FURTHER SOUTH INTO THE  
DRY/STABLE AIR MASS RESIDING OVER THE MID-ATLANTIC REGION.  
 
BY WEDNESDAY, THE FRONT WILL SLOWLY SAG SOUTHWARD INTO NORTHERN  
WV/VA AND THE THREAT FOR AFTERNOON/EVENING DEVELOPMENT OF  
SHOWERS AND THUNDERSTORMS NEAR THE FRONT WILL BEGIN TO INCREASE  
INTO AT LEAST THE CHANCE CATEGORY. WHILE MOST OF THAT ACTIVITY  
ON WEDNESDAY SHOULD STILL REMAIN NORTH OF I-64, ANOTHER AREA OF  
CONCERN FOR SHOWER/THUNDERSTORM DEVELOPMENT WILL BE ACROSS THE  
HIGH COUNTRY OF NORTHWEST NC AND INTO FAR SOUTHWEST VA, WHERE  
MOISTURE LEVELS BEGIN TO INCREASE NOTABLY AND COMBINED WITH  
DIFFERENTIAL AND DIURNAL HEATING SHOULD LEAD TO SCATTERED  
AFTERNOON/EVENING SHOWERS/THUNDERSTORMS. STILL YET ON WEDNESDAY,  
DO NOT SEE ANY AREAS EXCEEDING CHANCE POPS JUST YET.  
 
FOR TEMPERATURES, WE WILL START THE WEEK WITH LOWS IN THE 40S  
AND DEWPOINTS IN THE 30S WORKING OUR WAY TO HIGHS MAINLY IN THE  
80S, 70S MOUNTAINS, BY WEDNESDAY. DEWPOINTS WILL SLOWLY CREEP  
UPWARD INTO THE 50S EAST AND 60S WEST BY WEDNESDAY.  
 
/CONFIDENCE IN FORECAST PARAMETERS/  
TEMPERATURES - MODERATE TO HIGH,  
PRECIPITATION PROBABILITIES - MODERATE,  
WINDS - MODERATE TO HIGH,  
THUNDERSTORM THREAT - LOW TO MODERATE.  
 

 
   
LONG TERM /THURSDAY THROUGH SATURDAY/
 
 
AS OF 215 PM EDT SUNDAY...  
 
WEATHER CONDITIONS BECOME MORE UNSETTLED AND PROBLEMATIC DURING  
THIS PERIOD AS THE AFOREMENTIONED FRONTAL BOUNDARY CONTINUES TO  
SAG SOUTHWARD FROM DAILY CONVECTIVE TRENDS. THURSDAY, THE AIR  
MASS BECOMES MUCH MORE UNSTABLE AND HUMID AS THE FRONTAL  
BOUNDARY LINGERS NEAR THE NC/VA BORDER. SCATTERED TO NUMEROUS  
SHOWERS AND THUNDERSTORMS ARE EXPECTED THURSDAY AND AT THIS  
POINT APPEARS TO BE ONE OF THE MOST LIKELY DAYS FOR THUNDERSTORM  
COVERAGE. THE RAINFALL AMOUNTS AND SEVERITY STILL IN QUESTION AT  
THIS POINT, BUT SOMETHING THAT WILL NEED TO BE ADDRESSED IN  
FUTURE FORECASTS. THE FRONT WILL LINGER ACROSS THE AREA FRIDAY  
AND SATURDAY WITH A CONTINUED GOOD CHANCE FOR SHOWERS AND  
THUNDERSTORMS. UPPER-LEVEL CONDITIONS BECOME MORE FAVORABLE FOR  
CONVECTION TOWARD THE WEEKEND AS A SERIES OF SHORT WAVES MOVE  
EAST TOWARD THE MID-ATLANTIC AND ALSO HELP TO BREAK DOWN THE  
RIDGE.  
 
ANOTHER CONCERN THAT WILL NEED TO BE WATCHED CAREFULLY AS WE  
MOVE TOWARD THE WEEKEND IS A TROPICAL SYSTEM EMANATING FROM THE  
WESTERN GULF. THE EXTENDED RANGE MODELS ARE ALL OVER THE PLACE  
WITH RESPECT TO THE LOCATION WHERE THIS WILL MOVE INLAND AND  
WHERE IT GOES AFTER THAT. THE ECMWF HAS BEEN THE MOST CONSISTENT  
FROM DAY-TO-DAY, TRACKING THIS SYSTEM EVENTUALLY THROUGH LA/AR  
AND THEN TURNING IT NORTHEAST INTO THE TN VALLEY. IF SO, THIS  
COULD HAVE AN ADDITIONAL IMPACT ON RAINFALL AND CONVECTION IN  
OUR AREA BY NEXT WEEKEND.  
 
BOTTOM LINE ENJOY THE FIRST HALF OF THE WEEK, BECAUSE THE LATER  
HALF CERTAINLY APPEARS UNSETTLED AND INCREASINGLY WET. AT LEAST  
WE WILL HAVE A FEW DAYS TO DRY OUT UNTIL WE GET THERE.  
 
TEMPERATURES WILL BE A BIT ABOVE NORMAL DURING THIS TIME FRAME  
WITH 850MB TEMPERATURES HOVERING IN THE +16C TO +19C RANGE FOR  
THE MOST PART. HOWEVER, WITH HUMIDITY LEVELS ALSO INCREASING AS  
WELL AS CLOUD COVER AND CONVECTION DURING THIS PERIOD, HAVE  
TENDED TO DROP ADVERTISED NBM READINGS A BIT. HIGHS WILL  
GENERALLY BE IN THE 70S MOUNTAINS AND 80S ELSEWHERE, NEARING 90  
ACROSS THE PIEDMONT, WITH LOWS MOSTLY IN THE 50S AND 60S, MAINLY  
60S TO EVEN NEAR 70 DURING THE MORE TROPICAL LATER PART OF THE  
WEEK.  
 

 
   
AVIATION /18Z SUNDAY THROUGH FRIDAY/
 
 
AS OF 145 PM EDT SUNDAY...  
 
VFR CONDITIONS CONTINUE TO PREVAIL THROUGH THE FORECAST PERIOD. LOOK  
FOR THE SUMMER TIME CUMULUS FIELD TO CONTINUE TO EXPAND AERIAL WISE  
THIS AFTERNOON BEFORE DIMINISHING OVERNIGHT. CLEAR SKIES PREVAIL  
TONIGHT WITH FOG STAYING IN THE DEEPEST VALLEYS, AWAY FROM ALL TAF  
SITES. LOOK FOR A CUMULUS FIELD TO START RETURNING AGAIN TOMORROW  
AROUND 15Z.HIGH CONFIDENCE IN CEILINGS,VISIBILITIES AND WINDS  
DURING THE TAF PERIOD.  
 
EXTENDED AVIATION DISCUSSION...  
 
VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH MONDAY. BY  
TUESDAY AND CERTAINLY WEDNESDAY, HIGH PRESSURE BUILDING ALOFT  
TO OUR WEST WILL RESULT IN AN UNSTABLE NORTHWEST FLOW DEVELOPING  
ACROSS THE MID-ATLANTIC REGION. WITH A VERY HOT AIR MASS  
PUSHING NORTHWARD INTO THE CENTRAL U.S., THIS OPENS THE DOOR TO  
RIDGE RIDER MCS TYPE CONVECTION. IN ADDITION, A WEAK FRONTAL  
BOUNDARY WILL DRIFT SOUTHWARD INTO THE AREA TUESDAY OR WEDNESDAY  
AND SERVE AS A FURTHER FOCUSING MECHANISM FOR CONVECTION. THUS,  
WE CAN EXPECTING AN INCREASING CHANCE FOR ESPECIALLY  
AFTERNOON/NIGHTTIME THUNDERSTORMS, WHICH COULD LEAD TO  
INCREASING PROBABILITY FOR MORNING LOW CLOUDS AND FOG. HOWEVER,  
NO WIDESPREAD SUB-VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH  
THE PERIOD. THE MAIN CONCERN WILL BE LATE DAY/EVENING  
CONVECTION AND ITS ASSOCIATED HAZARDS AS WELL AS PATCHY TO AREAS  
OF FOG DURING THE 08Z-14Z TIME FRAME, ESPECIALLY AT LOCATIONS  
SUCH AS LWB AND BCB. WINDS APPEAR AS IF THEY WILL BE LIGHT AND  
VARIABLE MUCH OF THE TIME FRAME.  
 

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

 
 

 
SYNOPSIS...RAB/RR  
NEAR TERM...RR  
SHORT TERM...RAB  
LONG TERM...RAB  
AVIATION...KK/RR  
 
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