628
FXUS61 KRNK 212322
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
722 PM EDT TUE JUL 21 2026
WHAT HAS CHANGED
A SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED FOR MOST OF THE AREA
EAST OF INTERSTATE 77. DAMAGING WINDS ARE THE MAIN THREAT, BUT
HAIL AND AN ISOLATED TORNADO OR TWO CANNOT BE RULED OUT.
A FLOOD WATCH IS ALSO IN EFFECT THROUGH TOMORROW FOR THE ENTIRE
AREA.
KEY MESSAGES
1) A SEVERE THUNDERSTORM WATCH IS IN EFFECT THROUGH 10 PM
TONIGHT, AND A FLOOD WATCH IN EFFECT FOR THE ENTIRE AREA THROUGH
TOMORROW FOR STRONG TO SEVERE SHOWERS AND THUNDERSTORMS.
DISCUSSION
KEY MESSAGE 1...A SEVERE THUNDERSTORM WATCH IS IN EFFECT THROUGH
10 PM TONIGHT, AND A FLOOD WATCH IN EFFECT FOR THE ENTIRE AREA
THROUGH TOMORROW FOR STRONG TO SEVERE SHOWERS AND THUNDERSTORMS.
THE LATEST SURFACE ANALYSIS SHOWS A WARM FRONT WELL NORTHEAST
OF THE AREA, WITH A COLD FRONT STRETCHING FROM THE EASTERN GREAT
LAKES TO IL AND WESTWARD. THIS WILL BE THE MAIN DRIVING FORCE
FOR SEVERE WEATHER LATER THIS EVENING. ALOFT, TROUGHING
ENCOMPASSES MUCH OF THE EASTERN STATES ALONG AND NORTH OF THE
MID ATLANTIC REGION.
THE FIRST WAVE OF POSITIVE VORTICITY ADVECTION WAS SHIFTING INTO
THE AREA AND HAD SPARKED A LINE OF STORMS MOVING THROUGH SE
WV AND INTO NORTHERN VA. THESE STORMS ARE MAINLY A FLOOD THREAT
IF THEY CONTINUE TO TRAIN. AS THEY SHIFT SOUTH AND INTERACT
WITH ADDITION INSTABILITY THIS AFTERNOON AND EVENING, EXPECT A
FEW STRONG TO SEVERE STORMS. ALONG THE COLD FRONT, MORE
WIDESPREAD CLUSTERS OF MULTICELLS PUSH SOUTH AFTER 4 TO 5 PM
AND TONIGHT. WET MICROBURSTS WILL BE THE MAIN CONCERN TODAY AND
TONIGHT, ALTHOUGH ALL CONVECTION MAY HAVE TORRENTIAL RAINFALL.
SHEAR BETWEEN 0-6 KM INCREASES TO 35 TO 45 KTS BY LATER THIS
AFTERNOON AND EVENING AS THE NOSE OF THE 300MB UPPER LEVEL JET
REACHES THE AREA, ALONG AND NORTH OF THE FRONT. ALSO CONCERNING
WILL BE THE INCREASING 0-1 KM SHEAR THAT MAY REACH 25 KTS, IN
THE VICINITY OF THE FRONT WHERE SURFACE WINDS MAY BACK. THIS
POINTS TOWARDS INCREASING LOW LEVEL ROTATION RESULTING IN A FEW
SUPERCELLS AND A SMALL TORNADO RISK.
THE COLD FRONT LOOKS TO SLOW DOWN AS IT CROSSES THE FORECAST
AREA FROM NORTH TO SOUTH, STALLING SOMEWHERE IN VA OR NORTHERN
NC OVERNIGHT. THUS THE HIGH THREAT FOR URBAN, SMALL STREAM, AND
FLASH FLOODING WILL CONTINUE OVERNIGHT INTO TOMORROW WITH
TRAINING CELLS ALONG THE BOUNDARY. CAMS ARE ALSO HINTING AT AN
MCV OR TWO IN THE AREA TOMORROW MORNING, WHICH WOULD SUPPORT
STRONGER AND HEAVIER STORMS. ADDITIONAL DEVELOPMENT IS EXPECTED
TOMORROW, WITH ADDITIONAL SHORT WAVE ENERGY AND FAVORABLE
KINEMATICS MOVING INTO THE MID ATLANTIC REGION. ALONG THE
FRONT, THE FLOODING THREAT WILL CONTINUE THROUGH INTO TOMORROW
NIGHT.
AS DRIER AIR BEGINS TO WORK IN FROM THE NORTH BY THURSDAY,
CHANCES FOR RAIN SINK SOUTH. AFTER A BRIEF BREAK, MORE CHANCES
FOR SHOWERS AND STORMS RETURN FRIDAY INTO THE WEEKEND, AS
ADDITIONAL MID LEVEL SHORT WAVES MOVE THROUGH. WITH THE NUMEROUS
CHANCES FOR RAIN AND CLOUD COVER IN THE FORECAST, TEMPERATURES
WILL BE IN THE 70S FOR THE ENTIRE AREA THURSDAY THROUGH
SATURDAY.
AVIATION /00Z WEDNESDAY THROUGH SUNDAY/
MOSTLY VFR CONDITIONS OBSERVED ACROSS THE AREA, WITH A FEW
POCKETS OF MVFR AT THIS TIME, THOUGH CEILINGS ARE LESS THAN 2KFT
IN SOME PLACES. ANOTHER ROUND OF RAIN WITH SOME EMBEDDED
THUNDERSTORMS IS MOVING INTO THE MOUNTAINS, THOUGH THE STRONGEST
STORMS ARE STILL OVER CENTRAL AND NORTHERN WV CURRENTLY. SOME
UNCERTAINTY IN HOW FAR EAST THE THUNDERSTORMS MAKE IT, BUT
HIGHER CONFIDENCE IN RAIN CONTINUING THROUGH THE OVERNIGHT.
EXPECT PERIODS OF MVFR TO IFR WITHIN SOME OF THE HEAVIER RAIN
SHOWERS, WITH QUICK REDUCTIONS IN VISIBILITY. STORMS WILL WANE
BY 06Z OR SO, WITH SHOWERS LINGERING FOR A FEW MORE HOURS. WIND
GUSTS BETWEEN 15 AND 20 KNOTS WILL ALSO CONTINUE INTO THE
OVERNIGHT HOURS, AND COULD GUST HIGHER NEAR THUNDERSTORMS.
THESE SHOWERS AND THUNDERSTORMS WILL HAVE THE POTENTIAL FOR
PRODUCING STRONG AND ERRATIC WINDS, AS WELL AS SOME HAIL AND AN
ISOLATED TORNADO CAN'T BE RULED OUT.
MORE SCATTERED SHOWERS AND STORMS ARE LIKELY WEDNESDAY
AFTERNOON, BUT MOST MODEL GUIDANCE HAS IT STAYING SOUTH OF
INTERSTATE 64, SO HAVE NOT INCLUDED ANY MENTION OF THUNDER FOR
KLWB FOR TOMORROW AT THIS TIME. HOWEVER, THERE IS HIGHER
PROBABILITY OF FOG DEVELOPING AT KLWB TONIGHT THROUGH WEDNESDAY
MORNING.
WINDS WILL TURN MORE WESTERLY IN THE MOUNTAINS FOR TOMORROW,
AFTER THE FRONTAL PASSAGE, BUT MOSTLY SOUTHWESTERLY IN THE
PIEDMONT. WIND SPEEDS SHOULD STAY BETWEEN 5 TO 10 KNOTS UNTIL
AFTER THE CURRENT TAF PERIOD ENDS, AT 00Z THURSDAY.
FORECAST CONFIDENCE IS MODERATE.
EXTENDED AVIATION OUTLOOK...
DRIER CONDITIONS MOVE IN FOR THURSDAY AND FRIDAY, WITH NO RAIN
CHANCES OUTSIDE OF DAN, THOUGH ONLY ISOLATED IN COVERAGE. BETTER
RAIN CHANCES RETURN FOR SATURDAY, AND SUNDAY LOOKS TO DRY OUT.
OVERNIGHT FOG WILL REMAIN POSSIBLE EACH NIGHT, PARTICULARLY AT
LWB.
RNK WATCHES/WARNINGS/ADVISORIES
VA...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR VAZ007-009>020-
022>024.
FLOOD WATCH THROUGH WEDNESDAY EVENING FOR VAZ032>035-043>047-
058-059.
NC...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR NCZ001-002-018.
FLOOD WATCH THROUGH WEDNESDAY EVENING FOR NCZ003>006-019-020.
WV...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR WVZ042>044-507-508.
DISCUSSION...AS/SH
AVIATION...AS/SH
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