289
FXUS61 KRNK 201924
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
324 PM EDT SUN SEP 20 2026
WHAT HAS CHANGED
NO SIGNIFICANT CHANGES TO THE FORECAST OTHER THAN TO TREND EVEN
COOLER FOR THE LATTER HALF OF THE WEEK. FORECAST COASTAL STORM
OFF NEW ENGLAND COAST SUGGESTS AN EXTENDED PERIOD OF COLD AIR
ADVECTION WEDNESDAY THROUGH FRIDAY.
KEY MESSAGES
1) UNSETTLED WEATHER EXPECTED THROUGH MIDWEEK AS A FRONT
REMAINS STALLED OVER THE REGION...TEMPERATURES TRENDING
NOTICEABLY COOLER BY WEDNESDAY.
DISCUSSION
KEY MESSAGE 1: UNSETTLED WEATHER EXPECTED THROUGH MIDWEEK AS A
FRONT REMAINS STALLED OVER THE REGION...TEMPERATURES TRENDING
NOTICEABLY COOLER BY WEDNESDAY.
CONVECTIVE ALLOWING MODELS HAVE SHOWERS AND STORMS DEVELOPING
ALONG THE BLUE RIDGE LATE THIS AFTERNOON AND MOVING SOUTHEAST
INTO THE PIEDMONT THIS EVENING BEFORE DISSIPATING AFTER SUNSET.
A FEW STRONG STORMS (ONE OR TWO SEVERE) ARE POSSIBLE, BUT THE
ENVIRONMENT IS MARGINAL WITH RESPECT TO SEVERE STORM AND
EXCESSIVE RAINFALL POTENTIAL. MLCAPE OF ABOUT 1000 J/KG IS NOTED
ALONG THE SOUTHERN BLUE RIDGE AND THIS WILL LIKELY FUEL A ROUND
OF THUNDERSTORMS THIS EVENING. DCAPE OF 500-800 J/KG SHOULD
ENHANCE THE DOWNDRAFT WINDS WITH ANY SHOWER ACTIVITY WITH
POTENTIAL TO PRODUCE SOME 25 TO 35 MPH WIND GUSTS WITH THE
STRONGER STORMS. NOT OVERLY CONCERNED WITH EXCESSIVE RAINFALL
PER ONGOING DROUGHT AND TRANSIENT NATURE OF ANY ACTIVITY THAT
DEVELOPS THROUGH THIS EVENING. ONCE THE SUN GOES DOWN, EXPECT
STORMS TO WEAKEN.
ANOTHER 24 HOURS OF HEAT AND HUMIDITY IS EXPECTED, THEN WE
SHOULD BEGIN TO TREND MUCH COOLER. A FRONT TO OUR NORTH WILL BE
THE CLASH ZONE FOR A MULTI-DAY PERIOD OF SHOWER ACTIVITY WITH
SEVERAL WAVES OF CONVECTIVELY INDUCED VORTICITY MOVING ALONG THE
FRONT SPAWNING PERIODIC SHOWERS AND THUNDERSTORMS AS THE FRONT
WORKS ITS WAY THROUGH THE AREA MONDAY AND TUESDAY. PASSAGE OF
THE FRONT MONDAY NIGHT WILL BRING A WIND SHIFT FROM THE NORTH
AND ONSET OF A COOLER AIR AIRMASS. THIS COOLER AIRMASS WILL
THEN DEEPEN AND BECOME MORE PRONOUNCED WEDNESDAY INTO THURSDAY
AS A COASTAL STORM DEVELOPS ALONG THE NORTHERN MID ATLANTIC
COAST WITH MODEL TRENDS DEVELOPING THIS INTO A HYBRID
SUBTROPICAL STORM OFF THE NEW ENGLAND COAST...A FEATURE THAT
LOOKS TO INFLUENCE OUR WEATHER FOR MULTIPLE DAYS IN THE FORM OF
STRONG COLD AIR ADVECTION...WINDS BLOWING FROM THE NORTH THROUGH
FRIDAY. PERSISTENT CLOUD COVER ASSOCIATED WITH THE COLDER
AIRMASS WILL THEN MUTE OUR TEMPERATURES WITH READINGS 10 TO 15
DEGREES BELOW THE SEASONAL NORM AND A FULL 20 TO 25 DEGREES
BELOW CURRENT OBSERVED VALUES.
DURING THIS TRANSITION, WE SHOULD EXPERIENCE MULTIPLE DAYS OF
SHOWERY WEATHER WITH POTENTIAL TO RECEIVE 1-2" OF RAIN. THIS
IS EXPECTED TO BE MUCH NEEDED RAINFALL, SO UNLESS WE SEE THE
ACTIVITY BECOME STATIONARY, WE DO NOT ANTICIPATE ISSUING ANY
FLOOD WATCH HEADLINES. IF THERE IS ANY FLOODING IT WOULD BE
LOCALIZED AND DURING THE TIME WHEN THE FRONT BACKDOORS INTO THE
AREA MONDAY NIGHT WHEN STORM CELL MOVEMENT ALONG THE BOUNDARY
TENDS TO BE NEARLY STATIONARY ALONG BLUE RIDGE AS IT WEDGES INTO
THE AREA FROM THE NORTHEAST.
THE BIGGER STORY WILL BE THE SIGNIFICANT COOL DOWN WITH
POTENTIAL TO REMAIN STUCK IN THE 50S AND 60S WEDNESDAY AND
THURSDAY. COLD AIR ADVECTION IS EXPECTED TO PERSIST FOR MULTIPLE
DAYS SO IT MAY TAKE UNTIL THE WEEKEND TO RETURN TO READINGS NEAR
NORMAL.
AVIATION /18Z SUNDAY THROUGH FRIDAY/
MAINLY VFR THROUGH THIS EVENING OUTSIDE ANY SHOWER AND
THUNDERSTORM ACTIVITY. CAMS FAVOR THE SOUTHERN BLUE RIDGE,
SOUTHWEST OF ROANOKE THIS AFTERNOON AND EVENING FOR THUNDERSTORM
DEVELOPMENT WHICH MAY IMPACT ROUTES BETWEEN ROA-CLT OR ROA-ATL.
AFTER THE DAYTIME DEEP CONVECTION FADES AT SUNSET, EXPECT RETURN
TO STABLE CONDITIONS WITH POTENTIAL FOR OVERNIGHT FOG AND
STRATUS FOR THE MOUNTAIN VALLEYS AND ACROSS AREAS THAT RECEIVED
ANY RAIN. A LATE NIGHT OR EARLY MORNING ROUND OF SHOWERS AND
THUNDERSTORMS MAY IMPACT WV TERMINALS MONDAY MORNING FROM STORM
ACTIVITY THAT CROSSES THE OHIO VALLEY OVERNIGHT.
EXTENDED AVIATION OUTLOOK...
RAIN CHANCES INCREASE MONDAY AND TUESDAY WITH NUMEROUS TO
WIDESPREAD COVERAGE. DURING THIS TIME EXPECT PERIODS OF SUB-VFR
CONDITIONS AND POTENTIAL HEAVY RAIN. FOG AT NIGHT CAN ALSO BE
EXPECTED, ESPECIALLY IN THE MOUNTAIN VALLEYS.
FOR THE LATTER HALF OF THE WEEK, GUSTY NORTH WINDS ARE EXPECTED
PER FORECAST OF STRONG CYCLONE DEVELOPING OFF THE NEW ENGLAND
COAST. CLOUDS AND SHOWERS FROM THIS FEATURE MAY LINGER OVER THE
MID-ATLANTIC THROUGH FRIDAY.
RNK WATCHES/WARNINGS/ADVISORIES
VA...NONE.
NC...NONE.
WV...NONE.
DISCUSSION...PM
AVIATION...PM
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