811
FXUS63 KJKL 201852
AFDJKL
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
252 PM EDT THU AUG 20 2026
KEY MESSAGES
- A COLD FRONT BRINGS SCATTERED TO WIDESPREAD THUNDERSTORMS TODAY
AND FRIDAY. A FEW STRONG WIND GUSTS AS WELL AS LOCALIZED
EXCESSIVE RAINFALL ARE POSSIBLE WITH STORMS, MAINLY TODAY INTO
TONIGHT.
- NOTICEABLY COOLER AND LESS HUMID AIR ARRIVES THIS WEEKEND AND
CONTINUES INTO EARLY NEXT WEEK.
UPDATE
ISSUED AT 1153 AM EDT THU AUG 20 2026
PRECIP HAS ENDED FOR ALL BUT A FEW LOCATIONS NEAR THE WV BORDER,
AND THAT SHOULD BE GONE SHORTLY. CAN'T RULE OUT SOME AFTERNOON
THUNDERSTORMS POPPING UP AS A COLD FRONT SAGS SOUTH INTO THE
AREA, BUT DELAYED (AND HENCE LIMITED) HEATING DUE TO MORNING
CLOUDS WILL HELP TO MINIMIZE THE POP.
SHORT TERM
(TODAY THROUGH FRIDAY)
ISSUED AT 400 AM EDT THU AUG 20 2026
ALL IS QUIET ACROSS EASTERN KENTUCKY EARLY THIS MORNING. FOG HAS
DEVELOPED THROUGH MANY OF THE MAINSTEM RIVER VALLEYS, THOUGH NOT AS
DENSE OR EXTENSIVE AS YESTERDAY. TEMPERATURES ARE ALSO SEVERAL
DEGREES WARMER THAN THIS TIME YESTERDAY, RANGING FROM THE MID 60S
IN THE COOLER NORTHEASTERN VALLEYS TO THE LOW TO MID 70S NEAR LAKE
CUMBERLAND. IT IS MUCH MORE UNSETTLED LOOKING UPSTREAM--THERE IS
AN MCS OVER WESTERN KENTUCKY AND NORTHWEST TENNESSEE WHILE A
SECOND MCS IS PASSING OVER CENTRAL AND SOUTHERN INDIANA.
INSTABILITY, HOWEVER, IS VERY MEDIOCRE ACROSS EASTERN KENTUCKY,
GENERALLY RANGING FROM 100 TO 250 J/KG OF MUCAPE. INTERESTINGLY
THOUGH, THIS UPSTREAM CONVECTION HAS BEEN ABLE TO MAINTAIN FAIRLY
WELL, THOUGH ON ONLY ABOUT 500 J/KG OF MUCAPE (BASED ON SPC
MESOANALYSIS) FEEDING INTO THE COMPLEXES ON A ~30 KT LOW-LEVEL
SOUTHWESTERLY JET. SO THE CONVECTIVE COMPLEXES, ESPECIALLY THE
SOUTHERN ONE WHICH IS ANCHORED ALONG A POOL OF 2.0+ INCH PWATS,
MAY BE ABLE TO HOLD TOGETHER BETTER THAN WHAT ONE WOULD TYPICALLY
EXPECT WITH SUCH WEAK CAPE AS BOTH SYSTEMS TRACK IN A GENERALLY
EASTERLY DIRECTION. THIS COMPLEXES ARE ALMOST CERTAINLY BEING
SUPPORTED BY UPPER-LEVEL FORCING INHERENT WITH BEING LOCATED JUST
EAST OF A POSITIVELY-TILTED 500 HPA TROUGH AXIS AND A MODERATELY
STRONG (FOR THIS TIME OF YEAR) UPPER-LEVEL VORT MAX. THERE IS
FURTHER UPPER-LEVEL SUPPORT IN THE FORM OF DIVERGENCE FROM THE
RIGHT ENTRANCE REGION OF THE 250 HPA JET DIPPING ACROSS THE OHIO
VALLEY. THE STRONGER FLOW IS THUS ALSO SUPPORTING SUFFICIENT
SHEAR (EBWD +/- 35 KTS) FOR CONTINUED CONVECTIVE ORGANIZATION.
FARTHER UPSTREAM, A SLUGGISH COLD FRONT EXTENDS FROM SOUTHERN
QUEBEC SOUTHWARD ACROSS THE EASTERN GREAT LAKES AND THEN
SOUTHWESTWARD TO KANSAS.
EASTERN KENTUCKY WILL SPEND THE ENTIRE SHORT-TERM PERIOD AFFLICTED BY
PERIODICALLY UNSETTLED WEATHER CAUSED BY PERTURBATIONS MOVING THROUGH
THE UPPER-LEVEL TROUGH AND THE SLOW-MOVING INCOMING COLD FRONT. THAT
FIRST PERTURBATION AND THE ATTENDANT MCSS WILL TRANSIT EASTWARD,
LIKELY IMPACTING EASTERN KENTUCKY BETWEEN 6 AM AND NOON. THIS ACTIVITY
WILL STILL LIKELY WEAKEN WITH TIME, THOUGH, AS ITS LOW-LEVEL
MOISTURE AND INSTABILITY INFLOW WEAKENS WITH EASTWARD EXTENT.
STRONG WINDS ARE STILL POSSIBLE ALONG THE LEADING EDGE OF THE
CONVECTION, BUT LOW-LEVEL CIN FROM NIGHTTIME RADIATIONAL COOLING
IS LIKELY TO LIMIT THE OVERALL MIXDOWN OF WINDS TO THE SURFACE.
THE WEAKEST CIN SHOULD BE NEAR LAKE CUMBERLAND AND THE KY/TN
BORDER, SO THAT WILL BE THE PRIMARY AREA TO WATCH FOR THE GUSTIEST
WINDS. MOST AREAS SHOULD JUST SEE A BLUSTERY BREEZE AS THE
SHOWERS AND STORMS ARRIVE, AND THEN SHOULD EXPERIENCE A PERIOD OF
RAIN WITH OCCASIONAL THUNDER. SOME MINOR POOR-DRAINAGE FLOODING
CANNOT BE RULED OUT WITH THIS INITIAL ROUND, BUT THE OVERALL
PROGRESSIVE NATURE OF THESE SYSTEMS AND A COUPLE DAYS OF DRYING
SHOULD MITIGATE ANY MORE SIGNIFICANT HYDRO CONCERNS.
ONCE THE REMNANTS OF THAT CONVECTION AND THE ATTENDANT UPPER-LEVEL
SUPPORT MOVE EAST, IT APPEARS THE COLD FRONT WILL SLOWLY SAG TO NEAR
THE LOWER OHIO RIVER BY MIDDAY, BUT WITH LITTLE FANFARE AS
INSTABILITY REMAINS WEAK AND NEGATIVE DIFFERENTIAL VORTICITY ADVECTION
INITIALLY SUPPRESSES LIFT. ANOTHER PERTURBATION DOES PASS THROUGH THE
APPROACHING 500HPA TROUGH AXIS THIS EVENING AND IS QUITE LIKELY
TO KICK OFF CONVECTION OVER TENNESSEE WHERE THERE IS BETTER
OPPORTUNITY FOR AFTERNOON DESTABILIZATION; CONFIDENCE IN
SUFFICIENT DESTABILIZATION FOR RENEWED CONVECTIVE DEVELOPMENT IS
LESS CERTAIN OVER EASTERN KENTUCKY, HOWEVER, THOUGH SOME OF THE
CAMS DO SUGGEST AT LEAST SCATTERED CONVECTION REDEVELOPING, MOSTLY
SOUTH OF THE MOUNTAIN PARKWAY. SHOULD CONVECTION DEVELOP AND BE
PERSISTENT, THE PARAMETER SPACE IS SUPPORTIVE OF TORRENTIAL
RAINFALL RATES WITH STORMS LATE TODAY INTO TONIGHT NEAR AND SOUTH
OF THE HAL ROGERS PARKWAY/KY-80 CORRIDOR. THE 500 HPA VORT MAX
PERTURBATION (EMBEDDED IN THE TROUGH AXIS) THEN SPINS ITS WAY
ACROSS KENTUCKY AND TENNESSEE DURING THE MORNING AND AFTERNOON ON
FRIDAY. CAMS VARY ON OVERALL CONVECTIVE REDEVELOPMENT/COVERAGE BY
MIDDAY OR EARLY AFTERNOON, BUT OVERALL CONVECTIVE INTENSITY
APPEARS ANEMIC. AT THE SURFACE, A WEAK WAVE OF LOW PRESSURE WILL
RIDE ALONG THE COLD FRONT AS IT INCHES SOUTHEAST ACROSS THE JKL
CWA. MODEL SOUNDINGS REVEAL A RELATIVELY SKINNY CAPE PROFILE AND A
LOT OF DRY AIR IN THE MID AND UPPER LEVELS--SO IT SEEMS THAT CAMS
ARE INDICATING THAT CONVECTION WILL STRUGGLE TO DEVELOP AND
MAINTAIN DUE TO SIGNIFICANT DRY AIR ENTRAINMENT. THAT FRONT (OR
WHATEVER IS LEFT OF IT) WASHES OUT OR DRIFTS SOUTH OF THE AREA BY
EVENING, WITH ENOUGH DRY AIR SEEPING IN FOR GRADUAL CLEARING.
IN SENSIBLE WEATHER TERMS, LOOK FOR A ROUND OF SHOWERS WITH SOME
THUNDER MOVING FROM WEST TO EAST BETWEEN 6 AM AND 12 PM TODAY. A
FEW PLACES COULD EXPERIENCE A PERIOD OF STRONG WINDS AS THE
ACTIVITY ARRIVES. A PERIOD OF CLOUDS AND THEN SOME PARTIAL SUN
FOLLOWS THE SHOWERS AND STORMS HEADING INTO THE AFTERNOON BEFORE
ADDITIONAL HIT-AND-MISS SHOWERS AND STORMS DEVELOP LATE IN THE DAY
AND EVENING, WITH THE GREATEST CHANCES CLOSER TO THE TN AND VA
BORDERS. IT WILL BE SEASONABLY WARM WITH HIGHS IN THE LOWER TO MID
80S WHILE TONIGHT'S LOW TEMPERATURES RANGE IN THE MID TO UPPER
60S. FOR FRIDAY, LOOK FOR A MIX OF CLOUDS, SUN, AND PERHAPS A FEW
POP-UP SHOWERS OR PERHAPS A THUNDERSTORM WITH HIGHS RANGING
THROUGH THE MID 80S.
LONG TERM
(SATURDAY THROUGH THURSDAY)
ISSUED AT 252 PM EDT THU AUG 20 2026
AT THE ONSET OF THE EXTENDED PERIOD, THE UPPER AIR PATTERN
CONTINUES TO FEATURE A PROMINENT UPPER-LEVEL RIDGE CENTERED OVER
THE INTERMOUNTAIN WEST AND FOUR CORNERS REGION. FURTHER EAST, A
LARGE, NEUTRALLY ORIENTED LONGWAVE TROUGH IS FORECAST TO COVER
PORTIONS OF THE CENTRAL AND EASTERN US. AN EMBEDDED SHORTWAVE
WITHIN THE LONGWAVE TROUGH IS MODELED TO DIG OUT OF NORTHWESTERN
CANADA INTO THE GREAT LAKES AND OHIO VALLEY OVER THE WEEKEND.
A COLD FRONT WILL CROSS INTO EASTERN KENTUCKY, LIKELY AROUND OR
AFTER 00Z SUNDAY (8 PM EDT SATURDAY). ISOLATED TO SCATTERED
SHOWERS AND STORMS ARE POSSIBLE AHEAD OF AND ALONG THIS COLD
FRONT; POPS REFLECT THIS THROUGH THE AFTERNOON INTO THE EARLY
EVENING. MODEL SOUNDINGS SUGGEST MLCAPE RANGING BETWEEN 900-1200
J/KG AT THE TIME OF THE FRONTAL PASSAGE, ALONG WITH DEW POINTS IN
THE UPPER 60S, AND ELEVATED DCAPE AROUND 800-870 J/KG DUE TO DRY
AIR IN THE MID-LEVELS. WITH 0-6KM EFFECTIVE BULK SHEAR AROUND 25
KTS, STORMS COULD BECOME BETTER ORGANIZED WITH POTENTIAL FOR
GUSTY AND ERRATIC WINDS. THE SPC HAS PLACED PORTIONS OF THE AREA
IN A MARGINAL RISK (LEVEL 1 OF 5) WHICH COVERS NEARLY ALL OF
EASTERN KENTUCKY NORTH AND EAST OF A SOMERSET-TO-LONDON LINE,
INCLUDING THE I-64, KY-15, AND US-23 CORRIDORS TO THE WV/VA
BORDERS. SOME MODELS VARY ON THE POSITIONING OF THE TROUGH, BUT
GENERAL THINKING IS STORMS SHOULD TAPER OFF ACROSS COUNTIES
BORDERING WEST VIRGINIA IN THE LATE EVENING.
HIGH PRESSURE BRIEFLY BUILDS ACROSS EASTERN KENTUCKY EARLY NEXT
WEEK, USHERING IN A COOLER AND DRIER AIRMASS. DEW POINTS LOWERING
INTO THE UPPER 50S AND LOWER 60S WILL BE A WELCOME RELIEF FROM
RECENT CONDITIONS. DRY WEATHER REMAINS SUNDAY THROUGH EARLY MONDAY.
MODEL DISCREPANCIES ARE RESULTING IN LOW, ISOLATED POPS FOR MONDAY
AND TUESDAY AFTERNOON. THIS STEMS FROM THE GFS BEING MORE
PROGRESSIVE WITH A SHORTWAVE TRACKING OUT OF THE CENTRAL PLAINS
INTO THE TENNESSEE VALLEY, BRINGING LOW-END RAIN CHANCES TO
PORTIONS OF THE FORECAST AREA. ON THE OTHER HAND, THE ECMWF TAKES
THE SHORTWAVE OUT OF THE CENTRAL PLAINS AND DIRECTS IT DEEPER INTO
THE SOUTHEAST, LEAVING THE AREA FREE AND CLEAR OF ACTIVE WEATHER.
THE NBM HAS RESOLVED THIS BY PLACING 15 PERCENT POPS ACROSS THE
AREA TO ACCOUNT FOR THE POSSIBILITY OF THE GFS SOLUTION.
BEYOND TUESDAY, MULTIPLE SHORTWAVES EMBEDDED IN THE UPPER-LEVEL
FLOW LOOK TO BRING ROUNDS OF SHOWER AND STORM CHANCES TO THE
AREA WEDNESDAY AND THURSDAY.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 158 PM EDT THU AUG 20 2026
DRY WEATHER AND MAINLY VFR CONDITIONS WERE PRESENT AT TAF
ISSUANCE, WITH THE EXCEPTION BEING MVFR CEILINGS IN SOME PLACES
NEAR/NORTH OF A LINE FROM KIOB TO KSJS. THE MVFR CEILINGS ARE
EXPECTED TO LIFT AND BREAK UP THIS AFTERNOON. THERE IS A POTENTIAL
FOR A FEW THUNDERSTORMS IN THE LATE AFTERNOON AND EARLY EVENING
AND AGAIN OVERNIGHT AND EARLY FRIDAY, MAINLY NEAR/SOUTH OF THE
CUMBERLAND PKWY/HAL ROGERS PKWY/KY HWY 80 CORRIDOR. THESE COULD
BRING ISOLATED IFR OR WORSE CONDITIONS. FOG IS ALSO EXPECTED
IN MANY LOCATIONS OVERNIGHT AND EARLY FRIDAY, WITH IFR OR WORSE
CONDITIONS. IMPROVEMENT TO VFR IS FORECAST AREA WIDE LATE MORNING
ON FRIDAY.
JKL WATCHES/WARNINGS/ADVISORIES
NONE.
UPDATE...HAL
SHORT TERM...GEERTSON
LONG TERM...GINNICK
AVIATION...HAL
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