805
FXUS63 KJKL 182034
AFDJKL
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
434 PM EDT TUE AUG 18 2026
KEY MESSAGES
- MAINLY DRY AND COOLER WEATHER RETURNS THROUGH WEDNESDAY, THOUGH
LOCALLY DENSE RIVER VALLEY FOG IS EXPECTED LATE TONIGHT.
- A COLD FRONT BRINGS SCATTERED TO WIDESPREAD THUNDERSTORMS
WEDNESDAY NIGHT AND THURSDAY, WITH A FEW STRONG WIND GUSTS AND
LOCALIZED HEAVY RAIN AND FLOODING POSSIBLE.
- NOTICEABLY COOLER AND LESS HUMID AIR ARRIVES THIS WEEKEND AND
CONTINUES INTO EARLY NEXT WEEK.
SHORT TERM
(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 425 PM EDT TUE AUG 18 2026
LATE THIS AFTERNOON, AN UPPER LEVEL LOW WAS CENTERED TO THE
SOUTHWEST OF HUDSON BAY WITH BROAD TROUGHING SOUTH INTO THE GREAT
LAKES TO MS VALLEY REGION WITH WESTERLY FLOW DOWNSTREAM ALOFT ACROSS
THE OH VALLEY TO MID ATLANTIC STATES. FURTHER SOUTHWEST, AN UPPER
LEVEL RIDGE WAS CENTERED IN THE SOUTHWEST CONUS AND THEN EXTENDED
NORTHWEST INTO OR. AT THE SURFACE, AN AREA OF HIGH PRESSURE WAS
CENTERED OVER THE LOWER OH VALLEY VICINITY WHILE A SFC LOW WAS IN
CANADA AND A FRONTAL ZONE EXTENDED INTO ONTARIO TO NORTHERN GREAT
LAKES TO SD TO MT.
TONIGHT AND WEDNESDAY, THE UPPER LOW IN CANADA WILL MEANDER ACROSS
THE SOUTHERN HUDSON BAY TO JAMES BAY REGION WITH UPPER TROUGHING
EXTENDING INTO THE GREAT LAKES TO LOWER OH VALLEY TO PORTIONS OF THE
MS VALLEY REGION. MEANWHILE, UPPER LEVEL RIDGING UPPER BUILDS INTO
THE NORTHWEST FROM THE DESERT SOUTHWEST/FOUR CORNERS. AT THE
SURFACE, HIGH PRESSURE WILL SLOWLY MOVE TO NEAR THE SW VA TO NE TN
AND SOUTHEASTERN KY AREA. ADDITIONAL SHORTWAVES IN NORTHWEST FLOW
MOVING AROUND THE WESTERN RIDGING WILL MOVE INTO THE CENTRAL CONUS
TO AND THE MID MS VALLEY TO LOWER OH VALLEY REGION BY LATE WEDNESDAY
AFTERNOON AND EVENING. FOR WEDNESDAY NIGHT, A SHORTWAVE TROUGH WILL
ENTER THE LOWER OH VALLEY FROM THE WEST WHILE A FRONTAL ZONE/SFC
TROUGH APPROACH. PW INITIALLY IN THE 25 TO 47 PERCENT RANGE OR 1 TO
1.3 INCHES THIS EVENING IS PROGGED TO DROP AS LOW AS THE 15TH TO
40TH PERCENTILE LATE THIS EVENING AND OVERNIGHT PER 12Z HREF. THIS
THEN REBOUNDS TO THE 45TH TO 50TH PERCENTILE NEAR THE VA BORDER TO
THE 85TH PERCENTILE, OR 1.15 TO 1.8 INCH RANGE THROUGH MID AFTERNOON
ON WEDNESDAY. MOISTURE IS TRANSPORTED FURTHER EAST AHEAD OF THE
SHORTWAVE TO END THE PERIOD INTO THE 70TH TO 85TH PERCENTILE (1.45
TO 1.85 INCH) RANGE NEAR SUNSET ON WEDNESDAY AND INCREASE A TAD MORE
BEFORE DAWN ON THURSDAY.
SFC HIGH PRESSURE BUILDING IN FOLLOWING RECENT RAINFALL AND DRY AIR
ALOFT WILL SET THE STAGE FOR FOG AT LEAST IN THE VALLEYS. SOME OF
THIS SHOULD BECOME DENSE AND THIS IS NOTED IN THE LATEST HWO. LOWS
MAINLY IN THE 60 TO 65 RANGE SHOULD BE QUITE REFRESHING FOLLOWING
THE HUMID WEATHER AS OF LATE. TEMPERATURES DO MODERATE BACK TO A
COUPLE OF DEGREES ABOVE NORMAL FOR WEDNESDAY UNDER MOSTLY SUNNY
SKIES. CONVECTION WILL BECOME MORE PROBABLE AS MOISTURE INCREASES
WEDNESDAY EVENING THROUGH WEDNESDAY NIGHT, WITH CHANCES SPREADING
FROM NORTHWEST TO SOUTHEAST. WITH THE INCREASING PW SOME LOCALLY
HEAVY AMOUNTS ARE NOT OF THE QUESTION IN THE NORTHWEST OR WEST LATE
WEDNESDAY NIGHT IF ANY HEAVY RAIN FALLS THEN COULD PRIME A FEW AREAS
FOR THE POSSIBILITY OF EXCESSIVE RAINFALL ON THURSDAY.
LONG TERM
(THURSDAY THROUGH TUESDAY)
ISSUED AT 330 PM EDT TUE AUG 18 2026
AT THE ONSET OF THE EXTENDED FORECAST PERIOD, LARGE-SCALE 500 MB
TROUGHING REMAINS ANCHORED ACROSS MUCH OF THE EASTERN CONUS. IN
THE PRE-DAWN HOURS THURSDAY, A NOCTURNAL 40-50 KT LOW-LEVEL JET
(LLJ) ORIENTED ACROSS WESTERN AND CENTRAL KENTUCKY WILL COINCIDE
WITH A SHORTWAVE PASSING THROUGH THE OHIO VALLEY. WHILE THE LLJ
WEAKENS TO 30-40 KTS AS IT SHIFTS INTO EASTERN KENTUCKY, ROUNDS OF
SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH THURSDAY. THE
FIRST ROUND WILL MOVE THROUGH DURING THE MORNING HOURS, FAVORING
AREAS ACROSS THE CUMBERLAND, SOUTHERN LICKING, AND BIG SANDY RIVER
BASINS NEAR THE TN, VA, AND WV BORDERS. A BRIEF LULL IN ACTIVITY
IS EXPECTED BEFORE REDEVELOPMENT OCCURS EARLY THURSDAY AFTERNOON
ALONG THE I-64 CORRIDOR, PROPAGATING SOUTH THROUGH THE REMAINDER
OF THE DAY. MODELS INDICATE DRIER AIR WORKING IN ALOFT BY LATE
AFTERNOON, WHICH COULD SUPPRESS RAIN CHANCES. HOWEVER, THE
ENVIRONMENT WILL SUPPORT PWAT VALUES NEAR 1.75 INCHES (80TH TO
85TH PERCENTILE OF CLIMATOLOGY). GIVEN SATURATED SOILS FROM RECENT
RAINFALL, ISOLATED INSTANCES OF MINOR FLOODING REMAIN POSSIBLE
THURSDAY THROUGH THURSDAY NIGHT, SUPPORTING WPCS MARGINAL RISK
(LEVEL 1 OF 4) FOR EXCESSIVE RAINFALL. ADEQUATE STORM MOTION
SHOULD KEEP ACTIVITY PROGRESSIVE, LIMITING WIDESPREAD FLASH
FLOODING POTENTIAL.
AS THE FRONTAL BOUNDARY ASSOCIATED WITH THURSDAYS CONVECTION LINGERS
NEAR THE AREA ON FRIDAY, SHOWER AND THUNDERSTORM CHANCES WILL
PERSIST, WITH THE HIGHEST PROBABILITIES DURING THE AFTERNOON ALONG
AND SOUTH OF THE HAL ROGERS PARKWAY / KY HIGHWAY 80 CORRIDOR.
BEYOND FRIDAY, MODELS AND ENSEMBLE GUIDANCE REMAIN IN BROAD
AGREEMENT ON A CONTINUED UPPER-LEVEL PATTERN FEATURING A RIDGE
OVER THE WESTERN CONUS AND TROUGHING ACROSS THE EAST, THOUGH
AMPLITUDE DIFFERENCES REMAIN. ANOTHER SHORTWAVE EMBEDDED WITHIN
THE LONGWAVE TROUGH IS PROJECTED TO DIG OUT OF THE UPPER MIDWEST
INTO THE GREAT LAKES AND OHIO VALLEY SATURDAY INTO SUNDAY.
MULTIPLE 00Z AI-BASED GUIDANCE SUITES FROM AUGUST 18TH SHOW
CONDITIONAL SEVERE POTENTIAL ON SATURDAY, PRIMARILY CENTERED OVER
SW PENNSYLVANIA, WITH LOWER PROBABILITIES (5-15%) EXTENDING
SOUTHWEST INTO EASTERN KENTUCKY. AT PRESENT, POPS SUPPORT ISOLATED
TO SCATTERED COVERAGE ACROSS THE LICKING AND BIG SANDY BASINS ON
SATURDAY. ISOLATED SHOWER OR STORM ACTIVITY MAY LINGER ACROSS THE
BIG SANDY EARLY SUNDAY MORNING; OTHERWISE, DRY WEATHER IS EXPECTED
TO RETURN THROUGH MONDAY MORNING. BY MONDAY AFTERNOON, GUIDANCE
DEPICTS ANOTHER UPPER-LEVEL LOW—WHICH A FEW MODELS ATTEMPT TO
CLOSE OFF—DIGGING SOUTHEAST FROM THE UPPER MIDWEST INTO THE
NORTHERN GREAT LAKES. THIS FEATURE COULD BRING ANOTHER ROUND OF
SHOWER AND THUNDERSTORM CHANCES TO THE AREA ON TUESDAY.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 155 PM EDT TUE AUG 18 2026
CUMULUS WAS PRESENT ACROSS THE REGION AT ISSUANCE TIME WITH ALL
AREAS IN OR CLIMBING INTO THE VFR RANGE WITH THESE AS HIGH
PRESSURE BUILDS INTO THE OH VALLEY AND USHERS DRIER AIR. MORE
WIDESPREAD FOG IS PROBABLE TONIGHT COMPARED TO LAST NIGHT AS THAT
HIGH PRESSURE SYSTEM CRESTS OVER EASTERN KENTUCKY. THIS FOG SHOULD
BRING REDUCTIONS TO MVFR INITIALLY AS EARLY AS 04Z IN SOME AREAS,
WITH SOME REDUCTIONS TO IFR OR LOWER IN MANY LOCATIONS BETWEEN 07Z
AND 08Z AND 12Z, BEFORE FOG BEGINS TO LIFT AND CATEGORIES IMPROVE
IN ALL AREAS BY 13Z TO 14Z. WEST NORTHWEST TO NORTHWEST WINDS AT
10KT OR LESS ARE EXPECTED TO BEGIN THE PERIOD, BEFORE BECOMING
LIGHT AND VARIABLE BY AROUND 00Z. WEST TO NORTHWEST WINDS AT LESS
THAN 10KT SHOULD RETURN TO END THE PERIOD ALONG WITH THE POTENTIAL
FOR A FEW CUMULUS AS WELL AFTER ABOUT 15Z.
JKL WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...JP
LONG TERM...GINNICK
AVIATION...JP
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