001
FXUS63 KJKL 272126
AFDJKL
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
526 PM EDT MON JUL 27 2026
KEY MESSAGES
- THUNDERSTORMS ARE EXPECTED TONIGHT, SOME OF WHICH COULD BE
SEVERE (DAMAGING WIND IS THE MAIN THREAT).
- THUNDERSTORMS ARE ALSO POSSIBLE ON TUESDAY, ESPECIALLY IN
SOUTHEAST KY.
- DRIER WEATHER WITH MODESTLY LOWER HUMIDITY BEHIND THE COLD FRONT
WILL LAST THROUGH THE REST OF THE WORK WEEK.
SHORT TERM
(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 525 PM EDT MON JUL 27 2026
A STRONG UPPER LEVEL HIGH IS OVER THE CENTRAL AND SOUTHERN HIGH
PLAINS LATE TODAY, WHILE TROUGHING IS OVER THE NORTHEAST CONUS.
NORTHWEST FLOW ALOFT IS PRESENT IN BETWEEN THESE FEATURES, WITH AN
EMBEDDED SHORTWAVE TROUGH OVER THE UPPER MIDWEST. THIS IS
SUPPORTING A WEAK SOUTHEASTWARD MOVING SURFACE LOW OVER THE UPPER
MIDWEST WITH A WARM FRONT EXTENDING SOUTHEAST FROM IT THROUGH KY.
VERY UNSTABLE CONDITIONS WERE PRESENT IN THE WARM SECTOR AHEAD OF
THE LOW, AND WITH BRISK WINDS ALOFT PRODUCING SHEAR, SEVERE
THUNDERSTORMS HAVE BEEN OCCURRING NEAR THE WARM FRONTAL BOUNDARY
AS THE LOW APPROACHES. THE REGIME GENERATING THE THUNDERSTORMS
WILL CONTINUE SHIFTING SOUTHEAST WITH TIME, BUT THERE IS RATHER
LOW CONFIDENCE IN EXACTLY HOW IT PLAYS OUT DURING THE NIGHT.
MESOSCALE MODELS HAVE VARYING MOUNTS OF SHEAR AND INSTABILITY AS
STORMS APPROACH TONIGHT, BUT GENERALLY SHOW POTENTIAL FOR A SEVERE
THREAT. SOME RUNS HAVE HAD CAPE NEAR OR ABOVE 4K J/KG COMBINED
WITH SUPPORTIVE SHEAR, BUT THE PARAMETERS ARE NOT CONSISTENT. A
BLENDED SOLUTION WOULD SUGGEST THE MOST LIKELY TIME FOR STORMS TO
BEGIN MOVING IN FROM THE NNW IS ABOUT 11 PM TO MIDNIGHT, WITH
ACTIVITY THEN PROGRESSING ACROSS THE AREA OVER THE NEXT SEVERAL
HOURS. HOWEVER, EXTRAPOLATION OF CURRENT THUNDERSTORMS OVER
CENTRAL IN WOULD BRING IT INTO THE NORTHERN END OF THE FORECAST
AREA AROUND 9 PM SHOULD THEY HOLD TOGETHER.
EVEN THOUGH INITIAL CONVECTION SHOULD BE THROUGH THE AREA BY
TUESDAY MORNING, WE WILL STILL BE IN THE WARM SECTOR AS WE MOVE
INTO THE DAY. AS THE LOW PASSES TO OUR NORTHEAST, ITS COLD FRONT
WILL DROP SOUTH THROUGH OUR AREA DURING THE DAY AND THERE IS SOME
POTENTIAL FOR MORE THUNDERSTORM DEVELOPMENT BEFORE THE COLD FRONT
ARRIVES. THIS THREAT IS MAINLY IN SOUTHEAST KY AROUND MID DAY OR
EARLY AFTERNOON, WITH SIGNIFICANT SURFACE BASED INSTABILITY
POSSIBLE. HOWEVER, MUCH DRIER AIR ALREADY ARRIVING AT MID LEVELS
MAY LIMIT EFFECTIVE INSTABILITY DUE TO ENTRAINMENT INTO CONVECTIVE
CURRENTS.
THE COLD FRONT WILL BE THROUGH THE AREA BY LATE IN THE DAY AND
MOST IF NOT ALL PRECIP SHOULD END AT THAT POINT. COLD/DRY
ADVECTION THEN LASTS THROUGH TUESDAY NIGHT AS A NEW AIR MASS
ARRIVES.
LONG TERM
(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 455 AM EDT MON JUL 27 2026
(A NEW LONG TERM DISCUSSION WILL BE SENT SHORTLY)
THE MAIN CHANGE TO THE GRIDS FOR THE FIRST PART OF THE EXTENDED
FORECAST THIS MORNING WAS PRIMARILY TO INCLUDE SOME SLIGHT
TERRAIN DISTINCTIONS INTO TEMPERATURES FOR WEDNESDAY NIGHT,
THOUGH SOME UNCERTAINTY REMAINS AS TO THE SKY COVER. STRONG 5H
RIDGING TO THE WEST STILL LOOKS TO SUPPORT A PERSISTENT GLIDE PATH
FOR MID-LEVEL SHORTWAVES TO DIVE INTO EASTERN KENTUCKY THROUGH
THE WORK WEEK, THOUGH VISITING SFC HIGH PRESSURE FROM WEDNESDAY
THROUGH FRIDAY LOOK TO KEEP THE WEATHER CALMER AND DRIER.
THE PREVIOUS LONG TERM DISCUSSION FOLLOWS:
THE LONG-TERM PERIOD OPENS TUESDAY MORNING WITH A PRONOUNCED ~596
DAM HIGH OVER THE SOUTHERN ROCKIES WITH A RIDGE AXIS EXTENDING
NORTHWARD INTO CENTRAL CANADA. MEANWHILE, TROUGHING EXTENDS
SOUTHWARD FROM AN AROUND 540 DAM LOW OVER NORTHERN QUEBEC TO ALONG
THE MID-ATLANTIC COAST. AN EMBEDDED SHORTWAVE TROUGH IS PRESENT
OVER THE LOWER GREAT LAKES. THIS WILL BE MIRRORED AT THE SURFACE
BY A 997 MB SURFACE LOW OVER LAKE ERIE. A WARM FRONT EXTENDS
SOUTHWARD FROM THAT LOW TO OVER THE SOUTHERN APPALACHIANS WHILE A
COLD FRONT ARCS SOUTHWEST FROM THE SURFACE LOW OVER SOUTHERN
INDIANA AND ILLINOIS AND THEN BEYOND TO OVER THE HIGH PLAINS OF
MONTANA. THIS WILL LEAVE EASTERN KENTUCKY IN THE LOW'S WARM
SECTOR AT DAYBREAK TUESDAY MORNING WITH A SEASONABLY MOIST AIR
MASS (PWATS AROUND 1.8 INCHES).
THE SURFACE LOW WILL SHIFT EASTWARD ALONG THE PA/NY TWIN TIERS
THROUGH THE DAY AND EVENING ON TUESDAY, DROPPING THE COLD FRONT
ACROSS THE COMMONWEALTH. SUBSTANTIAL UNCERTAINTY REMAINS AS TO
INSTABILITY RECOVERY AHEAD OF THIS BOUNDARY GIVEN THE LIKELIHOOD FOR
CONVECTION EARLY IN THE DAY, AND ESPECIALLY PRIOR TO SUNRISE WITH A
POTENTIAL MCS. IF THE FRONTAL ARRIVAL IS SLOWER AND GREATER
DESTABILIZATION OCCURS, UNSEASONABLY STRONG NORTHWESTERLY FLOW ALOFT
WOULD SUPPORT ROBUST SHEAR AND ORGANIZED CONVECTION. CONVERSELY,
A QUICKER FRONTAL PASSAGE WOULD TEND TO FAVOR KEEPING ANY STRONGER
ORGANIZED CONVECTION CONFINED TO FAR SOUTHEASTERN KENTUCKY OR
PERHAPS ENTIRELY SOUTHEAST OF OUR CWA. IN ADDITION TO THE
CONVECTIVE POTENTIAL, TUESDAY DOES APPEAR BREEZY WITH SOME
MOMENTUM TRANSFER MIXING TO THE SURFACE FROM A LOW-LEVEL JET (30+
KT AT 850 HPA). THE HIGH PWATS COULD ALSO FAVOR SOME ISOLATED
HEAVY RAINFALL. ANY HYDRO PROBLEMS WOULD PROBABLY OCCUR WHERE
SUBSTANTIAL RAINFALL OCCURRED DURING THE LAST 12 HOURS OF THE
SHORT-TERM PERIOD; BY TUESDAY, THE STRONG FLOW ALOFT SHOULD KEEP
CELL MOTIONS QUITE PROGRESSIVE.
ONCE THE FRONT CLEARS THE AREA, COOLER AND DRIER AIR WILL FILTER IN
ON TUESDAY NIGHT AND WEDNESDAY, WITH LREF MEAN PRECIPITABLE WATER
VALUES DROPPING TO BETWEEN 0.75 AND 1.00 INCH, OR NEAR THE 10TH
PERCENTILE RELATIVE TO CLIMATOLOGY. ALOFT, RIDGING WILL REMAIN OVER
THE WEST WHILE TROUGHING LINGERS OVER EASTERN CANADA AND MUCH OF
THE EASTERN CONUS. SURFACE HIGH PRESSURE DRIFTING SOUTH FROM
ONTARIO AND QUEBEC WILL ENSURE DRY CONDITIONS THROUGH FRIDAY.
ANOTHER SHORTWAVE TROUGH DROPS INTO THE BROADER TROUGH DURING THE
UPCOMING WEEKEND. THIS WILL FOSTER ANOTHER SURFACE LOW DEVELOPING
OVER THE PLAINS AND DRIFTING TOWARD THE TENNESSEE VALLEY
VICINITY, BRINGING BACK HIGHER PWATS AND THE RENEWED THREAT OF
CONVECTION FOR SATURDAY AND SUNDAY.
IN SENSIBLE WEATHER TERMS, LOOK FOR A HIGH CHANCE OF SHOWERS AND
THUNDERSTORMS (POPS OF 60 TO 90 PERCENT, HIGHEST IN FAR EASTERN
AND SOUTHEASTERN KENTUCKY) ON TUESDAY. IF SUBSTANTIAL SUNSHINE
MATERIALIZES, SOME OF THE STORMS COULD BE STRONG TO SEVERE AND
ALSO PRODUCE HEAVY DOWNPOURS. IT WILL BE WARM AND HUMID WITH HIGHS
IN THE 80S. FAIR WEATHER FOLLOWS FOR TUESDAY NIGHT THROUGH FRIDAY
WITH HIGHS IN THE LOW TO MID 80S AND LOWS MOSTLY FROM 60 TO 65F.
AS THE THREAT OF SHOWERS AND THUNDERSTORMS RETURNS FOR SATURDAY
AND SUNDAY, DAILY HIGH TEMPERATURES WILL REMAIN AT SIMILAR LEVELS,
BUT NIGHTTIME LOWS WILL MODERATE TO BETWEEN 65 AND 70F WITH
HIGHER HUMIDITY LEVELS.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 227 PM EDT MON JUL 27 2026
MAINLY VFR CONDITIONS WERE PRESENT AT THE START OF THE PERIOD,
WITH ONLY SOME VERY SPARSE MVFR CEILINGS WHICH WERE DISAPPEARING.
VFR CONDITIONS ARE FORECAST TO LAST WELL INTO TONIGHT. AN AREA OF
THUNDERSTORMS IS EXPECTED TO MOVE INTO THE REGION FROM THE NORTH
NORTHWEST LATE TONIGHT. THERE IS A LARGE DEGREE OF UNCERTAINTY AS
TO HOW THESE STORMS WILL EVOLVE WITH TIME AS THEY APPROACH. A
TEMPO GROUP WITH IFR CONDITIONS WAS USED IN THE TAFS DURING WHAT
LOOKED LIKE THE MOST LIKELY TIME FOR ACTIVITY OVERNIGHT. THERE IS
SOME POTENTIAL FOR STRONG WINDS WITH THESE STORMS, BUT FORECAST
CONFIDENCE IS RATHER LOW. BEHIND THESE STORMS, MAINLY VFR
CONDITIONS ARE TENTATIVELY FORECAST GOING INTO THE DAY TUESDAY.
JKL WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...HAL
LONG TERM...JKL
AVIATION...HAL
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