571
FXUS63 KJKL 021447
AFDJKL
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
1047 AM EDT WED SEP 2 2026
KEY MESSAGES
- HOT CONDITIONS ARE EXPECTED THROUGH FRIDAY. A HEAT ADVISORY HAS
BEEN ISSUED FOR TODAY AND THURSDAY WHERE CONFIDENCE IS HIGHEST
IN REACHING MAJOR HEATRISK CRITERIA. AFTERNOON HEAT INDICES ARE
FORECAST TO TOP 100 DEGREES IN MANY LOCATIONS THROUGH FRIDAY.
- SHOWERS AND THUNDERSTORMS ARE POSSIBLE AT TIMES FROM THURSDAY
AFTERNOON THROUGH THE WEEKEND.
UPDATE
ISSUED AT 1047 AM EDT WED SEP 2 2026
FOG HAS BURNED OFF IN THE VALLEYS AS OF UPDATE TIME AND
TEMPERATURES ARE RISING SHARPLY UNDER THE STILL STRONG EARLY
SEPTEMBER SUN. EXPECT WIDESPREAD HIGHS IN THE LOWER TO MIDDLE 90S
THIS AFTERNOON WITH HEAT INDICES PEAKING IN THE 100 TO 105F
RANGE.
SHORT TERM
(TODAY THROUGH THURSDAY)
ISSUED AT 407 AM EDT WED SEP 2 2026
THE AREA WILL REMAIN UNDER THE INFLUENCE OF A STRONG UPPER LEVEL
HIGH/RIDGE THROUGH THURSDAY EVENING, WITH HOT AND DRY CONDITIONS
CONTINUING. THUS, A GENERAL PERSISTENCE FORECAST SUFFICES, THOUGH
WITH DAYTIME HIGHS INCREASING A DEGREE OR THREE TODAY INTO
THURSDAY, AND POSSIBLY EXTENDING INTO FRIDAY DEPENDENT ON ANY
POTENTIAL CLOUDS OR SHOWER/THUNDERSTORM ACTIVITY.
A HEAT ADVISORY WAS ISSUED FOR MUCH OF OUR NORTHEASTERN, EAST-
CENTRAL, AND SOUTH-CENTRAL COUNTIES FOR TODAY AND THURSDAY. WHILE
SUBJECTIVE ADVISORY CRITERIA OF 105-DEGREE HEAT INDEX VALUES IS
NOT LIKELY TO BE MET IN MOST LOCATIONS, OBJECTIVE HEATRISK
GUIDANCE SUGGEST A MODERATE TO HIGH CHANCE (45 TO 90 PERCENT) OF
REACHING MAJOR HEATRISK CRITERIA, WHICH MEANS THAT ALL PERSONS
WITHOUT ADEQUATE HYDRATION AND/OR COOLING ARE SUSCEPTIBLE TO HEAT
STRESS OR ILLNESS. THE HEAT ADVISORY WAS ISSUED PRIMARILY FOR
THOSE AREAS WHERE OVERNIGHT LOWS ARE MOSTLY EXPECTED TO REMAIN IN
THE LOWER 70S INSTEAD OF THE UPPER 60S, WHICH LIMITS THE AMOUNT OF
OVERNIGHT RELIEF FROM THE OPPRESSIVE AFTERNOON HEAT. THIS INCLUDES
THE INTERSTATE 64 CORRIDOR, PLUS LOCATIONS GENERALLY ALONG AND
WEST OF THE CUMBERLAND PLATEAU ESCARPMENT.
MANY MODELS SUGGEST A LOW POTENTIAL FOR ISOLATED SHOWERS AND/OR
THUNDERSTORMS THURSDAY AFTERNOON, SO NBM POPS WERE BUMPED UP A BIT
FOR THURSDAY AFTERNOON. THIS ACTIVITY WILL NOT BE SUFFICIENTLY
WIDESPREAD TO PROVIDE RELIEF FROM THE HEAT.
VALLEY FOG WILL CONTINUE TO DEVELOP EACH NIGHT, BURNING OFF TOWARD
MID-MORNING.
LONG TERM
(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 353 AM EDT WED SEP 2 2026
AS THE LONG TERM PERIOD OPENS, THE AXIS OF AN ANOMALOUSLY STRONG 500
MB RIDGE WILL HAVE SHIFTED SOUTH AND EXTEND FROM THE CAROLINAS TO
WESTERN KY, CENTERED OVER THE VICINITY OF THE SOUTHERN APPALACHIANS.
BY FRIDAY, A 500 MB TROUGH IS EXPECTED TO EXTEND ACROSS EASTERN
SECTIONS OF THE GREAT LAKES TO THE MID ATLANTIC STATES FROM A CLOSED
UPPER LEVEL LOW OVER QUEBEC. MULTIPLE SHORTWAVES ARE PROGGED TO BE
MOVING IN NORTHWEST FLOW ACROSS THE GREAT LAKES TO MID ATLANTIC AT
THAT TIME. THE UPPER RIDGE SHOULD BE AT LEAST TEMPORARILY LESS
AMPLIFIED AT THAT POINT, WITH THE RIDGE BECOMING CENTERED FURTHER
WEST IN THE MID MS VALLEY VICINITY AND PLAINS BY FRIDAY INTO FRIDAY
NIGHT. THIS WILL ALL OCCUR DOWNSTREAM OF AN UPPER LOW IN THE
VICINITY OF THE PACIFIC NORTHWEST AND TROUGH IN THE WESTERN
CONUS.
TEMPERATURES ON FRIDAY SHOULD STILL BE HOT, OWING TO CONTINUED
INFLUENCE FROM THIS RIDGE; HOWEVER, HIGHS SHOULD TREND COOLER
COMPARED TO MIDWEEK AS THE FORECAST AREA FINDS ITSELF MORE ON THE
PERIPHERY OF THIS RIDGING RATHER THAN BEING DIRECTLY BENEATH IT. IN
TERMS OF SENSIBLE WEATHER IMPACTS, THERE IS HIGH CONFIDENCE THAT
TEMPERATURES WILL BE FIRMLY ABOVE AVERAGE BY AROUND 10 DEGREES OR
SO; THUS, THE MAIN FORECAST QUESTION DURING THIS PERIOD IS JUST HOW
HOT IT WILL GET ON FRIDAY BEFORE POTENTIAL CONVECTIVE DEVELOPMENT.
DETERMINISTIC GUIDANCE IS GENERALLY SPLIT INTO TWO CAMPS IN THIS
REGARD: EITHER DEW POINTS ARE LOWER WITH A HIGHER AIR TEMPERATURE
(GFS AND MEX), OR DEWPOINTS ARE HIGHER WITH A LOWER AIR TEMPERATURE
(ECMWF AND ECX). THE DRIER SOLUTIONS HAVE PROVEN UNREPRESENTATIVE IN
THIS PATTERN THUS FAR AND TOO WARM BY SEVERAL DEGREES, LARGELY
BECAUSE OF UNREALISTICALLY DEEP MIXING. GIVEN THIS BIAS, IT SEEMS
MORE LIKELY THAT A COOLER AND HIGHER DEWPOINT SOLUTION WOULD
CONTINUE FROM THE NEAR TERM INTO THE DAY ON FRIDAY, WITH THE NBM
DETERMINISTIC HIGHS OFFERING A REASONABLE MIDDLE GROUND. IN SUPPORT
OF THIS, THE FLOW BETWEEN THE RIDGE OF SURFACE HIGH PRESSURE JUST
SOUTH OF THE FORECAST AREA AND A COLD FRONT ASSOCIATED WITH THE
UPPER LOW IN CANADA AND TROUGHING INTO THE EASTERN GREAT LAKES
SAGGING TOWARD THE LOWER OH VALLEY REGION AND MID ATLANTIC SHOULD
PROMOTE SOUTHWESTERLY TO WESTERLY WINDS ACROSS THE FORECAST AREA,
MAINTAINING THESE HIGHER DEWPOINTS. MEANWHILE, DEWPOINTS WERE
LARGELY MAINTAINED, EXPECTED TO BE GENERALLY IN THE UPPER 60S TO
LOWER 70S ACROSS THE REGION. THIS WILL KEEP APPARENT TEMPERATURES
GENERALLY JUST BELOW HEAT ADVISORY CRITERIA, BUT TRIPLE DIGIT HEAT
INDICES ARE STILL ANTICIPATED AT LEAST BRIEFLY THOUGH CONVECTIVE
DEVELOPMENT ON FRIDAY SHOULD PROVIDE RELIEF AT LEAST IN SOME AREAS.
PRECEDING THE DAY ON FRIDAY, RELIEF WILL BE RELATIVELY LIMITED;
CLEAR SKIES AND HIGH PRESSURE WILL ALLOW FOR A MODEST RIDGE-VALLEY
SPLIT, BUT LOW TEMPERATURES WILL STILL GENERALLY FALL INTO THE LOW
70S ON RIDGES AND THE UPPER 60S IN VALLEYS (WHERE TYPICAL FOG
FORMATION IS EXPECTED).
BY THE WEEKEND, THE AXIS AND BASE OF THE UPPER LEVEL TROUGH WILL BE
TO OUR EAST AND SOUTHEAST, WITH AMPLIFYING RIDGING WEST OF THE
FORECAST AREA OVER THE GREAT PLAINS. THIS PATTERN WILL PLACE EASTERN
KENTUCKY IN A NORTHWEST FLOW REGIME ALOFT. AT LEAST A SLIGHT CHANCE
OF SHOWERS AND STORMS REMAIN FOR FRIDAY NIGHT AS THE COLD FRONT SAGS
INTO THE AREA. CHANCES FOR CONVECTION LIKELY PEAK ON SATURDAY,
MAINLY IN THE SCATTERED RANGE, IN CONJUNCTION WITH COLD FRONT
CONTINUING TO SAG SOUTH AND SOUTHWEST AND THE POTENTIAL FOR MULTIPLE
SHORTWAVES EMBEDDED WITHIN THIS NORTHWESTERLY FLOW. AS IS TYPICAL IN
THESE PATTERNS, MODEL SPREAD AND UNCERTAINTY REMAIN QUITE HIGH,
PARTICULARLY IN REGARD TO THE TIMING OF THESE FEATURES FOR FRIDAY
NIGHT TO SATURDAY; ACCORDINGLY, NBM POPS REMAIN QUITE BROAD BRUSHED
FOR NOW, WITH SMALL CHANCES LINGERING INTO SUNDAY, REPRESENTING THE
AVERAGING OF NUMEROUS DIFFERENT TIMING SOLUTIONS.
THUS, AS TIMING AND PRESENCE OF INDIVIDUAL WAVES BECOMES MORE
CERTAIN, POPS WILL BEAR SOME REFINING LATER TO END THE WEEK. THIS
NORTHWEST FLOW PATTERN WILL ALLOW TEMPERATURES TO RETURN CLOSER TO
NORMAL, WITH HIGHS MAINLY IN THE MID TO UPPER 80S EXPECTED FOR
SUNDAY AND CONTINUING INTO TUESDAY. RIDGING ALSO LOOKS TO BUILD BACK
TOWARD OUR AREA EARLY NEXT WEEK, WHICH RESULTS IN DIMINISHING POPS
BY MONDAY AND TUESDAY AND POTENTIALLY MORE CONFINED TO THE VA
BORDER.
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 708 AM EDT WED SEP 2 2026
VFR CONDITIONS WILL LARGELY PREVAIL DURING THE THE TAF PERIOD,
THOUGH AREAS OF VALLEY FOG ARE FORECAST THROUGH ~13Z THIS MORNING,
WITH REDEVELOPMENT TONIGHT GENERALLY BEGINNING BETWEEN 03Z-06Z AND
CONTINUING THROUGH THE END OF THE TAF PERIOD. CONFIDENCE IN FOG
REACHING ANY TAF SITE IS TOO LOW TO INCLUDE AT THIS TIME, HOWEVER.
WINDS WILL REMAIN LIGHT AND VARIABLE, BEFORE BECOMING
SOUTHWESTERLY THIS MORNING WHILE REMAINING UNDER 10 KTS.
EXPECT CU FIELDS TO DEVELOP ~15Z WITH DIURNAL HEATING AND A MOIST
AIRMASS.
JKL WATCHES/WARNINGS/ADVISORIES
HEAT ADVISORY UNTIL 8 PM EDT THURSDAY FOR KYZ044-050>052-058>060-
068-069-079-080-083>085-104.
UPDATE...GEERTSON
SHORT TERM...CMC
LONG TERM...FAGAN/JP
AVIATION...CMC
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page