555
FXUS63 KPAH 041117
AFDPAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
617 AM CDT FRI SEP 4 2026
KEY MESSAGES
- AN EXTREME HEAT WARNING REMAINS IN EFFECT THROUGH SATURDAY FOR
A PROLONGED DANGEROUS HEATWAVE WITH DAILY HEAT INDEX VALUES
RANGING FROM 103-110 DEGREES. THERE IS A 30-90% CHANCE OF
TRIPLE DIGIT HEAT INDEX VALUES CONTINUING INTO SUNDAY OVER
SOUTHEAST MISSOURI, THE PURCHASE AREA OF KENTUCKY, AND
ADJACENT PORTIONS OF SOUTHERN ILLINOIS.
- NEAR RECORD HIGH TEMPERATURES IN THE UPPER 90S TO AROUND 100
DEGREES AND NEAR RECORD WARM OVERNIGHT LOW TEMPERATURES IN
THE MID TO UPPER 70S ARE EXPECTED TO CONTINUE THROUGH AT LEAST
SATURDAY. THESE HIGH AND LOW TEMPERATURES ARE 10-15 DEGREES
ABOVE NORMAL, AND WILL ELEVATE HEAT IMPACTS TO AN EXTREME
LEVEL EVEN MORE THROUGH THE START OF THE HOLIDAY WEEKEND.
- AN ISOLATED SHOWER OR THUNDERSTORM CANNOT BE RULED OUT OVER
MUCH OF THE REGION THIS AFTERNOON, AND WIDELY SCATTERED
SHOWERS AND STORMS WILL BE POSSIBLE MAINLY OVER THE EVANSVILLE
TRI STATE AND THE PENNYRILE REGION OF WEST KENTUCKY SATURDAY
AFTERNOON. LITTLE RELIEF FROM THE HEAT IS EXPECTED, WITH ONLY
A 10-25% CHANCE OF RAINFALL EXCEEDING A TENTH OF AN INCH WHERE
ISOLATED SHOWERS AND THUNDERSTORMS OCCUR.
- LABOR DAY WILL BE THE CHOICE DAY OF THE WEEKEND, WITH HIGHS
MOSTLY IN THE LOWER 90S, MUCH LESS HUMIDITY, AND A LIGHT
NORTHEAST WIND. THE RELATIVE COOL DOWN WILL BE SHORT-LIVED, AS
TRIPLE DIGIT HEAT INDICES RETURN FOR MUCH OF THE QUAD STATE
TUESDAY THROUGH THURSDAY.
DISCUSSION
ISSUED AT 255 AM CDT FRI SEP 4 2026
THE EXTREME HEAT WARNING CONTINUES UNCHANGED THROUGH SATURDAY.
DESPITE THE UPPER RIDGE WEAKENING SOME HEADING INTO THE
WEEKEND, IT REMAINS FIRMLY ENTRENCHED OVER THE REGION AND HIGH
TEMPERATURES WILL CONTINUE TO REACH THE UPPER 90S AND TRIPLE
DIGITS. IN ADDITION, DEWPOINTS ARE EXPECTED TO TREND A DEGREE OR
TWO HIGHER FOR TODAY AND SATURDAY, WHICH SHOULD KEEP HEAT
INDICES OVER MOST OF THE QUAD STATE IN THE 105-110 RANGE. THE
INCREASED DEWPOINTS SHOULD ALLOW LOW TEMPERATURES TO HOLD UP
MORE INTO THE MIDDLE AND POSSIBLY UPPER 70S OVER MOST OF THE
REGION THIS MORNING AND TONIGHT, SO THERE WILL BE LITTLE RELIEF
FROM THE HEAT EVEN AT NIGHT.
THE NBM AND LREF CONTINUE TO INDICATE THAT THERE IS AT LEAST A
50% CHANCE OF TRIPLE DIGIT HEAT INDICES OVER THE SOUTHWESTERN
HALF OF THE QUAD STATE SUNDAY, BUT THE CHANCE OF 105+ IS 30% OR
LESS EVEN OVER CARTER AND RIPLEY COUNTIES. A HEAT ADVISORY WILL
MOST LIKELY BE NEEDED OVER SOUTHEAST MISSOURI WHERE HEAT
INDICES 100-104 ARE EXPECTED SUNDAY. HOWEVER, THERE ARE SIGNS OF
INCREASED CONVECTIVE ACTIVITY SATURDAY AFTERNOON AND EVENING
AND A HEALTHY NORTHEAST FETCH SUNDAY, WHICH CAST SOME DOUBT ON
THE THERMODYNAMIC CONDITIONS. THE BOTTOM LINE IS THAT FORECAST
CONFIDENCE IS NOT HIGH ENOUGH TO ISSUE ANY HEAT HEADLINES FOR
SUNDAY AT THIS TIME.
WITH THE SOMEWHAT WEAKENING UPPER RIDGE OVERHEAD AND INCREASED
LOW-LEVEL MOISTURE EXPECTED TODAY, MUCH OF THE MOST RECENT CAM
DATA DEVELOPS ISOLATED CONVECTION OVER MUCH OF THE QUAD STATE
THIS AFTERNOON. AT THIS TIME, IT LOOKS LIKE SOUTHWEST INDIANA
AND THE I-64 CORRIDOR IN SOUTHERN ILLINOIS WILL REMAIN DRY, BUT
ELSEWHERE A BRIEF DOWNPOUR AND A FEW STRAY LIGHTNING STRIKES
WILL BE POSSIBLE. LOCALLY GUSTY WINDS WILL ALSO BE POSSIBLE WITH
ANY THUNDERSTORMS THIS AFTERNOON.
WITH SIMILAR THERMODYNAMICS EXPECTED SATURDAY, AND THE APPROACH
OF THE BACKDOOR COLD FRONT AND FURTHER WEAKENING OF THE UPPER
RIDGE OVER THE QUAD STATE, IT WOULD SEEM LIKE AT LEAST SCATTERED
THUNDERSTORMS WOULD BE A GOOD BET OVER MUCH OF THE REGION. THE
RRFS INDICATES MODERATE TO STRONG INSTABILITY OVER MUCH OF THE
REGION, WITH 0-6KM SHEAR OVER 40KTS OVER THE TRI STATE AREA. IT
GENERATES SOME FAIRLY ROBUST CONVECTION OVER THE NORTHERN HALF
OF THE REGION IN THE MID TO LATE AFTERNOON. THE THUNDERSTORMS
WILL MOVE SOUTHEAST AND SHOULD DISSIPATE BY SUNSET. THE RRFS
EVEN DEVELOPS SOME ISOLATED STORMS OVER THE OZARK FOOTHILLS OF
SOUTHEAST MISSOURI. MUCH OF SOUTHWEST INDIANA IS IN A MARGINAL
RISK OF SEVERE STORMS SATURDAY AFTERNOON AND EVENING, DUE TO THE
INCREASED SHEAR. DAMAGING WINDS WOULD BE THE PRIMARY SEVERE
CONCERN. IT CERTAINLY WOULD NOT BE SURPRISING TO SEE MORE
COVERAGE OF THUNDERSTORMS THROUGHOUT THE QUAD STATE SATURDAY. WE
WILL KEEP AN EYE ON THE FORECAST TRENDS.
THE PREPONDERANCE OF EVIDENCE SUPPORTS A DRY FORECAST FOR SUNDAY
AND LABOR DAY, WITH LESS HOT CONDITIONS AND A MORE MARKED
DECREASE IN HUMIDITY. DEWPOINTS MONDAY WILL BE IN THE UPPER 50S
TO LOWER 60S OVER MOST OF THE REGION, MAKING THE HOLIDAY THE
CHOICE DAY OF THE WEEKEND.
THE UPPER RIDGE POPS RIGHT BACK OVER THE AREA THROUGH THE MIDDLE
OF NEXT WEEK, AND AS SOUTH WINDS BRING INCREASING LOW-LEVEL
MOISTURE BACK NORTH ACROSS THE REGION BEGINNING TUESDAY, HIGHS
IN THE MIDDLE 90S AND SOME TRIPLE DIGIT HEAT INDICES WILL
RETURN. WEDNESDAY MAY REQUIRE ANOTHER HEAT ADVISORY FOR THE
ENTIRE REGION. THERE IS CONSIDERABLE UNCERTAINTY FOR THE END OF
THE WEEK IN REGARDS TO THE STRENGTH OF THE UPPER RIDGE AND
POTENTIAL FOR NORTHWEST FLOW ALOFT TO RETURN TO THE QUAD STATE.
IT IS POSSIBLE THAT WE COULD SEE A COLD FRONT AND DECENT CHANCE
OF CONVECTION AT SOME POINT THURSDAY INTO FRIDAY, BUT GIVEN THE
PERSISTENCE OF THIS UPPER RIDGE IT MIGHT BE DIFFICULT TO KILL.
AVIATION /12Z TAFS THROUGH 12Z SATURDAY/
ISSUED AT 617 AM CDT FRI SEP 4 2026
ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE OVER MUCH OF
THE REGION THIS AFTERNOON. THE BEST CHANCE OF IMPACTING A
TERMINAL WILL BE AT KPAH. SOME FOG FORMATION SEEMS A BIT MORE
LIKELY LATE TONIGHT DUE TO HIGHER DEWPOINTS EXPECTED. ADDED SOME
PREVAILING MVFR FOG AT KCGI, BUT WON'T BE SURPRISED IF IT GOES
LOWER. KPAH COULD ALSO BE IMPACTED, BUT CONFIDENCE IS TOO LOW TO
MENTION AT THIS TIME.
PAH WATCHES/WARNINGS/ADVISORIES
IL...EXTREME HEAT WARNING UNTIL 8 PM CDT SATURDAY FOR ILZ075>078-
080>094.
MO...EXTREME HEAT WARNING UNTIL 8 PM CDT SATURDAY FOR MOZ076-086-
087-100-107>112-114.
IN...EXTREME HEAT WARNING UNTIL 8 PM CDT /9 PM EDT/ SATURDAY FOR
INZ081-082-085>088.
KY...EXTREME HEAT WARNING UNTIL 8 PM CDT SATURDAY FOR KYZ001>022.
DISCUSSION...DRS
AVIATION...DRS
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