textproduct: Paducah

KEY MESSAGES

- Isolated to scattered thunderstorms are expected along a cold front this afternoon. A few strong to severe storms are possible between 12-7PM.

- An extreme heat warning goes into effect this morning through the evening. Heat index values of 110 to 115 degrees are possible.

- Unhealthy air quality conditions from the Ontario wildfire smoke will likely continue today mainly across portions of southern Illinois and southwest Indiana.

DISCUSSION

Issued at 107 AM CDT Tue Jul 21 2026

A deep upper level trough across the Great Lakes will drive a cold front south through the Ohio Valley and Quad State today. A 50 knot mid level jet on the upshear side of the trough axis will lead to increasing deep layer shear through the afternoon. Moisture pooling ahead of the front will lead to dewpoints in the upper 70s to near 80. This along with steep mid level lapse rates will lead to a strongly unstable airmass characterized by CAPE values of 4000+ J/Kg. Some uncertainty exits in the convective mode but damaging winds seem to be the main threat given theta-e differences above 30 K and very strong instability. Can't completely rule out a tornado if any boundary can interact with this strongly unstable airmass but overall the potential is low. Torrential downpours will also be capable of causing localized flash flooding issues with runoff on roadways.

An Extreme Heat Warning remains in effect for today as heat index values climb into the 110 to 115 degrees. Locations along I-64 are only under a Heat Advisory as the earlier timing of storms will help to keep heat indices a bit cooler in the 105 to 109 range. Its not completely clear if cloud cover will clear out in time which may delay heating a bit. Several models do show clouds clearing out by late morning though which would still allow for several hours of heating. The front pushes through Tuesday evening with high pressure settling across the Midwest Wednesday into Thursday. Much drier and cooler conditions are expected with highs only in the low to mid 80s with lower humidity. Another shortwave brings rain chances back into the area by Friday. Rain chances will likely continue into the weekend with warming temperatures back into the 90s.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 610 PM CDT Mon Jul 20 2026

Timing of tomorrow's convective chances is the key in this issuance. Confidence is not the highest and so PROB30s were used for EVV, OWB, and PAH. Convection should stay clear of MVN and CGI but this is not a guarantee. Light winds tonight turn west- southwest between 6-11 kts Tuesday morning with isolated gusts around 20 kts.

PAH WATCHES/WARNINGS/ADVISORIES

IL...Heat Advisory until 11 AM CDT this morning for ILZ075-080>082- 084>094. Extreme Heat Warning from 11 AM this morning to 7 PM CDT this evening for ILZ075-080>094. Heat Advisory from 11 AM this morning to 7 PM CDT this evening for ILZ076>078. MO...Heat Advisory until 11 AM CDT this morning for MOZ076-086-087- 100-107>112-114. Extreme Heat Warning from 11 AM this morning to 7 PM CDT this evening for MOZ076-086-087-100-107>112-114. IN...Extreme Heat Warning from 11 AM this morning to 7 PM CDT this evening for INZ085>088. Heat Advisory from 11 AM CDT /noon EDT/ this morning to 7 PM CDT /8 PM EDT/ this evening for INZ081-082. KY...Heat Advisory until 11 AM CDT this morning for KYZ001>017-021- 022. Extreme Heat Warning from 11 AM this morning to 7 PM CDT this evening for KYZ001>022.