textproduct: Paducah

KEY MESSAGES

- An Extreme Heat Warning continues thru tomorrow with Heat Indices peaking in the triple digits up to near 115 degrees.

- Storm chances, including strong storm chances, are best with frontal passages Sunday night and Thursday. Both frontal passages bring cooler temperatures and lower humidity.

DISCUSSION

Issued at 1241 PM CDT Sat Aug 15 2026

When you look at an upper level chart you can see about a 600dm ridge at 500mb centered just to the southwest of the area. The thermometer at the surface apparently sees the same thing as our temperatures are approaching the mid 90s across the southern half of the area and upper 80s in the northeast. Dewpoints are mixing down, mercifully, just a tiny bit into the mid 70s. Heat index values are still over 105 or headed that way amid clear skies. With the deep mixing LCL heights are up over 8000 ft which will significantly limit any prospects of showers or storms this afternoon.

Tomorrow looks just as hot with max apparent Ts in the 105-110 range. The cumulative heat of this extended streak will continue to make for a dangerous situation. Our newer "Heat Risk" tool still shows level 3 and 4 (out of 4) categorization across the entire CWA.

A zonal jet max to the north finally builds far enough south Sunday to nudge a cold front through Sunday night into Monday. Deep mixing produces very high LCL heights again tomorrow and that hot (relatively drier) air near the surface may limit parcel buoyancy somewhat, but 1500-2000 J/kg of MLCAPE looks to still be available when the front pushes through giving us decent shower and thunderstorm chances if the front can lift the parcels high enough to get going. If they do the potential for localized downbursts/winds will be there given the high 0-3km theta-e difference and low level inverted V/DCAPE.

Wednesday and Thursday a shortwave trough works off the Rockies and into the central plains and upper midwest. This kicks up flow out of the southwest and the lift and moisture look likely to combine to produce shower and thunderstorm chances. Deterministic GFS is a little sharper with this wave but the ECMWF also has it as do most ensemble members. Will need to watch for some severe weather potential if that signal remains given the lift/deep shear available with a warm and humid airmass. Low level shear actually creeps up just a bit in the GFS deterministic run. CSU-ML and CIPS analogs are also flickering just a bit over that period as well. Once the shortwave passes a cold front seems to have a respectable chance to make it into the area by the weekend. The current deterministic forecast has highs in the mid 80s with dewpoints in the mid 60s, which would feel positively Baltic compared to what we have seen for the last week!

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1141 AM CDT Sat Aug 15 2026

Outflow from convection to the north has shifted sfc winds to the north northeast across parts of southern Illinois and SWIN. It likely has largely made its furthest trek southward and the larger flow supports a shift more to the west and southwest with time today. Speeds should still be relatively light. VFR flight conditions are expected through the period. Light to moderate west winds are forecast on Sunday with convection probably holding off til after the new TAF period.

PAH WATCHES/WARNINGS/ADVISORIES

IL...Extreme Heat Warning until 8 PM CDT Sunday for ILZ075>078- 080>094. MO...Extreme Heat Warning until 8 PM CDT Sunday for MOZ076-086-087- 100-107>112-114. IN...Extreme Heat Warning until 8 PM CDT /9 PM EDT/ Sunday for INZ081-082-085>088. KY...Extreme Heat Warning until 8 PM CDT Sunday for KYZ001>022.