textproduct: Paducah

KEY MESSAGES

- There is a 30-60% chance of daily showers and thunderstorms through the entire weekend. Rain chances peak during the afternoon hours, but the one exception is Saturday evening when a stronger gusty storm cannot be ruled out in the northeast across southwest Indiana.

- A Heat Advisory is now in effect from Saturday afternoon through Tuesday evening for southwest portions of the region. Daily high temperatures trend more into the lower 90s through early next week with heat index values between 100-105 degrees.

- Northerly flow may briefly cause moderate unhealthy air quality conditions across the far north on Sunday while the latter half of next week may pose a more impactful risk due to the ongoing Northwestern Ontario wildfire smoke.

DISCUSSION

Issued at 1156 AM CDT Fri Jul 17 2026

Daily scattered showers and isolated thunderstorms will continue today through the weekend as a weak shortwave trough moves across the FA this afternoon. Rain chances around 30-60% peak during the afternoon hours. With PWAT's around 2.00-2.15 inches combined with sfc mixing ratios around 19-20 g/kg, hourly rainfall rates will be capable of exceeding 2 inches per hour that will quickly yield typical ponding and runoff on roadways in low-lying locations. The shear increases to 15-20 kts on Saturday with 2000-2500 J/kg of MLCAPE. Combined with a theta-e difference of 25-30K and sfc-3km lapse rates around 7.0-7.5 C/km, there remains the potential for an isolated strong to severe storm in the northeast mainly across southwest Indiana where SPC has a marginal risk in their D2 outlook. As a cold front approaches Saturday evening from the north, timing may not line up with the best instability. The 12z HRRR shows a trailing line of storms not clipping the FA until closer to Midnight, separate from widely scattered pulse storms during peak heating.

The aformentioned cold front briefly stalls in the vicinity of I-64 on Sunday before lifting back north. There is the potential for brief moderate unhealthy air quality conditions north of the front, but PM2.5 values of 50-60 ug/m3 typically are still acceptable for most groups. The bigger concern however will be the hot and humid conditions. After collaborating with WFO LSX, have issued a Heat Advisory from Saturday afternoon through Tuesday evening for all of southeast Missouri, and portions of southern Illinois and far western Kentucky. 4 consecutive days of heat index values between 100-105 degrees are expected; however, there is the potential for values to near 110 degrees across the entire region on Tuesday. While another cold front approaches by Tuesday evening, the front may pose another risk for a few isolated strong to severe storms with modest improvement in both wind shear and forcing.

Temperatures trend about 5 degrees below normal on Wednesday into the latter half of next week behind the front. Highs by the NBM are progged to reach only the low to mid 80s. However, northerly flow associated with upper-level troughing over the Ohio Valley may yield a greater risk for poor air quality conditions due to the ongoing wildfires in Canada, and will be something to monitor more in the coming days.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1156 AM CDT Fri Jul 17 2026

Scattered showers and isolated thunderstorms will continue to increase in coverage this afternoon across the region, with KEVV/KOWB experiencing the greatest coverage. Heavy downpours can briefly cause IFR or lower vsby reductions, while MVFR conditions will be more prevailing when storms are in the vicinity. Winds tonight turn light & variable, but increase to 6-8 kts out of the west Saturday morning.

PAH WATCHES/WARNINGS/ADVISORIES

IL...Heat Advisory from noon Saturday to 7 PM CDT Tuesday for ILZ080-081-084>086-088>090-092>094. MO...Heat Advisory from noon Saturday to 7 PM CDT Tuesday for MOZ076-086-087-100-107>112-114. IN...None. KY...Heat Advisory from noon Saturday to 7 PM CDT Tuesday for KYZ001>009.