textproduct: Paducah

KEY MESSAGES

- An Extreme Heat Warning remains in effect through 8 PM this evening. Temperatures will once again push 100 today, while heat index values will range from 105 to 110. There is a 30-50% chance of triple digit heat index values continuing into Sunday mainly over western portions of southeast Missouri. - Scattered showers and thunderstorms will be possible throughout the Quad State this afternoon and evening. Gusty winds, lightning and brief heavy downpours will be the primary concerns.

- Labor Day will be the choice day of the weekend, with highs around 90, much less humidity, and a light northeast wind. The relative cool down will be brief, as triple digit heat index values return for much of the Quad State Tuesday through at least Wednesday.

DISCUSSION

Issued at 231 AM CDT Sat Sep 5 2026

At last, we have arrived at the last day of the Extreme Heat Warning! Heat indices 105 to 110 are once again expected, as temperatures climb to near 100 throughout the Quad State. No changes were made to the Excessive Heat Warning this morning.

We briefly considered issuing a Heat Advisory or Extreme Heat Warning for Sunday over the western 4 counties in southeast Missouri, but decided to let the day shift take one more look at it. The NBM's triple digit heat indices have trended downward and farther west in the last 24 hours, and with an increased chance of convection for today and a healthy dry northeast fetch expected Sunday, it is no forgone conclusion that any of the area will reach 100 Sunday.

We already had a few showers and even a lightning strike or two develop just northeast of the area in the last hour or so. Some of the 00Z and later guidance develops showers along the I-64 corridor later this morning mostly after daybreak. Not sure exactly why that is happening, but the early morning development lends a bit of confidence for this later development. We may need to add some small PoPs in the far north this morning.

The main concern today will be scattered showers and thunderstorms. There are no obvious convergent boundaries to focus development, but there are a couple of possibilities offered up by the latest guidance. One would have scattered storms developing over or just north of the Tri State after 19Z, and then moving south or even southwest through much of the area into the evening. A second possibility would be for development from the Perryville and Pinckneyville areas southeast into the Pennyrile also after 19Z. These storms would also move southeast into evening. A combination of 00Z ARW and 3km NAM was used to combine these two possibilities by showing development after 19Z that progresses southwest through the entire area through the late afternoon and evening.

CAPE of 2000-3000J/kg and DCAPE well over 1000J/kg will lead to a strong potential for gusty convective winds throughout the area. However, 0-6km shear of 30-40kts over the Evansville Tri State and Pennyrile could support a few severe storms with damaging winds there. Otherwise, lightning and locally heavy rainfall will be possible throughout the area. We could see quite a few outflow boundaries bouncing around the area, sustaining development into the evening. The convection should be done by 06Z and the rest of the weekend will be dry.

The forecast has trended a bit cooler Sunday and Monday. A few locations may not reach 90 degrees either day. However, the upper-level ridge will build right back over the Quad State by Tuesday morning and south winds will develop at the surface later Tuesday. That combination will persist through Wednesday when much of the region will see a return to triple digit heat indices. Right now it looks like more in the 100-105 range, which would not require a Heat Advisory.

The upper ridge will eventually break down again Wednesday night into Thursday, and that will bring another decent chance of convection and another cold front through the area by Friday. Confidence in the details for the end of the work week is low at this time. However, moderate instability is reasonable to assume for Thursday, and some increased mid and upper-level flow could support a few stronger storms.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 631 AM CDT Sat Sep 5 2026

Scattered TSRA are a decent bet across the region after 19Z, and they could continue well into the evening. Some strong outflow winds could impact more locations than the actual storms do. Prob30s seemed reasonable at all sites mainly in the afternoon across the north and the late afternoon and evening in the south. A persistent light northeast breeze is expected behind the convection and should persist all night. Guidance is rather aggressive with fog and low clouds tonight, but with the wind, fog is not a likely outcome. However, we did throw in an MVFR ceiling across the northern sites beginning around 09Z.

PAH WATCHES/WARNINGS/ADVISORIES

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