135
FXUS63 KPAH 051131
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
631 AM CDT Sat Sep 5 2026

.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.

&&

$$

DISCUSSION...DRS
AVIATION...DRS