765
FXUS63 KPAH 201745
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
1245 PM CDT Mon Jul 20 2026

.KEY MESSAGES...

- Daily chances of showers and thunderstorms continue into
  Tuesday. A few isolated strong to severe storms are possible
  between 12-7PM when rain chances peak at 40-60%. Localized
  flash flooding issues are also possible with heavy rainfall
  rates.

- A Heat Advisory and Extreme Heat Warning are both now in
  effect through Tuesday evening. Heat index values of 100 to
  106 are expected today and 110 to 116 on Tuesday.

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

&&

.DISCUSSION...
Issued at 1244 PM CDT Mon Jul 20 2026

Weak northwest flow aloft and a sfc boundary will allow for isolated
rain chances this afternoon, especially across southeast Missouri.
The boundary lifts north overnight with some improvement to the
unhealthy air quality conditions across portions of southern
Illinois and southwest Indiana on Tuesday. However, a strong
cold front will begin to approach the FA from the northwest with
increasing shear from a 40-50 kt jet at 700-500 mb. While most
of the CAMs show the bulk of scattered convection occurring
during the afternoon hours, the FV3/ARW have a decaying complex
of storms moving across southwest Indiana after 12z. Meanwhile,
the HRRR/NSSL show scattered development mainly south of the
Ohio confined to the afternoon hours. Despite the uncertainty,
the risk for isolated strong to severe storms will be the
greatest between 12-7PM when 4000 to 5000 J/kg of MLCAPE is
progged by the RAP13 along with 7.0 C/km sfc-3km lapse rate.
Although the best shear will be lagging behind the front, a
robust theta-e difference of 30-40K will favor 60-70 mph
damaging wind gusts as the main hazard of concern. Torrential
downpours will also be capable of causing localized flash
flooding issues with runoff on roadways.

A Heat Advisory and Extreme Heat Warning are now in effect through
Tuesday as heat index values between 110 to 116 are progged for
tomorrow. However, 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. High temperatures
in the low to mid 90s are expected over most of the FA setting
the stage for the hottest day of the week. The air quality will
also still be unhealthy across portions of southern Illinois and
southwest Indiana due to the wildfires in Canada. Temperatures
will then be 10 degrees cooler behind the front on Wednesday
with highs only in the low to mid 80s. Humidity levels will
also be significantly lower with dewpoints dipping down into the
60s and 50s. Rain chances return on Friday as a shortwave moves
through, followed by a significant warming trend with an
increase in humidity over the weekend as the eastern extent of a
597 dm ridge over the southern Plains builds in. Temperatures by
early next week will once again reach the 90s.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1244 PM CDT Mon Jul 20 2026

Lingering pockets of MVFR cigs will scatter out to VFR this
afternoon across the entire region. There is a 20% chance of an
isolated thundershower, especially at KCGI, but coverage is too
low to include TAF mention. Rain chances increase to 30% at
KEVV/KOWB Tuesday morning as there is uncertainty in a decaying
complex of storms. 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 Tuesday for ILZ075-080>082-
     084>094.
     Extreme Heat Warning from 11 AM to 7 PM CDT Tuesday for ILZ075-
     080>094.
     Heat Advisory from 11 AM to 7 PM CDT Tuesday for ILZ076>078.
MO...Heat Advisory until 11 AM CDT Tuesday for MOZ076-086-087-100-
     107>112-114.
     Extreme Heat Warning from 11 AM to 7 PM CDT Tuesday for MOZ076-
     086-087-100-107>112-114.
IN...Extreme Heat Warning from 11 AM to 7 PM CDT Tuesday for
     INZ085>088.
     Heat Advisory from 11 AM CDT /noon EDT/ to 7 PM CDT /8 PM EDT/
     Tuesday for INZ081-082.
     Air Quality Alert until 11 PM CDT /midnight EDT/ this evening
     for INZ081-082-085>088.
KY...Heat Advisory until 11 AM CDT Tuesday for KYZ001>017-021-022.
     Extreme Heat Warning from 11 AM to 7 PM CDT Tuesday for
     KYZ001>022.

&&

$$

DISCUSSION...DW
AVIATION...DW