797
FXUS63 KPAH 150731
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
231 AM CDT Mon Jul 15 2024

.KEY MESSAGES...

- Hazardous heat and humidity will continue through Tuesday
  afternoon. A Heat Advisory remains in effect until then for
  the entire region.

- A slow-moving cold front will move into the region late
  Tuesday through late Wednesday. A few rounds of showers and
  thunderstorms are possible, which will produce locally heavy
  rain and localized flooding issues.

- Canadian high pressure will bring a welcome break from the
  heat and humidity beginning Thursday through next weekend.

&&

.DISCUSSION...
Issued at 230 AM CDT Mon Jul 15 2024

Today through Wednesday night... Hazardous heat and humidity
will remain the primary weather story for the first two days of
the work week. High pressure centered over the southeast CONUS
will continue to pump plenty of heat and humidity in the area.
High temperatures today and Tuesday will again reach the lower
to middle 90s. Combined with dew point temperatures in the
middle to upper 70s. Apparent temperatures of 105 to 110 degrees
will be widespread, so no changes are planned to the ongoing
Heat Advisory which runs through 01z Wednesday. Overnight lows
tonight will be quite stuffy, only fall into the middle to upper
70s.

A transition to a cooler pattern will begins Tuesday afternoon
as a baroclinic zone associated with a stout area of high
pressure moving southward from the southern Canadian Prairie
Provinces. This will result in increasing chances of
thunderstorms beginning from north to south mainly Tuesday
afternoon along the I-64 corridor. These storms and associated
debris clouds may provide some localized relief from the heat,
but confidence in major temperature modifications occurring was
too low to trim the ongoing Heat Advisory area for Tuesday.

Shower and thunderstorm coverage will ramp up Tuesday night as
a weak H5 trough passes through the region. Combined with
elevated PWAT and specific humidity values, efficient rainfall
production within any convection that develops seems likely.
This will lead to a risk of locally heavy rain Tuesday night
into Wednesday and possibly Wednesday night. Latest WPC QPF has
a broad brush of 1-2" of rain forecast across the region during
this time, with locally higher amounts up to 3" over the Wabash
River valley.

In addition to the heavy rain risk, the environment across the
north half of the region will be quite unstable, with 3000-4000
J/kg of SBCAPE present. However bulk shear will be limited. A
few severe-level wind gusts cannot be ruled out from downbursts
during the afternoon and evening hours, and the latest SPC Day 2
Outlook included the northern half of the forecast area in a
Marginal Risk of severe thunderstorms.

As the frontal boundary sags southward during the day on
Wednesday, so will the higher PoPs. Widespread clouds and rain
will limit high temperatures to the middle to upper 80s.
However, dew point temperatures will still be sticky, in the
lower to middle 70s. Cooler, less humid air will begin to filter
into the region Wednesday night, with low temperatures dropping
into the middle to upper 60s.

Thursday through Sunday...The frontal boundary will finally
clear the region early on Thursday, allowing for much cooler and
drier air to filter into the area. High temperatures will only
reach the upper 70s to lower 80s on Thursday. Temperatures will
increase slightly on Friday and Saturday, climbing into the
lower to middle 80s. Overnight lows will be refreshing, dipping
into the upper 50s to lower 60s!

The next chance of rain looks to arrive late next weekend as a
disturbance passes south of the region across the Tennessee
River Valley. This will result in a chance of showers and
thunderstorms returning to the forecast Sunday afternoon across
the KY Pennyrile. High temperatures will be slightly warmer on
Sunday as well, reaching the middle to upper 80s.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1155 PM CDT Sun Jul 14 2024

Light south winds have been slow to calm completely tonight.
This may limit fog formation but the moisture in the air will be
sufficient for fog if winds can calm. Otherwise southwest winds
and VFR conditions are forecast through the period. Convection
may become an issue in the MVN/EVV curator by 05-06z Tuesday.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Heat Advisory until 8 PM CDT Tuesday for ILZ075>078-080>094.
MO...Heat Advisory until 8 PM CDT Tuesday for MOZ076-086-087-100-
     107>112-114.
IN...Heat Advisory until 8 PM CDT /9 PM EDT/ Tuesday for INZ081-082-
     085>088.
KY...Heat Advisory until 8 PM CDT Tuesday for KYZ001>022.

&&

$$

DISCUSSION...DWS
AVIATION...JGG