048
FXUS63 KPAH 161045 AAB
AFDPAH

Area Forecast Discussion...UPDATED
National Weather Service Paducah KY
545 AM CDT Wed Jul 16 2025

.KEY MESSAGES...

- Daily chances for scattered showers and storms continue
  through the weekend into next week. Strongest storms pose an
  isolated threat for damaging winds. Heavy rainfall and
  localized flash flooding is possible.

- Heat index values of 103 to 107 are expected for the next
  couple of days as humidity takes a step upward.

&&

.DISCUSSION...
Issued at 140 AM CDT Wed Jul 16 2025

A very weak upper shortwave is departing to the east with very
high column moisture persisting. Another shortwave is rolling
over the KS/IA plains but probably won`t make it this far
south. Convection may be a little suppressed by trailing
subsidence from the current weak shortwave but convective
temperatures look to be between 86-88 degrees F which should be
more than achievable. Convection will then fire in an
environment with about 2500-3000 J/kg of MLCAPE, 2.2 inch PWATs
but exceptionally weak low and deep layer flow. This should
result in storms with strong initial updrafts that really
struggle for organization. The strongest cells will come with a
respectable downburst potential and there may be another round
of non-supercell tornado/funnel type situations similar to what
we saw on Tuesday. Although the low level vorticity looks to be
lower than it was on Tuesday for now.

Heat is the other topic of the day. With slightly suppressed
initial convection dewpoints are expected to rise another degree
or two which should put parts of the area into the 105 degree
heat index range. The entire CWA will be close but the risk is
highest across parts of SEMO, southern Illinois and far west
Kentucky. The risk for heat advisory criteria conditions appears
higher tomorrow and the current forecast has the entire quad-
state at or above criteria, will hold off on that headline for
now though as its highly dependent on convective trends.

The upper jet lays more west to east on Thursday and a surface
front starts to approach from the north. GFS/NAM/HRRR bring the
front close enough to the area to increase shower and
thunderstorm coverage where the ECMWF is a little further north.
If it gets all the way into the area the risk for flash flooding
with storms training west to east along the front would rise
significantly. For now we look more adjacent to that risk. But
large buoyancy (2500 J/kg MLCAPE) deep warm cloud layer depth,
and PWATs at 2.2" make it impossible to ignore at least some
flooding potential. Downbursts would also be possible and we
will need to watch to see if deep layer shear overachieves the
10-15 kts currently indicated as the jet dips a little further
south. In short don`t be too shocked for Thursday to end up
pretty stormy over southern Illinois and southwest Indiana.

The front shifts more north on Friday and we get weak jet-level
ascent and low-layer warm advection which would presumably lead
to better coverage of a little stratiform precip and showers and
thunderstorms.

The pattern shifts to a little more of a southerly low level
flow through the weekend with scattered showers and storms and
more persistent low level moisture advection. The extended will
depend in part on any tropical cyclone development in the Gulf
into the weekend as the deterministic GFS solution depends on
their being at least a little something there. The ECMWF has
some retrograde TUTT type lows working to our south that
increases amplitude of the upper level flow a little but these
type features would be hard to model and track at that range.
What does appear fairly likely is a persistent shower and
thunderstorm pattern amid heat and humidity.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 545 AM CDT Wed Jul 16 2025

Localized fog and low stratus at a few sites should mix out
quickly this morning. Convection will be a factor area-wide this
afternoon but may start a little later and be less in coverage
than what we have seen the last week or so. Light wind overnight
should keep visibility up but if that slackens the moisture
fields will be primed for fog.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Heat Advisory from noon today to 7 PM CDT this evening for
     ILZ084-085-088>090-092>094.
MO...Heat Advisory from noon today to 7 PM CDT this evening for
     MOZ086-087-100-109>112-114.
IN...None.
KY...Heat Advisory from noon today to 7 PM CDT this evening for
     KYZ001>009.

&&

$$

DISCUSSION...JGG
AVIATION...JGG