836
FXUS63 KPAH 251900
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
200 PM CDT Sat May 25 2024

.KEY MESSAGES...

- Sunday looks like a very volatile day with 2 main rounds of
  severe weather potential. The range of possibilities covers
  everything from the pre-dawn period through the evening. High
  end threats for tornadoes, damaging winds, and large hail will
  all be possible.

- In addition to the all modes severe weather potential,
  intense heavy rainfall may produce localized flood
  issues...especially for locations that recently received such.
  We`ve issued a Flood Watch for the entire region from tonight
  through Sunday night to account for this potential.

- A much needed respite from the active weather pattern is in
  store for the bulk of next week therafter, as we return to
  drier weather and near seasonal temperatures.

&&

.DISCUSSION...
Issued at 200 PM CDT Sat May 25 2024

We expect 2 primary rounds of potential severe storms. The first
round will begin after midnight tonight...probably closer to
morning, as a short wave lobe of energy leads storm genesis from
IA/IL/MO with the convective threat extending southward into our
CWA. Bulk shear here increases from around 25 kts at 06z to nearly
double that by 12z. Lapse rates are increasing from about 6C to
around 7C during that time frame, for the area of concern. Lower 3KM
helicity increases from about 150 to 250 m2/s2 during this time.
MUCapes grow from about 1500 Joules to nearly double that by mid
morning, when we lose the 200-300 Joules of CIN. If/as this line of
convection moves east, an enhanced risk of strong- severe damaging
winds may materialize tmrw morning. Soundings and shear vectors
suggest bowing elements of the line may also lend toward a surging
and thus supercell/large hail threat as well, if/where this occurs.

Despite this morning round`s perhaps stabilizing effect, the models
insist we soup up again and quickly so during the afternoon. MUCapes
reach/exceed 4000 Joules/KG while lapse rates hike upwards to 8C.
CIN is effectively gone and there is now 300 m2/s2 of helicity in
the lower 3 KM to work with. If there are any boundaries layed out
from the morning that cells might coalesce upon, discrete supercells
would be possible with the attendant damaging winds/large hail
threats. It`s also possible this does not materialize, and we await
the incoming (main) line of storms later Sunday afternoon and
evening. This comes to fruition with all our parameters at their
peak, so our entire region has been upgraded to an Enhanced Risk
with hacking for all severe modes at their high end potential.

Other hazards include the potential for localized flooding as
any/all storms will operate in a soupy/high PW environ and be
capable of locally heavy downpours. Given our recent receipt of
heavy rains causing localized flood issues for at least a few
of our municipalities, we`ll go ahead and enter Watch mode with
a good portion of our neighbors as any repeat or intense heavy
rains may cause flooding, esp in these more sensitive/recently
saturated locations.

While ongoing storms may continue their life, in general, the
system departs and activity wanes by or certainly after midnight
Sunday night. Maybe there is some lingering early Monday
morning pop in our east, but after that, we go dry and seasonal
for the bulk of the remainder of the week (some small pops
return again by week`s end).

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 200 PM CDT Sat May 25 2024

MVFR to low VFR bases SCT-BKN this afternoon will improve to fully
VFR by or before day`s end. Flight rules remain Visual thereafter,
until late tonight. That`s when the first round of storms will be
incoming, and offer restrictions to at least MVFR for both
CIGS/VSBYS. Stronger storms may yield gusty winds and potential IFR
restrictions, but these were precluded from mention this
package.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Flood Watch from 1 AM CDT Sunday through Monday morning for
     ILZ075>078-080>094.
MO...Flood Watch from 1 AM CDT Sunday through Monday morning for
     MOZ076-086-087-100-107>112-114.
IN...Flood Watch from 1 AM CDT /2 AM EDT/ Sunday through Monday
     morning for INZ081-082-085>088.
KY...Flood Watch from 1 AM CDT Sunday through Monday morning for
     KYZ001>022.

&&

$$