816
FXUS63 KPAH 202336
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
636 PM CDT Mon May 20 2024

.KEY MESSAGES...

- Hot the next couple days.

- A front stalls over the area Wednesday into Thursday bringing
  a daily chances of rain and thunderstorms through this
  weekend.

- Severe thunderstorm and more likely, flash flood risks will emerge
  in the Wednesday through Sunday period but each days risk
  will depend on prior activity and will have to be evaluated
  day to day.

&&

.DISCUSSION...
Issued at 309 PM CDT Mon May 20 2024

This afternoon, there is a piece of shortwave energy working through
the northern portions of the CWA, which may touch off a few showers
and thunderstorms from around Perry County MO/IL through around
Wayne County, IL. These should diminish near or just after sunset. A
strong storm or two will be possible.

High pressure will be in place over the Eastern Seaboard through
Tuesday afternoon, allowing southerly flow to steadily increase off
the Gulf of Mexico. A ridged pattern will be in place through
Tuesday afternoon, allowing temperatures to warm well into the 80s
or even low 90s for a good portion of the Quad State area.
Conditions are expected to remain dry with the better forcing along
the frontal boundary well to the west and northwest of the area. A
shortwave is expected to dive into the northern Plains by late
Tuesday morning, which will allow a surface low to quickly intensify
as it lifts northeast toward the western Great Lakes. Model guidance
still points toward an MCS developing over the Plains into southwest
MO before shifting eastward through the night, likely reaching the
Quad State very late Tuesday night into early Wednesday morning. If
the MCS is strong enough to push into the area with the ridged
pattern, then widespread showers and thunderstorms will arrive by
daybreak on Wednesday. As winds increase ahead of these features,
sustained winds may reach close to Lake Wind Advisory criteria
(15mph) by Tuesday afternoon.

Wednesday is still looking like a messy rainy/stormy day across much
of the Quad State area. The morning MCS would keep cloud cover and
showers/storms in the forecast through most of the morning with a
frontal boundary set to shift into the area during the afternoon.
The combination of increased moisture (PWATs around 1.8 inches), lift
along the frontal boundary and instability, will lead to increasing
chances for showers and thunderstorms. The area will also be in the
right-entrance region of an upper jet max, leading to broad scale
upward vertical motion over the Quad State. All this points toward
widespread shower and thunderstorm activity throughout the day into
Wednesday night. The slight risk is warranted across the Quad State
for Wednesday; however, this may be somewhat conditional. If
widespread showers and storms are ongoing throughout the day, then
it may be difficult to realize the 2000-3000 J/kg of instability
being painted out by the models guidance. In sort of a flip flop
from this morning, the GFS has greater instability than the NAM does
with the 12Z guidance. Shear be enough for organized severe (around
30kts), but it will largely depend on how the early morning
convection behaves and whether it linger through much of the
morning. Either way, heavy rainfall will be an issue especially due
to rainfall rates in thunderstorms and saturated soils from recent
rainfall. Most of the area is highlighted in a Slight Risk for
Excessive Rainfall on Wednesday.

The frontal boundary will remain near the area through the end of
the week and even into the weekend with additional shortwave energy
passing through the area. This will lead to multiple waves of
showers and thunderstorms. Moisture is still ample so any showers or
storms will be capable of producing very heavy rainfall, gusty winds
and hail. The greatest risk will be associated with each shortwave;
however, determining the exact details on those is very difficult
with much lead time. There will be a continued risk for at least
isolated flash flooding into the weekend.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 629 PM CDT Mon May 20 2024

The forecast is dry through Tuesday with VFR conditions
expected. Light winds overnight will increase to between 10-15
knots with gusts up to 25 knots in the afternoon.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.

&&

$$

DISCUSSION...KC
AVIATION...AD