609
FXUS63 KPAH 072336
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
636 PM CDT Tue May 7 2024

.KEY MESSAGES...

- Remain weather aware today through Wednesday evening as
  multiple rounds of severe weather are expected, and the
  potential exists for a higher end storm system Wednesday.

- Scattered showers and thunderstorms are expected to develop
  from mid-afternoon through the evening, with some of these
  storms strong to severe.

- Storms begin again Wednesday morning as a warm front lifts
  northward. A more significant and widespread severe
  thunderstorm outbreak is expected as a storm complex moves
  across the forecast area later in the day Wednesday, with a
  cold front bringing additional storms in the evening.

- Repeated rounds of heavy rainfall can result in localized
  flooding issues, with the highest chances Wednesday afternoon
  and evening.

- Cooler and drier air moves in for the end of the week and
  weekend with highs in the 70s and lower humidity.

&&

.DISCUSSION...
Issued at 304 PM CDT Tue May 7 2024

Following the morning storms, skies have remained mostly cloudy
across the Quad State region. Despite the patches of cloud
cover, temperatures have risen to the upper 70s to the lower
80s. The first initial afternoon showers have struggled to get
going, with better convection north of the forecast area.

The environment has many robust parameters this afternoon.
SBCAPE above 3000 with MLCAPE above 2000-2500 provides plenty
of instability. 0-6km shear is around 60 kts (higher to the
northwest outside the CWA), and STP is at 3-4, while 0-3 km
shear is 20-35 kts for now. While dew points are near 70, storms
are not firing at this time. One parameter that is lacking is
mid-level lapse rates which are around 6-6.5 C/km and slight
capping is present around 850 mb. The right exit region of the
jet is near I-64 at this time, also limiting development, but
should shift away to the northeast by the evening. Models focus
late afternoon development further near the I-64 corridor with
surface convergence near St Louis on satellite, though storms
are possible elsewhere. These storms are more likely to take the
form of discrete cells/supercells. For the evening hours, the
more favorable development will be near and south of the Ohio
River, with a more patchy linear development. All severe hazards
remain possible with these storms, albeit with hail potential
skewed more towards the afternoon hours rather than later in the
evening. Flooding potential today is fairly limited, as long as
any linear development this evening progresses southward. This
rainfall would set the stage for tomorrow.

For the overnight hours, a brief break in rainfall is
anticipated. Partial clearing, especially in the north, could
allow for brief development of patchy fog with calm winds. The
cold front stalls out overnight, reversing course back north
during the morning as a warm front as low pressure tracks
northeastward from Oklahoma towards St Louis. Models differ in
positioning, strength, and timing, but are better aligned on
morning convection developing with the warm front. Strong to
severe storms are possible, more likely later in the morning.

After these repeated rounds of storms today and tomorrow
morning, the main event is likely to be a robust squall line
moving through during the afternoon hours tomorrow. Supercells
are possible ahead of the squall line which, depending on
morning activity, may encounter a clear warm sector environment
suitable for a sustained track. Models differ on whether the
afternoon MCS remains connected with the cold front in Arkansas
or surges out ahead. CAPE is roughly as high as today, and more
robust helicity and shear are expected along with mid-level
lapse rates rising to around 8C/km, providing a much more
favorable environment if the morning storms progress far enough
to allow for recovery before the afternoon MCS. The main MCS
should limit any follow up storm development but portions of
SEMO or Western Kentucky that stay just south of the afternoon
storms will have better lingering potential for the evening. All
hazards are on the table, including significant wind or strong
tornadoes.

With the warm front in the morning, and robust storm activity in
the afternoon, along with prior rainfall, localized flooding
issues are likely to develop Wednesday. Exact positioning is
limited due to uncertainty in warm front location and stalling
potential.

Cooler and much drier air surges in Wednesday night following
the front. More seasonal temperatures are expected for the end
of week and weekend with fairly dry weather as most models keep
a Great Lakes system to our northeast for the weekend. A Four
Corners system tracks eastward, returning PoPs to the forecast
early next week.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 629 PM CDT Tue May 7 2024

Convection is struggling to get going this evening; however, not
completely out of the question to have a few showers and storms
over the next two to three hours. Gusty winds and heavy
downpours will be the main threats along with brief MVFR
conditions. A break can be expected in any convection overnight,
but some fog may form, especially where rainfall occurs. A warm
front will lift north through the area Wednesday bringing more
widespread chances for showers and storms early in the afternoon
and especially toward the evening hours. Severe weather with
gusty winds and hail will be possible.

&&

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

&&

$$

DISCUSSION...ATL
AVIATION...KC