571
FXUS63 KPAH 241148
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
648 AM CDT Fri May 24 2024

.KEY MESSAGES...

- Scattered thunderstorms are possible today and tonight. A few
  severe thunderstorms will be possible this afternoon into the
  evening. Large hail and damaging winds will be the main
  concerns.

- Numerous thunderstorms are expected Sunday afternoon and
  evening. Severe storms are likely with damaging winds, large
  hail, and tornadoes all possible.

- Dry conditions with near normal temperatures will be the rule
  for much of next week.

&&

.DISCUSSION...
Issued at 346 AM CDT Fri May 24 2024

Some patches of fog have developed along and northwest of a Mt
Vernon Illinois to Greenville, Kentucky line. An occasional
southeasterly breeze should keep dense fog from setting in, but
we will continue to monitor for the need to issue a Special
Weather Statement or a Dense Fog Advisory.

Scattered thunderstorms are expected to develop mid to late
morning along and east of the Mississippi River. These storms
will race northeast and should exit the region by 3 PM. Moderate
to strong instability may develop by late morning, but the wind
fields will be very weak. Therefore, a few of these storms may
briefly pulse up to produce some strong winds, but organized
severe storms are not expected.

Late this afternoon, more scattered storms may develop or move
into southeast Missouri and southern Illinois. Wind fields will
increase sufficiently to support a severe storm threat with
these storms as they attempt to push eastward across the region.
Large hail and damaging winds will be the primary concerns, but
a tornado or two cannot be ruled out.

A chance of thunderstorms will continue overnight tonight ahead
of a cold front that will reach west Kentucky before daybreak
Saturday. A small chance of showers and storms will linger into
Saturday in the far east and southeast portions of the Quad
State. No severe weather is expected overnight tonight through
Saturday night. The cold front will bring in some drier air to
northwest portions of the region.

South winds will increase on Sunday and may briefly approach
Lake Wind Advisory levels over portions of southeast Missouri.
We have no plans to issue an Advisory at this time, but the
strong winds will push lower 70 dewpoints back north through
the entire Quad State quickly Sunday morning. Along with
temperatures reaching the upper 80s, the increase moisture will
lead to very strong instability developing by afternoon
throughout the Quad State. This is made possible by the presence
of a healthy cap. Wind fields will increase Saturday night and
will be very strong and supportive of supercells and a severe
squall line in the afternoon and evening.

The main concern for the prospective severe storm outbreak
Sunday is convective initiation. Any remnant convection from
Saturday night and any significant upper-level forcing will pass
to the north of the Quad State, but one or more outflow
boundaries will likely provide a focus for thunderstorm
development. The initial thunderstorms are likely to quickly
become severe supercells with all severe hazards possible.
Confidence in where these boundaries will be by Sunday afternoon
is low, but they should be sufficiently close to allow storms to
impact at least the northeast half of the Quad State.

Model soundings reveal very steep lapse rates in the low and
mid levels, and very dry air in the mid and upper levels.
Therefore, there should be strong potential for rapid cold pool
development which would favor quick upscale growth to a severe
QLCS. Given the instability available, large hail cannot be
ruled out even in a linear system, but the primary concern with
the line will be damaging winds and tornadoes. Given the
impressive parameter space the models are generating, some high
end severe events (EF2+ tornadoes, 75+ mph winds, and 2+"
diameter hail) will be possible, especially over the northeast
half of the Quad State.

Some chance PoPs will linger into Monday as a final impulse
rides southeast on the back side of a developing Great Lakes
upper trough. For Monday night through at least Thursday dry
northwest flow aloft is expected, with cool, dry high pressure
in control at the surface. The flow may relax enough by next
Friday to allow an upper-level disturbance to bring a chance of
showers and thunderstorms to the Quad State. For the short work
week, it will be mostly dry with low humidity and near normal
temperatures.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 648 AM CDT Fri May 24 2024

MVFR ceilings are expected for a few hours this morning at most
locations. The LIFR ceiling at KEVV will improve quickly, but
MVFR ceilings may linger through the morning. An area of showers
may impact KPAH by mid-morning. As they move northeast they may
develop into thunderstorms as they approach KEVV and KOWB around
18Z. Handled this convection with a vicinity mention. Later this
afternoon through tonight there is a chance of thunderstorms
moving eastward through the entire region. Confidence in the
coverage and timing is too low to mention explicitly in the
forecast. South winds may gust to around 20kts this afternoon. A
cold front will reach KMVN and KCGI late tonight. MVFR or lower
conditions are possible throughout the area overnight.

&&

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

&&

$$

DISCUSSION...
AVIATION...DRS