805
FXUS63 KPAH 230835
AFDPAH

Area Forecast Discussion
National Weather Service Paducah KY
335 AM CDT Thu May 23 2024

.KEY MESSAGES...

- A chance of thunderstorms is forecast daily through Monday.
  Confidence in the details of timing and intensity is fairly
  low.

- The greatest coverage and intensity of thunderstorms is
  currently expected to be Friday, and especially Sunday.

- By Monday or Tuesday northwest flow aloft and surface high
  pressure should bring an end to the humidity and storm chances
  for a few days.

&&

.DISCUSSION...
Issued at 335 AM CDT Thu May 23 2024

The Quad State will remain in a nearly zonal flow aloft through
the weekend. This will result in a very active period with daily
chances of showers and thunderstorms. Temperatures will be
modulated by convection and associated cloud cover, but should
be at or above normal through Sunday.

A weak frontal boundary, oriented from southwest to northeast,
nearly bisects the area as of 08Z. Aloft, a weak disturbance
will generate mostly elevated convection across the area
through daybreak. The convection will push eastward through the
morning and may be south and east of the region by early
afternoon. Wind shear is very weak and instability is weak to
moderate. A few strong cores could produce some small hail or a
healthy wind gust, but organized severe storms are not expected
today.

A weak mid/upper-level ridge should keep the area relatively
quiet this afternoon and night, before another disturbance
arrives late tonight and Friday. The latest guidance continues
to struggle with the convective details, but the best guess at
this time is that convection will develop mainly over the
southeast half of the area at some point in the morning,
possibly before sunrise. Instability and shear will be limited
for this activity, so heavy rainfall and lightning would be the
primary concerns.

Later Friday, there are signs in most of the CAM guidance for a
line of storms or clusters of storms to move eastward into the
region at some point from midday through the afternoon. Moderate
to strong instability may develop ahead of it, and shear will be
increasing through the afternoon. This could result in some
severe storms, with all modes of severe possible. The storms would
likely weaken as they move eastward through the region and
encounter lesser shear and possibly a worked over airmass. A
weak cold front will attempt to move through the region Friday
night and this will keep a chance of thunderstorms in the
forecast through the night, especially in the east.

The front is likely to stall out over the region Saturday, as a
short-wave ridge builds aloft. South of the front, moderate to
strong instability could develop, but shear will be relatively
weak once again. The presence of the ridge could prevent
convective initiation, despite the weak front that will likely
wash out through the day. However, if a storm gets going, a few
strong to severe storms will be possible, with a damaging wind
threat and possible some hail.

Late Saturday night the remnants of convection over the Plains
will push into the area, as another disturbance approaches.
Shear will be substantial, and instability could be as well.
In the low-levels, this will resemble a warm front or surge of
warm advection which would continue into Sunday morning.
Damaging winds, large hail, and tornadoes will all be possible.

Guidance really generates some strong instability behind this
early activity Sunday and if the associated cold front pushes
into the region in the late afternoon or evening, more severe
storms are a decent bet. All modes of severe would be in play.

There is significant spread in the 00Z guidance with respect to
the upper pattern heading into next week, but they all generally
agree that by Tuesday a trough will set up over the Great Lakes.
This would bring northwest flow aloft and dry surface high
pressure to the Quad State for the middle of next week. But
before this occurs, the 00Z GFS brings one more storm system
eastward through the region Monday afternoon and evening. The
00Z ECMWF does not have this system, but if it were to occur we
could have another round of severe storms Monday afternoon and
evening.

Once the northwest flow aloft sets up, temperatures will drop to
or a little bit below normal. Most importantly, dewpoints will
drop back into the 50s, resulting in more pleasant humidity.
Summer is about here, and northwest flow in the summertime is
wrought with the potential for MCS development, so it would not
be surprising if we end up getting wet again by next Thursday.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1137 PM CDT Wed May 22 2024

Only major adjustment since the 00z TAF issuance is to increase
coverage and intensity of IFR/MVFR low stratus near PAH/OWB/EVV.
These clouds will mix out gradually as showers and isolated
thunderstorm move into the area from the west in the 09-13z
window. This activity will wind down in the late morning to
early afternoon with lingering MVFR bases rising back to VFR by
mid to late afternoon and continuing through the evening.

Light and variable winds overnight will become S to SW at 5-10
kts after daybreak and persist through the great majority of the
forecast period.

&&

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

&&

$$

DISCUSSION...CW
AVIATION...DWS