350
FXUS63 KILX 271052
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
552 AM CDT Mon May 27 2024

.KEY MESSAGES...

- Scattered thunderstorms (20-30% chance) will pose a threat of
  gusty winds this afternoon into the evening, primarily between 4
  PM and 9 PM. There is a level 1 of 5 risk of damaging winds.

- Tuesday afternoon/evening will also feature scattered storms
  capable of gusty winds (20% chance), mainly north of I-74.

- High pressure takes control for the latter half of the week,
  with dry weather Wednesday through Friday.

&&

.SHORT TERM...  (Through Late Tonight)
Issued at 237 AM CDT Mon May 27 2024

Early Monday morning, sfc low pressure was positioned over the
Great Lakes region, with an attendant cold front extending
through north- central IN into east-central IL. As of 2am/07z the
front had moved past a Danville to Taylorville line, but had not
yet reached Paris- to-Effingham. A few spotty showers have
developed near and just ahead of the front, so kept some low
chance PoPs during the first few hours of the forecast period.
These showers should be east of the area by daybreak today.

Today, central IL will be in the post-frontal airmass, which will
feature persistent northwest winds gusting 20-30 mph. A digging
shortwave will approach from the northwest by mid-afternoon,
leading to scattered showers/storms. Instability progs are rather
weak, less than 750 J/kg, but forecast soundings have consistently
shown a deep- inverted V profile beneath the cloud bases, which
are expected to be over 4000 feet. Efficient evaporative cooling
beneath these cloud bases could lead to sporadic strong downdrafts
capable of producing strong wind gusts. This assessment is
supported by high- res guidance, as the 27.00z HREF indicates a
20-40% chance of gusts over 45 mph with these storms. There is a
marginal risk (level 1 of 5) for damaging winds. Other severe
hazards (hail, tornadoes) are not expected.

Radar estimates suggest that nearly all of the CWA has received
at least a half inch of rain since Friday, and a majority of the
CWA has received over 1". That will hopefully stymie any blowing
dust concerns with these gusty thunderstorms.

Erwin

.LONG TERM...  (Tuesday through Sunday)
Issued at 237 AM CDT Mon May 27 2024

Tuesday looks fairly similar to Monday, with continued cyclonic
(northwesterly) flow and another shortwave approaching during the
afternoon which could kick off more showers/storms, mainly north
of I-74 (20% chance). Forecast soundings for Tuesday show similar
signatures to Monday, so gusty winds will once again be possible
with any storms that form.

Conditions are looking quite enjoyable Wed thru Fri as upper level
ridging set up over the central Plains, resulting in
strengthening, broad sfc high pressure over the Upper
Midwest/Ontario. These features will gradually shift east during
the latter half of the week, but will provide mostly dry weather
Wednesday-Friday while temperatures steadily warm each day. By
Fri, highs return to near normal, around 80F. Dewpoints in the
upper 40s/low 50s will make it feel quite refreshing.

Into the weekend, the upper ridge shifts east while a trough
approaches from the west, returning precip to the forecast Sat-
Sun. Early indications are that the severe weather potential with
this system is quite low, owing to limited moisture return.

Erwin

&&

.AVIATION...  (For the 12z TAFs through 12z Tuesday Morning)
Issued at 552 AM CDT Mon May 27 2024

An MVFR cloud deck is present across the terminals at the start of
the period, but a return to VFR conditions is expected to occur
from west to east during the first 2-4 hours of the period.
Northwest winds will persist through the period, with gusts around
20-22 knots during the day. Scattered storms are possible during
the late afternoon-evening, mainly between 23-03z.

Erwin

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$