215
FXUS63 KILX 152330
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
630 PM CDT Thu Aug 15 2024

.KEY MESSAGES...

- Main window for severe weather tonight is expected between 9 pm
  and 2 am, with scattered wind damage the primary concern.

- Some shower and storm activity will linger Friday and Saturday,
  as a slow moving upper low drifts across the Great Lakes.

- An extended period of cooler conditions is expected Saturday
  into the middle of next week, with temperatures about 5-8
  degrees below seasonal normals.


&&

.SHORT TERM...  (Through Late Friday Afternoon)
Issued at 300 PM CDT Thu Aug 15 2024

Lingering showers early this afternoon have finally been showing
more of a diminishing trend, with most of the activity now around
Champaign and Danville. Some clearing has occurred over western
Illinois into adjacent areas of Missouri, allowing surface based
CAPE`s to reach around 3000 J/kg per recent SPC mesoanalysis.
Convective initiation is expected over central Iowa and north
central Missouri over the next few hours, which should arrive in
western Illinois toward 9-10 pm. A few of the CAM`s have also been
showing development over south central Illinois late in the
afternoon, and surface analysis does show a weak north/south
boundary roughly near Vandalia, which could be a source of
initiation. Will keep the lower (30%) PoP`s going in that area
for that reason, with most of the PoP adjustments focused on the
timing of the main convection later in the evening. Latest Day1
convective outlook maintains a level 2 risk of severe weather,
with the main window focused between 9 pm and 2 am.

Upper currently over northeast North Dakota is progged to move
to central Wisconsin by Friday afternoon. Much of the convective
activity should be out of our area early Friday morning, but a few
storms can`t be ruled out late afternoon or early evening as the
attendant surface boundary swings through the region. Think the
best chance of this occurring will be near and north of I-74 near
a small lower level jet max dropping into northern Illinois.

With the slower arrival of the main cold front, temperatures
Friday should still reach the mid 80s. However, some drier air
will begin to work in during the afternoon, easing the heat index
back a bit.

Geelhart

.LONG TERM...  (Saturday through Next Thursday)
Issued at 300 PM CDT Thu Aug 15 2024

Upper level progression of systems will be slow through the
weekend, as Hurricane Ernesto lifts northward across the western
Atlantic. This will result in the upper ridge amplifying across
the Rockies. Broad troughing will continue over the eastern U.S.
into early next week. Between these two, northwest flow into the
Midwest will provide a cooler weather pattern that persists
through this period. Highs in the upper 70s to around 80 degrees
are expected, with dew points dropping into the 50s by early
Monday. Rain-wise, the slow progression of the upper low over the
Great Lakes will provide a risk of scattered showers on Saturday
and perhaps into early Sunday, with surface high pressure
providing dry conditions after that.

Geelhart

&&

.AVIATION...  (For the 00z TAFs through 00z Friday Evening)
Issued at 630 PM CDT Thu Aug 15 2024

VFR conditions and southerly winds will be in place this evening
as thunderstorms develop over Iowa and Missouri. These storms
will move across central Illinois overnight. MVFR ceilings are
expected to linger behind the storms for several hours Friday
morning. Winds will set up out of the west mid to late Friday
morning and conditions should return to VFR the remainder of the
period.

Deubelbeiss

&&

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

$$