298
FXUS63 KILX 192301
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
601 PM CDT Wed Jun 19 2024

.KEY MESSAGES...

- Hot and humid conditions will continue across central and
  southeast IL for many days. The hottest conditions of the
  upcoming 7 days look to be Friday and Saturday when air
  temperatures climb into the mid 90s, and heat index values peak
  near or just above 100 degrees.

- Isolated thunderstorms will be possible mainly northwest of the
  IL river this evening and again Thursday, with a better chance
  for thunderstorms arriving Saturday night into Sunday as a cold
  front moves through Illinois.

&&

.DISCUSSION...
Issued at 335 PM CDT Wed Jun 19 2024

A frontal zone trailing from Lake Michigan southward to near the
OK/TX panhandle area is beginning to develop some thunderstorms in
the section near the Mississippi River, as well as a growing
cluster in north-central MO. This activity should creep eastward
late this afternoon and evening and promote at least isolated
storms into the Illinois River Valley. The latest HRRR model run
focuses activity just west of the Illinois River well into the
evening, while other available high resolution models keep
activity primarily west of the ILX forecast area. Have opted to
extend PoPs farther east and later into the evening than previous
forecast with this HRRR run, although kept at slight chance/20
percent. With effective bulk shear exceeding 30 kts in a corridor
around the Mississippi River, SPC has continued a Marginal Risk
for severe thunderstorms containing damaging wind gusts that
extends into parts of Knox County.

Another disturbance looks to track along the stalled front
Thursday, promoting additional thunderstorm chances.

High pressure and dry conditions look to prevail Friday into
Saturday, then an upper level wave looks to drive the frontal zone
through central IL over the weekend promoting more widespread and
perhaps stronger thunderstorm activity, although at present,
timing looks to be unfavorable for severe storms, arriving late at
night. At this point, have 30 to 70 PoPs with this feature,
highest NW of the Illinois River.

Temperatures should be quite hot through Saturday, as the warm
pre-frontal air mass dominates, and dewpoints around 70 are
forecast. Expect highs in the low to mid 90s, peaking Saturday.
Heat index should be well into the 90s, if not exceeding 100
Friday and Saturday. A bit of a respite is forecast for Sunday and
Monday with temperatures maxing out around 90, then more hot
weather is forecast again starting Tuesday.

37

&&

.AVIATION...  (For the 00z TAFs through 00z Thursday Evening)
Issued at 601 PM CDT Wed Jun 19 2024

Diurnal cu and a couple isolated showers will dissipate this
evening, leaving mostly clear skies and light southeast winds
overnight. Winds to veer southwest after sunrise near/under 10 kt
through 00z. Diurnal cu will again be prevalent on Thursday, with
a few isolated showers/storms around, but coverage way to low to
mention in TAFs.

25

&&

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

$$