917
FXUS63 KILX 172007
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
307 PM CDT Mon Jun 17 2024

.KEY MESSAGES...

- Seasonably hot and humid weather will prevail this week. Heat
  index values will peak in the upper 90s to around 100 degrees
  Tuesday afternoon through Saturday afternoon.

- Isolated thunderstorms will be possible from time to time over
  the next few days...with a better chance for thunderstorms
  arriving late Saturday into Sunday.

&&

.SHORT TERM...(Tonight through Tuesday Night)
Issued at 307 PM CDT Mon Jun 17 2024

19z/2pm radar imagery shows isolated convection across the KILX
CWA...particularly east of I-57 and west of the Illinois River.
The isolated storms will persist until sunset, followed by dry
conditions from mid-evening through much of the overnight period.
CAMs have consistently been showing renewed convective development
associated with a subtle short-wave trough pivoting northward
from the lower Mississippi River Valley late tonight into early
Tuesday morning. Based on model consensus, it appears most of the
activity will focus along/east of I-57 after 09z/3am. Have included
20-30 PoPs across this area accordingly. After the early morning
showers fade, disorganized diurnal convection will re-develop
within the highly unstable airmass Tuesday afternoon. Areal
coverage will remain quite low, so have only included 20 PoPs at
this time. Lows tonight will only drop into the lower to middle
70s while highs on Tuesday will climb into the lower 90s. Maximum
heat index values will peak in the upper 90s to around 100 degrees
Tuesday afternoon.

Barnes

.LONG TERM...(Wednesday through Next Monday)
Issued at 307 PM CDT Mon Jun 17 2024

Upper high currently centered over the Carolinas will build
southwestward over the next couple of days, cutting off the flow
of deep-layer moisture from the Gulf of Mexico. With this moisture
shunted into Texas and remaining well S/SW of central Illinois,
diurnal storm chances will decrease Wednesday through Friday. Will
need to keep an eye on a weak cold front that will try to drop
southward out of the Northern Plains, but think most of its associated
convection will remain N/NW of the area across Iowa/Wisconsin.
Have confined low chance PoPs to locations along/northwest of the
Illinois River during that period, but think most locations will
remain dry. Main story will be the hot weather as heat index
values routinely peak at around 100 degrees. Hottest days will
likely be Friday/Saturday when air temperatures climb into the
middle and perhaps upper 90s in a few spots and heat index values
reach 100-105 degrees.

As has been advertised by the models for the past several runs, a
significant short-wave trough is expected to traverse the country
and push a cold front into central Illinois this weekend. 12z Jun
17 GFS and ECMWF are in relatively good agreement, showing the
front arriving Saturday night. As a result, have included chance
PoPs (30-50%) Saturday night into Sunday. Once the front departs,
cooler and less humid weather is expected early next week as highs
drop back into the middle to upper 80s by Monday.

Barnes

&&

.AVIATION...  (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1238 PM CDT Mon Jun 17 2024

VFR conditions will prevail through the entire 18z TAF period.
Isolated convection will develop this afternoon...primarily
along/east of the I-57 corridor. Confidence of a storm impacting a
terminal is very low, so have opted not to include thunder at
this time. After a lull in precip chances after sunset, several
models suggest isolated convection once again firing along/east of
I-57 toward dawn Tuesday. Have carried VCSH at both KDEC and KCMI
to account for this possibility. Winds will initially be SW at
10-15kt with gusts of around 20kt. While the gusts will diminish
toward sunset, sustained SW winds of 10-15kt will continue through
the night. Gusts of 20kt or greater will resume by mid-morning
Tuesday.

Barnes

&&

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

$$