862
FXUS63 KILX 101953
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
253 PM CDT Wed Jul 10 2024

.KEY MESSAGES...

- Scattered showers and thunderstorms are expected into Friday.
  Locally heavy rain will be the main concern.

- Trends continue to point toward heat and humidity building early
  next week, with the heat index above 100 degrees as early as
  Sunday.

&&

.SHORT TERM...  (Through Thursday)
Issued at 252 PM CDT Wed Jul 10 2024

Latest water vapor imagery shows a compact upper low and
associated trough across northern Iowa. Ahead of this, a band of
showers and scattered storms has developed from near Mattoon into
northern Illinois west of Rockford. This band appears to have
initiated near a lingering surface boundary, with the NAM Nest
handling it the best, keeping sporadic activity into the
afternoon. With the Iowa activity, the ARW appeared to initiate
it the best, though several of the high-res models show a general
increase in activity as the wave gets closer to Illinois. PoP`s
have been increased into the 40-50% range into early evening over
the northern half of the forecast area, though the latest HRRR and
FV3 suggest decent chances continuing as late as midnight. While
parameters for any severe weather in our area are meager, an
increase in precipitable water values to around 1.5 inches early
this evening point toward locally heavy rain with the stronger
storms, currently favored north of I-74. The upper trough will not
be in any hurry to exit, so a repeat of pop-up showers/storms is
expected Thursday, especially afternoon.

Geelhart


.LONG TERM...  (Friday through Next Wednesday)
Issued at 252 PM CDT Wed Jul 10 2024

Upper level high pressure ridge, currently anchored across the
Desert Southwest into Saskatchewan, will gradually build eastward
through the weekend, though flattening a tad. By early next week,
a large portion of the central and southern CONUS will be under
its influence, with the main storm track along the Canadian
border. A few more showers/storms will start the weekend with
another wave scooting out ahead of the ridge, but main focus for
convective activity will be with potential MCS activity along the
periphery of the ridge. The GFS holds the ridge on a little longer
with the storm track mainly north, while the European model
settles a boundary closer to our area. At this range, will keep
PoP`s in the 20-30% range while things shake out a little more.

With the heat, WPC guidance continues to suggest a >40% chance of
heat index values reaching 105 degrees (local heat advisory
criteria) Monday and Tuesday. Much will depend on the
aforementioned MCS activity and any residual cloud cover, but
evapotranspiration season is in full swing and dew points well
into the 70s may counter any suppressed temperatures. As it is,
high temperatures in the 90-95 degree range are still expected
Sunday through Tuesday.

Geelhart

&&

.AVIATION...  (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1255 PM CDT Wed Jul 10 2024

VFR conditions are expected to prevail through the TAF period.
Widespread diurnal cumulus is developing across the region now with
3kft ceilings. The coverage of the cumulus will continue to increase
today to BKN with ceilings expected to raise to 4kft by the
afternoon. Scattered showers and thunderstorms should arrive from
the NW after 22z/5pm and hang around until 04z/11pm once they weaken
to just showers. With the saturated ground from the recent rain and
calm winds tonight, some locations around the I-74 corridor in
Illinois may have areas of fog develop by the early morning hours
tomorrow.

Peine

&&

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

$$