754
FXUS63 KILX 110446
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1146 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.

&&

.UPDATE...
Issued at 841 PM CDT Wed Jul 10 2024

Scattered showers and thunderstorms continue along the I-74
corridor this evening while more isolated activity is in place
further south. A number of outflow boundaries have surged well
ahead of storms in the area which along with loss of daytime
heating should allow convection to diminish in coverage over the
next few hours. Will maintain some isolated mention of precip for
portions of central Illinois overnight as an upper low currently
over Iowa digs slowly southeast tonight.

Deubelbeiss

&&

.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 06z TAFs through 06z Thursday Night)
Issued at 1145 PM CDT Wed Jul 10 2024

Showers and thunderstorms will continue to taper off with most of
the area dry overnight outside of an off chance for an isolated
storm. Scattered clouds will be in place overnight, but if any
substantial clearing occurs, then fog may develop, especially
along the I-74 corridor which saw multiple rounds of precip
Wednesday. Winds will be light and variable overnight, then set up
out of the NE Thursday. Scattered showers and storms are possible
again Wednesday afternoon and evening, with the greatest coverage
expected across east central Illinois.

Deubelbeiss

&&

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

$$