656
FXUS63 KILX 300138
AFDILX

Area Forecast Discussion...Updated
National Weather Service Lincoln IL
838 PM CDT Wed May 29 2024

.KEY MESSAGES...

- Rain chances (greater than 50% probability) return by Saturday,
  with additional chances extending into next week.

- Heat and humidity will build by the middle of next week with
  WBGT values creeping toward a Moderate Threat (level 3 of 5).

&&

.UPDATE...
Issued at 838 PM CDT Wed May 29 2024

A lake breeze was pressing southwest into central IL this evening,
showing up as a fine line on radar imagery stretched from Lacon to
Champaign at 830 pm. Northeast winds briefly gust up to around 20
mph behind the boundary with dewpoints dropping off a few degrees.
Skies will trend clear overnight with the dry airmass in place and
winds will eventually go light/variable behind the boundary. This
will provide for good radiational cooling and lows in the lower
50s for most, and a few upper 40s in favored cool spots.

25

&&

.DISCUSSION...
Issued at 1240 PM CDT Wed May 29 2024

The stretch of dry and pleasant weather will run through Friday,
at least, as central Illinois remains under the influence of a
high- amplitude ridge and its attendant surface high pressure.

A pattern change will occur Friday as a northern stream trough
emerges and effectively pushes the ridge of high pressure eastward
into the Mid-Atlantic region. At the same time, a shortwave trough
will begin lifting northeastward across the Ozarks and into the
Mississippi Valley. This feature will help draw moist Gulf air
northward into central Illinois and augment the forcing/ascent
needed for rain.

Stubborn mid-level dry air could delay the onset of rain for
central Illinois on Saturday, but the evolution of certain
features such as the LLJ could support rain earlier in the day.
Any nocturnal convection that occurs upstream Friday evening will
likely outrun instability as it pushes eastward overnight, and
instability progs look fairly poor over central Illinois by
Saturday afternoon. But, the devil will be in the details for
thunderstorm potential, as a more favorable LLJ position than
currently depicted and/or a decaying MCV could afford better
convective coverage.

A subsident pattern behind the departing shortwave should keep
Sunday dry, but then additional shortwave activity is expected to
push across the Plains and into central Illinois by Monday with
additional rain chances throughout early next week.

Perhaps the greater threat as we head into next week will be the
heat as mid-to-upper 80s temps return to the region Tuesday and
Wednesday ahead of the next frontal system. Wet Bulb Globe
Temperatures (WBGT) during this time will have reading in the
lower 80s, which corresponds to a moderate heat threat (level 3 of
5).


MJA

&&

.AVIATION...  (For the 00z TAFs through 00z Thursday Evening)
Issued at 608 PM CDT Wed May 29 2024

Diurnal cumulus will dissipate over the next hour, leaving clear
skies overnight. A drier airmass working in from the northeast on
Thursday will lead to primarily clear skies, possibly some diurnal
cu towards KSPI/KDEC. Winds to be light/under 10 kt from the
northeast to east through Thursday afternoon.

25

&&

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

$$