743
FXUS63 KILX 310401
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1101 PM CDT Thu May 30 2024

.KEY MESSAGES...

- Showers and thunderstorms return to the forecast Friday night
  into Saturday (70-80 percent chance). Severe storms are not
  expected but there is around a 30 percent chance for some areas
  to see over an inch of rain.

- Additional showers and storms are expected Monday through
  Wednesday of next week.

&&

.UPDATE...
Issued at 808 PM CDT Thu May 30 2024

Light but persistent easterly flow has brought quite the dewpoint
gradient to central IL, ranging from the upper 30s at Bloomington
and Danville to the lower 50s in west central IL. Convective
debris high clouds well east of a north-south oriented
thunderstorm complex stretched across western IA and eastern KS,
will thicken somewhat overnight. This will keep lows a few degrees
warmer than last night, mainly in the mid 50s.

25

&&

.DISCUSSION...
Issued at 152 PM CDT Thu May 30 2024

This afternoon, high pressure is centered over the western Great
Lakes with ridging extending across east central Illinois and to
the lower Mississippi Valley. To our west, troughing stretches
across much of the Great Plains. In the near term, fair weather
will continue across central Illinois under the influence of the
ridge. As the ridge shifts to our east Friday, S/SW flow will
overspread central Illinois. A favorable fetch off of the Gulf of
Mexico will advect higher dewpoints towards central Illinois.
While this will be partially offset Friday by deep mixing into dry
mid levels, dew points will eventually build back into the 60s
over the weekend. Meanwhile, a shortwave trough is progged to push
across central Illinois Friday night into Saturday. This will
bring the next chance for showers and thunderstorms to the area.
Given the unfavorable diurnal timing of the wave, instability will
be weak (around 200-300 J/kg MUCAPE) and elevated, rooted
generally between 700-900mb. Severe storms are not expected due to
these conditions, but locally heavy rain appears possible. PWats
are expected to increase to around 1.6 inches and the slow moving
upper level disturbance and weak flow aloft in the vicinity of the
wave will result in slower storm motions. HREF LPMM (which only
covers through 12Z Saturday) shows a narrow swath of 1.5-2.0
inches of rain. NBM 90th percentile shows similar values across
the area through Saturday evening.

Behind the departing wave, ridging will briefly build back across
central Illinois Sunday providing a break in the rain chances most
of the day. Warm and humid conditions are expected instead with
highs in the lower 80s and dew points in the lower to mid 60s.

An initially zonal upper pattern early next week will gradually
give wave to digging trough evolving into a closed upper low by
midweek. There will be some chances for showers and storms Monday
and Tuesday as low amplitude waves move through the zonal flow,
but precip chances continue Wednesday as the closed upper low
digs into the Upper Midwest. Forecast PoPs are a bit broad brushed
Monday through Wednesday owing to timing differences in the
models, and anticipate plenty of dry hours on those days despite
the persistent chance PoPs. In addition, the midweek system could
be accompanied by an increase in shear and instability so
wouldn`t rule out some severe weather potential somewhere in the
region, though at this distance plenty can change.

Deubelbeiss

&&

.AVIATION...  (For the 06z TAFs through 06z Friday Night)
Issued at 1101 PM CDT Thu May 30 2024

Another round of VFR TAFs with scattered cirrus tonight and
scattered cu Friday late morning to afternoon. Light
east winds tonight veer southeast by mid-morning and gust to
around 20 kt through late afternoon. A weather system moving in
from the southwest will bring increasing mid level clouds and a
few showers after 00z.

25

&&

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

$$