018
FXUS63 KILX 190743
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
243 AM CDT Thu Sep 19 2024

.KEY MESSAGES...

- Summer-like warmth continues the next few days with more
  seasonal temperatures returning for the start of the new week.

- A more unsettled pattern arrives beginning tonight as a few
  upper systems bring periodic chances for showers and storms
  through at least early next week.

&&

.DISCUSSION...
Issued at 243 AM CDT Thu Sep 19 2024

An upper Rex block is in the process of breaking down late this week
as a series of upper disturbances from the western CONUS work
through the Upper Mississippi Valley and Midwest states in the
coming days. Satellite imagery shows exiting cirrus over eastern
parts of the state, with clear skies west of there. Temperatures as
of 2 am range from the upper 50s to low 60s. Dewpoints in the 50s
should allow air temperatures to drop a few more degrees through
daybreak. Daytime temperatures will continue to run seasonally high
the next several days with highs peaking in the middle 80s to around
90 degrees.

After a rather dry start to the month, precipitation chances return
late tonight into Friday as an upper shortwave lifts from the
northern Plains into the southern Canadian Prairies. A cold front
will approach from the west late tonight, bringing scattered
showers and storms to areas mainly near/west of I-57 through
Friday morning. A lull in precipitation will be seen late Friday
morning as the front stalls out across the area. Showers and
storms may redevelop along the front Friday afternoon as daytime
heating and seasonably high dewpoints result in 1000-1500 J/kg of
instability. Although the upper wave will be north of here by this
time the stalled out boundary paired with increasing mid-level
flow should allow some stronger storms to develop from mid
afternoon through early evening. A SPC marginal risk has been
introduced with the threat of damaging downburst winds and large
hail being the main concerns.

A stronger upper wave currently spinning off the coast of California
will bring better chances for precipitation and beneficial
rainfall this weekend into early next week. A couple shortwaves
will work through the area Saturday night into Sunday before the
main wave approaches late Sunday night. Periodic chances for
showers and storms will exist through at least Monday night with
the heaviest push of rainfall coming late Sunday night into Monday
morning as a ~30 kt LLJ noses feeds into a warm front. QPF
amounts look beneficial from this second system, though likely
won`t come close to erasing our ongoing deficit. The NBM shows
favorable probabilities (50-70%) of seeing at least 1 inch of rain
west of I- 55, with about a 30-40% of 2 inches or more.

Temperatures turn cooler for the start of the new week with highs
Monday through Thursday looking to stay near or below 80s degrees.

NMA

&&

.AVIATION...  (For the 06z TAFs through 06z Thursday Night)
Issued at 1147 PM CDT Wed Sep 18 2024

High pressure is over central Illinois late this evening and will
remain overnight resulting in light and variable or calm winds and
VFR conditions. Some high clouds are in place overnight.
Thursday, the ridge axis will inch east allowing a light southerly
breeze around 10 kt to spread in from the west, reaching the
central Illinois terminals except for CMI.


Deubelbeiss

&&

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

$$