226
FXUS63 KLOT 191725
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1125 AM CST Wed Nov 19 2025

.KEY MESSAGES...

- Seasonable temperatures are expected the rest of the week,
  though not a lot of sunshine.

&&

.DISCUSSION...
Issued at 245 AM CST Wed Nov 19 2025

Stratus deck currently blankets much of Illinois, Indiana, Iowa,
and adjacent portions of southern Wisconsin and lower Michigan.
This stratus is trapped beneath a sharp inversion seen around
900mb on recent ACARs flights out of MDW. Recent GOES nighttime
microphysics RGB imagery does show some erosion of the stratus
across southeast WI and southern Lake Michigan. Tuesday evening
sounding from KAPX showed a very dry low level air mass in place
across northern lower Michigan and northeasterly flow
near/below the inversion is likely advecting drier air
southwestward and helping chip away at the stratus.

Low confidence at how far any clearing from this erosion of the
stratus deck will get into northeast IL/northwest IN this
morning before low level flow veers more southeasterly and
likely results in a sloshing back northwest of the stratus. For
now, leaned toward mainly cloudy conditions in the grids for
today and only show a few degree temp recovery for highs because
of that. Should skies clear more than expected over northeast
IL, then temps would likely need to be nudged upward a few
degrees.

If there is any clearing early today, that should give way to a
return of stratus this afternoon and likely hanging on through
Wednesday night as light southerly flow and lingering inversion
keep stratus locked in. Southerly flow should pick up a bit
Thursday and that may be enough to push the stratus deck north
of the area, but confidence in that is quite low. Even if
stratus were to move out Thursday, extensive mid-high level
cloudiness would likely keep skies fairly cloudy as moisture
streams northeastward ahead of a southern stream trough.

NBM remains on the warmer end of the spectrum with high temps
Thursday. If the stratus clears out and especially if there are
breaks in the mid-high level cloudiness, then it is possible
that we could see highs well into the 50s, but seems more likely
that cloud cover should keep it cooler. Nudged forecast highs
down a bit over northeastern CWA Thursday, but could definitely
see forecast highs needing further lowering as confidence
increases in skies remaining cloudy.

Still looking like a split flow regime will be the rule through
the upcoming weekend with a deep longwave southern stream trough
over the southwestern U.S. and with the northern stream buckling
south into the Great Lakes. It`s looking increasingly likely
that confluent flow between northern stream and southern stream
should lead to a dampening of any energy emanating from the
western southern stream trough and attempting to move east
across into the central/eastern U.S. In addition to dampening
any shortwaves into the confluent flow, the west-northwesterly
flow in the northern stream will probably keep meaningful rain
chances mostly suppressed to the south of our CWA.

The time lagged nature of the NBM plus a few rogue ensemble
members continue to result in pops much of the Thursday-
Saturday time frame. In collaboration with neighboring offices,
pops were removed Thursday and lowered some Friday into
Saturday. As it looks now, areas of north of I-80 may not see
much, if any, rain late this week and over the weekend. South of
I-80, especially well south into central Illinois, stands the
best chances for seeing any rain and even there chances are
dwindling by the day.

Seasonable temperatures are expected into the weekend with
probably a tendency toward above average temps for the first
half of next week.

- Izzi

&&

.AVIATION /18Z TAFS THROUGH 00Z FRIDAY/...
Issued at 1125 AM CST Wed Nov 19 2025

The key aviation messages are:

- Prevailing MVFR cigs likely through the TAF period

- Potential for periods of BR and/or -DZ, greatest INVOF RFD,
  but could extend east to the Chicago area sites tonight into
  Thursday morning

Widespread MVFR stratus appears likely to remain in place
through the TAF period. Some vsby restrictions due to BR and or
some light -DZ are possible at RFD later this afternoon. The
main signal for -DZ/BR is later this evening, overnight, and
into early Thursday morning. Have introduced a TEMPO group for
IFR cigs and vsbys at RFD to cover the period of greatest signal
for flight category reductions, but it`s conceivable IFR
conditions extend beyond what`s advertised in the current TAF.

Confidence in IFR remains too low at this time to justify an
inclusion at the Chicago-area terminals at this time. With
moisture expected to increase through the day on Thursday, vsbys
may end up prevailing in the 5-7 sm range into the afternoon.

Light/variable to southeasterly winds will become southerly and
eventually southwesterly late tonight.

Carlaw

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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