Leonore, Illinois Weather Forecast Discussion

795
FXUS63 KLOT 250527
AFDLOT
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1227 AM CDT Thu Sep 25 2025
.KEY MESSAGES...
- A few lake effect showers can`t be ruled out near the lake
  overnight into Thursday morning (20-30% chance).
- Drier conditions are expected to end the week as temperatures
  inch back into the 80s over the weekend.
&&
.DISCUSSION...
Issued at 248 PM CDT Wed Sep 24 2025
Through Thursday Night:
A broad upper low continues to spiral over northern MI and is
starting to phase with the shortwave trough traversing across
eastern KS and MO. While northern IL and northwest IN are
sandwiched between these features and under some broad ascent,
mid-level moisture is somewhat sparse which has allowed for
drier conditions to prevail and this is expected to remain the
case through tonight for most. That said, there are a couple of
showers trying to develop along a frontal boundary in central IL
which may briefly brush our southern CWA through sunset. Hence
a 20% chance for isolated showers has been maintained for areas
along and south of a Pontiac to Rensselaer line. Additionally,
there remains the chance for some lake effect showers to develop
tonight into Thursday morning as a vort max (currently over
northern Lake Michigan) pivots through the area. With the upper
low being analyzed a bit further east than originally thought
the lake induced instability does not seem to be as impressive
as guidance suggested yesterday so suspect coverage of lake
effect showers will be rather spotty. Nevertheless, the 7000-
8000 ft deep moisture profiles and stout convergence still looks
to be sufficient to maintain the 20-30% POPs along the IL and
northwest IN lake shores.
Any lake effect showers that do materialize tonight will
gradually pivot into northwest IN Thursday morning and then exit
by midday. Therefore, Thursday looks to be a dry day with
otherwise partly cloudy skies. Though, the breezy northwest
winds will keep temperatures on the more seasonable side with
highs in the low to mid-70s.
Friday through Wednesday:
The previously advertised upper ridge will be building into the
Great Lakes as we head into Friday and persist through at least
the middle of next week. As a result, dry conditions will once
again dominate the forecast with south-southwest winds advecting
in more above average temperatures to close out September. So
expect highs during this period to be in the upper 70s to
mid-80s each day with overnight lows in the mid-50s. While a
weak cold front is still expected to swing through the area late
Sunday into Monday, the lack of moisture and cold air with it
look to offer little change to the forecast. However, the front
will allow winds to favor a more easterly direction and make it
more favorable for daily lake breezes to move onshore Monday,
Tuesday, and Wednesday. Thus temperatures near the lake these
days will be a bit cooler in the low to mid-70s.
Yack
&&
.AVIATION /06Z TAFS THROUGH 12Z FRIDAY/...
Issued at 1227 AM CDT Thu Sep 25 2025
Pockets of MVFR cigs will be possible this morning, with the
greatest chances near the lake. At GYY, light lake effect
showers may develop in the vicinity, but have pushed the timing
back closer to daybreak. The low-level flow will back to the
northwest this afternoon which should shunt any lingering
precipitation east of the terminal.
Winds will largely be northwesterly this morning, but will turn
northeasterly, first at GYY and then at MDW and possibly ORD.
Confidence in the NE wind shift timing is lowest at ORD, and
it`s conceivable this wind shift struggles to make it fully
through the airfield.
Tonight into Friday morning: winds will ease and trend towards
light and variable. With clearing skies, there is some potential
for BR/FG development, mainly near GYY and perhaps DPA, but just
beyond the end of the current TAF windows.
Carlaw
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...Beach Hazards Statement until 7 AM CDT this morning for ILZ006-
     ILZ103-ILZ104.
IN...Beach Hazards Statement through this afternoon for INZ001-
     INZ002.
LM...Small Craft Advisory until 7 AM CDT this morning for the IL
     and IN nearshore waters.
&&
$$
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NWS LOT Office Area Forecast Discussion