Purdue University-Calumet Indiana Weather Forecast Discussion

021
FXUS63 KLOT 130523
AFDLOT
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1223 AM CDT Mon Oct 13 2025
.KEY MESSAGES...
- A few light showers/sprinkles can`t be ruled out late
  tonight/early Monday AM and again Tuesday night, otherwise
  mainly dry and near-seasonable conditions are expected
  through Thursday.
- The pattern turns more active heading into the upcoming
  weekend with increasing rain chances (30-50%).
&&
.DISCUSSION...
Issued at 303 PM CDT Sun Oct 12 2025
It`s another pleasant fall day out there with temperatures in
the 60s to lower 70s and generally light southeasterly breezes
with increasing high cloud coverage drifting in across northern
Illinois.
A strong upper level short wave is progged to lift across the
northern Plains into Ontario tonight into Monday. Warm advection
advection ahead of an associated surface cold front will lead
to increased shower coverage over Iowa into the evening. Dry
air in the low-to-mid levels will prevent any meaningful
rainfall occurring into the local area as it drifts northeast.
However, a few light showers/sprinkles can`t be ruled out late
tonight into Monday morning, mainly west of the Chicago metro
and I-55 in Illinois (20% chance) where enough mid-level
saturation could allow some rain drops to reach the surface.
Any spotty showers should end by the afternoon with forecast
highs on Monday in the low to mid 70s areawide with very light
winds.
Winds eventually flop northeasterly late Monday (albeit still
very light) with the expectation that they increase on Tuesday
through Wednesday. This will lead to generally cooler
conditions midweek with highs in the 60s areawide on Wendesday.
A few showers can`t be ruled out Tuesday night as a weak
disturbance rounds the upper ridge, though confidence remains
generally low and overall favors very light amounts if it does
occur.
Dry weather then likely continues midweek as the upper level
ridge builds northeast across the region paired with expanding
surface high pressure. Ensemble guidance continues to support
the return of a more active pattern for the end of next week
with increasing shower chances heading into the weekend (30-50%)
and perhaps a rumble of thunder. Something to keep an eye on
over the coming days.
Petr
&&
.AVIATION /06Z TAFS THROUGH 12Z TUESDAY/...
Issued at 1223 AM CDT Mon Oct 13 2025
There are no significant aviation forecast concerns anticipated
through the current TAF period.
A line of light rain showers is currently shifting eastward into
northwestern IL at the time of this writing. While some of this
activity could reach KRFD after 08Z, the line of showers
continues to show signs of weakening as it runs into a drier
low-level airmass across northern IL. Accordingly, we are not
expecting any real impacts, should any of these showers hold
together. Farther east towards the Chicago area terminals, dry
weather is anticipated overnight. If any light showers or
sprinkles were to make it into the Chicago area, this would
likely not occur until sometime mid to late this morning.
However, the chances for this are too low (

NWS LOT Office Area Forecast Discussion