142
FXUS63 KLOT 021937
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
137 PM CST Mon Nov 2 2026

.KEY MESSAGES...

- A few showers are expected late this afternoon into this
  evening, mainly well northwest of a Chicago to Peru line.

- It`ll be windy and unseasonably warm Tuesday.

- Showers are likely late Tuesday, Tuesday night, into Wednesday
  morning, with a good soaking rainfall expected over much of
  the area.

- A return to more seasonable temperatures expected late this
  week into the upcoming weekend.

&&

.DISCUSSION...
Issued at 137 PM CST Mon Nov 2 2026

A long wave trough over the U.S. Rockies into the Great Plains
is moving slowly eastward. Water vapor imagery early this
afternoon shows a pair of closed mid-upper level lows embedded
within the broader trough. One located over the northern Plains
will shear out/open up as it moves northeastward into a more
confluent flow. An embedded lead shortwave trough in advance of
this upper low over the Cornbelt is supporting a band of
showers across Minnesota south into eastern IA and far NW IL.
This shower activity is likely being aided by strong warm air
advection in advance of an approaching warm front. The southern
flanks of this shower activity will likely graze our
northwestern and far northern CWA late this afternoon into this
evening.

The aforementioned warm front extending from western MN
southeast to the lower Ohio Valley will move northward tonight.
In the wake of the warm front, temperatures and dewpoints will
likely slowly rise into/through the 60s tonight. By sunrise
Tuesday, temperatures will likely be in the low to mid 60s,
which is about 10F above the normal highs for this time of
year. Strong and gusty southerly winds will provide for a steady
feed of unseasonably warm and humid (by Nov standards) air
through the day Tuesday.

Low cloudiness will likely at least partially scatter out in
the wake of tonight`s warm front. Some breaks in the overcast or
at least thinning of the overcast should allow temps to inch
upward into the lower 70s over the eastern half or so of the
CWA, including most of the Chicago metro area. If there is a
bit more in the way of breaks in the cloudiness Tuesday, it is
certainly plausible that highs could push into well into the 70s
given the progged near record warm 925mb temps.

A tight pressure gradient will support strong and gusty
southerly winds. Just how strong the winds get Tuesday will
depend on the depth of mixing/how warm temps get. Showers will
likely arrive in our western CWA Tuesday morning, this should
result in high temps "only" in the 60s and will likely limit the
magnitude of the winds and especially gusts some. Farther east
where temps will be warmer, gusts of 30 to 35 mph are likely
with some potential for some 40+ mph gusts with any more
significant thinning of the cloudiness. Time window for the
strongest winds/gusts should be mid morning through early to mid
afternoon, with winds/gusts easing as cloud cover thickens and
especially as rain spreads slowly eastward.

As for rain chances, they will be tied to the second closed
mid-upper level low, which is noted on water vapor imagery
approaching the OK/TX Panhandle region. This upper low is
progged to move eastward today before rounding the base of the
parent trough and lifting north later tonight into Tuesday.
Strong synoptic forcing is expected as this embedded trough is
progged to become negatively tilted as it moves north into the
Cornbelt Tuesday afternoon and evening. This strong forcing
coupled with PWATs near/just over 300% of normal should result
in a large shield of showers, some locally heavy moving slowly
east across the Mississippi Valley Tuesday. In our area, showers
should arrive near/west of I-39 Tuesday morning, but with
southerly mid-upper level flow, this activity should be slow to
spread east across our CWA Tuesday. In fact, rain may hold off
until after dark across eastern IL and northwest Indiana. Waves
of showers are expected Tuesday night into Wednesday morning.
Widespread rainfall totals of a half inch to an inch are
expected, heaviest totals likely over western CWA.

Upper level pattern across the country is progged to get quite
blocky during the middle and end of the upcoming work week. The
result looks to be the upper low over the Cornbelt getting stuck
meandering around the Midwest/western Great Lakes. Smaller scale
vorts pivoting around this meandering upper low will likely
result in periodic showers through at least the remainder of the
work week. Timing of these individual impulses rotating around
the upper low are hard to pin down. There will likely be many
rain free times in between some showery periods.

A return to more seasonable temperatures is expected after
tomorrow`s warmth. A cold front will usher in a cooler, Pacific
origin air mass Tuesday night into Wednesday. Cloud cover and
lingering rain will likely result in near steady if not slowly
falling temps Wednesday, but still a bit above the mid 50s
averages for early November. Cloud cover and some wind will
likely limit the diurnal temp swings Wednesday night through
Saturday. NBM low temps appear significantly too cool with
nighttime lows, especially Thursday night and Friday night.
Later forecasts will likely need to bump those lows up into the
40s with daytime highs inching up mostly into the lower 50s by
later this week into the first part of the weekend.

- Izzi

&&

.AVIATION /18Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 1201 PM CST Mon Nov 2 2026

Key messages for the 18Z TAF period:

* MVFR cigs through Tuesday with periods of IFR

* Pockets of drizzle possible overnight into Tuesday with
  showers expected during the afternoon

* Gusty southerly winds, especially on Tuesday

Low MVFR cigs are parked over Chicagoland early this afternoon
with IFR found farther inland, including over RFD. RFD is
expected to lift to MVFR late in the afternoon. MVFR cigs are
then anticipated through the daytime on Tuesday with periods of
IFR possible.

A weak signal exists for a brief push of drizzle and IFR cigs
across Chicagoland late this afternoon. Chances in these impacts
materializing are too low to include in the TAFs. A better
signal exists overnight into early Tuesday. A system of true
rain showers will then move in from the west during the day.
Rain could reach RFD as early as mid-morning and Chicago by
early afternoon, but chances are highest later into the
afternoon.

Meanwhile, southerly winds at around 10 to 12 kt sustained will
continue to gust as high as 20 kt through the afternoon and
into the 20 to 25 kt range for much of the evening and
overnight. Tuesday late morning and afternoon are expected to
see regular gusts out of the south to 30 to 35 kt.

Doom

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory from 6 PM this evening to 6 AM CST
     Wednesday for the IL nearshore waters.

     Small Craft Advisory from 9 AM Tuesday to 6 AM CST Wednesday
     for the IN nearshore waters.

&&

$$

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