197
FXUS63 KLOT 140526
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
1226 AM CDT Thu May 14 2026

.KEY MESSAGES...

- After a relatively cool Wednesday, temperatures will trend
  upward through the weekend and into early next week.

- Chances for periodic showers and storms will return to the
  area Thursday night and last through early next week. Some
  storms may be severe, particularly Saturday through Tuesday.

&&

.DISCUSSION...
Issued at 1234 PM CDT Wed May 13 2026

Regional satellite imagery early this afternoon shows expansive
cyclonic flow across the Great Lakes associated with a surface
low pressure system moving across southern Ontario. The passage
of an upper-level shortwave embedded within the parent trough
over southern Lake Michigan allowed for a lake breeze to shift
well inland this afternoon, which is leading to a gradient in
temperatures ranging from the lower 60s west of I-39 to upper
40s along the shore. When combined with blustery north to
northwesterly winds, it feels more like March than May outside
(though the largely sunny skies are welcome).

Tonight, a surface high pressure system will quickly move into
the region causing surface winds to become nearly calm and skies
to clear. Temperatures will hence be poised to plummet
overnight with lows expected to bottom out in the upper 30s to
lower 40s. Patchy frost may develop in the typical cold spots by
daybreak.

The surface high pressure system will only slowly shift away
from the region throughout the day on Thursday, leading to
fairly calm winds. Mostly sunny skies and a gradual increase in
low-level warm air advection will help highs rise into the upper
60s to lower 70s. The exception will be along the Lake Michigan
shoreline where a lake breeze will hold temperatures in the low
to mid 50s.

Thursday night onward:

Toward the end of the week, the upper-level pattern will
transition from predominantly upper-level cyclonic flow across
the northern United States to zonal and eventually
southwesterly flow. The net result will be a gradual warming and
moistening trend leading to more seasonable to above-average
temperatures and periodic shots of showers and storms. Note that
some storms could be severe in the general region, particularly
Saturday through Tuesday. Ensemble guidance suggests a break in
the warm and stormy pattern toward the middle of next week.

Borchardt

&&

.AVIATION /06Z TAFS THROUGH 12Z FRIDAY/...
Issued at 1226 AM CDT Thu May 14 2026

High pressure currently over northern Illinois will result in
calm or VRB (SW to NNW) winds around or less than 5 knots
through mid-morning, then favor N/NNE through the remainder of
the morning. A lake breeze will then shift winds E around 10
knots early in the afternoon. Expect winds under 10 knots to
gradually veer ESE to SSE tonight. Around or shortly after
sunrise Friday, winds will veer SSE to SSW while beginning to
gust over 20 knots.

VFR conditions are expected through the period. Decaying mid-
level SHRA may cross or pass just south of the terminals around
sunrise Friday.

Kluber

&&

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

&&

$$

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