FXUS63 KLOT 201726

AFDLOT



Area Forecast Discussion

National Weather Service Chicago/Romeoville, IL

1226 PM CDT Fri Mar 20 2026



.KEY MESSAGES...



- Spring-like temperatures through the weekend, though Lake 

  Michigan will moderate temperatures along the shoreline.



- Cooler temperatures are expected early next week after a cold

  front passes on Sunday.



&&



.DISCUSSION...

Issued at 207 AM CDT Fri Mar 20 2026



An anomalously strong upper-level ridge over the southwest 

CONUS will gradually deamplify while shifting across the central

CONUS through the weekend. During this time, a pair of sheared 

waves originating from the Pacific Northwest will cross the 

Great Lakes region.



A shallow lake-enhanced cold front that crossed northern 

Illinois Thursday afternoon/evening has since washed out over or

just south of the CWA early this morning. Developing low-level 

southwest flow and some diurnal heating ahead of the first wave 

will quickly mix out the front across at least the south half of

the CWA, possibly to the I-88 corridor, through early 

afternoon. Another cold front associated with the first wave 

will then shift SSW across northern Illinois through the 

afternoon. Highs across the Chicago metro, especially near the 

lake, will hinge significantly on the timing of the frontal 

passage. Expectations are that highs will range from near 60 

along the Wisconsin state line to the mid 70s toward central 

Illinois, with temps quickly falling into the 40s near the lake 

and 50s inland mid to late afternoon.



The front will retreat/wash-out amid developing breezy 

southwest winds on Saturday ahead of the second wave to the 

north. While some morning stratus may linger across northern 

Illinois in the morning, modest WAA will push temps back into 

the mid 60s north to mid 70s south.



The cold front tied to the second wave is expected to cross the

area from north to south Sunday morning into early afternoon. A

relatively dry airmass ahead of the front as well as strong low

and mid-level capping suggests a dry frontal passage. A band of

anafrontal precip with perhaps an embedded elevated 

thunderstorm is possible late Saturday morning through the 

afternoon amid temps falling into the 40s.



Broader WNW flow across the northern CONUS will take hold 

across much of next week, with a continued series of waves 

crossing somewhere across the Great Lakes region. Cooler but 

seasonable conditions will prevail as high pressure passes north

of the area Monday and Tuesday. However, a compact wave removed

from the stronger WNW flow aloft is progged to pass just 

southwest of the area on Tuesday and may brush the area with a 

few showers. Dry conditions and warming temperatures are favored

Wednesday and Thursday ahead of a stronger trough passing north

of the area. 



Kluber



&&



.AVIATION /18Z TAFS THROUGH 00Z SUNDAY/...

Issued at 1226 PM CDT Fri Mar 20 2026



Key Aviation Messages for the current TAF period:



- A lake breeze is expected at Chicago terminals this afternoon

  switching wind directions to the northeast.



VFR conditions are expected through the forecast period with no

precipitation. Winds will be around 10 to 15 knots each 

afternoon. The only challenge is the direction. Prevailing winds

this afternoon will be out of the northwest. A lake breeze is 

expected to develop this afternoon and move inland switching 

Chicago terminals over to the northeast. Winds will diminish 

overnight and turn to the east before settling in the southeast 

around or just after daybreak. As the winds return to 10 knots 

in the afternoon, they'll veer to the southwest.



DK



&&



.LOT WATCHES/WARNINGS/ADVISORIES...

IL...None.

IN...None.

LM...None.



&&



$$



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