FXUS63 KLOT 190031

AFDLOT



Area Forecast Discussion

National Weather Service Chicago/Romeoville, IL

731 PM CDT Wed Mar 18 2026



.KEY MESSAGES...



- Another clipper system may deliver rain showers tonight 

  (Wednesday night) into Thursday morning. 



- Temperatures will warm toward the 60s to locally lower 70s

  Friday and Saturday. A cold front passage Saturday night into

  Sunday will bring a sharp cool down, especially near the lake.



&&



.DISCUSSION...

Issued at 113 PM CDT Wed Mar 18 2026



Another weak clipper system will move southeast across the 

region late tonight into Thursday morning bringing a chance of 

rain showers. Much of the guidance is trending drier with really

only the HRRR showing several hours of showers moving through 

the area around and after daybreak Thursday morning. Quite a bit

of dry air in the low levels that any precipitation would have 

to overcome and given these trends have lowered pops some and 

also adjusted timing later with pops continuing across northwest

IN through late Thursday morning. Temps will likely drop into 

the lower 30s, possibly upper 20s over the deeper snowpack 

areas, this evening and then slowly rise through the overnight 

hours. However, confidence is low for temp trends tonight into 

Thursday morning and if rain showers do develop, there will be a

low chance for freezing rain and this will need to be monitored

later this evening into the overnight hours. Currently, do not 

have any freezing rain mention during this time period.



Temps begin to warm into the 50s for most of the area Thursday,

though easterly winds will keep the lakeshore areas and far

northeast IL cooler. A lake breeze may move inland Thursday

afternoon, spreading the cooler air further inland.



Southwest winds on Friday will allow warmer temps all the way to

the lakeshore with 60s across northern IL and lower 70s across

central IL. A cold front is expected to move south across the 

area Friday afternoon into Friday evening with uncertainty for

timing. When it does, there will be a large temperature drop for

the lakeshore areas. Winds shift back around to the southwest on 

Saturday with highs back into the upper 60s/lower 70s for much

of the area.



Another stronger cold front is expected to move across the area

on Sunday and there remains quite a bit of uncertainty for its

timing/location. There seems to be a slowly increasing consensus

for the cold front to be moving through the local area Sunday

morning, which would allow for much cooler temps (40s) across 

the northern cwa/lake shore and then quite warm temps (60s/70s)

across the south. Only change to the blended grids was to lower

temps for the lakeshore areas given the increasing chances for

onshore winds for much of Sunday. There is also a low chance for

a few showers with this front on Sunday. Dry weather is

expected early next week. cms



&&



.AVIATION /00Z TAFS THROUGH 06Z FRIDAY/...

Issued at 731 PM CDT Wed Mar 18 2026



No major forecast concerns for the terminals through Thursday

evening. A subtle upper disturbance will slide overhead tonight

and result in increasing VFR clouds tonight into Thursday. 

While there still remains a low chance for some spotty 

showers/sprinkles late tonight (15-20% chance), guidance 

continues to trend much drier and thus confidence on any 

precipitation at the terminals is too low for a formal mention. 

That said, if any rain does materialize no impacts are expected 

as precipitation rates will be light and should limit any 

visibility concerns. Furthermore, ceilings mid-day Thursday 

also look to remain VFR given the drier air though a couple of 

1500-2000 ft clouds may pass through at times.



There is also a low chance for some patchy fog late tonight at

RFD, but given the large (10-15 degree) temperature-dew point

spreads confidence is low on fog materializing. 



Otherwise, expect light and variable winds tonight to become

southeast Thursday morning with speeds around 7-10 kts. Though,

the Chicago terminals and GYY will likely see a period of east-

northeast winds due to a lake breeze. Winds will then begin to

turn more southerly Thursday evening as a surface high slides

overhead. 



Yack



&&



.LOT WATCHES/WARNINGS/ADVISORIES...

IL...None.

IN...None.

LM...None.



&&



$$



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