Crystal Lake, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

703
FXUS63 KDVN 011022
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
522 AM CDT Sun Jun 1 2025

.KEY MESSAGES...

- Smoke aloft from Canadian wildfires will continue to stream
  southward into early next week. Some of the smoke could mix
  down to the surface and lead to reduced air quality at times.

- An active pattern returns Tuesday through Thursday of next
  week, bringing higher chances for widespread showers and
  storms. Some storms could become strong to severe on Tuesday,
  although confidence remains low on the details and overall
  potential.

- Beneficial rain is expected next week, with most of it falling
  Tuesday and Tuesday night. The NBM has a 60-70% chance for 1"
  or more of rainfall across most of the outlook area for the
  Tuesday through Thursday time frame.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 300 AM CDT Sun Jun 1 2025

Today: A pleasant and warm end to the weekend is expected with
highs ranging from the upper 70s north and east of the Quad
Cities to the low/mid 80s elsewhere. High pressure in control
over the Upper Mississippi Valley and Great Lakes regions will
lead to light winds and low humidity with dewpoints in the
40s/50s. Wildfire smoke from forest fires in Canada will
continue to move over the region, but should stay aloft today
due to minimal boundary layer mixing. Temperatures tonight will
fall into the 50s for lows.

Monday: The surface high will slide off to the east, leading to
a warm southerly return flow across a large portion of the
Midwest. Steady low-level warm air advection (850mb temps in the
mid to upper teens C) will help to push highs into the mid to
upper 80s, with a few locations potentially reaching around 90
degrees. However, with dewpoints only in the mid 50s to near
60, the heat index will closely match the air temperature. It
will be another day dealing with wildfire smoke initially aloft
and a hazy sky. There is some potential for lower smoke
concentrations to mix down to the surface with the breezy south
winds developing, which could lead to minor reductions in air
quality.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Issued at 300 AM CDT Sun Jun 1 2025

For Tuesday through Thursday, a more active pattern is expected as
an upper-level trough and attendant cold front approaches the
region. Abundant moisture from the Gulf should advect higher PWAT
values around 1.7 to 2.0 inches per the GEFS ensemble plumes by
Tuesday afternoon. This first trough should phase in with a southern
stream trough coming from the southwestern CONUS, arriving on
Thursday. Combined, these two waves will result in a prolonged
period of rainfall chances Tuesday through Thursday (though not a
complete washout), with a soaking rainfall expected across the
area. Looking at a 72-hr period from Tuesday through Thursday,
NBM exceedance probabilities of one inch or more of total
rainfall is between 50 to 70 percent and between 20 to 40
percent for two inches or more.

It`s still a little early to assess specific details for the
severe weather potential, which will depend on the timing of the
cold front Tuesday. Machine learning guidance continues to
highlight the area with lower-end severe weather probabilities
(~15%) and SPC has a Day 3 Slight Risk (level 2 of 5) over
nearly the entire forecast area. Expect some adjustments to
these coverage details as we get closer to the event as new
models become available. Further out in the extended, a brief
reprieve from the wet weather is anticipated later Thursday
into Friday.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 516 AM CDT Sun Jun 1 2025

High pressure will lead to VFR conditions and light winds (under
10 kts) through the period. Wildfire smoke aloft will remain
over the area, but do not expect it to mix to the surface today.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.

&&

$$

SHORT TERM...Uttech
LONG TERM...Schultz/Uttech
AVIATION...Uttech