Crystal Lake, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

013
FXUS63 KDVN 142302
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
502 PM CST Wed Jan 14 2026

.KEY MESSAGES...

-  Decreasing winds, mainly clear and colder for tonight.

- The next clipper to bring light snow later Thu afternoon and night,
  then continued cold with off and on snow showers through at
  least Saturday. Gusty winds with the snow showers possible on
  Friday.

- The cold and active clipper pattern looks to continue for much
  of next week.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 215 PM CST Wed Jan 14 2026

Upstream sfc ridge acrs the upper MO RVR Valley to slide acrs the
area under high amplitude north-northwesterlies for a mainly clear
and cold night with low temps well down in the teens. Then attention
turns to the next weather-making wave seen on water vapor imagery
currently acrs the B.C. Pacific NW. Latest suite of models in good
agreement in handling this wave and it`s ridge-riding journey as it
moves inland and then dumps down acrs the southwestern GRT LKS and
the local area by Friday morning. Upper jet progs suggest enough
rounding energy to develop a large cut-off upper low, possibly multi-
centered, acrs the upper MS RVR Valley and GRT LKS into Saturday.
Back to Thursday, low to mid level flow backing to a warming
southwesterly draw to help high temps to recover mainly in the upper
20s to lower 30s despite increasing mid deck warm air advection
(WAA) clouds.

Some top-down saturation needed, but condensation pressure
deficits(Cond P-Defs) lower enough for a wing of light snow in
the clippers southeastern elevated WAA flank. This precip wing
to continue to develop and sweep down acrs the local CWA through
much of Thu evening, before changing over to a more sctrd or
isolated snow shower regime Late Thu night into early Friday
morning. With dry air to overcome and much of initial lift going
into saturation, most of the latest solutions continue to trend
of less and less snow amounts for Thu night. Most areas now
look to get an inch or less of accumulation by late Thu night
with the WAA snows, and just minor localized additional snow
acumms with the snow showers late Thu night and Friday morning.
But interesting the P-WAT/forcing combo method supports some 2
inch amounts possible. For now will hold the party line with the
1 inch or less. Thu night low temps held up in the mid to upper
20s by the clipper.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 215 PM CST Wed Jan 14 2026

Friday...The latest vort max ensembles suggest a nice wing off the
developing western GRT LKS upper vortex will look to sweep acrs the
area on Friday. Looking at fcst soundings, this day could be
interesting as they develop steep low to mid level vertical profiles
by afternoon. This instability could make for some feisty snow
showers again with wind gusts to at least 40 MPH and localized
additional snow acumm swaths into early evening. There may be support
for some squall-like showers if current parameters are correct. Also
the deep mix up over H85 MB will make the most of high temp
potential on Friday with highs well above normal in the mid to upper
30s. But then a late day flow/fetch change to the northwest and
north will cold advect for a large diurnal chill down by Sat morning.

Saturday through Tuesday...The cold core upper low will set the
stage for a below normal cold Saturday and Sunday with occasional
snow showers and flurries, especially Saturday. Sunday temps may be
helped on the milder side by a passing clipper to the north and
northeast. If this system verifies, we may have some snow showers
late in the day or Sunday night in the following cold push in the
wake of this system. Cold re-enforcng air flowing down acrs the
region behind this system for Monday with below normal values again
Long range thermal profiles suggest that if we have any snow cover
for Monday night, there may be some below zero temps occurring
especially north. The active clipper pattern then looks to extend
for most of the rest of next week.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 503 PM CST Wed Jan 14 2026

VFR conditions expected through the TAF cycle. Gusty northwest
winds to diminish in the next 3-5 hours with clear skies. A
surface ridge will bring light winds overnight with a wind shift
to the southwest late morning Thursday. Clouds will increase
late in the period ahead of the next weather system with a
chance of snow showers late afternoon/evening. Confidence on
timing and location too low to include any mention at this time.

&&

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

&&

$$

SHORT TERM...12
LONG TERM...12
AVIATION...Gross