Crystal Lake, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

248
FXUS63 KDVN 161720
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1120 AM CST Mon Feb 16 2026

.KEY MESSAGES...

- Anomalously warm temperatures will be seen through at least
  Wednesday. Record highs are possible today along with the
  potential for record warm lows tonight through Wednesday.
  Refer to the climate section for further information.

- Elevated fire weather conditions will result in very high fire
  danger today through Wednesday. Avoid outdoor burning if
  possible!

- Scattered showers (30-50%) Tuesday night with a low chance
  (20%) of thunderstorms.

- Additional precipitation chances (30-60%) Thursday into Friday,
  with rain possibly mixing with or changing to snow as
  temperatures trend cooler and closer to more seasonable levels.

&&

.UPDATE...
Issued at 523 AM CST Mon Feb 16 2026

Webcams, observations and GOES Nighttime Microphysics imagery
all reveal an expansion of dense fog across parts Whiteside,
Henry, Bureau and Putnam counties in IL and have issued a Dense
Fog Advisory until 15z for these areas.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 230 AM CST Mon Feb 16 2026

A surface high pressure ridge is shifting eastward toward the Ohio
Valley early this morning, with southerly return flow/warm
advection commencing ahead of an approaching weak cool front
extending from MN through SD. The onset of low level WAA and
increase in high cloudiness has promoted rising temperatures
through the 30s and lower 40s, which is above our normal highs
this time of year and a sure sign of yet another anomalously warm
day ahead. Obs reveal some patchy fog occurring near/south of a
Burlington, Iowa to Princeton, Illinois line within a plume of
higher surface dew points (40F+).

High cloudiness should thin/decrease as the day progresses
allowing for more in the way of solar insolation, as a 125+ kt
h250 jet lifts just to our north. This increasing sunshine
will be coincident with peak heating and the arrival
of a h925 thermal ridge (10c to 12c). This all supports another
day of early Spring-like temperatures and likely record breaking
warmth with highs in the low to mid 60s. As the case this time
of year anomalous warmth will be paired with gusty winds, which
are likely to gust 20-30+ mph at times later this morning and
afternoon from the S/SW - a very favorable vector for warming.
These gusty winds will combine with the very dry fuels and warm
temperatures to create elevated fire weather conditions with
a very high fire danger. These conditions will be favorable for
fire spread, so please avoid outdoor burning if at all possible.

Tonight into Tuesday, general consensus of deterministic and
ensemble guidance supports the weak cool front sliding down
into our northern service area (roughly north of Hwy 30) before
stalling. Limited forcing and moisture precludes any precipitation
during this time. This boundary could serve as the focus for
fog development late tonight/Tuesday morning across our northern
counties, but confidence is low. Confidence is higher that
above normal warmth will persist south of the boundary in
residual southerly flow along with another uptick in high clouds,
with some near record warm lows possible in the upper 30s and
lower 40s. Cooler readings in the lower to mid 30s, albeit still
above normal will be found north of Hwy 30 in closer proximity
to the boundary.

On Tuesday, thermally not much change expected south of the
front owing to more widespread lower to mid 60s. Across our
far north near the front, temperatures may remain in the 50s
again still well above normal. Records are mostly in the
lower 70s except for Dubuque in the mid 60s, and thus while still
anomalously warm it`s unlikely we`ll see record highs. Once
again another breezy and warm day will bring a renewed concern
for elevated fire weather conditions and a very high fire danger.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 230 AM CST Mon Feb 16 2026

An upper level wave and attendant surface low pressure system will
shift from the Northern Plains into the northern Great Lakes by
Wednesday morning. Mid level moist advection and ascent aided by
the terminus of a 50-55+ kt LLJ will likely foster scattered elevated
showers Tuesday evening/night. Best chances favor north of Hwy 30
along/north of an advancing warm front. Can`t rule out isolated
rumbles of thunder with steepening mid level lapse rates. This
round of WAA precip will likely shift to our north by late Tuesday
evening. Then, we may have to keep tabs on a cold front that will
make inroads late Tuesday night and Wednesday morning for the potential
of a few more thunderstorms. However, there is plenty of uncertainty
as forcing looks rather nebulous with weak low level convergence, and
there is also plenty of uncertainty on the extent of moisture in the
pre-frontal warm sector. Some of the more aggressive CAMs with
convection are notably higher on moisture with FV3 depicting PWATs
over 1 inch, while HRRR shows surface dew points in the lower to mid
50s. The surface parcel trajectories are from the southern Rockies and
southern Plains, which are largely in drought and thus concerns both
may be overdone. Will need to keep an eye on this as HRRR/NAM soundings
show possibly 35-50 kt of wind near the top of the ML, which if were to
verify could support marginal severe gusts. Confidence is low though on
this potential. Where confidence is high is with another night of
anomalously warm lows Tuesday night, with the potential for record warm
lows well into the 40s and lower 50s as the area largely basks in the warm
sector.

Wednesday will be another breezy day, and also another unseasonably mild
day due to weak cool advection and deeper mixing with abundant sunshine.
This should propel highs back into the 60s nearly areawide, especially
given the anomalously warm launch point with temps in the 40s to around
50.

Heading into late week the deterministic and ensembles generally favor
another storm system moving across the region Thursday into Friday.
This will bring another chance of precipitation. However, there
continues to be a lot of variance in both the track and strength of
the system. Nonetheless, this system may have a better chance at
producing more widespread precipitation with the general consensus
favoring the track near the area. Will hope this continues as we really
need the moisture. With the track near the area, we would likely see
rain to start with the potential to mix with or change to snow on the
backside as cooler air moves in. Still a ways off and plenty of
uncertainty on the exact track and strength, which will be critical
in determining these finer details of the sensible weather. Confidence
is high though that we`ll be trending cooler and more closer to seasonal
averages for temperatures next weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1115 AM CST Mon Feb 16 2026

Nocturnal inversion should break no later than 19z/16 allowing
higher momentum air to create gusts up to 25 knots through
sunset. Boundary layer restablizes after sunset with winds
dropping to under 10 knots with the potential for patchy MVFR
VSBYS. Inversion breaks again 16-18z/17 with the potential for
gusts to 30 knots. Looking further ahead there are signals
suggesting LLWS developing after 00z/18 across eastern Iowa and
northern Illinois.

&&

.CLIMATE...
Issued at 229 PM CST Sat Feb 14 2026

Record high temperatures for February 16th

Burlington, IA.......68 in 1921
Cedar Rapids, IA.....67 in 1921
Dubuque, IA..........60 in 1921 and previous years
Moline, IL...........60 in 1921

Record warm lows for February 16th

Dubuque, IA..........37 in 1882
Moline, IL...........38 in 1998 and previous years

Record warm lows for February 17th

Dubuque, IA..........37 in 2011
Moline, IL...........42 in 2011 and previous years

Record warm lows for February 18th

Dubuque, IA..........37 in 1981
Moline, IL...........43 in 1997

&&

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

&&

$$

UPDATE...McClure
SHORT TERM...McClure
LONG TERM...McClure
AVIATION...08
CLIMATE...08