Crystal Lake, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

180
FXUS63 KDVN 261112
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
612 AM CDT Thu Mar 26 2026

...Updated for 12z Aviation...

.KEY MESSAGES...

- Strong to severe storms are possible this afternoon into this
  evening especially along and south of Highway 30. There is
  lower confidence in the northern extent of storms today and
  higher confidence south of Interstate 80.

- Elevated fire danger today, mainly south of I-80.

- Blustery and noticeably cooler on Friday then another warming
  trend begins this weekend and continues into next week. The
  next chance of rain is Monday night through Tuesday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 206 AM CDT Thu Mar 26 2026

A shortwave is forecast to move from the northern Plains into
the Great Lakes this evening and drive a cold front southward
across the area as a surface low moves along the front this
afternoon. Models have trended faster with the frontal passage
through the area for today with the cold front surging across
the area with the front moving into the Highway 20 corridor
around 10 AM to Interstate 80 by 1 PM then exiting into
northern Missouri and central Illinois by 7 PM this evening.
Winds will be southwesterly ahead of the front with gusts up to
25 MPH then turn to the north behind the front then northeast
with gusts up to 30 to 35 MPH. High temperatures for today may
occur during the morning hours north of Interstate 80 with
temperatures falling during the late afternoon south of
Interstate 80. High temperatures today are forecast to range
from the mid 60s along the Highway 20 corridor to the upper 80s
in far northeast Missouri and west central Illinois. These
temperatures result in near record high temperatures at
Burlington (84, 1981).

The faster timing of the front is increasing confidence that
storm development will be limited to along the front or behind
it with strong lift associated with the surging cold front.
Models have a very limited window for surface based CAPE and
model soundings continue to show an inversion or elevated warm
layer in place through the day today. Think that this indicates
storms will be elevated with the primary threat for large hail
with any supercells that develop. 0 to 6 km shear vectors are
parallel to the front favoring storms that will grow upscale
into lines of storms and produce damaging winds. Isolated
tornadoes are also possible. Both the latest HRRR and 4 KM NAM
Nest runs favor thunderstorm development later this afternoon
near 7 PM mainly south of Interstate 80 in the vicinity of the
front with rain showers farther to the north. A thunderstorm
threat is expected to linger south of a Fairfield to Galesburg
line through 10 PM. The Storm Prediction Center has moved the
Enhanced Risk of severe storms to the east of Bureau and Putnam
Counties. There is a Marginal (level 1 out of 5) Risk south of a
Williamsburg to Maquoketa to Rockford Illinois. There is a
Slight (level 2 out of 5) Risk of severe storms east of a line
from Kirksville to Mount Pleasant to Moline to Prophetstown
Illinois.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Issued at 206 AM CDT Thu Mar 26 2026

There is little change in the forecast during the long term
period, and included the previous long term discussion with
some minor edits.

Friday still appearing to be a blustery post-frontal day with
temperatures in the 40s and the areas south of I-80 lucky to breach
50 degrees. Wind gusts up to 30 MPH are possible through the
day.

Then a re-bounding western upper high and strengthening thermal
ridge to our southwest will build northeastward again starting
another warming trend across the area Saturday and especially into
the end of the longer range. Ensembles continue to bring a piece of
ridge-riding wave energy with some moisture return to produce the
next round of showers and thunderstorms Monday night into Tuesday.
Along with this chance their may be the potential for stronger
storms again. Then even longer range guidance continues to show an
active pattern evolving if the western CONUS upper trof can get
established.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 555 AM CDT Thu Mar 26 2026

VFR conditions expected to persist into early afternoon. A warm
front will lift through the area this morning and followed by
a cold frontal passage this afternoon. Winds could be rather
variable at KCID and KDBQ until the cold front moves through
toward midday/early afternoon and progresses southward through
KMLI and KBRL by 20z-23z. SW winds become gusty to 20+ kt at
KMLI and KBRL ahead of the cold front, then turn gusty from the
N/NE at all the terminals after it passes with a period of
gusts 30+ kt possible amidst generally 15-25 kt winds. Spotty
showers are expected this morning north of I-80 and will
increase this afternoon/evening behind the cold front for a
period of time. There is also a chance for thunderstorms (30%)
near KMLI and especially KBRL (60%) around 00z through 04z with
MVFR to local IFR conditions (mainly for visibility). Hail will
also be possible with the strongest activity. Guidance varies on
extent of low clouds overnight/early Friday morning, but there
is some potential for bands of MVFR ceilings aided by strengthening
NE flow off Lake Michigan.

&&

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

&&

$$

SHORT TERM...Cousins
LONG TERM...12
AVIATION...McClure