Crystal Lake, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

401
FXUS63 KDVN 141131
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
531 AM CST Sat Feb 14 2026

...Updated for 12z Aviation...

.KEY MESSAGES...

- Anomalous warmth to persist into the middle of next week.
  Record highs are possible Monday (2/16).

- Aside from a chance of rain well south of I-80 on Saturday,
  largely dry weather is in store through early next week
  fueling increasing precipitation deficits and worsening drought
  conditions.

- Precipitation chances return to the forecast toward mid-week and
  persist through late next week as the pattern turns more active.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 255 AM CST Sat Feb 14 2026

It`s another tranquil and frosty early morning across the area with a
strong, shallow low level inversion, mainly clear skies, dry low level
air and light to near calm winds providing an excellent radiational
cooling setup. This is leading to a vast array of temperatures ranging
from the low to mid 20s in favored drainage and valleys to the mid 30s.

High level cloud cover was beginning to increase in our southern service
area, as a low pressure system emerges from the Southern Rockies
into the southern Great Plains with the associated precipitation shield
in the WAA and upper diffluence spreading as far north as near the
I-70 corridor in eastern KS and western MO. This system will slide
eastward into the Lower Mississippi Valley over the next 24 hours keeping
the bulk of the precipitation to our south. Much of the CAMs and
hi-res ensembles have trended a bit southward on QPF with a rather sharp
cutoff on measurable rain on the north side given the reservoir of dry
air reinforced by developing easterly mid level flow. Latest HREF
LPMM keeps measurable rain mostly near a Memphis, MO to Macomb, IL
line on southward. Will continue with rain chances mainly south of Hwy 34
this afternoon through evening with theta-e advection on 315k surface.

Increasing cloud cover today for much of the area may limit solar
insolation fostering a bit of uncertainty with high temperatures.
925 hPa temperatures progged at 7c to 9c support at least low to mid 50s,
with the potential for upper 50s to around 60 in areas that see
sufficient/filtered solar insolation and more mixing dry adiabatically.

Overnight into Sunday morning as high pressure begins to build in this
should lead to a decrease in cloud cover. This could lead to patchy
fog with lowering dewpoint depressions and minimum temperatures breaching
crossover temperatures. Lows look to be mainly in the 30s, but timing
and extent of the decrease in clouds will be pivotal to lows (slower =
higher side of 30s and possibly around 40 in some areas, faster = lower
side of 30s with some upper 20s possible).

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 255 AM CST Sat Feb 14 2026

Models remain consistent on building in a mid level ridge over most of the
central CONUS through early next week. At the surface, high pressure
will build in Sunday before shifting east on Monday with strengthening
southerly return flow/warm advection commencing. 2m temperature anomalies
continue to support highs 15-25+ degrees above normal within anomalously
warm air (NAEFS and GEFS 1-2 standard deviations on 850 hPa temperatures).
This supports highs well into the 50s with some 60s on Sunday and then
more widespread readings around 60 to near 65 on Monday that will challenge
record highs for some (see climate section below).

Tuesday through Thursday represents a period of greater uncertainty both
in regards to temperatures and precipitation chances, as the pattern is
set to turn active. The first of two shortwaves during the period will
likely form an upper low into the Upper Midwest while developing a surface
cyclone that tracks from the Dakotas to WI late Tuesday into Wednesday.
Strengthening fgen beneath the left exit region of a 140+ kt upper jet will
foster precip chances (20-50%) Tuesday night into early Wednesday particularly
north of I-80. However, with a ramping 50+ kt nocturnal LLJ Tuesday night
will have to keep tabs on moisture return for some potential of convection,
but right now general consensus is too dry or slow moistening of low levels
to preclude higher PoPs and further southward expansion. This advection is
atop a backdoor surface front that is shown to bisect the region on
Tuesday, which could make for a bit of tricky temperature forecast and
gradient - coolest north /albeit still unseasonably mild in the 50s/ to warmest
south in the 60s. On Wednesday we could see another somewhat challenging
temperature forecast initially warm sectored with the front returning north
as a warm front before a cold front moves into north/west portions of the
area. Once again we could see another temperature gradient of 10-15+ degrees
from the 50s to well in the 60s. NBM quartiles depict the challenge and
uncertainty on temperatures with spreads of 10-15+ degrees in 25th to 75th
percentiles on highs Tuesday and Wednesday, greatest north of I-80 generally.
Despite this uncertainty the message remains largely the same with still well
above normal temperatures through mid-week.

A second shortwave is expected to arrive around Thursday bringing another chance
of precipitation, as energy ejects out from a broad western CONUS trough
and ripples along a tight mid level baroclinic zone. This could foster a
stronger/deeper low sub 990 hPa per several ensemble members of GFS and ECMWF.
Potentially another convective signal with this system although moisture and
instability profiles are not very impressive, but this could change and will
need monitoring in the days ahead given the potential negative tilt wave
and strength of the baroclinic zone fostering possibly a stronger system, which
would support increased moisture and instability potential. As this system
passes late week it will drag down cooler air and could result in a chance of
snow with any residual moisture in the wrap-around before temperatures trend
back toward more seasonable levels heading into next weekend.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 525 AM CST Sat Feb 14 2026

Shallow, patchy fog MVFR fog potential is low at the start of the TAF period,
mainly at CID and DBQ. Otherwise, a low pressure system will track well south
of the region through tonight keeping the bulk of any measurable rain and
lower ceilings south of BRL. Probabilities for rain at BRL remain too low (20%)
for mention. Should any rain occur at BRL it would be very light and mostly
sprinkles with no impacts to visibility. Conditions as a result are expected to
remain VFR at all TAF sites through this evening. Overnight /after 06z-09z/,
as clouds likely decrease there is a signal in guidance for patchy fog. I have
added mention of MVFR visibility toward the end of the TAF period at CID and BRL
where HREF probabilities for <3SM are highest at 50-60%.

&&

.CLIMATE...
Issued at 108 AM CST Fri Feb 13 2026

Record High Temperatures for February 16th

Dubuque: 60 (1921)
Moline : 60 (2022)

&&

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

&&

$$

SHORT TERM...McClure
LONG TERM...McClure
AVIATION...McClure
CLIMATE...McClure