356
FXUS63 KDVN 120556
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1256 AM CDT Tue May 12 2026

.KEY MESSAGES...

- A clipper-like system late tonight into Tuesday is forecast to
  bring scattered showers and isolated thunderstorms to the
  region (20-50%).

- Warm up expected late week with temperatures reaching into the
  70s/80s by Friday as the next storm system approaches.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 215 PM CDT Mon May 11 2026

Beautiful weather expected for the rest of today with light
winds and highs in the mid 60s to low 70s for most areas. High
pressure will shift to the east tonight into the Great Lakes
region, resulting in an increase in southeasterly flow with
gusts reaching 20-25 kts late. A shortwave trough axis is
forecast to reach central to northern Minnesota by early Tuesday
AM with a trailing zone of WAA and associated scattered showers
extending southward into portions of north-central Iowa. Given
this placement, most of the local area should stay dry overnight
with plenty of dry air to overcome before the lower atmosphere
begins to saturate more into mid Tuesday morning.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 215 PM CDT Mon May 11 2026

Tuesday...A shortwave trough diving south from Ontario will
generate a mid-level f-gen band over Wisconsin and northern
Illinois, providing cloud cover and light rain to our northern
CWA. As the clipper-like low pressure swings into northern
Wisconsin, a cold front is pushed southward into the area.
Limited moisture return from the south should limit
precipitation coverage to along the front. Storms that do
develop are forecast to move southeastward around 45 mph.
Therefore, it will not take a lot of mixing to transport this
momentum to the surface which is why the SPC has a Marginal (1
out of 5) Risk for severe storms across the eastern outlook
area with damaging winds as the primary threat. Regardless of
storm development, southwesterly winds are forecast to gust up
to 35-45 mph ahead of the front and advect in warmer air as seen
with highs forecast in the upper 70s to lower 80s. Areal
coverage of storms for the late afternoon and evening looks to
remain isolated with limiting factors being meager low-level
moisture (dewpoints in the 40s to lower 50s) and weak
instability (HREF MUCAPE only a few hundred J/kg up to ~500
J/kg).

As the cold front clears the area by sunset, northwesterly flow
settles in with gusts still up to 35 mph possible. As the skies
clear out, the lows should drop back into the low 50s despite
the huge warm up during the day.

Wednesday...Northwesterly flow aloft returns as the region will
be sandwiched between a longwave trough to the east and ridging
over the Rockies. Conditions will be mostly dry besides some
light lingering showers in northern Illinois from a weak surface
trough on the backside of the low pressure over Upstate New
York. Northerly flow is forecast to cool down highs Wednesday
back into the mid-60s to mid-70s across the area, similar to
conditions on Monday. Lows on Wednesday night are forecast to
drop back into the 40s as the winds go nearly calm. There is the
potential for radiational fog to develop, but the probabilities
are still low.

Thursday-Friday...A shortwave trough over the northern Rockies
ejects into the Northern Plains, shifting the ridge axis over
the Upper Mississippi River Valley on Thursday. This will deepen
a developing mid-latitude cyclone over Saskatchewan as a cold
front propagates east of the Rockies. Once again, the low-level
flow returns to southerly ahead of this next low pressure
system, advecting in warmer and more moist air, but unlike
Tuesday, the prolonged period of return flow will allow PWATs to
gradually climb Thursday into Friday morning above 1 inch. A
pre-frontal trough will support isolated showers and
thunderstorms overnight on Thursday into Friday morning, but
model uncertainty grows as we get into Friday on the exact
timing of the cold front. The ECMWF ensembles have the low
pressure over Saskatchewan booking it eastward across Canada
with the mid-level trough, pushing the front through on Friday
night, but the GFS ensembles has a bimodal distribution in
solutions with a group agreeing with the ECMWF and another with
a slower low pressure system over the Northern Plains. This will
have a great influence on the timing and coverage of storms
that develop on Friday as seen by the spread in LREF 6-hourly
precipitation of 0.25 inch across the CWA.

Regardless, there will be a warming trend starting Thursday into
Friday with highs in the 80s becoming more likely (40-60%) across
the entire CWA.

Saturday-Sunday...While Saturday`s weather will be dependent on
if the cold front Friday night clears the area, there is
greater agreement among ensemble models that another low
pressure system will develop across the Great Plains on Sunday,
bringing PoPs back up across the region. PWATS will likely stay
above 1 inch through the weekend as seen in the LREF probability
of exceedance being 60-80%, keeping the threat of heavy
rainfall elevated.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1256 AM CDT Tue May 12 2026

Despite the passing cold front and clouds, VFR conditions are
expected through the next 24 hours with the main focus on gusty
conditions as the wind shifts from southeast to northwest. Wind
gusts above 30 knots are possible ahead of the front during the
afternoon. Previous TAFs had LLWS for KCID, KDBQ, and KMLI, but
it was removed from this issuance due to a lake breeze
enhancement of surface winds and gusts, primarily north of I-80.
KBRL retains LLWS as a 35-45 knot low-level jet develops prior
to sunrise above weaker surface winds. The front will also bring
a chance (20-40%) for SHRA across the area, but only PROB30s
for -SHRA were given to KDBQ and KMLI due to greater low-level
saturation. Regardless, ceilings will remain above 8 kft in the
VFR category. Skies are forecasted to clear out during the
evening from north to south as winds shift to the northwest.

&&

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

&&

$$

SHORT TERM...Uttech
LONG TERM...Delaune/Uttech
AVIATION...Delaune