402
FXUS63 KDVN 062341
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
641 PM CDT Wed May 6 2026

.KEY MESSAGES...

- Frost tonight mainly north of I-80 and in river valleys. Some
  localized freezing temps possible.

- There is a chance (20-40%) of diurnal showers Thursday and Friday.
  Not all areas will receive rainfall.

- Active pattern late weekend into next week, with best chances
  (40-70%) of showers/isolated thunderstorms Saturday night-
  Sunday.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 220 PM CDT Wed May 6 2026

Early afternoon water vapor shows several shortwaves upstream in the
cyclonic flow aloft tied to the large deep Hudson Bay trough. The
first wave over northern IA is providing an increase in cloud cover
with bases generally under 7kft along with the diurnal Cu gradually
expanding. 18z surface observations already show northwest winds
gusting up to 30kts, with very dry dewpoints in the low to mid 20s
evident of deep mixing as shown on our 18z DVN sounding up to 770
mb. We also saw a -2.8C 850mb temp which is in the Top 25
coldest May soundings in our period of record per SPC
climatology. Quite chilly for early May for sure!

Shortwave trough to swing east into WI/IL late afternoon and
evening, with subsidence behind allowing for clouds to quickly clear
after sunset. With such a dry boundary layer, there will be a period
from 9pm to 4a where temperatures quickly drop into the middle
30s. NBM probabilities of temps<36 degrees tonight have
increased and are now 60-90% north of I-80. Dewpoints to remain
in the mid to upper 20s, which will still allow frost formation
north of I-80. As a result in collaboration with neighboring
offices, a frost advisory has been issued from 06-13z Thursday.
Will have to watch upstream cloud trends across the Dakotas and
MN this evening/tonight closely, as these may reach the
northern border of the CWA early Thursday thereby keeping us a
tad warmer. Conversely, if clouds completely clear out and winds
go completely calm, we could even see freezing temps or even a
few degrees lower, especially in rural and poor drainage areas.

Thursday...another shortwave in the northwest flow aloft to bring an
increase in clouds early in the day. 12z CAMs, RAP soundings, and
low level convergence progs show sufficient lift and moisture to
bring scattered showers primarily south of Hwy 30 late
morning/afternoon. Can`t rule out an isolated rumble of thunder or
two as well with 700-500mb theta-e lapse rates progged around
0. Have introduced slight/chance PoPs for this activity, but do
want to mention not all areas will receive rain. Low level winds
increase through the day and we should see another day of deep
mixing/gusty winds near 30kts. Afternoon temps to be warmer but
still below normal, with readings topping out in the low to mid
60s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Issued at 220 PM CDT Wed May 6 2026

Northwesterly flow will continue to impact the region through early
next week, accompanied by near-daily disturbances embedded in the
flow.

After precipitation tapers off Thursday night, northwest flow will
briefly return before another disturbance passes through late
Friday. Limited moisture will keep precipitation widespread but
light, with a 10-30% chance of QPF greater than 0.10 inches. Given
elevated lapse rates into late afternoon, some thunderstorms may be
possible (10-20%) with these showers.

Low-level southerly flow behind the departing system will advect
warm air into the region into Saturday. As a result, temperatures
Saturday are expected to rise to above-normal, which should be
pleasant following the recent stretch of below-normal temperatures.

Sunday will bring the next precipitation chances as a wave
translates through, accompanied by a surface low. Additional
moisture advection ahead of this low, while weak, will provide
moisture for another widespread but light precipitation event.
Current QPF totals have a 20-50% chance of exceeding 0.10 inches.
The area of highest accumulation continues to shift given
uncertainty in the track of the low but remains along the southern
half of the CWA. We will briefly return to northwest flow on Monday
before another system moves through Tuesday, bringing the next
chance (30-40%) for precipitation.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 628 PM CDT Wed May 6 2026

High pressure is forecast to move across the area tonight
brining clearing skies and light and variable winds. Another
disturbance is quick on its heals with winds increasing after 12
UTC as the surface high shifts to the east. As winds turn to the
west behind a front, speeds of 8 to 12 knots are forecast with
gusts up to 20 knots. Showers and thunderstorms are possible at
KCID, KMLI, and KBRL between 15 UTC and 00 UTC Friday but
confidence is low on whether they will occur so left them out
of the TAFs for this issuance. For these reasons, VFR conditions
are expected through the period.


&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Frost Advisory from 1 AM to 8 AM CDT Thursday for IAZ040>042-
     051>054-063>068.
IL...Frost Advisory from 1 AM to 8 AM CDT Thursday for ILZ001-002-
     007-009-015>018.
MO...None.

&&

$$

SHORT TERM...Gross
LONG TERM...Ellingworth
AVIATION...Cousins