Pontoosuc, Illinois Weather Forecast Discussion

433
FXUS63 KDVN 060529
AFDDVN
Area Forecast Discussion
National Weather Service Quad Cities IA IL
1229 AM CDT Mon Oct 6 2025
...Updated for 06z Aviation...
.KEY MESSAGES...
- Rain is likely (60-80%) for much of the area between late
  tonight through Monday night along a slow moving cold front,
  and will be followed by cooler, more seasonable early fall
  temperatures.
&&
.SHORT TERM /THROUGH TUESDAY/...
Issued at 145 PM CDT Sun Oct 5 2025
Another warm and breezy fall day is found over our entire area
today, with some thin cumulus dotting the sky in an otherwise cloud
free warm sector.  Temperatures as of 1 PM have reached the lower
80s, and highs in the mid to upper 80s look on target for today. Dew
point values have remained in the mid to upper 50s so far today, but
may mixed down a few more degrees this afternoon, resulting in RH
values of 25-35%  The breezy conditions of 15 to 25 mph, with a few
gusts to 30 mph will continue through early evening, resulting in
elevated fire conditions, mainly in AG fields yet to be harvested.
This will be the last warm/windy day for some time given our
calendar date, and transition towards a much cooler pattern in the
week ahead. As was the case yesterday, we`re monitoring satellite
and radar for any fire related problems / Hot Spots.
Rain will arrive in our northwestern counties tonight, and oh so
slowly progress southeast into our area towards morning, continuing
through the day Monday. This slow transition of the front will make
for a challenging temperature forecast Monday, with clouds and off
and on rain northwest allowing for cool temperatures, meanwhile sun
and yet another warm day is expected southeast.  The transition
zone, which includes Iowa City, the Quad Cities, Ottumwa, and
Clinton could be cooler or warmer than forecast based on the frontal
movement. I`m going low 60s northwest to mid 80s east, with a narrow
transition from near 80 to lower 70s in a gradient that bisects our
area from southwest to northeast along the front at mid day.
While CAPE will be fading with this system as it moves through, all
areas could see a rumble of thunder as the front rolls past  in the
next 30 hours.  As noted from the AFD last night, shear does
increase, but mainly post frontal, in a stable environment, so no
severe weather is expected.  Rainfall wise, there remains great
uncertainty of any amounts over 0.25" with most areas seeing 0.01 to
0.10, a negligible amount given our dryness. Some CAMs continue
to show swathes of 0.50 or so, but this is a low possibility as
the mean is closer to 0.10 to 0.30 for the entire event in our
area. In general, probability of higher amounts has dropped in
the past 24 hours.
Monday night, rains will continue, with the best synoptic lift
passing through, resulting in the highest pops around 60-80 percent.
This will occur with CAA with lows in the mid 40s to mid 50s under
clouds. This cool start sets the stage for a cool Tuesday with highs
in the mid to upper 60s with a gradual break up of clouds through
the afternoon.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 145 PM CDT Sun Oct 5 2025
Wednesday through Friday remain near normal, which is much cooler
than recent days. Highs in the 60s to 70s, with lows in the 40s
Tuesday and Wednesday nights (50s Thurs / Fri nights). Open up those
windows and say "ahh".   That pattern will be brought to us by a
large, but progressive Canadian high pressure.  Some energy working
down across the region in northwest flow aloft and attendant surface
troughs/reinforcing cool fronts will be accompanied by some rain
chances (20-30%) Thursday and Friday. We`ll start to warm back up
next weekend and just beyond with CPC`s 8-14 day outlook showing
probabilities of 70-80% for above normal temperatures October 12-18.
Meanwhile, probabilities are leaning toward below normal
precipitation during that time.
&&
.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1220 AM CDT Mon Oct 6 2025
Cold front approaching CID at the beginning of the TAF period
and will pass through the terminals gradually from northwest
to southeast on Monday. Post-frontal showers (and possibly a
couple of storms) will progress into the vicinity of CID 08z-14z
and possibly DBQ although dry air upstream may continue to erode
and subsequently slow/delay precipitation arrival at the MS river
sites. Initially the precipitation will be focused around CID
and eventually DBQ today with CIGs lowering through VFR and
then MVFR with more column saturation and deepening cool air
advection, with even a chance for some spotty IFR CIGs for a
time later this morning through midday. Otherwise, predominantly
VFR at MLI and BRL today, with an initial precipitation chance
arriving by later Monday afternoon until sunset with pre-frontal
showers and a chance for a few storms. Monday night, anticipate
an uptick in shower coverage as the night progresses with
synoptic scale lift increases attendant to an upper level jet
atop the frontal zone with conditions lower VFR to MVFR with
spotty IFR.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.
&&
$$
SHORT TERM...Ervin
LONG TERM...Ervin/McClure
AVIATION...McClure

NWS DVN Office Area Forecast Discussion