Sigourney, Iowa Weather Forecast Discussion

185
FXUS63 KDVN 111911
AFDDVN
Area Forecast Discussion
National Weather Service Quad Cities IA IL
211 PM CDT Thu Sep 11 2025
.KEY MESSAGES...
- Summer heat returns this weekend, although without the extreme
  summer humidity. Hot temperatures last into next week.
&&
.SHORT TERM /THROUGH FRIDAY/...
Issued at 210 PM CDT Thu Sep 11 2025
High pressure well to our northeast will continue pushing off to
the southeast into New England through Friday. We`ll likely keep
just enough wind flow overnight to prevent significant fog
formation. Upper ridging nudges in from the east Friday,
opening up some even warmer temperatures for us. We`ll see highs
a few degrees warmer than today. Although the hottest
temperatures are still to come.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 210 PM CDT Thu Sep 11 2025
The upper ridge crests over our area on Saturday into Sunday,
likely bringing the hottest temperatures of this air mass.
Widespread 90s are likely for highs both days, though humidity
will be mercifully lower than what we typically see in summer.
The worst of the humidity remains locked in over the Gulf where
an easterly flow has pushed it into Mexico. More limited
moisture has been transported northward through the Plains and
we`ll start to get in on some low to mid 60s dewpoints as the
ridge shifts east and southwesterly mid level flow begins. That
will be enough to bring the heat index up a degree or two over
the actual temperature, but likely remaining below critical
thresholds. The GFS continues to struggle with mixing the low
levels too deep and thus brings much warmer temperatures in the
core of the ridge Saturday and Sunday. Now that we`re within a
couple days of this forecast there are a few more sources which
go into the NBM at this range, and thus NBM forecast highs have
come down. We collaborated to lower these a bit further again,
into the low to mid 90s in line with most non-GFS guidance
sources.
The large trough upstream of our ridge will begin to break down
and shift a significant chunk of its energy eastward into the
Plains on Sunday. Guidance is now moving this trough a little
more north and a little less east, so it`s less clear that we`ll
get any precipitation out of this locally. However, hot and
moderately humid conditions will lead to instability each
afternoon, so we can`t rule out a few pop up showers or storms
each day. With the trough now likely to stay mainly to our west,
the ridge is also likely to remain in more firm control of our
area extending into early next week. Thus the hot weather
continues, though perhaps a couple of degrees cooler than this
weekend.
Long range guidance varies considerably when it comes to
multiple troughs to our west and the resulting impact on the
ridge during the middle to later part of next week. As a result,
we`re not very confident on how long the heat will last and
when our next significant rain chances will be. When the ridge
finally releases its grip and a trough moves in will be our best
shot at more widespread rainfall and a shift toward cooler
temperatures. At this point that doesn`t look likely until
Wednesday at the earliest, but potentially not until the end of
next week.
&&
.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1202 PM CDT Thu Sep 11 2025
Light winds become a bit more southeasterly today under a mostly
clear sky. We could see some patchy fog near DBQ again early
tomorrow morning, but at the moment the wind direction is not
expected to be ideal for upslope fog there. Otherwise VFR
conditions prevail.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.
&&
$$
SHORT TERM...Kimble
LONG TERM...Kimble
AVIATION...Kimble

NWS DVN Office Area Forecast Discussion