Scotch Grove, Iowa Weather Forecast Discussion

532
FXUS63 KDVN 182318
AFDDVN
Area Forecast Discussion
National Weather Service Quad Cities IA IL
618 PM CDT Thu Sep 18 2025
.KEY MESSAGES...
- On and off showers and thunderstorms are expected through the
  weekend and potentially into early next week.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 230 PM CDT Thu Sep 18 2025
The long advertised trough has finally arrived. The first wave
pushing around this trough has brought widespread light showers
and a few embedded storms to much of the region today, mainly
west of the Mississippi River. The trough isn`t moving east very
fast, so the best rain chances remain in the west overnight
tonight. Another round of showers and storms is expected to
develop over Kansas and Missouri, rotating northeast into our
region overnight. Instability is pretty poor in our area
considering the clouds and rain for most of the day. This should
limit the severe weather threat locally. Overall confidence is
less than normal on the timing and location of this activity.
High resolution convective allowing guidance is not as
consistent in messy scenarios like this where convection has
already begun. A mesoanalysis using satellite and regional radar
can lead to a better forecast. Much of Missouri has had more sun
today, with a clear wave moving out of Kansas soon to overlap
with this better instability. Thus this scenario of storms
firing over Missouri in the next several hours does look
reasonable, though it`s not clear how far north they`ll get. It
seems more likely that we get remnant rainfall from dying storms
or perhaps impacted by a peripheral stratiform rain region from
a broader developing complex to our south.
The large trough continues to spin near the region on Friday.
The embedded wave moving through tonight may actually shift east
Friday morning and lead to less coverage of showers tomorrow,
but I don`t think we can put a lot of confidence in that just
yet. These troughs have a lot of embedded waves which then get
enhanced by convection. Timing and tracking the embedded waves
is often more frustrating than useful. So as long as this trough
remains near the area we really can`t rule out batches of
showers or thunderstorms just about any time. Temperatures
tomorrow depend on cloud cover. As seen today, if we are cloudy
and rainy then it won`t warm up quite as much. For now a middle
ground of around 80 is forecast.
&&
.LONG TERM /FRIDAY THROUGH THURSDAY/...
Issued at 230 PM CDT Thu Sep 18 2025
The slow moving trough to our north gradually pulls away to our
east through the weekend. But so long as it remains in the area,
we`ll still have those periods of showers and thunderstorms.
Temperatures remain seasonably warm, buoyed especially at night
by dewpoints in the 60s. If we do manage to get some daytime
heating then we`ll develop more instability and create a better
potential for thunderstorms, but timing of the embedded waves
within this trough is too uncertain to have a clear idea if
we`ll ever develop a better chance for strong thunderstorms. The
last more defined trough rotates around the broader trough on
Sunday. Since it has a little more agreement among the guidance
it is giving us our highest PoP of the weekend late Sunday into
Sunday night. Overall rainfall amounts this weekend will be
fairly light aside from areas that get persistent thunderstorms.
These areas could see locally significant rainfall, but may be
few and far between.
For next week we see long wave ridging in the northern stream
rising through the Canadian prairies. This has been fairly
consistent in the forecast for several days now. However,
guidance is coming into better agreement on another trough
sliding underneath the ridge and hanging out somewhere in the
central US for much of next week. The character and location of
this trough varies considerably in the guidance at this point
(from Wyoming to the Ozarks to the Great Lakes), but there is
broader agreement on the existence of this trough. Because of
this, our forecast high temperatures are a bit cooler next week,
near normal for this time of year in the 70s, rather than a
return to hot weather which would be expected under a cleaner
ridge. Low temperatures remain buoyed by continued humidity,
dewpoints in the 60s. Rain chances are even less clear as that
will depend pretty strongly on the nature and location of the
trough and any associated embedded waves. At the moment the
official NBM forecast keeps low chances of rain just about every
period of the forecast due to that rather large uncertainty.
But the likely result is that there will be some dry days next
week, we just don`t have enough clarity yet to know which ones
will be dry and which will be wetter.
&&
.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 614 PM CDT Thu Sep 18 2025
Light winds and VFR conditions will continue through this
evening, in the wake of the shower activity that is exiting into
Wisconsin. Another round of showers and a few thunderstorms is
expected to arrive in eastern Iowa after 03Z, and into TAF sites
by the 04z to 10Z time frame overnight. Generally this activity
will be VFR, but could be MVFR in any storms and with occasional
activity through the night, conditions are expected to generally
lower to MVFR at times through mid morning. This is especially
true in northeast Iowa, but is a low 20% threat at all sites.
Conditions Friday will generally be VFR, but some additional
showers and storms may be possible at times. We are not certain
of timing and coverage at this point.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.
&&
$$
SHORT TERM...Kimble
LONG TERM...Kimble
AVIATION...Ervin

NWS DVN Office Area Forecast Discussion