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Office: DMX

FXUS63 KDMX 170811

Area Forecast Discussion
National Weather Service Des Moines IA
311 AM CDT Wed Aug 17 2022

.DISCUSSION.../Today through Tuesday/
Issued at 311 AM CDT Wed Aug 17 2022

Key Messages:
- Pleasant temperatures through end of week and weekend
- Thunderstorms return to the forecast late Thursday/Friday, likely
lingering into the weekend


GOES Nighttime Microphysics satellite imagery paints a tranquil
picture across Iowa this morning as high pressure has settled across
the region. This imagery, augmented with a few surface
observations, indicate that a few areas of light patchy fog have
developed but thus far has been of little impact and largely
occurring in parts of Nebraska and the river valleys of northeast
Iowa. Pleasant seasonal temperatures are forecast for this
afternoon with high pressure keeping the area dry. A weak
shortwave, currently visible in water vapor imagery across North
Dakota and Minnesota early this morning, will pass north of the
area this afternoon, however high pressure here and increasing dry
air evident in model soundings will prevent most activity in
Iowa. In fact, recent trends in CAM guidance have backed off on
the precipitation chances both in northern Iowa and in areas

A quick moving shortwave will drop south out of Canada (this system
is also visible in water vapor imagery early this morning over
the Saskatchewan province) into Thursday with the leading cold
front making it into Northwest Iowa late in the day. This system
quickly deepens into a cutoff upper level low and slows down,
stalling out across the upper midwest. The front should move
across the area Friday with more widespread thunderstorm chances.
SPC has outlined a marginal risk along the front in Iowa for this
fairly low severe chance with modest CAPE and shear. As the
previous discussion suggested, this system with stretching within
the vicinity of the surface low is a classic setup for funnel
clouds. For now the surface low is progged to track across
northern to central Iowa, though this can certainly change as
additional data is available. As is typical with cutoff upper
lows, light precipitation will linger into the weekend as the
system slows down. Model solutions diverge in how long it will
linger, with the more progressive GFS ushering it out of the area
Saturday night while the slower Euro keeps precipitation chances
into Sunday. &&

.AVIATION.../For the 06Z TAFS through 06Z Wednesday night/
Issued at 1141 PM CDT Tue Aug 16 2022

VFR conditions are expected to remain across all terminals through
the period. A chance remains for localized patchy fog between
06-12z mainly over the western parts of the state, though overall
confidence remains low. Mostly clear skies are expected into
Wednesday morning, then patchy cumulus clouds are expected to
develop into the afternoon with light winds, with little to no
impact expected.





Office: DVN FXUS63 KDVN 170710 AFDDVN Area Forecast Discussion National Weather Service Quad Cities IA IL 210 AM CDT Wed Aug 17 2022 .SYNOPSIS... Issued at 131 AM CDT Wed Aug 17 2022 High pressure is found over the region, with light east winds and mostly clear skies. With dewpoints falling slowly through the 50s, morning lows will be pretty chilly in the 50s as well. && .SHORT TERM...(Today and tonight) Issued at 131 AM CDT Wed Aug 17 2022 This morning's taste of early Fall weather will give way to a beautifully mild afternoon, with sunshine and light winds. Highs in the upper 70s to lower 80s are on target, making for a pretty large diurnal today, close to 30 degrees in some areas. Tonight, under clear skies and light winds, lows will once again fall to the upper 50s to low 60s. .LONG TERM...(Thursday through Tuesday) Issued at 131 AM CDT Wed Aug 17 2022 Thursday will be another pleasant day with highs in the lower 80s. Friday night through Sunday, there remains good model consensus that a strong wave will drop into the mean upper trof over the northern CONUS, results in at least 2 days of dealing with an upper low overhead. Both the GFS and ECMWF show significant rainfall falling in this period, with two main rounds of possible showers and thunderstorms. The first, appears likely Friday and Friday night, then another towards Saturday afternoon as the upper low center moves overhead. These storms should be slow moving, and with cool air aloft, we should not be capable of producing any high CAPE, but rather releasing that potential through quick daytime upticks in coverage of showers/storms. As to who gets rain amounts over 0.25 on any time or day, it's going to be very challenging, as mesoscale details will be important, but we don't know what they will look like yet. Over all, the period also continua to look cloudy, with highs limited to the upper 70s. As to when the blocking pattern will break down, the blended model solution says it's moving out Monday. This is due to the western ridge getting nudged east by a wave over topping the PAC NW. I'm still leery of a cut off moving off after only developing a couple days earlier, but this will be something we just need to wait and see. Through all the chances for rain ahead, clear skis now, and cloudy days behind us, it's remarkable that the forecast highs are nearly consistent this entire time, in the upper 70s to low 80s each day. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1213 AM CDT Wed Aug 17 2022 Dry air continues to slowly move in on the light east winds. This should keep fog from becoming a problem tonight, and thus, a VFR one line TAF is forecast at all sites. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...Ervin SHORT TERM...Ervin LONG TERM...Ervin AVIATION...Ervin