Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 262053
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
353 PM CDT Wed Jul 26 2017

.SHORT TERM.../Tonight through Thursday/
Issued at 332 PM CDT Wed Jul 26 2017

Currently the cold front extends along/near the Highway 30
corridor then south to Audubon and Omaha. The front will slowly
sag to the south this evening and stall or slow even further along
the IA/MO border. North of the boundary I am not looking for much.
Lower stratus has already settled in and any precip will be light
to moderate. A storm is possible but confidence is low.

Further south, slightly better instability resides but forcing has
pretty much shifted east and weakened and shear is pathetic except
for the far south and into Missouri. As a result I see little
chance for a severe storm, unless, potentially as the storm
weakens a strong wind gust could occur. Warm cloud depths are on
the order of 14Kft and deep moisture extends to above 700 mb so
these storms are going to be efficient rain producers however
there isn`t enough instability to get them going...even along the
boundary. The storms that do occur this evening will
be heavy rain producers but the lack of expected precip this
morning and the fact that corn is up and the ground is able to
take a lot of rain and repeated heavy rainfall is unlikely (though
still possible) has resulted in my dropping the flash flood watch
across all but the far south where the best shear will reside and
the front has yet to pass. This may be too bold if the front
stalls further north but at this point does not seem likely.

Fog may occur across the north and northeast where precip fell
this morning and skies clear later tonight.

.LONG TERM.../Thursday night through Wednesday/
Issued at 332 PM CDT Wed Jul 26 2017

There is little to discuss in the long term as high pressure
remains mainly in control of the weather across the Upper Midwest.
A couple of shortwaves attempt to break down the ridge Monday
through Wednesday but Gulf moisture is effectively cut off from
the region, instability is marginal and shear is unimpressive so
any storms that may develop would not be sustained or much of a
severe or heavy rain threat. Temps will be cooler than what we`ve
seen in a while but still 70`s and 80`s so seasonal.

&&

.AVIATION.../For the 18Z TAFS through 18Z Thursday afternoon/
Issued at 1235 PM CDT Wed Jul 26 2017

At 18Z cold front roughly from DEH through BNW and DNS and moving
slowly southeast.  VFR conditions presently will become MVFR aft 20Z
when storm coverage is forecast to increase.  Vsby may be impacted
by heavy rainfall as well.  Post frontal tonight MVFR to local IFR
cigs are forecast.  Some patchy fog is possible which would produce
MVFR vsbys as well.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through late tonight for IAZ081>086-092>097.

&&

$$

SHORT TERM...FAB
LONG TERM...FAB
AVIATION...FAB


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