Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 261137
AFDDMX

AREA FORECAST DISCUSSION
National Weather Service Des Moines IA
637 AM CDT Mon Sep 26 2016

.SHORT TERM.../Today/
Issued at 229 AM CDT Mon Sep 26 2016

Main upper system will pass from northern Minnesota into the Upper
Great Lakes today as a Canadian airmass pushes across much of the
Midwest including Iowa.  Broad scale subsidence will ensure sunny
skies across the area today with thermal trof becoming established
across Wisconsin.  Central Iowa will be on the backside of the
thermal gradient with temperatures becoming warmer to the south and
west today.  Otherwise, deep mixing is expected today with higher
winds aloft making it down to the surface, especially across the
north. Therefore, anticipate breezy conditions by midday with gusts
of 35 to 40 mph occurring in northern Iowa weakening to gusts of 25
mph in the far south.

.LONG TERM.../Tonight through Sunday/
Issued at 229 AM CDT Mon Sep 26 2016

Summary...Remains quiet with regards to consequential weather,
though periods of windy conditions remain for Tue and Wed.
Temperatures mostly to remain on the cool side to seasonable for
this time of year, with Wed looking coolest for the week. Widespread
precipitation unlikely to return before next week.

Tonight through Thursday....Through this period models remain in
good consensus, with Euro remaining slightly further west. A couple
of changes from previous forecasts though, including cooler
temperatures Wed, increased winds Tue/Wed and increased cloud cover
Wed. Changes primarily driven by hedging towards the Euro solution.
Over last couple runs NAM/GFS/Canadian trended toward Euro, so
growing confidence in further hedging that direction. PV anomalies
riding around the low will drive cloud cover, which may not be high
enough still. Should that occur, already lowered highs Wed would
need to be lowered another degree or two into the low 60s. Winds
Tue/Wed will be around 15kts at time with gusts in excess of 20kts,
again driven by proximity of upper low and surface gradient
reflection. Should good mixing occur, at least partially cloud cover
dependent Wed, gusts may approach 25kts as flow in the 900-850mb
layer around 25kts both days. Temperatures primarily mid to upper
60s through this time frame.

Friday through Sunday....Euro and GFS solutions continue to diverge
at this point, with GFS trending towards Euro. That said, little
consequence overall for the region. Should Euro come to fruition,
possible east sees an opportunity for an isolated shower, but
confidence remains low that low will retrograde west enough. While
models disagree with handling of the closed low, both dig in a
trough into the Pacific Northwest during the weekend. Resulting in
SW flow over Iowa and opportunity for showers early next week.
Temperatures eek into the low 70s through the weekend.

&&

.AVIATION.../For the 12Z TAFS through 12Z Tuesday morning/
Issued at 637 AM CDT Mon Sep 26 2016

Little in the way of aviation concerns for duration of forecast
with unrestricted ceilings and visibilities. Surface winds will be
strong from the west northwest today but become light tonight.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...Cogil
LONG TERM...Curtis
AVIATION...Cogil



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