Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 052341

National Weather Service Des Moines IA
541 PM CST Mon Dec 5 2016

.SHORT TERM.../Tonight through Tuesday/
Issued at 353 PM CST Mon Dec 5 2016

Not much change to the forecast for tonight and Tuesday. Precip/virga
across the Northwest is allowing stronger winds aloft
to mix down producing strong wind gusts in the Northwest. These
wi nds will continue into the evening. An upper low will continue
to trek across the Northern Plains dragging a cold front across
the forecast area. Moisture will deepen with time and there is a
period of stronger forcing which will mainly affect the Northern
half of the CWA. Precip will start as light rain/sprinkles then
switch over to snow late evening overnight as the front pushes
East. We are not looking for much in the way of precip or snowfall
with the system. Post frontal on Tuesday...we will be in fairly
strong cold advection and winds will be quite brisk during the
day. Temps will be some 15 to 20 degrees colder than today.

.LONG TERM.../Tuesday night through Monday/
Issued at 353 PM CST Mon Dec 5 2016

Cold advection will continue through Thursday as a deep trough
and Canadian high pressure pushes across the Rockies into the
Central Plains. Both the Euro and GFS suggest precip near the base
of the trough. The GFS has been dry for Iowa while the Euro has
been pushing precip further South with each successive run.
Precip this last run is also now South of Iowa and with that I
have removed measurable precip from the forecast but did mention
flurries across the North associated with the second push of cold
air. We will remain cold through Friday with highs in the teens
and 20`s and lows around zero to 10 above.

Warm advection returns Friday night into Saturday night ahead of
the next low and this will bring the next chance for snow to the
region. Despite the warm advection...temps will still be cold
enough for snow. There will likely be some locations receiving
measurable snow but it is too far out to determine amounts and


.AVIATION.../For the 00Z TAFS through 00Z Tuesday evening/
Issued at 542 PM CST Mon Dec 5 2016

Main concerns will be IFR cigs and wind. Tonight...areas of low
clouds will reform over snowpack northeast/eastern Iowa and fill
west toward KALO/KOTM/KMCW while brief lowering of MVFR deck
accompanies passing cold front with -RASN. Winds remain out of
south with gusts through 04-05z then lighter SW with front in
vcty. By 12z-16z...stronger mixing with west winds and lifting
cigs will result in 16G25-30kts much of daytime hours 12z-00z
Tuesday. Will monitor cloud and wind trends for next package as
well. /rev




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