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FXUS63 KDMX 111151

Area Forecast Discussion
National Weather Service Des Moines IA
549 AM CST Wed Dec 11 2019

.DISCUSSION.../Today through Tuesday/
Issued at 349 AM CST Wed Dec 11 2019

Area of snow is progressing as expected across Iowa. Heaviest snow
extends from Webster City to Marshalltown to Cedar Rapids where 
visibilities at 3 AM were between three quarters of a mile and a 
mile and a half. Lighter snow does extend back further west but 
this is having little to impact as visibilities are better than 4 
miles. The main band is on track to exit the state around 6 AM 
with lighter snow trailing far eastern portions of the forecast 
area until 8 AM or so. By 15Z all that remains is some shallow 
moisture and no forcing as that will be in far eastern Iowa. 
Clouds and possibly a few flurries east is what we will see 
through the morning. Clearing is forecast to commence by late 
morning or early afternoon however we will remain in cold 
advection through much of today so highs will not be pleasant 
today with only a small recovery from morning lows. 

Another in the parade of shortwaves to cross the region will move 
across the area tonight.  A surface low will develop over the Plains 
and track east across the state from tonight through Thursday 
afternoon.  As the low tracks east, it will lift a warm front across 
the state.  Highs on Thursday will be considerably warmer than 
today...especially across central and southern Iowa.  As the 
shortwave crosses the state late tonight into Thursday, lift/forcing
will increase across the state with the best forcing occurring 
across northern Iowa. Moisture does not look as good with this 
system so northern locations may see a dusting with southern areas
seeing little to no precip. We do lose ice introduction for a 
brief period Thursday morning before the precip pulls out so there
is a mention of freezing drizzle across the far northeast. Not 
expecting any impacts since if it falls, it will fall atop 
whatever light snow occurs first with the system. 

Yet another shortwave will pass through the region on Friday into 
Saturday but moisture is again in question and so any precip if it 
occurs should be light.  Colder air will accompany this system so 
precip will be in the form of snow.  

Colder air will remain in place through the weekend but precip 
chances do not look as good today as they did yesterday. Another 
fairly strong shortwave develops over the west but models take this 
system mainly across the Southern Plains and the precip with it. 

There is some uncertainty as to how this wave, as it develops into a 
trough, will move with some potential for it to bring precip early 
next week but confidence is too low for anything more than a mention 
of slight chance PoPs.


.AVIATION.../For the 12Z TAFS through 12Z Thursday morning/
Issued at 549 AM CST Wed Dec 11 2019

Improving conditions through 15Z.  Mainly MVFR cigs/vsbys in light 
snow will become VFR.  TAF locations may see a brief period of gusty 
winds behind the departing system.  LLWS is likely as winds off the 
surface are some 25 to 40 kts stronger than near surface winds.



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