Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 220905

Area Forecast Discussion
National Weather Service Des Moines IA
405 AM CDT Wed Mar 22 2017

.SHORT TERM.../Today through Tonight/
Issued at 341 AM CDT Wed Mar 22 2017

warm air/theta-e advection moves across Western/Northern Iowa
today along with a quick shot of forcing this morning. this will
bring a quick shot of light precip across these areas this
morning. The precip will start out as snow early this a.m. then
mix with rain as we get towards mid morning before lifting
Northeast by late morning. Not looking at much in the way of
precip as soundings show some dry air off the surface and not much
moisture aloft.

Tonight an upper ridge moves overhead so expecting mainly dry
conditions tonight. Temps will not be as cold as we have seen
tonight as we get into another round of weak warm advection.

.LONG TERM.../Thursday through Tuesday/
Issued at 341 AM CDT Wed Mar 22 2017

On Thursday the upper ridge moves East as a deep trough digs into
the West. A surface low develops with a frontal boundary extending
into West central to Northeast Iowa by Thursday evening. Showers
and perhaps some thunderstorms are possible Thursday late morning
and afternoon associated with an initial surge of theta-e
advection and frontogenetical forcing. Precip should be ongoing
into Thursday evening but I do expect a break in the precip across
Southern into central Iowa.

Friday through Friday night an upper low develops from the trough
and becomes stacked with the surface low. This will slow the
progression of the system as it treks Eastward and will allow for
decent moisture, instability and some forcing to work into Iowa.
We should see some prolonged precip and some thunderstorms Friday
and Friday evening.

On Saturday we will be caught in deformation zone precip and while
thunderstorm chances diminish, it will be a wet day with moderate
rainfall at times. It looks to me as though we may even see this
precip linger into Sunday morning before finally shifting East out
of the state.

For the rest of the long term...the weather will remain unsettled
as numerous fairly strong shortwaves move from West to East across
the U.S. At this time however it appears that these systems will
move across the Southern U.S. and mainly graze Southern Iowa. On
Monday a Northern stream wave seems to phase with the Southern
stream system and bring us at least a slight chance of precip.

Temp-wise, Friday will be the warmest day in the forecast period
but temps will be quite mild through the period with highs in the
40`s and 50`s.


.AVIATION.../For the 06Z TAFS through 06Z Wednesday night/
Issued at 1148 PM CDT Tue Mar 21 2017

Surface ridge north of Iowa will continue to slowly move southeast
through Wednesday evening. North to northeast surface winds
overnight will become southeast and increase on Wednesday and
continue into Wednesday night. Mid and high level ceilings will
push across much of central Iowa overnight int Wednesday morning
and remain through the rest of the forecast period. However, these
ceilings will remain VFR with unrestricted visibilities.




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