Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 160526

Area Forecast Discussion
National Weather Service Des Moines IA
1126 PM CST Wed Feb 15 2017

Issued at 706 PM CST Wed Feb 15 2017

Forecast lows for Thursday morning were lowered by a degree or
two across most of central Iowa. While there is some high level
moisture streaming overhead, temperatures have been falling off a
little quicker than forecast the last few hours. Otherwise,
current forecast seems on track.


.SHORT TERM.../Tonight through Thursday/
Issued at 328 PM CST Wed Feb 15 2017

Weak warm advection will begin late tonight into Thursday and this
will kick off our start to much warmer temps.  Forecast soundings
show a pretty stout inversion developing due to the warm air aloft
so mixing will be limited and as such, surface winds will not be
strong.  However from the inversion upward West winds increase
dramatically to between 30 to 40kts.  This will lead to some low
level wind shear transitioning Southeast across the forecast area
mainly along and South of a line from Fort Dodge to Ottumwa tonight.
On Thursday mainly clear skies and a Southerly wind will lead to
high from the mid 40`s Northeast to the mid 60`s South.

.LONG TERM.../Thursday night through Wednesday/
Issued at 328 PM CST Wed Feb 15 2017

On Friday we will be in strong warm advection with better mixing
expected which will allow temps to climb to the mid 50`s Northeast
to around 70 Southwest.

On Friday night a weak boundary will slide across the state but
there will be little to no moisture to work with and as a result, we
will see some scattered high clouds and only slightly cooler highs
for Saturday but still unbelievably mild for mid February.  For
Sunday we are back into warm advection so temps will be warmer once
again by a few degrees.

Monday into Tuesday still looks wet but models are still showing
fairly significant differences.  QPF is much lower with the 12Z run
then last night`s run and the system does look fairly progressive so
I am not so sure about the flooding potential at this point.  The
warm up will melt ice and we may see some ice jamming on rivers but
reports of limited snowpack...lower model qpf forecasts and the
progressive nature of this system are causing me to back off one the
large scale flood threat.

Once the system passes we return to a zonal flow with highs still
very mild for this time of year. Highs into midweek will be in
the 50`s to around 60 with little chance for precip.


.AVIATION.../For the 06Z TAFS through 06Z Thursday night/
Issued at 1122 PM CST Wed Feb 15 2017

Conditions will remain VFR through the TAF period at all
terminals. A several hour period of low level wind shear is
expected to affect KFOD, then KDSM, and finally KOTM later tonight
into tomorrow morning.




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