Area Forecast Discussion
Issued by NWS Des Moines, IA

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000
FXUS63 KDMX 252340
AFDDMX

AREA FORECAST DISCUSSION
National Weather Service Des Moines IA
540 PM CST Fri Nov 25 2016

.SHORT TERM.../Tonight through Saturday/
Issued at 247 PM CST Fri Nov 25 2016

Evolution of stratus clouds departing taking place mainly as
expected. Weak frontal boundary/trough tracking through the region
now with sunshine returning to the western areas at this time. Hires
soundings and model data suggest that clearing will occur most areas
this evening with some additional clouds and possible fog over the
northeast between 09z-13z Saturday morning. Lows will drop into the
mid to upper 20s northeast with lower 30s over central and southern
regions with light winds. Otherwise warm air advection and much
warmer conditions can be expected for the afternoon hours. The only
other clouds expected will be some cirrus spilling southeast over
Iowa during the daytime hours. Light south southwest winds will dry
out conditions over the region as well.

.LONG TERM.../Saturday night through Friday/
Issued at 247 PM CST Fri Nov 25 2016

Warm advection continues into Saturday night and Sunday as
shortwave ejects across the southern Rockies and into the central
Plains. Have increased overnight lows Saturday night given the
decent southerly flow and warm advection. As the system pulls out
into the Plains on Sunday, a strong surge of moisture will push
into the state with good theta-e advection by afternoon spreading
north through the state. Showers will develop and expand in
coverage during the afternoon as the moisture pushes northward.
Models still indicate some weak elevated instability and have
continued the threat of a few storms by afternoon as well. The
main surge of moisture will continue in northern Iowa during the
evening before lifting into Minnesota and Wisconsin on Sunday
night. Showers and isolated storms will decrease in coverage
quickly during the evening with only scattered activity overnight
with warm sector over the state. Have also increased temperatures
on Sunday night with southerly flow continuing, cloudy skies and
higher dewpoints across the state.

Much of the remainder of the forecast will be dominated by large
upper low that meanders across the northern Midwest through
midweek. This will keep a constant threat of very light
precipitation across northern Iowa with cooler readings across
Iowa. This system will finally begin to slide east on by later in
the work week with slowly moderating temperatures and dry
conditions on Thursday into Friday.

&&

.AVIATION.../For the 00Z TAFS through 00Z Saturday evening/
Issued at 539 PM CST Fri Nov 25 2016

Mainly VFR conditions will prevail through the TAF period. Sole
exception will be stratus/fog possibly affecting MCW and ALO
overnight. MVFR stratus deck moving out this evening will likely
clear ALO before 02Z, but in the clear air behind these clouds
light winds should allow for radiative fog/stratus to form as
indicated by high-resolution models. However, location of any
resulting IFR or lower ceilings/visibilities will be closely tied
to ridge axis currently lying very near MCW/ALO, and it remains
very unclear whether any stratus/fog will affect those terminals
or remain just to their northeast. Have indicated some MVFR fog
in the 00Z TAFs, but expect that if it forms just a bit further
west then amendments will be necessary overnight.

&&

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

&&

$$

SHORT TERM...REV
LONG TERM...Cogil
AVIATION...Lee



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