Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 171013
AFDDMX

AREA FORECAST DISCUSSION
National Weather Service Des Moines IA
413 AM CST Tue Jan 17 2017

.SHORT TERM.../Today through Tonight/
Issued at 414 AM CST Tue Jan 17 2017

Lingering dense fog through 12-13z this morning across the
eastern portions of the forecast area are expected. It has already
shown signs of dissipating with the increase of wind speeds but
left the advisory going as portions of Tama, Poweshiek, Black
Hawk, and Jasper reporting 1/4 mile visibility. Other concern was
patchy freezing drizzle over northern Iowa but current weak band
is moving through the MCW area and looks to be quickly east of the
forecast area by 11z or so.

The back edge of the low stratus deck is just entering the far
northwest corner of Iowa and latest trajectory looks to finally push
east of the forecast area late this afternoon, likely after 22-23z,
if not later. Extended the cloud cover through the early evening
across the east with the lingering stratus. Otherwise, temperatures
remain on par for today and tonight and made no significant changes
to the ongoing forecast.

.LONG TERM.../Wednesday through Monday/
Issued at 414 AM CST Tue Jan 17 2017

Overall pattern will remain quite active into the longer term with
strong onshore flow onto Pacific Coast with several shortwaves
passing through the central United States. There will be a brief
break at the start of the period with quiet weather after the
current storm departs. However, upper low across the southwest
United States will drift northward by later in the work week. Low
level moisture will surge northward Wednesday night into Thursday
with stratus developing across much of Iowa. In addition, overall
airmass will be relatively warm for mid-January with temperatures
holding above normal from Wednesday into the weekend.

As the various systems lift into the Midwest into the weekend,
forcing will spread across the state from time to time. The
limiting factor for widespread precipitation will be deeper
moisture as most of it will be confined to the near surface status
layer with dry mid levels. However, there will be brief periods
where this is not the case and some light rain will occur from
late Thursday into Saturday. However, the best threat of
precipitation through the next weekend will arrive on Sunday as a
system clips southern Iowa. Deeper moisture is forecast to spread
into the state with some light precipitation possible. At this
time, the bulk of precipitation chances from Thursday into Sunday
should be rain, although there is some threat of snow in the north
from time to time.

&&

.AVIATION.../For the 06Z TAFS through 06Z Tuesday night/
Issued at 1152 PM CST Mon Jan 16 2017

Messy aviation fcst as LIFR and IFR conditions run prevalent
throughout the TAF period. Challenge will be when to lift vsbys
to IFR. Went with TEMPO groups as cigs should hover near 500ft for
many sites. Tuesday challenge will when sites lift to MVFR during
the afternoon period and if they will reach VFR, or if HZ
conditions will prevail overnight from moisture from pvs system.


&&

.DMX WATCHES/WARNINGS/ADVISORIES...
Dense Fog Advisory until 6 AM CST early this morning for IAZ038-
039-049-050-061-062-074-075-085-086.

&&

$$

SHORT TERM...Podrazik
LONG TERM...Cogil
AVIATION...Kotenberg



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