Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 272358

National Weather Service Des Moines IA
652 PM CDT Thu Oct 27 2016

.SHORT TERM.../This evening through Friday/
Issued at 317 PM CDT Thu Oct 27 2016

Surface high pressure will slide over central to eastern
Iowa overnight. With decent radiational cooling across the east to
northeast, fog looks to develop in this location towards Friday
morning. Only caveat is the WAA developing past 06z, mainly across
the west but could start as early as 09z in eastern portions of the
CWA. Low confidence with any widespread dense fog attm.

.LONG TERM.../Friday night through Thursday/
Issued at 317 PM CDT Thu Oct 27 2016

Summary...No major changes to the overall forecast with decent model
consensus through the weekend, then precip placement discrepancies
next week.. Temperatures will roller coaster a bit with warm and
windy days Fri and Mon well into the 70s. Widespread precipitation
chances generally hard to come by with isolated opportunities
Saturday across the N/NE, then chances primarily across southern
half of he state beginning late Tue night and through the rest of
the week.

Tomorrow through Monday...This period will be highlighted by periods
of breezy/gusty winds and temperature swings. Upper level ridging
will begin to build in overnight, along with increasing southerly
surface flow. While the depth of mixing is a bit uncertain, there is
little doubt that it will tap into 30-35kt winds aloft, resulting in
gusts around 30kts to go along with sustained winds around 20kts.
The mixing and southerly flow will boost temps well into the 70s,
possibly touching 80 in locations around I-80 on south. Saturday
will see a weak cool front push through during the morning/afternoon
hours, flipping winds northerly and cooling highs into the upper
50s/low 60s by Sunday. With moisture return and WAA ongoing, clouds
will increase Sat, along with slight chances for some isolated rain,
primarily across the N/NE Sat afternoon/evening. After the cooler
conditions Sun, Mon will rapidly warms again as ridging, southerly
flow, and breezy conditions return. Again, degree of mixing will
ultimately determine winds and temps. Temps well into 70s across
south to around 70 north. Winds once again strong with tight surface
gradient as low pressure passes to the north, expecting upwards of
20+ kt sustained and 35+ kt gusts possible, especially should GFS
soundings/mixing depth come to fruition.

Tuesday through Thursday...Good model consensus generally ends
during this time frame. While large scale pattern depicted similarly
into mid week, GFS more aggressive with weak wave moving through Tue
night sparking off precipitation while Euro/Can remain dry. Inclined
to lean dry with GFS tendency to be overly aggressive, but kept
slight chances in for the time being. Beyond Tue night, blends keep
POPs primarily across southern half of Iowa through remainder of the
forecast. Problem being that Euro and GFS depict precipitation
opportunities at different times for differing reasons, resulting in
the never ending POPs. Certainly that will not be the case, however
confidence in one model over the other is not high enough to
completely remove a window of POPs at the moment.


.AVIATION.../For the 00Z TAFS through 00Z Friday evening/
Issued at 652 PM CDT Thu Oct 27 2016

VFR cigs expected through the forecast period for the most part.
There is some potential for patchy MVFR vsbys over the east in fog
from 09Z through 12Z and some chance for MVFR cigs as well but low
confidence in anything more than patchy conditions.  Surface winds
become southerly and will mix to about 880 mb but wind speeds in
this shallow layer will be 30 to 40kts so it will be breezy late
morning through mid afternoon.




SHORT TERM...Podrazik
LONG TERM...Curtis
AVIATION...FAB is the U.S. government's official web portal to all federal, state and local government web resources and services.