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Area forecast discussion 
National Weather Service Des Moines Iowa
632 am CDT Tuesday Oct 13 2015

Short term /today/...
issued at 324 am CDT Tuesday Oct 13 2015

Area of high pressure to continue to build into the central US at
the surface...with the surface pressure gradient loosening through the day.
Therefore expect breezy conditions to begin the day...with winds
subsiding and especially the gustiness toward late afternoon/early
evening. Weak shortwave energy to drop southeastward through the
County Warning Area...may bring some middle/high cloudiness to the state this morning
into the afternoon. However should still see plenty of sun and 850 mb
temperatures moderate some...but the cooler start to the day will yield maximum
temperatures a bit cooler today than readings from Monday. Also kept the
far northeast a bit cooler where cloud cover may be a bit thicker
through the day.

Long term /tonight through Monday/...
issued at 324 am CDT Tuesday Oct 13 2015

Sensible weather will be negligible initially until pattern change
occurs by early next week. Polar jet will remain in the vicinity of
Iowa...not quite far enough south to get our weather too active with
sufficient moisture. A weak wave will ride jet through MO valley
baroclinic zone with little forcing or moisture late Wednesday with
attention turning to passage of somewhat stronger wave and
lift/subsidence couplet Thursday. 00z GFS and European model (ecmwf) have not come to a
consensus as of yet with respect to timing or placement. GFS
forcing is faster and more focused to the northeast...while the
European model (ecmwf) is slower and forcing slightly weaker and broader.
Northeast Iowa would seem to be on the common edge of both solutions
favorable areas so have token mention of slight chances extreme
NE...but certainly nothing significant. Another turn to cooler
temperatures will likely be the biggest sensible weather effect of
this system with the coolest temperatures of the season thus far.
Surface high should settle into Iowa/Minnesota by early Sat with mins in
the upper 20s to middle 30s producing widespread frost or freezing
conditions. This may end the growing season in some
locations...especially NE with mins there expected below 30f.

The passage of a short wave ridge sun will end our prolonged northwest flow
as Alaska trough currently around 163w eventually breaks down as it
reaches the western Continental U.S.. this flip to southwesterly flow will finally return
a period of warm advection and the question turns to when to re-
introduce precipitation. Previous forecast was dry Sun night...and
although the 00z GFS is more bullish the European model (ecmwf) remains dry so will
hold off any mention until Monday. Warm advection persists into the
night...with temperatures rebounding briefly back above normal...but
best chances appear to be just beyond the current valid period
into Tuesday when upper trough reaches the MO valley and kinematic
forcing increases fairly sharply just ahead of surface feature and
its passage.


issued at 632 am CDT Tuesday Oct 13 2015

VFR conditions throughout the taf forecast period. Northwesterly
winds picking up again today...then diminishing around sunset this


Dmx watches/warnings/advisories...none.



Short term...beerends
long term...small

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