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Area forecast discussion 
National Weather Service Des Moines Iowa
643 PM CDT Thursday Oct 8 2015

Short term /tonight/...
issued at 301 PM CDT Thursday Oct 8 2015

Initial surface boundary currently moving across central Iowa is
primarily a moisture discontinuity with dew points lowering into
the upper 40s. Temperatures have been jumping into the lower 80s
over southeast Iowa as good mixing occurring. The primary cold
advection is just entering northern Iowa and this will progress
across the state through this evening. An example is temperatures
dropping 7 degrees at Austin Minnesota in the last hour. The primary
short wave energy has passed well to the northeast of the state
today. Another upper level system is shifting southeast through
South Dakota and Nebraska. This system will have some very high
based precipitation passing over far southwest Iowa however the
bulk of any falling hydrometeors will evaporate and result in
virga. The other challenge overnight will be cloud trends. A large
stratus shield will drop southeast from the eastern Dakotas and
Minnesota. These clouds should move across the northeast half of
the area and may reach further southwest. The clouds will help
hold temperatures up a bit despite the passing boundary.

Long term /Friday through Thursday/...
issued at 301 PM CDT Thursday Oct 8 2015

Clouds to begin Friday will be commons...especially across the
east. Drier air pushing in as high pressure settles in to the area
will lead to quickly clearing conditions and relatively good
mixing to 875 mb and near surface super adiabatic lapse rates will
help push highs into the low to middle 60s. Warm advection will
quickly return Friday night into Saturday with a switch to
southwest winds with the high pressure shifting southeast. Highs
on Saturday will be in the 70s. A strong thermal ridge will be
over Iowa on Sunday and along with breezy southwest winds may push
high temperatures to near record highs. Have pushed highs into the
low to middle 80s. Have Des Moines forecast to tie the record high of
86. Des Moines record high is anomalously low compared to other
record highs in the upper 80s to near 90. Another boundary will
pass through dry Sunday night as a very warm and dry air mass will
be in place above the boundary and capping any potential
precipitation chances. These temperatures will cool into Monday then
generally seasonal to above seasonal temperatures through next
week and dry conditions in a general zonal flow pattern.


issued at 640 PM CDT Thursday Oct 8 2015

Biggest concern will be southward push of MVFR stratus across Minnesota.
Consensus of hi res models suggests this will continue dropping
through Iowa affecting taf sites north to S 01z-08z or so...lasting into
Friday morning before dissipating. There may also be some light
sprinkles over southern sections as High Plains upper wave moves from
NE into Iowa. Have omitted mention for now however as feel best
potential would remain south of kdsm and kotm.


Dmx watches/warnings/advisories...none.



Short term...donavon
long term...donavon

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