Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 190443

National Weather Service Des Moines IA
1137 PM CDT Tue Oct 18 2016

.SHORT TERM.../This evening through Wednesday/
Issued at 335 PM CDT Tue Oct 18 2016

There is little sensible weather of concern tonight. The jet
continues to be active from Oregon through the Rockies long wave
trough into the Great Lakes. However with no short waves noted
upstream and a stable, dry airmass in place and cold advection
aloft the forecast remains dry.

.LONG TERM.../Wednesday night through Tuesday/
Issued at 335 PM CDT Tue Oct 18 2016

The forecast into early next week is fairly inactive outside of
potential precip windows Wed Night and again toward next Tuesday.
The NV short wave currently in the base of the western CONUS trough
will be slow to evolve only reaching the Plains by Wednesday. This
will spread mid level kinematic forcing into central and southern
Iowa during the day with warm/theta-e advection just brushing
southern sections. Deep moisture will be hard to come by however so
it will take awhile to even approach sufficient moisture depth
for precip. Any thermodynamic support looks to be gone by 00z Thu,
but lingering mid level forcing/DPVA may be sufficient to squeeze
out some higher based light rain over all but the NE third of the
forecast area.

After mild weather today through Wednesday, temperatures will cool
somewhat as the system departs to end the work week but still remain
fairly typical heading into late October. Higher amplitude, dry NW
flow will remain in place through the start of the weekend before
transitioning into SW flow to end the period. This will return other
period of mild temperatures and potentially some warm advection
showers or possibly a few thunderstorms by Tuesday.


.AVIATION.../For the 06Z TAFS through 06Z Wednesday night/
Issued at 1137 PM CDT Tue Oct 18 2016

VFR conditions are expected through the forecast period with light
and variable wind generally becoming North at 10kts or less. An
upper level trough will approach by late in the period finally
passing through the state by 18Z Thursday.  Most of the forcing with
this stays West then goes South of the state only brushing Western
Iowa.  There is such a deep layer of dry air from just off the
surface to around 10KFt that I do not see much threat of precip.
Maybe sprinkles if we can get enough forcing into Western/Southern
TAF locations but the main impact will be an increase in mid clouds.





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