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Area forecast discussion 
National Weather Service Des Moines Iowa
653 PM CDT Wednesday Oct 22 2014

Short term /tonight/...
issued at 356 PM CDT Wednesday Oct 22 2014

A band of clouds and light to moderate showers is approaching from
the west in conjunction with a modest low pressure trough. Ahead of
this band south southeast breezes have allowed for another mild day
across the forecast area with patchy middle level clouds and
temperatures rising into the 60s. Primary forecast challenge tonight
is timing the progression of the rain into and across the
area...which appears to be a bit slower than expected as the
periphery of the ridge just to our east is proving fairly strong.
Nevertheless...regional radar trends and high res models indicate
that the showers will still reach our western counties by late
evening and our eastern counties by around sunrise Thursday.
Forecast soundings indicate some marginal elevated instability so
have retained isolated thunder mention...but generally just a period
of steady light to moderate rain can be expected in most areas.

Long term /Thursday through Wednesday/...
issued at 356 PM CDT Wednesday Oct 22 2014

Precipitation will likely be lingering over the far east after 12z
Thursday however much drier air infiltrating from the west will
quickly move in and end precipitation chances for the day. Expect
mild temperatures and clearing skies by the afternoon. In
addition...prime viewing conditions for the partial solar eclipse
which looks to peak around 530 PM Thursday afternoon. The next
Theta-E advection plume arrives already Thursday night into early
Friday morning ahead of short wave energy moving in from the west.
Have increase cloud cover for Friday and have slightly modified
temperatures down however discontinuity in the vertical moisture
profile precludes addition precipitation chances at this time.
Certainly will continue to evaluate the moisture profile between
850-500 mb Friday morning as better saturation would lead to the
potential for a few showers.

Still expecting an outstanding day Saturday as high pressure
enters from the west. Low pressure dropping southeast into the
northeast Continental U.S. May slow the high pressure ridge progression to
the east on Sunday. This may result in a cooler southeast flow
for Sunday that would limit highs to the 60s as opposed to the low
to middle 70s if the flow becomes a bit more progressive. The next
cold front arrives late Monday into Monday night. An increasing
low level jet and steeping middle level lapse rates will promote
MUCAPES around 500 j/kg therefore have included thunderstorms
Monday night. Much cooler temperatures arrive with 850 mb
temperatures dropping to near 0c Tuesday and Wednesday.

&&

Aviation...23/00z
issued at 652 PM CDT Wednesday Oct 22 2014

Primary concern will be how much to degrade conditions with
passage of 5-8 hour period of weak convection. Models are very
bullish bringing ceilings down...and while that has occurred in
isolated spots per recent observation...main drop to MVFR has been due to
visibilities. Will continue that trend...with drop to more widespread
MVFR ceilings not occurring until after precipitation ends. This period
should be followed by VFR and clearing into midday and the
afternoon. There may be a few periods of thunder...but have
omitted wording for now and will play the short term trends for
updates rather than blanket ts for a prolonged period.

&&

Dmx watches/warnings/advisories...none.

&&

$$

Short term...Lee
long term...donavon
aviation...small

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