Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 260329

Area Forecast Discussion
National Weather Service Des Moines IA
1029 PM CDT Thu Aug 25 2016

.DISCUSSION... Issued at 143 PM CDT Thu Aug 25 2016

Southwest flow aloft pattern to continue across the region tonight
into Friday, with the main upper level trough set to push east
through the region over the weekend. Shortwave energy continues to
lift northeastward through the region, allowing for showers and
storms to form along a somewhat stalled out boundary to the south of
Iowa. Therefore any precipitation into tonight should remain south
of the CWA. A stronger shortwave trough to lift northeastward toward
the state pushing the boundary northward as a warm front Friday into
Friday night. An associated strong push of theta-e advection
oriented across the western/northern CWA by Friday afternoon into
the overnight hours. Overall CAPE somewhat limited so expect thunder
chances with more showery/isolated thunder across the north as
precipitation is expected to spread north/northeastward across the
CWA late Friday into Friday night. Deep layer shear a bit better
especially as precip moves into SW Iowa Late Friday afternoon into
the evening, so the marginal threat of a severe storm looking ok
there given the CAPE limitations. The associated surface low to be
situated across north central Iowa by late Friday night, maintaining
that threat for isolated thunderstorms and brief heavy rainfall
across the eastern half of the CWA late Friday night. Any stronger
storms expected to be more progressive but will have to monitor
expected rainfall for the northeastern portion of the CWA that has
already had heavy rainfall in the past few days, and is dealing with
some river flooding.

Forecast becomes more muddied into next week with a large broad
upper ridge building in aloft. Shortwave energy to traverse through
the broad upper ridge and may bring intermittent chances for
showers/storms so will basically broadbrush pops through the period.
Hard to nail down any timing with this ring of fire type scenario,
and keeps the chances for widespread rainfall limited through the
week. The best chances through the forecast period will still  be
this Friday into early Saturday. The broad upper level ridging
should lead to gradual warming trend into next week, after a few
cooler days with highs only in the 70s for Friday into Saturday.


.AVIATION.../For the 06Z TAFS through 06Z Friday night/
Issued at 1026 PM CDT Thu Aug 25 2016

Will continue to see widespread VFR conditions overnight into
Friday with mid and high ceilings across the state. Ceilings will
begin to lower late in the period with showers and a few storms
entering southern Iowa as a warm front approaches. Visibilities
will remain unrestricted through tomorrow but some restrictions
will develop in and around any showers and storms late tomorrow
afternoon in the south and west. Surface winds will be light and
variable overnight and increase from the east to southeast on





SHORT TERM...Beerends
LONG TERM...Beerends
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