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Area forecast discussion 
National Weather Service Des Moines Iowa
249 PM CDT sun Sep 21 2014

Short term /tonight/...
issued at 249 PM CDT sun Sep 21 2014

Low pressure over eastern Great Lakes will move northeast
tonight. Secondary cold front dropping south now has increased cumulus
field this afternoon over much of the area and along the
boundary...mixing as well. As ridge settles into the area
tonight...winds will become light north then SW by early Monday
morning over the west. Otherwise expecting the clouds to depart
with generally clear skies across the area. Temperatures will be
cool...especially northeast as highs today have been held back due
to more extensive cloud cover. Elsewhere...mins will be cooler in
River Valley areas with dsm benefiting from light NE flow
overnight which will shelter the reading at the apt. By late
tonight as ridge axis moves east...light west-southwest flow will return
across the west. Minor thickness rises overnight indicate slight
warming in column...and should mitigate chances for fog overnight
except for the eastern counties which might see some patchy fog
toward sunrise.

Long term /Monday through Sunday/...
issued at 249 PM CDT sun Sep 21 2014

Little has changed in the long term forecast today. On Monday and
Monday night a fairly week but deep layered ridge will cross the
area...making for another sunny and dry late Summer day with light
winds. From Tuesday into Wednesday an upper level trough will
slowly move from Nebraska and the Dakotas up into
Minnesota...bringing clouds with some light showers and a few
thunderstorms. However...most of the rain will be light and
confined to western Iowa and have tapered probability of precipitation a bit in that
direction. By late Wednesday much of the energy within the 500 mb
trough will be scooped out into the northern stream and up to
Canada...however some of it will be left behind as a blocking
pattern sets up across most of the Continental U.S. By Wednesday night. This
pattern will be characterized by two 500 mb high pressure across the southeast U.S. And the other along The
Rockies into the northern High Plains...while in between them the
remnant broad and weak trough will stretch from the southern High
Plains up across Iowa and the Midwest. Subsequently this trough
will be squeezed out with general deep layer ridging building
across the central U.S. This general evolution will result in
dry weather from Wednesday night or Thursday morning Onward but
with temperatures held somewhat in check by the weak trough aloft.
That means iowans will be treated to more mostly sunny and mild
weather for the latter half of the week and next weekend...with
light to modest breezes and high temperatures generally in the
70s. No real change to this pattern is seen until at least early
next week after the end of the seven day forecast.


issued at 1233 PM CDT sun Sep 21 2014

MVFR ceilings northeast will continue through 23-00z when cumulus field
will scatter out and ceilings lift prior to sunset. Winds remain an
issue northeast with cold air advection...another upper level
trough passage...and mixing. High builds east tonight with light
winds and sky clear-few conditions through 02z...then sky clear. After 15z Monday
winds become more SW with few035 as drier air moves into the area
from the west and winds relax throughout the region.


Dmx watches/warnings/advisories...none.



Short term...rev
long term...Lee

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