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Area forecast discussion 
National Weather Service quadrant cities Iowa Illinois
921 PM CDT Tuesday Oct 6 2015

issued at 918 PM CDT Tuesday Oct 6 2015

Cloud cover has been increased tonight due to a weak upper level
disturbance moving through the area. The additional cloud cover
raises questions regarding fog potential late tonight and
Wednesday morning. The patchy fog wording will remain for now but
may be reduced in areal coverage in a later update.


issued at 240 PM CDT Tuesday Oct 6 2015

Moisture under the large-scale subsidence inversion
around 875-850mb is very shallow compared to previous few days which
has resulted in better boundary layer mixing and mostly clear skies
over parts of the dvn County Warning Area. Although...stratus have held on all day
across far southeast Iowa into west-central Illinois and over NE Missouri.
Temperatures were in the lower 70s on average.


Short term...(this evening through wednesday)
issued at 240 PM CDT Tuesday Oct 6 2015

Tonight and Wednesday...periods of scattered to broken stratus are again
forecast overnight. Best chances for prolonged clearing will be east
of a Dubuque-to-Quad Cities line. Synoptic setup and local fall
climatology support development of localized dense radiation
fog...especially in valley locations. Clearing is most likely along
and north of I-80...and these areas are favored for localized
dense fog. Have added patchy fog to the grids all but the
northwest counties. After morning lows in the 50s...temperatures will
warm nicely into the lower 70s far north to middle/upper 70s

Long term...(wednesday night through tuesday)
issued at 240 PM CDT Tuesday Oct 6 2015

The main highlights of the long term forecast period include one
window of rain...followed by a brief cool-down then unseasonably
warm weather.

A cold front will approach far western Iowa late Wednesday night.
The GFS is a fast outlier among the synoptic scale models and have
opted to keep the forecast dry through 12z Thursday. The front
will push through the forecast area Thursday afternoon and
evening. NAM bufr soundings suggest precipitable water values around 1.5 inches
with the frontal passage...moisture that is likely overdone. Have trended
probability of precipitation down slightly...with likelies limited to only the far north
closer to the more favorable forcing. The forecast area remains
outlooked in the marginal risk area for isolated large hail on
Thursday...but at this point am not very excited about the
instability/shear combo to support 1 inch hail. Thursday will be
quite warm...low 70s north to low 80s south...then substantially
cooler on Friday...generally in the 60 to 65 degree range. The
temperatures roller coaster returns through the weekend into early
next week...with a warming trend back into the middle 70s to low 80s.
Dry weather still expected after Thursday evening.


Aviation...(for the 00z tafs through 00z Wednesday evening)
issued at 624 PM CDT Tuesday Oct 6 2015

VFR conditions will be seen through 06z/07 as high pressure moves
through the Midwest. After 06z/07 clearing skies should allow MVFR
conditions to develop with localized IFR or LIFR conditions by
sunrise. After sunrise Wednesday...conditions will slowly improve
to VFR through 18z/07.


Dvn watches/warnings/advisories...


short term...uttech
long term...rp Kinney

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