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Area forecast discussion 
National Weather Service Quad Cities Iowa Illinois
704 am CDT Friday Jul 29 2016

..aviation update...

issued at 305 am CDT Fri Jul 29 2016

Upper level trough axis extended from WI to Kansas and was producing
scattered showers and isolated thunderstorms. In the dvn cwa low
stratus had spread into the northern half with temperatures in the
60s to around 70.


Short term...(today and tonight)
issued at 305 am CDT Fri Jul 29 2016

Today: upper level trough and pocket of cooler air aloft will
slide into the cwa. There should be enough breaks in the cloud
cover to allow for just enough instability to trigger scattered
showers and a few thunderstorms. Pops will be kept at 30-40
percent, with the higher pops in the north and east where the
better forcing will exist. With MLCAPES maximized at 1000 j/kg
and deep layer shear very weak we are looking at garden variety
thunderstorms. Steering winds are rather light so the showers and
storms will be slow moving. Of course any storm can produce gusty
winds, lightning and heavy downpours. Afternoon highs will be in
the mid 70s to around 80.

Tonight: slow moving upper level trough will still be over the
area but with the loss of heating any showers or storms will
gradually diminish. Lows should be in the lower to mid 60s.

Long term...(saturday through thursday)
issued at 305 am CDT Fri Jul 29 2016

Saturday, a vort Max and moisture convergence along a weak surface
trough will likely support some scattered thunderstorms, especially
across the northeast half of the forecast area. No severe weather is
anticipated. Northeast surface winds will keep temps at Bay, with
afternoon highs in the upper 70s to low 80s.

For Sunday, the upper ridge will begin to build to the west of the
forecast area with afternoon highs back close to seasonal normals.
Synoptic models continue to suggest a warm front nosing into the
southwest with scattered storms possible Sunday night. Again, the
severe weather threat is low.

Looking ahead to next week, the main theme is the return of more hot
and humid weather, with periodic chances for thunderstorms. At least
scattered storms cannot be ruled out of any period at this point,
but there is plenty of model variability in the track and timing of
various short wave troughs and the strength of the cap. Monday night
into Tuesday may be favored for an organized thunderstorm complex.
Afternoon heat index values will flirt with the 100 degree mark at
times, largely dependent on cloud trends.


Aviation...(for the 12z tafs through 12z Saturday morning)
issued at 703 am CDT Fri Jul 29 2016

Widespread IFR in low stratus and patchy fog this morning, then
gradually improving to VFR conds this afternoon. An upper level
trough will spread scattered showers and a few thundestorms across
the taf sites today and this evening. The better coverage looks to
be in northeast Iowa/northern Illinois so have added a vcsh at kdbq. Low
confidence to add rain to the other sites. North to northeast winds
less than 10 knots through this period.


Dvn watches/warnings/advisories...


short term...haase
long term...rp Kinney

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