Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 261007
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
407 AM CST Sat Nov 26 2016

.SYNOPSIS...
Issued at 334 AM CST Sat Nov 26 2016

06Z surface data has high pressure from the Great Lakes into the
lower Mississippi Valley. Dew points were in the 30s from the Ohio
Valley west into the Plains. Dew points in the 40s and higher were
across the deep South and Gulf Coast.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 334 AM CST Sat Nov 26 2016

The light winds from the high pressure has allowed patchy fog to
develop across parts of the area. This patchy fog will continue
through sunrise and then slowly dissipate.

Quiet and dry conditions will be seen today and tonight as the high
pressure moves into the Ohio Valley. Temperatures will average above
normal.

.LONG TERM...(Sunday through Friday)
ISSUED AT 334 AM CST Sat Nov 26 2016

The main focus continues to be with a moderate rain event Sunday night
with rain chances lingering through Monday night, then turning
cooler mid to late week.

Overall good agreement exists from the deterministic models with
ejecting a vigorous storm system from the Rockies and eventually closing
it off over the Northern Plains and Upper Midwest early next week.
Strong moisture transport/convergence is depicted on the nose of a
strong 50+ kt low level jet ahead of this system later in the day on
Sunday and Sunday night, which will lead to a maturing rain shield
lifting across the region during this time. Storm chances remain low
but will maintain isolated mention with near neutral stability, and
given strength of lift and magnitude of low to mid level moisture
advection despite being beneath generally weak 700-500 mb lapse rates.
Main thunder potential will likely reside with initial precipitation
Sun PM/eve and also Mon PM ahead of dry slot. Typically WAA precipitation
tends to arrive quicker than the models suggest, especially in the
stronger WAA regimes and as such I have added some small pops southwest
cwa late Sunday morning. The precipitation late Sunday and Sunday night
should be quite progressive considering the elevated nature of the
showers, as well as the strong low to mid level flow. This should preclude
rain amounts from being too heavy and generally in range of 0.25 to
0.75 inches, which is also supported by precipitable water values around
1 inch and overall moderate forcing. Aside from the rain, expect mild
conditions with southerly winds becoming breezy at 15-25+ mph in
strengthening pressure gradient, with stronger gusts in excess of 30-35
mph possible at times Sunday night in mix down of momentum from strong low
level jet.

Monday, the majority of the measurable rain should have ended by 12z
or shortly thereafter. However, some drizzle or light rain may
persist ahead of front and dry slot with occluding system to our northwest.
The front and dry slot will look to serve as a focus for renewed
shower development during the afternoon and evening, with a few rumbles
of thunder possible as some models showing weak instability to around
250 J/kg 0-6km MUCAPE. Highest pops look to focus near and especially
east of the Mississippi River. At the same time, will be watching a
secondary maturing rain shield develop to our south ahead of a shortwave
traversing the mean longwave trough over the Plains. This rain shield
is likely to stay to our southeast across portions of Missouri through
central and southern Illinois. Additional rain amounts for our area on
Monday and Monday night look to be mainly light and mostly around 0.25
inch east to 0.10 inch or less west.

Tuesday through Friday, look to feature cooler temperatures and bouts
of cloudiness as the region is under an extended period of cyclonic flow
as a stacked low slowly traverses the Upper Midwest and Great Lakes.
May have to watch mainly northern sections of the cwa Wednesday into
Thursday for a chance of rain/snow showers with energy shuttled down in
west/northwest flow and strengthening CAA.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
ISSUED AT 1116 PM CST Fri Nov 25 2016

Patchy IFR and MVFR fog is developing in the area of light wind
and clear skies on the back side of the surface ridge. Area TAF
sites are expected to see MVFR visibilities due to the fog
overnight.  Fog should dissipate shortly after sunrise with VFR
conditions the remainder of the TAF period.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&

$$

SYNOPSIS...08
SHORT TERM...08
LONG TERM...McClure
AVIATION...DMD



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