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Issued by NWS Quad Cities, IA IL

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NOUS43 KDVN 271142

Public Information Statement
National Weather Service Quad Cities IA IL
542 AM CST Sun Nov 27 2016

Area Forecast Discussion
National Weather Service Quad Cities IA IL
424 AM CST Sun Nov 27 2016

Issued at 340 AM CST Sun Nov 27 2016

06Z surface data has high pressure over the Ohio Valley with a
developing storm system in southeast Colorado. Dew points were in
the 20s and 30s across the Midwest with 40s and 50s in the southern


.SHORT TERM...(Today and Tonight)
ISSUED AT 340 AM CST Sun Nov 27 2016

Quiet conditions will continue through sunrise as clouds from the
Plains storm system move east.

After sunrise, clouds will be on the increase during the morning as
moisture aloft moves into the area. The lack of forcing and dry
atmosphere will keep a majority of the area dry through mid-day. The
exception may be the far southwest parts of the area where some
sprinkles are possible by late morning.

During the afternoon hours, forcing across the area increases
significantly. This forcing will interact with the moisture moving
into the area and allow rain to develop. The rain may initially
develop as individual showers but will quickly grow upscale into a
large rain area. By late afternoon forcing aloft increases further
which should allow isolated embedded thunderstorms to develop west
of the Mississippi.

Tonight, forcing and moisture will maximize during the evening
hours. Widespread rain with isolated embedded thunderstorms will be
seen. After midnight, the strongest forcing shifts east of the area
as dry air aloft beings moving into the area. The isolated embedded
thunderstorms will quickly end from west to east and the overall
areal coverage of rain will also decrease.

No severe storms are expected this afternoon or tonight as the
thunderstorms will not be surface based. If the elevated storms can
transport the strong winds aloft to the surface by means of a
downdraft, then brief gusty winds up to 40 mph may be possible.

.LONG TERM...(Monday through Saturday)
ISSUED AT 340 AM CST Sun Nov 27 2016

Main focus is with storm chances Monday pm/eve and potential for
a few strong storms should convection occur. Then, the theme
will be turning colder mid to late week with temperatures more
seasonable, with even some prospects for rain/snow showers north.

Bulk of forcing will have exited by 12z Monday, thus the start
of the day should have seen the brunt of the measurable rain
having ended. However, continued isentropic ascent and 850 mb
theta-e advecton will likely promote areas of light rain and
drizzle throughout the morning with only minor additional amounts.
Monday afternoon and evening will see dry slot and front
eventually pass through the region with occluding system to our
northwest. Forcing appears fairly minimal, as region positioned
between vertically stacked system over the Northern Plains and a
shortwave trough lifting toward the Ohio Valley. Nonetheless,
sufficient low level convergence, albeit weak coupled with
surface dew points well into the 40s to near 50 degrees beneath
steepening mid level lapse rates in left exit region of upper
level jet may be sufficient for at least scattered convection
ahead of dry slot/front interface by mid Monday afternoon through
mid evening per slower ECM/GFS timing. Despite weak instability
with narrow axis of 0-6km MUCAPE up to around 250 j/kg, high shear
in veering low to mid level wind profiles with 0-1km SRH of
200-300 m2/s2 and 0-1km bulk shear of 25-30 kts near and east of
the Mississippi River offers very favorable HSLC environment that
will need to be monitored quite closely should convection occur.

Given the occluding nature of the system, the main cold front
doesn`t arrive until Tuesday afternoon. Thus, we should be able to
squeeze out one more day of above normal temperatures on Tuesday.
Have left forecast dry ahead of the front with limited low level
moisture and lack of forcing.

Wednesday through Saturday looks to be dominated by cyclonic flow
and cold advection as stacked low weakens while shifting through
the Great Lakes. This will result in prolonged period of
cloudiness, and colder temperatures with readings more typical of
late November. Forecast is dry, but continue needing to watch
the late Wednesday through Thursday timeframe for rain/snow shower
chances mainly north with remnants of devolving low translating
southeast. Lows during this period likely too cold by 2-5+
degrees if indeed skies remain cloudy, as recent cloudy stretch
yielded diurnals around 5 degrees whereas currently forecasting
around 10 degree diurnals with highs upper 30s to around 40 and
lows upper 20s to around 30.


.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
ISSUED AT 514 PM CST Sat Nov 26 2016

A clear and VFR night is expected overnight with high confidence.
Sunday morning, rain and MVFR cigs will push towards eastern Iowa,
and by early to mid afternoon, this is expected to spread over all
of the region. The rain and MVFR cigs will continue once started,
through the evening hours Sunday night. Winds will be 10 to 15 kts
through the period from the southeast after 14Z Sunday, prior to
that, south at 5 to 10 kts.




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