Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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404
FXUS63 KDVN 182319
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
519 PM CST Sat Nov 18 2017

...AVIATION UPDATE...

.SYNOPSIS...
Issued at 321 PM CST Sat Nov 18 2017

The main cold front and associated precip has surged east through
the region, leaving the area open to brisk cold air advection in
incoming ridge`s tight pressure gradient. Aloft, sharply digging
upper trof axis was also sliding to the east of the MS RVR Valley
and toward the OH RVR Valley, driving long linear convective event
down acrs those areas. after this trof pushes to the east, the
upcoming week to be characterized by mainly dry weather with up and
down temp trends.

&&

.SHORT TERM...(This Evening through Sunday)
ISSUED AT 321 PM CST Sat Nov 18 2017

Tonight...Northern plains ridge axis on track to slide southeastward
acrs the area through Sunday morning. General clearing trends to
continue, but secondary wing of stratocu acrs southeastern MN into
central IA to propagate in northwesterly steering flow down acrs the
local area by this evening. RH progs of several HiRes near term
models vary on handling this deck, from eroding it leaving mainly
clear skies tonight, to expanding it into mostly cloudy skies acrs
much of the area until it clears again from NW-to-SE toward sunrise
Sunday morning. With extent of incoming drying and subsidence, will
be less pessimistic with the cloud cover. Brisk northwest winds of 15
to 25 MPH and gusts over 30 MPH this evening to diminish to 10-15
MPH overnight into early Sunday morning. Cold air advection pattern
out of eastern Dakotas/western MN source region should translate
into lows well down in the 20s. If it were not for the mixing winds,
there would be lows in the teens in some spots. If the sfc winds
maintain in the 10-15 MPH range overnight, they will generate wind
chills in the upper single digits to low teens north of I80 by
Sunday morning, with low to mid teen values to the south.

Sunday...Upstream ridge axis will slide east-southeastward through
the area, but take most of the day to do so. Thus southerly return
flow not a factor until Sunday night. So despite some insolation,
cold start to the day and west-northwest sfc winds to make for a
chilly day in the 30s to low 40s...with the 40s occurring in the
southwestern half of the fcst area.   ..12..

.LONG TERM...(Sunday Night through next Saturday)
ISSUED AT 321 PM CST Sat Nov 18 2017

...Dry weather with up and down temperatures this week...

Sunday Night and Monday...A nearly zonal flow aloft and southwest
surface winds will produce mainly clear skies Sunday night and sunny
skies on Monday. Low temperatures will be in the mid 30s Sunday
night with highs in the mid 50s on Monday.

Tuesday...a large longwave ridge will build over the intermountain
west with a deep trough developing over the eastern half of the
country. This pattern change will produce an northwest flow aloft
over the midwest. A strong cold front is progged to move through the
forecast area around midday. Cold air advection will begin in
earnest after the frontal passage producing gusty northwest winds.
Tuesday`s high temperatures will be in the upper 30s to mid 40s, but
will fall as the cold air builds in. It will be cold overnight with
low temperatures in the teens to near 20.

Wednesday...This will be the coldest day of the week. Skies will
remain mainly sunny as surface high pressure settles over Oklahoma
and Missouri. High temperatures will only be in the low to mid 30s.
with overnight lows in the 20s.

Thanksgiving Day and Friday...Skies will remain dry as surface winds
shift to the southwest producing solid warm air advection over the
region. High temperatures on Thanksgiving will be in the mid 40s.
Highs on Friday are expected to be around 50 north of Interstate 80
with temperatures in the mid, to possilby upper 50s, across the
south. Low temperatures will be in the 30s.

Saturday...A shortwave trough will push through the northwest flow
aloft bringing the next chance of precipitation. Temperatures will
be in the 40s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
ISSUED AT 516 PM CST Sat Nov 18 2017

Cold high pressure will sweep into the region overnight, wiht
northwest winds between 15 and 28 kts overnight, decreasing to
around 10 to 15 kts toward midnight and early morning. A narrow
band of MVFR stratocumulus is found from near Waterloo to
southwest Wisconsin. Models expand this and keep the entire area
cloudy through about 8Z tonight. However, the current trend of the
small cloud area is dissipating, and I will only offer a tempo of
MVFR clouds at DBQ and scattered elsewhere. This cloud ceiling
will be the only impact potential during the next 24 hours of VFR
weather.

&&

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

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...Kuhl
AVIATION...Ervin



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