Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 071202
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
602 AM CST Thu Dec 7 2017

...AVIATION UPDATE...

.SYNOPSIS...
Issued at 255 AM CST Thu Dec 7 2017

Weak upper level disturbance rotating southeast across the cwa has
produced flurries and pockets of very light snow early this
morning. Otherwise, stratus was covering the cwa and temperatures
were cold, in the teens to lower 20s at most locations.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 255 AM CST Thu Dec 7 2017

Forecast focus on quiet but cold weather in the short term.

Today: High pressure centered in the central Plains will shift
into the southern Plains, with weak ridging into the dvn cwa.
Subsidence in the wake of the disturbance currently moving through
will allow for skies to become sunny across all of the cwa as the
morning progresses. Despite the sunshine for much of the day,
this will be a cold day with afternoon max temperatures only in
the 20s. Northwest winds of 10 to 20 mph will keep wind chills in
the single digits and teens.

Tonight: Weak ridge will push southeast of the area overnight.
Skies should be clear most of the night, but then warm air
advection clouds will increase towards morning in our nw cwa. This
will be ahead of another upper level disturbance dropping southeast
in the flow. Minimum temperatures will bottom out in the teens,
with wind chills in the single digits.

HAASE

.LONG TERM...(Friday through Wednesday)
ISSUED AT 255 AM CST Thu Dec 7 2017

A strong upper short wave trof will pass near to just northeast of
the area Friday and Friday night, and with that we will be close to
a rather intense, but short lived forcing event. For us, the most
likely scenario remains a quick shot of snow in the far northeast
tip of the CWA followed by strong winds and cold advection. I feel
confident that will be the case, as the low is unlikely to travel
farther southwest of the upper wave. Nearly all clipper event snows
occur along and to the "left" of the surface low track, which in
this case is from eastern MN to southeast WI. So, our entire area
will see strong warm advection Friday afternoon and evening, but
probably will have trouble saturating for snow. The far
northeastern and eastern counties should saturate for at least a 3
hour period, resulting in up to an inch of snow there. Farther
west, the saturation should be much more fleeting, and for now
will continue with a POP gradient to slight chance, but in the
end, we may need to just buffer the accumulating area with
flurries. Quickly on the heels of the snow threat, the cold
advection will slam the area once again with winds of 20 to 30
mph, possibly higher. This will drive temperatures back to the
upper teens to lower 20s by morning and continue through Saturday,
resulting in highs only in the mid 20s north to lower 30s south.
Wind chills Saturday should remain in the lower teens most of the
day.

A fast transition in northwest flow to a warm up is forecat for
Sunday and Monday, where highs climb back to the mid 30s to mid 40s.
The next cool down is for Monday afternoon and night, with another
clipper passing near the north.  Lower pops for rain and snow in the
aftenroon will give way to dry cold advection overnight. Another
clipper is forecast for Tuesday night and Wednesday, which could
bring snow to the area. The pattern does not show any significant
snow accumulation threat, but is now focusing on the periods where
it`s probably more than the passing flurries of late.

ERVIN

&&

.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
ISSUED AT 600 AM CST Thu Dec 7 2017

VFR conds through this taf cycle with weak high pressure ridge
over the area. Northwest winds 10 to 20 knots today then becoming
southwest tonight at less than 10 knots.

&&

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

$$

SYNOPSIS...Haase
SHORT TERM...Haase
LONG TERM...Ervin
AVIATION...Haase



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