Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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778
FXUS63 KDVN 210519
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1119 PM CST Mon Nov 20 2017

...AVIATION UPDATE...

.SYNOPSIS...
Issued at 305 PM CST Mon Nov 20 2017

Strong WAA in advance of a cold front over the Northern and Central
Plains, combined with deep mixing aided by abundant sunshine and
gusty SW winds has pushed temps well above normal today and in the
mid 50s to lower 60s. These warmer temps and gusty winds combined
with lowering RH and dry surface fuels also leading to a very high
fire danger this afternoon. The aforementioned cold front will
sweep across the area late tonight through early Tuesday morning,
and will bring a marked change to colder conditions on brisk NW winds
Tuesday.

&&

.SHORT TERM...(This Evening through Tuesday)
ISSUED AT 305 PM CST Mon Nov 20 2017

Cold front will sweep across the area in the pre-dawn to mid morning
hours on Tuesday. Much of tonight will be spent in the pre-frontal
warm sector characterized by continued gusty SSW winds, which along
with increasing high clouds will aid in more of a gradual descent on
temps tonight, until late NW CWA when cold front begins to make
inroads. As a result, lows will vary from coldest NW (lower 30s) to
warmest SE (around 40/lower 40s). On Tuesday, temps only expected to
rebound a few degrees from AM lows before strengthening CAA on brisk NW
winds likely results in falling temps through the 30s. Forecast
soundings supportive of gusts around 30 mph, but added momentum transfer
due to strong CAA could aid in some areas being not far off from
wind advisory criteria (sustained 30 mph and/or gusts to 45 mph) per
Tropopause pressure (down to 500-600 mb per NAM) and Potential Vorticity.
Also, potential for some light precip streaking toward CWA on Tue
from the Plains attendant to band of mid level frontogenetical forcing.
This forcing is shown to weaken considerably while approaching. In
addition, soundings show top down saturation to around 7-9kft agl with
a large dry wedge beneath. Therefore, have left out any mention as
thinking mainly virga although can`t rule out some sprinkles or maybe even
a flurry in some areas by mid morning exiting midday south/east of the
Quad Cities.

.LONG TERM...(Tuesday Night through Monday)
ISSUED AT 305 PM CST Mon Nov 20 2017

Mainly dry weather, and variable temperature fluctuations still on
track through the long term. Travel conditions for Thanksgiving
still look good for a large part of the CONUS, with any potential
travel spots being in the Pacific NW and portions of the far SE.

After a cold midweek, it still looks like a decent albeit short term
warm-up is in store late week peaking on Friday. Nudged highs on Friday
up above blended guidance and more in range from mid 50s to lower 60s.
However, 925 mb temps on GFS and ECMWF are shown to be several degs
warmer (10-14C) than those of today (9C) with gusty SW winds, thus
potential to be much warmer than going forecast with more widespread
lower to middle 60s and possibly a few upper 60s. These temps would be
very close to record highs. Temps then look to return near to below
normal next weekend with the passage of another cold front, leading to
highs in the 30s to lower 40s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday Night)
ISSUED AT 1118 PM CST Mon Nov 20 2017

Southwest winds around 10 to 12 kts will continue overnight, as
an approaching cold front brings high clouds to the region. The
cold front will arrive in the mid morning hours Tuesday, as winds
switch to northwest and increase to 15 to 25 kts...with northeast
Iowa seeing winds up to 30 kts. At this time, low clouds are not
expected to form near or behind the front. After sunset Tuesday
evening, winds will decrease to around 10 kts.

&&

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

$$

SYNOPSIS...McClure
SHORT TERM...McClure
LONG TERM...McClure
AVIATION...Ervin



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