Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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335
FXUS63 KDVN 050950 AAA
AFDDVN

Area Forecast Discussion...UPDATED
National Weather Service Quad Cities IA IL
350 AM CST Mon Dec 5 2016

.UPDATE...
Issued at 349 AM CST Mon Dec 5 2016

Have gone with a dense fog advisory due to expanding fog across
the area. At this time will keep it close to the boundary with the
snowpack and stratus clouds. The stratus clouds could continue
this morning and that would inhibit expansion east of the dense
fog. However, not completely sold on that idea, as such will
expand the advisory east if it becomes more clear that it needs to
be.

&&

.SYNOPSIS...
Issued at 255 AM CST Mon Dec 5 2016

Cloud cover over a fresh fallen snow has lead to temperatures
staying near or just above freezing tonight across the area. This
has lead to the development of dense fog across the western CWA.
High pressure across the area will drive todays weather.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 255 AM CST Mon Dec 5 2016

Surface high pressure and a snowpack are the main drivers during
the day today, before another weak boundary moves into the area
overnight. As previous shifts mentioned, the snowpack has
definitely thrown the blended and cons guidance into too warm
temps. The GFS, HRRR and NAM have a good handle on snowpack.
Started with the superblend then tweaked highs to just above
freezing over the snowpack. This likely will lead to fog most of
the day today over that snowpack. This could one of these days
where we see dense fog develop this morning and last all day. I`m
not confident enough to go there yet, however it isn`t out of the
realm.

Later tonight, a boundary sweeps through northern zones. Have gone
with schc pops across the area. The forcing for this appears weak
so schc pops are warranted. Hires guidance also has a broken band
of precip across this area. The thermal boundary suggests mixed
precip, with a rain/fzra/ changing to all snow.

.LONG TERM...(Tuesday through Sunday)
ISSUED AT 255 AM CST Mon Dec 5 2016

Dry to generally dry with below normal temperatures.

Long Term Forecast Confidence Assessment...good or above average
with risk of some flurries or light snow Wednesday/Thursday and then
better chances for snow this weekend.  Forecast highs and lows
should tend to be mostly within 3 degrees of forecast.

Tuesday...Minor changes mostly for sky conditions.  Partly Cloudy
and colder with northwest winds of 10 to 15+ MPH.  Highs lower 30s
northwest to upper 30s far southeast. Tuesday night...clearing and
cold with northwest winds of 10 to 20 MPH. Lows upper teens
northwest to the middle 20s southeast remain reasonable.

Wednesday and Thursday...Little changes made with risk of some
passing flurries or light snow south with little or no accumulations
from passing disturbance with a brisk northwest wind.  Trimmed
temperatures a few degrees. Highs mostly in the lower to middle 20s.
Mins in the upper single digits to middle teens remain on track.
Northwest wind of 15 to 25 MPH with cold wind chills Thursday &
Friday AM still likely to fall to near zero or below zero for
several hours.

Friday...Fair and remaining quite cold with light westerly winds as
high pressure moves in.  Highs still in the 20s with mins mostly
still in the teens.

Saturday and Sunday...minor changes made.  Unsettled with a chance
or likelihood of snow as passing disturbance moves through with poor
confidence due to track and strength of disturbance from the west.
This uncertainty will likely take another couple of days to clarify.
Trends and jet axis do suggest some light to potentially moderate
snow totals may occur near to over the area. Highs mostly in the 25
to 35 degree range.  Area lows generally in the lower 20s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
ISSUED AT 1139 PM CST Sun Dec 4 2016

Confidence in the potential for dense fog tonight is lower than
in the previous forecast cycle which is reflected in less
pessimistic conditions in the latest forecasts. Widespread IFR
conditions, primarily due to low ceilings, are likely to remain in
place overnight through at least the morning hours Monday. A
general trend of visibilities lowering through MVFR range, then dipping
into IFR for several hours due to fog remains in place, but there
is not enough confidence to mention VLIFR conditions. South winds
developing on Monday should lead to VFR conditions by afternoon,
but lingering stratus and MVFR conditions cannot be ruled out.


&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Dense Fog Advisory until noon CST today for Benton-Buchanan-
     Delaware-Des Moines-Henry IA-Iowa-Jefferson-Johnson-Keokuk-
     Lee-Linn-Louisa-Van Buren-Washington.

IL...Dense Fog Advisory until noon CST today for Hancock-Henderson-
     McDonough.

MO...Dense Fog Advisory until noon CST today for Clark-Scotland.

&&

$$

UPDATE...Gibbs
SYNOPSIS...Gibbs
SHORT TERM...Gibbs
LONG TERM...Nichols
AVIATION...Sheets



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