Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 031206 AAA
AFDDVN

Area Forecast Discussion...UPDATED
National Weather Service Quad Cities IA IL
606 AM CST Sat Dec 3 2016

...AVIATION UPDATE...

.SYNOPSIS...
Issued at 308 AM CST Sat Dec 3 2016

Early this morning water vapor depicted a shortwave trof located
over eastern WY and western SD. At the surface, high pressure
remained across the area. Low level clouds remained across the
area as high level clouds associated with a 110 to 120 kt H3 jet
rushed into the area. Radar returns across KS suggested that rain
and snow were falling across this area. This shortwave trof and
the precipitation occurring across the Great Plains will track
towards the area today and tonight and provide our first real shot
of accumulating snow CWA wide.

&&

.SHORT TERM...(Today and Tonight)
ISSUED AT 308 AM CST Sat Dec 3 2016

Low level stratus looks to be eroding from the SW early this
morning, only to be filled in with high level clouds before the
wave approaches the area. Some areas of filtered sun could be
possible early, before the moisture overtakes the area. Models
are in good agreement with the overall track for precip later
tonight across the CWA, in which the bulk of the precip will track
across the CWA. Onset of precip will favor snow, with the
exception of mixed with rain along and south of Hwy 34. Highs
today will be above freezing across the CWA. These temps and the
ground temps will likely lead to high uncertainty as to how much
snow will fall across the area.

The warm ground and surface temps barely making it freezing
tonight, will likely cause a large amount of snow to melt on
contact. Guidance also suggests that the overall forcing for
precip will be weak until close to 12z Sunday. This coupled with
the temperatures means the best chance for accumulating snow will
be on grassy and elevated surfaces where cooling can occur faster.
Current snowfall amounts through 12z will likely be on grassy and
raised surfaces, as the better snowfall rate doesn`t occur until
after 12z Sunday.

.LONG TERM...(Sunday through Friday)
ISSUED AT 308 AM CST Sat Dec 3 2016

Wet snow and rain event Sunday main forecast issue with an unsettled
pattern mid/late late next week with increasing chances of snow,
then turning sharply colder by Friday.

Long Term Forecast Confidence Assessment...still poor or below
average with amounts of snow or rain/snow due to relatively warm
ground. Ground temperatures should be mostly in the 33 to 35
degree range with surface temperatures above freezing.  Thus, most
roads should remain wet, especially south of I-80 with mostly slush
north.  The snow on grassy surfaces is likely to melt with time
and be much less by late PM Sunday.  Next, dynamic regime flow
supporting chance of snow and colder with heaviest snow suggested to
be to our south and east.

Sunday...Local tools continue to suggest areas of a wet snow in the
morning with a rain/snow mix mostly southwest sections before ending
by mid to late day.   Local forcing and thermal tools support much
of the snow may melt and suggests half inch far south to locally 2+
inches of wet snow to briefly accumulate on mostly grassy and
elevated surfaces. Slushy roads may be possible north 1/2 or so
of the area in the early to mid morning hours. Highs should be 35 to
40+ degrees NE to SW with most and possibly all the snow to melt
south of highway 34 by late PM. Even in the north it is likely the
wet snow will melt or compact from 2+ inches to possibly 1 inch or
less by late PM. Sunday night... at least partial clearing with lows
upper 20s to around 30 degrees south which is correctly trending
colder from last night.  In areas that still have snow some mid 20
degrees lows are possible. Since most or all the wet snow should
melt on area roadways, a snow advisory is unlikely at this time.

Monday...have removed POPS with increasing clouds late into the night
ahead of next disturbance from the south.  Highs mostly in the lower
40s allowing for the last of any snow on Sunday to melt. Monday
night clouds to arrive with chance of light rain or light rain and
snow mix by morning over mostly south sections. With most clouds and
any light precipitation the forecast mins of around 30 degrees are
possibly at least 2 to 3 degrees too cold with mins at or just above
freezing very possible for later shifts to consider.

Tuesday...Colder air on northwest winds of 10 to 15+ MPH will keep
highs 35 to around 40 degrees suggested with a chance of light snow
and flurries suggested.  Tuesday night...as colder air continue to
filter in and is stronger than earlier supported have trimmed lows
into the upper teens NW to lower 20s SW winds increase to 10 to 20+
MPH.

Wednesday and Thursday...colder air is deeper and supporting most of
the energy in the southwest US to stay to our south and east. Still
enough energy to support chance POPS and light snow is still very
possible over much of the region.  Have lowered temperatures by up
to 5 degrees with highs mostly in the 20s and mins in the teens.
Wind chill values by Thursday & Friday AM may fall to below zero.

Friday...at least mostly fair and still quite cold and diminishing
winds as high pressure moves nearby.  Highs still in the 20s
with mins  mostly still  in the teens Friday night.

Saturday...passing disturbance to the north may spawn some light
snow with south winds allowing for temperatures milder with highs
upper 20s to lower 30s and lows in the 20s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
ISSUED AT 555 AM CST Sat Dec 3 2016

MVFR cigs will be the main weather concern in the TAF period.
Southern and central TAF sites may see VFR later this am and into
the afternoon before low level moisture makes its way into the
area. Snow and RASN will be possible across the area after 06z.

&&

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

$$

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


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