Area Forecast Discussion
Issued by NWS Kansas City/Pleasant Hill, MO

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938
FXUS63 KEAX 101745
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
1145 AM CST Sat Dec 10 2016

.Discussion...
Issued at 303 AM CST SAT DEC 10 2016

Fast, quasi-zonal upper-level flow will persist through much of the
forecast. Models continue to show light precipitation moving into
the area late Saturday night/early Sunday morning. Forecast
soundings show a dual layer of saturation, separated by 5000 ft or
more. This is close to the highest thickness for any seeder-feeder
mechanism so it`s likely any precipitation that does fall will be in
the form of drizzle, or freezing drizzle where temperatures are cold
enough to support freezing on contact with the ground. But given the
flirtation with the max depth of the dry layer there could be
pockets of rain and snow as well. Overall, QPF looks very low,
perhaps only a hundredth of an inch or two so any icing will be
minimal before temperatures warm enough during the day. But that
said, that light amount is enough to cause slick roads for anyone
heading out Sunday morning so people will need to be alert for that
potential.

That system will quickly move east and we will likely see close to
normal conditions for Monday. That taste of normality will be short-
lived as another surge of cold air arrives for the middle portions
of next week. By Tuesday morning, temperatures will be back into the
20s and will likely stay there through the rest of the forecast. But
for the later half of the week, there may be one or more shots for
snow. Uncertainty is fairly high, given the fast flow across the
CONUS, and models are having a difficult time resolving the quick-
moving upper troughs that would provide the needed lift to support
snow. The ECMWF moves a wave across the area Wednesday, spreading
snow across the northern half of Missouri. The GFS Moves a wave
across the area Thursday, spreading light snow across the area. The
main takeaway here is that it looks to be cold enough to support
snow but given the upper pattern, timing any wave strong enough to
spread precipitation into the area is very uncertain at this time.

Both the ECMWF and the GFS produce accumulating snow late next week.
This appears to be in an area of broad ascent, ahead of a deepening
trough over the western half of the country and in an area of
favorable lift from the strong upper jet. It`s still very early to
have much confidence in what these models are depicting but it will
need to be watched.

&&

.Aviation...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1137 AM CST SAT DEC 10 2016

Low clouds will remain in place for the majority of the day, with
perhaps brief breaks in the clouds. CIGs will eventually come down
overnight to MVFR, and ultimately IFR by the early Sunday morning
hours. Due to widespread guidance agreement with respect to IFR level
clouds, confidence is medium to high that cloud levels will drop
below 1000 feet by Sunday morning. Light drizzle will also be
possible with this activity. Surface temperatures should be at or
above freezing for KMKC/KMCI/KIXD, however wouldn`t rule out a very
brief window of an hour or two where temperatures will still be very
near or slightly below freezing before warming up to the middle 30s
and lower 40s. KSTJ has a better chance of seeing drizzle while
temperatures are still below freezing, but again should only occur
concurrently for a couple hours before warming above freezing by the
end of this forecast cycle.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&

$$

Discussion...CDB
Aviation...Leighton



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