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

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FXUS63 KEAX 132322
AFDEAX

AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
522 PM CST Sat Jan 13 2018

.Discussion...
Issued at 258 PM CST SAT JAN 13 2018

Surface ridge in place over the forecast area keeping things
chilly this Saturday afternoon. This ridge will shift east with
time, which will get some southerly winds moving into the area
through the overnight period. This warm air advection should start
a moistening process that will get the atmosphere primed for some
light snow to form once a shortwave trough moves into the area
from the northern High Plains. In the mid levels northwest flow
continues to dominate the area, as it has most of this winter.
Radar echoes and IR imagery indicates an area of light snow over
western South Dakota and NW Nebraska. The mid level ascent
associated with this area of light snow will make its way into
northeast Kansas and west Central Missouri later tonight. Timing
of this wave is a bit in question still, with the NAM/GFS
indicating snow starting in the area after midnight, lasting
through mid morning Sunday. The HRRR has been fairly consistent
with bringing the wave and precipitation into the area a couple
hours earlier than the NAM. Will need to watch this carefully, but
the early indication of the HRRR might have some difficulties
considering the dry low levels that any snow will have to compete
with before saturation. Moisture will be limited and the duration
of lift will be rather short, relegated to around 3-5 hours,
therefore QPF for this Sunday morning system will be very light,
on the order of around .05" across the advisory area. Snow ratios
around 15 to 20:1 will yield amounts around an inch, with some
areas perhaps seeing 1-2 inches before the quick hitting system
moves out of the area by Sunday afternoon.

A second round of snow will move into the area Monday night into
Sunday morning. While this system isn`t expected to bring much in
the way of new snow, it may be a bit more widespread with
accumulations. In the mid levels another weak shortwave trough
will glide through the area from the north/northwest. A surface
and low level ridge will plow through the area, bringing stiff
northerly winds. Mid level frontogenesis will bring a second quick
hitting period of snow Sunday night into Monday morning. Once
again, considering the moisture limitations and short duration of
snow, only expecting around an inch to 2 inches with this round of
Monday morning snow. All told with these two systems we can expect
roughly 1 to 3 inches of snow across most of the area, with the
western half of the CWA seeing slightly more snow than the eastern
half. Winds remaining in the 10 to 20 mph range with very cold air
moving in behind the low level cold front will bring wind chills
down to around 15 to 25 below across far northern Missouri and
down to around 15 below along the I-70/MO River corridor Monday
night into Tuesday morning.

The middle part of next week looks to be dry as high pressure
settles into the low levels. This ridge will keep temperatures
cool for Tuesday and Wednesday. By Thursday mid level ridging
moves into the area, with some western low level troughing, which
will bring a warm up into the Thursday/Friday time period. Expect
Thursday to finally reach above freezing, with Friday being
perhaps 5 to 10 degrees above normal. A closed low in the mid
levels should veer south of the forecast area on Friday, but there
is a potential for some clouds and maybe a low chance for some
light rain across the far southern CWA as this system passes to
the south. A more significant system is possible toward next
weekend, as models continue to show a trough coming on shore and
eventually ejecting into the plains. Timing/location/intensity of
this trough is very much in the air, so will forego details this
far out, but it`s a system that bears some watching as we go
through next week.

&&

.Aviation...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 513 PM CST SAT JAN 13 2018

The main impact through the forecast period will be in the form of
light snow during the overnight hours through early Sunday
morning. Initial overhead precip prior to 06Z should evaporate
given existing dry lower levels. This will eventually be overcome
with precip making its way to the surface shortly after 06Z,
while increasing in coverage near 09Z - 10Z. Ceiling heights will
degrade to MVFR during this time, with IFR visibilities also
possible Sunday morning. Conditions will gradually improve by the
late morning. A secondary round of snowfall is then possible
Sunday night.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
KS...Winter Weather Advisory from midnight tonight to noon CST Sunday
     for KSZ025-057-060-103>105.

MO...Winter Weather Advisory from midnight tonight to noon CST Sunday
     for MOZ028-029-037-043-053.

&&

$$

Discussion...Leighton
Aviation...Welsh



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