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Area forecast discussion
National Weather Service Kansas City/Pleasant Hill MO
539 PM CST Sat Dec 14 2019

Discussion...
issued at 320 PM CST Sat Dec 14 2019

Primary forecast focus is on the Sunday-Monday winter storm.

Key messages...

1. Two rounds of winter weather are expected Sunday into Monday. The
first will develop through the morning and increase into the
afternoon, Sunday. Light snow is expected to gradually develop
through the course of the day. Around sunset, expect a lull in
activity, with instances of freezing drizzle becoming a concern for
locations across central Missouri, the Northern Ozarks and southwest
into southeast Kansas. Through the early morning, hours, snow
chances will increase across the region, through Monday morning, as
the second round commences.

2. At the moment, a wide swath of 1 to 4 inches of snow is currently
expected across eastern Kansas and across most of northern and
central Missouri. Locally higher amounts up to 5 inches are possible
with the greatest amounts, up to 6 inches in central and eastern
Missouri. Minor ice accumulations are possible into southeast Kansas
and southern Missouri, along the Ozark Plateau. A few hundredths
cannot be ruled out.

3. Confidence/concerns: subtle differences in the track of the low
pressure centers as they move across Sunday and Monday continue to
make it a significant challenge to lock down where the heaviest snow
bands will set up. Overall, it's looking like the heaviest snow will
fall somewhere from mid-Missouri to the east, but even a 20 mile
shift in the low could have significant impact.

4. Regardless of snow amounts, impacts to travel could be
significant in many areas. Remember to slow down and give yourself
plenty of time to get to your destination.

Technical discussion...

An open short wave trough crossing Bitterroot Range, currently
visible on WV, will continue to advance east and southeast overnight
into early Sunday. Ahead of this trough, an area of broad ascent
will exist on the northeastern periphery of the larger surface
trough stretched across the Southern Plains. The influence of this
short wave will result in gradually increasing snow chances
through the day, Sunday. The best chances will exist across
eastern Kansas into western Missouri through the afternoon, where
upwards of a dusting to an inch of snow is possible, with locally
higher amounts approaching two inches by sunset.

Around sunset, expect a lull in winter precipitation for a few
hours, before the southern short wave trough pivots and lifts east
and northeast approaching the region through midnight. In response,
across southeastern Kansas into southwestern Missouri, up on the
Ozark Plateau and lakes region, BUFKIT soundings continue to suggest
a marked lack of cloud ice with this initial advance of the
trough. However, fairly saturated lower to mid levels continue to
suggest a concern for off and on freezing drizzle late Sunday into
early Monday, with very light icing possible, a few hundredths of
an inch.

Cloud ice will then increase rather quickly through the morning as
the 500mb short wave finally pushes eastward into the plains. Snow
becomes the primary precipitation type across the area through
Monday. The greatest chances for snow will exist after sunrise
through midday Monday. An additional 1 to 2 inches is likely through
the day across much of the region with locations across central
Missouri getting an additional 2 to 3 inches.

Most guidance has slowed a bit, with light snow lingering through
Monday evening, through sunset across eastern Missouri. In response,
extended the Winter Storm Watch for central and eastern Missouri
through midnight, Monday. Still concerned that a swath of central or
north central and eastern Missouri could see over 6 inches of snow.

Beyond Monday, Tuesday through the end of the week, a dry and quiet
forecast is on tap, with highs in the 40s most days.

&&

Aviation...(for the 00z tafs through 00z Sunday evening)
issued at 534 PM CST Sat Dec 14 2019

A difficult forecast through this period with an approaching
winter storm moving into the area. There is still some uncertainty
on how far north the moderate snow will make it, but overall
confidence on timing is high. Light snow and some reduced
visibility is possible after 7-8z, but dry air aloft will keep
visibilities and ceilings above MVFR. As the lower part of the
atmosphere becomes more saturated snowfall rates will increase
which will reduce visibility to IFR and ceilings to low MVFR after
sunrise. The heaviest snowfall rates (0.5-1" per hour) look to be
between 15z and 18z where LIFR visibility is possible. IFR
ceilings will finally move into the region around 18z and last
through the period. The snow will start to lighten up towards the
end of the period, but a transition to a mix of freezing drizzle
and snow is possible going into Sunday evening, especially south
of the Missouri River.

&&

Eax watches/warnings/advisories...
Kansas...Winter Weather Advisory from 9 am Sunday to 6 PM CST Monday for
ksz025-057-060-102>105.

MO...Winter Storm Watch from Sunday morning through Monday evening
for moz007-008-014>017-022>025-031>033-039-040-046.

Winter Weather Advisory from 9 am Sunday to 6 PM CST Monday for
moz001>006-011>013-020-021-028>030-037-038-043>045-053-054.

&&

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