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Area forecast discussion 
National Weather Service Kansas City/Pleasant Hill MO
538 PM CST Sat Dec 3 2016

Discussion...
issued at 330 PM CST Sat Dec 3 2016

Only minor changes to the package as forecast remains on track and
model consistency through the mid-range has improved.

As expected, a cut-off low has evolved over northern Mexico, with an
expansive area of warm air advection and ascent spreading through
the southern and Central Plains. Surface temperatures have warmed
into the middle 40s to lower 50s across much of the cwa, with the
exception of far northwest Missouri where northeasterly winds have allowed
cooler temperatures to reside. A secondary shortwave trough over the
Central Plains will approach the area tonight, with deep ascent and
saturation through the column. Precipitation is expected to
overspread the County Warning Area during the evening. Based on forecast soundings
across eastern Kansas into Missouri, the thermal profile supports
the large majority of this precipitation will be in the form of
rain, with a warm layer in the lowest 2kft, and wet-bulb
temperatures in the mid-30s. The lone exception may be an occasional
period of rain mixing or briefly changing to snow in locations
closest to the Iowa border with higher rates of precipitation. Any
snow that does occur is not expected to cause any impacts, especially
with relatively warm ground temperatures and temperatures in the
middle 30s.

Precipitation will quickly exit the area by late morning Sunday,
with clouds clearing from west to east during the afternoon hours.
With little cold air associated with this system and some sunshine
during the afternoon, temperatures will remain rather mild behind
the departing system, with highs on Sunday in the middle 40s to near
50. The area will find itself under a weak ridge in advance of the
next large western trough on Monday, with dry conditions and high
temperatures a couple degrees warmer. The cutoff low over northern
Mexico opens and ejects into the lower Mississippi Valley Monday
night. Central Missouri may see a slight chance for showers Monday
night as the outskirts of the upper waves influence and a surface
cold front move through the area. Behind the front, much cooler and
dry conditions will prevail on Tuesday - beginning a period of
colder weather for the region.

Focus shifts to the next weather system Wednesday into Wednesday
night. Operational models have come into better agreement with the
timing and evolution of the next large upper trough. Both the GFS
and Euro now show a well-defined vort Max located across eastern
Kansas at 18z Wed, with roughly west-east 850 mb frontogenesis laid across
the area. These features likewise produce a swath of precipitation
across an already cold airmass with a thermal profile supportive of
snow. Confidence is increasing for some accumulating snowfall Wed
into Wed night across the forecast area. Early indications suggest
the highest snowfall totals located across ec Kansas into wc MO, where 1
to 2 inches of snow may occur, with lighter amounts points north.
These preliminary totals and locations are more likely to change
with time as the system evolves and becomes better sampled.
Confidence is high that a much colder airmass will settle into the
County Warning Area by mid/late week. Highs in the 20s and lows in the teens seem
reasonable, esp with 850 mb temps on the order of -12 to -16c.

&&

Aviation...(for the 00z tafs through 00z Sunday evening)
issued at 535 PM CST Sat Dec 3 2016

The forecast period will start out as VFR but it won't take long for
conditions to deteriorate as light rain showers and low ceilings
move into the area tonight around 04z. MVFR conditions are
anticipated first for a few hours later tonight then ceilings will
drop to LIFR. The LIFR ceilings will move from the northwest to
southeast not long after midnight and stick around through mid-
morning. Visibilities will be around 3sm during this time period. The
rain should move out between 14z-15z and ceilings will begin to
lift. By noon tomorrow we should be back in VFR conditions. Fairly
light winds will gradually shift throughout the period from easterly
to westerly as a weak boundary moves through the forecast area.

&&

Eax watches/warnings/advisories...
Kansas...none.
MO...none.
&&

$$

Discussion...Blair
aviation...cdb/grana

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