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

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FXUS63 KEAX 210357
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
957 PM CST Sat Dec 20 2014

.SHORT TERM...(This Evening through Tuesday)
Issued at 338 PM CST SAT DEC 20 2014

Tonight/Sunday: Low stratus has remained firmly in place for most of
the area today, with the exception of periodic sunshine over far
eastern Kansas and portions of the KC Metro. The back edge of the
stratus has teased the western forecast area for much of the day,
but eastern progress of the clearing has slowed and probabilities
are increasing that low clouds will hold for the remainder of the
daylight hours and eventually expand in coverage tonight. Warm
air/moisture advection will allow for patchy fog to develop
overnight. With dewpoints currently in the middle 30s, minimum
temperatures tonight will only fall into middle 30s. On Sunday, the
near-saturated surface layer will deepen upon continued moisture
advection. The first in a series of shortwave troughs will approach
the CWA during the day, with weak ascent overspreading the area.
While this lift doesn`t appear to be impressive, it may be
sufficient to occasionally produce patchy drizzle during the day.
Very light model QPF values hint at the potential for such a
scenario. Have continued mention of patchy drizzle on Sunday with
cloudy skies. Afternoon temperatures will be warmer than today, with
highs reaching the middle 40s in many areas.

Sunday Night through Tuesday: A much stronger upper disturbance will
drop southeast into the Central Plains Sunday night into Monday upon
the nose of a 140+kt upper jet. Strong mid-level ascent will
overspread the CWA on Monday, with a surface cold front projected to
move through late in the day. Along and ahead of the front,
scattered to widespread precipitation will develop on Monday.
Precipitation will be in the form of rain as a deep warm sector
(>0C) will be in place ahead of the front. The highest probabilities
will be north of Interstate 70, where up to one-quarter of an inch
of rain will be possible. Model consensus shows cooler and drier air
to move in behind the front Monday evening, bringing an end to the
precipitation from west to east. Much of the area should remain dry
on Tuesday with the exception of the southeastern quarter of the
CWA, where some models suggest banded precipitation to form on the
backside of a surface low projected to move across southeast
Missouri during the day. It is worth noting there is quite a spread
in model solutions with regards to the position of the surface low
track. As for temperatures on Tuesday, cooler air will keep readings
near seasonal levels for this time of year, with highs ranging from
the middle 30s to the lower 40s.

.LONG TERM...(Sunday Night through Tuesday Night)
Issued at 338 PM CST SAT DEC 20 2014

For the later half of the forecast, starting Wednesday and going
through Christmas and the days following, conditions will be on a bit
of a roller coaster with an eye towards precipitation.

Wednesday a shortwave trough will be deepening on its way into the
Great Basin to our west while a deep central CONUS trough exits the
Plains States to our east. Forecast focus is on the shortwave
heading into the Great Basin as previous models runs have advertised
this trough deepening as it moved into the Plains, with the
potential for some precipitation in our area for Christmas and
Friday. Latest runs of both the GFS and ECMWF have backed off this
wet solution for our particular area as the models are now resolving
that the trough wont dig as far south; with the main body of the
trough moving east through the Northern Plains Thursday night,
dragging a large shear axis behind it through the rest of the
Central and Southern Plains Friday through Saturday. This does not
bode well for a locally White Christmas as temperatures ahead of the
trough, through the daylight hours of Christmas, will warm above
normal thanks to a southerly wind that day --normal ranges in the
upper 30s for this time of year--. Christmas also might be the one
day where the clouds clear out for the day. More notably though, the
latest solutions paint a dry picture for Thursday night through
Friday as the main body of the trough generates some snow to our
north --Iowa and Minnesota-- Christmas Night into Friday, and the
shear axis brings some rain/thunderstorms to our south and east by
Friday afternoon and night as it begins to intercept the Gulf
moisture return. As a result have pulled back the Chance POPs that
model guidance provided today, trimming them to Slight Chance for
Thursday Night and Friday given the current 12Z model runs. However,
the solution for our weather Christmas day and Boxing day could
change a lot between now and then, so confidence is a bit marginal
at this time.

Otherwise, as the shear axis for the main trough moves through it
will bring a cold front sweeping back into the region, with the
potential for a morning high temperature Friday and falling
temperatures during the afternoon hours. This will keep the weekend
after Christmas a cold one --highs in the 30s--.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
Issued at 957 PM CST SAT DEC 20 2014

VFR to high-end MVFR ceilings are expected at all TAF sites through
the next few hours, then moisture surging up from the southwest will
bring a stratus deck based around or slightly above 1 kft into the
region between 10z-14z. Ceilings should remain between 1-2 kft
through the rest of Saturday, and some patchy light drizzle is
possible during the afternoon and evening hours.

&&

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

$$

SHORT TERM...Blair
LONG TERM...Cutter
AVIATION...Laflin






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