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000
FXUS63 KEAX 071808
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
ISSUED BY NATIONAL WEATHER SERVICE TOPEKA KS
1201 PM CST FRI MAR 7 2014

...Update to Aviation Forecast Discussion...

.DISCUSSION...(Today and Tonight)
Issued at 408 AM CST FRI MAR 7 2014

Water vapor imagery early this morning shows a lee-side trough
developing across the front range of the Rocky Mountains in response
to a shortwave currently amplifying as it moves across the Great
Basin. Models continue to advertise a bit of energy emanating east
across the Central Plains today while the bulk of the trough settles
south into the Four Corners region. The bit of energy expelled to the
east will likely interact with the leading edge of the surface high
oozing south through the northern Plains today. While there is some
moisture and lift to be had along the leading edge of the surface
high, much of said moisture and lift will be rather shallow to begin
with which will likely lead to precipitation type issues with the
forecast. Model soundings indicate that as precipitation begins later
tonight across northern Missouri the thermal profile will be a bit
warm aloft, then as the sounding cools finding ice nuclei could be an
issue as it takes till nearly sunrise Saturday for the dendritic
growth zone to fully saturate. Have opted for a wintry mix of weather
types for late tonight through Saturday morning as a result. This
includes starting the precipitation type as a combination of rain and
drizzle, then converting the type from north to south to a mix of
freezing drizzle/sleet/snow as cold air advection continues through
the night. Precipitation totals do not look to be very high, with a
glaze of ice possible with less than a half inch of sleet/snow
accumulation. Current accumulations do not look sufficient to warrant
an advisory, but the combination of freezing drizzle/sleet/snow will
need careful attention.

By Saturday morning the emanating shortwave will have moved well to
our east with a cool surface high continuing to press south across
Kansas and Missouri. However, as the main bulk of the Great Basin
trough sinks into the Four Corners region --on its way to becoming a
compact low across Mexico-- the resulting energy left in the northern
stream will move across Missouri, likely interacting with the
elevated frontal boundary that the cool surface high pushed into
southern Missouri. Latest model cross sections from both the NAM and
GFS highlight strong mid-level lift through the late morning to
afternoon hours across southern Missouri as the baroclinic zone and
shortwave energy interact. However, thermal profiles continue to play
havoc with precipitation type forecasting as surface temperatures
across eastern Kansas and Missouri are still expected to warm
slightly as the surface high --bringing the cold air-- is just not
that cold. However, did up the potential for accumulating snow across
east central Kansas and west central Missouri where lift seems
strongest and a snowfall rate might be able to overcome any melting
layer. Limited residence time of the Saturday event should limit
accumulations, but strong lift looks to warrant around an inch of
snow accumulation in areas along and south of Highway 50.

Otherwise...temperatures will be cool Saturday thanks to the modest
cool surface high that will settle through late tonight, but in
general the northern stream jet will remain to our north thus
letting more seasonal temperatures prevail. Looking at a little
above normal for Sunday --50s--, with much above normal by Monday
--60s--. However, warmer temperatures will not be a permanent fixture
just yet as another cold front looks to sweep through Tuesday,
possibly bringing some precipitation chances with it.


&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1203 PM CST FRI MAR 7 2014

Only made minor adjustments to previous forecast. Switched winds to
the north in the 21/00Z timeframe. 1500/1200ft cigs move into sites
a few hours later with freezing precipitation starting in the 06/07z
window.  Should be a period of freezing drizzle mixed with sleet at
MCI/MKC until warm nose cools enough to be all freezing drizzle by
12z. Expect drizzle will slowly end in the 15-18z window but will
leave to next forecaster to add an ending time as is so late in the
forecast period.


&&

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

$$

DISCUSSION...Cutter
AVIATION...KC at TOP