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

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FXUS63 KEAX 152133

333 PM CST Mon Dec 15 2014

Issued at 332 PM CST MON DEC 15 2014

Short Term (Tonight through Wednesday):

The nearly stacked low, which has brought rain to the area last
night through this afternoon, has moved into northwestern Missouri.
This low will continue to track enewd across northern Missouri this
evening and into southeastern Iowa tonight. Expect mainly just light
and drizzle the rest of this evening into the overnight hours before
the system pulls it the southern Great Lakes by early tomorrow
morning. Temperatures are quickly falling on the backside of the
system as strong CAA is ongoing with strong and gusty northwest
winds. There is a very small chance that temperatures may drop below
freezing across extreme northwest Missouri before moisture pushes
east an there could be a brief period of freezing drizzle.
Otherwise, the remainder of the short term looks cold and dry.
Strong cold air advection will continue through most of the day on
Tuesday keeping highs in the 30s across the forecast area. Surface
high pressure will then build into the area tomorrow evening and
remain over the area through the day on Wednesday. This will
continue the chilly conditions with lows dropping into the upper
teens to mid 20s Tuesday night and highs again only in the 30s

Extended Forecast (Wednesday night through Monday):

The extended period becomes a little more interesting in regards to
the potential for winter weather with two systems of interest. The
first system will look to affect the area Wednesday night into
Thursday. A upper level trough will push on shore along the Pacific
Coast on Tuesday night and will move into the Four Corners region by
Wednesday night. A lead shortwave ejecting out from this trough will
move into the central and southern Plains by Wednesday night. Models
try to develop light precipitation across the Plains however as it
pushes eastward into the local area dry air is in place. NAM models
soundings suggest the the lowest 4-5kft of the profile remain dry
and never saturate leading to a dry forecast. The GFS and to a
lesser extent the EC do show top down saturation however the EC
shows no moisture in the snow growth zone by the time the lower
levels saturate leading to freezing drizzle. The GFS still does have
moisture in the snow growth zone by the time the column saturates as
well as an area of enhanced elevated frontogenesis which would
support a quick burst of snow mainly south of I-70 capable of
producing up to an inch of snow. Consequently, with three vastly
different solutions have kept precip chances only in the chance
category with the potential for freezing drizzle or light snow
Wednesday night into Thursday.

The second chance for potential wintry precipitation will come
during the Friday to Saturday timeframe. This chance for
precipitation will be associated with the aforementioned upper level
(Four Corners) trough. Timing and track of this system will be the
main caveat to the forecast. The GFS has a much quicker, flatter,
and more progressive wave as it moves from the southern Plains into
the Lower Mississippi River Valley on the day Friday. Subsequent
model run keep pushing this storm track south however, the GFS still
suggests the chance for light snow on Friday across the entire
forecast area with the exception of extreme northern Missouri with
the heaviest totals across central Missouri. The EC solution is
slower, deeper and evening further south with the storm track. This
would leave the local area dry with precipitation passing south of
the forecast area on Friday into Friday night. As such have snow
chance on Friday and Friday night across the south CWA.

High pressure then looks to build into the region on Saturday with
dry conditions and temperatures in the 30s. Beyond that, model
solutions diverge however, a return to southerly flow on the
backside of the surface high should signal a warming trend as we
head through the latter half of the weekend into the beginning of
next week.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon)
Issued at 1110 AM CST MON DEC 15 2014

Most of the activity associated with the storm system has worked its
way well to the east. However, we may see additional spotty showers
as the back side of the storm moves over the state border. Expecting
these to clear out of the area by 00Z as low center continues to trek
eastward. Ceilings will gradually improve after this time frame and
are looking to more readily scatter out Tuesday morning. The other
significant feature to consider is the steady gusty winds as they
turn northwesterly with the arrival of the cold front.




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