Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 110532

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1132 PM CST Sat Dec 10 2016

.SHORT TERM...(Tonight through Tuesday)
Issued at 316 PM CST Sat Dec 10 2016

Early-afternoon water vapor imagery reveals a largely quasi-zonal
flow regime present over the CONUS with an embedded short-wave
trough located over the northern Inter-mountain Region. This
disturbance is forecast to amplify as it translates through the
northern Plains into the upper Great Lakes Sunday into Sunday
night. In the low levels, an associated cyclone located over the
central High Plains this afternoon will rapidly develop across the
central Plains and into the upper Midwest by Sunday evening.
Meanwhile, a trailing cold front will advance southeast through
the mid and lower Missouri Valleys.

A low-level warm advection regime will remain in place across the
mid Missouri Valley tonight, downstream from the surface cyclone
and approaching mid-level disturbance. This forcing for ascent
will maintain a back-building band of snow on the immediate
northeast periphery of our area, suggesting the continued
potential for flurries or some light snow across our northeast
counties overnight. While not included in the official forecast, we
will have to watch for the potential for some light freezing
drizzle over far southeast Nebraska into southwest Iowa late
tonight into Sunday morning.

On Sunday, the above-mentioned cold front will advance through the
area with the best precipitation potential remaining to our east.
A surface high will quickly develop through the mid Missouri
Valley Sunday night ahead of the next, more substantial cold front
which will surge southeast through the region Monday afternoon and
evening. The warmest temperatures this forecast period are
anticipated ahead of the front Monday afternoon with readings
ranging from the lower to mid 30s north to lower 40s south.
Forecast soundings indicate relatively dry mid-level conditions
with the frontal passage which should limit the potential for
measurable precipitation. However, saturation within the frontal
inversion could yield some drizzle immediately behind the front.

Monday night into Tuesday, a surface high will build southeast
through the area with lows ranging from around zero north to
around 10 southeast. Highs on Tuesday will top out in the upper
teens to lower 20s.

.LONG TERM...(Tuesday night through Saturday)
Issued at 316 PM CST Sat Dec 10 2016

At the onset of the extended range, 12z model data indicate an
upper low over central Canada with a low-amplitude cyclonic flow
regime over the lower 48. The upper low and associated trough will
shift east toward the Atlantic Coast by late next week in response
to an upstream trough moving from the eastern Pacific into the
Interior West. With regard to sensible weather concerns, this large-
scale pattern evolution will support the continuation seasonably
cold temperatures through the week. Frontogenetical forcing
arising from increasingly confluent flow will yield a chance of
light snow on Tuesday night into Wednesday, and Wednesday night
into Thursday.

By late next week, there continues to be indications that a
more significant synoptic system could impact the Great Plains
with the potential for a more substantial winter weather event
across our area. While considerable spread still exists amongst
available model guidance with respect to the timing and geometry
of this weather system, enough of a signal exists to at least
indicate a potential threat.


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1130 PM CST Sat Dec 10 2016

Mainly just mid and high level clouds were over the area as of
11 pm local time. Expect that there will be some low clouds moving
up into southeast Nebraska late tonight with MVFR ceilings
possible. There could also be another area of low clouds behind
the cold front as it moves into northeast Nebraska toward 12Z.
MVFR ceilings could hold in all day at KOMA but expect VFR
conditions at KOFK and KLNK by mid afternoon.




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