Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 251149
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
549 AM CST Sat Feb 25 2017

.SHORT TERM...(today through Monday)
Issued at 305 AM CST Sat Feb 25 2017

A vigorous mid-level trough centered over the MS Valley early this
morning will advance east today in response to the progression of
an upstream system from central Canada into the north-central
CONUS. In the low levels, a surface high over the central High
Plains will shift southeast, supporting the development of a
warmer, low-level air flow pattern across the mid MO Valley today.
Passing clouds and the fresh snow cover will modulate the warming
potential with afternoon highs ranging from around 30 north to
upper 30s south.

On Sunday, a weak shortwave trough will pass to our south with no
apparent impact on sensible weather. We will continue to see
further modification of the low-level air mass with highs in the
mid 30s north to mid to upper 40s south.

By Monday, the amplification of a western U.S. trough will
promote the development of a southwest flow pattern downstream
across the Rockies. A resultant deepening of a lee cyclone is
forecast over eastern CO, which in turn, will encourage
strengthening south winds and warmer temperatures across the
central Plains (i.e. mid 40s to mid 50s in our area).

.LONG TERM...(Monday night through Friday)
Issued at 305 AM CST Sat Feb 25 2017

The western U.S. trough mentioned above will progress through the
Interior West on Tuesday before emerging into the Great Plains
Tuesday night into Wednesday. This upper-air pattern evolution
will contribute to the migration of a surface low from eastern CO
to the vicinity of northeast KS or southeast NE by 12z/Tuesday,
with the low accelerating northeast thereafter. Strengthening low-
level warm advection and frontogenetical forcing ahead of and to
the north of the surface low will yield an increasing chance of
light precipitation Monday night into Tuesday. There is
considerable variability in model guidance with respect to the
extent of precipitation coverage, as well as precipitation type at
that time. Due to the uncertainty, we will simply mention a
transition from light rain to snow and wait for better model
clarity.

As mentioned above, the primary mid-level trough will emerge into
the Plains Tuesday night into Wednesday. This will result in the
tightening of the lower to mid-tropospheric baroclinic zone
situated just to our south. Associated frontogenetic forcing will
be sufficient to warrant a low probability of precipitation across
our southern counties late Tuesday night.

During the latter half of the work week, the large-scale pattern
will transition to a broad trough over eastern North America with
a ridge in the west. A resultant northwest flow pattern will
prevail over the north-central CONUS with generally dry and mild
weather expected.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 547 AM CST Sat Feb 25 2017

VFR conditions are expected at all sites through the TAF cycle,
with scattered ceilings of 15-25kft and unrestricted visibility.
Winds will shift from northwest to southwest, but with speeds
around 6 kt or less, have just mentioned variable direction.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&

$$

SHORT TERM...Mead
LONG TERM...Mead
AVIATION...Mayes



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