Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 090858

Area Forecast Discussion
National Weather Service Hastings NE
258 AM CST Fri Dec 9 2016

.SHORT TERM...(Today and tonight)
Issued at 249 AM CST Fri Dec 9 2016

It`s been a cold night across our area under the influence of a
1040mb surface high pressure system. In good radiating conditions
with clear skies for much of the night, temperatures at 08z were
in the single digits both above and below zero with Ord the
coldest spot at -2F.

The surface ridge axis will shift east today and the arctic airmass
will dislodge allowing for temperatures to moderate a few degrees.
The warming will be tempered by increasing cloud cover and
readings are expected to reach the mid/upper 20s for highs. An
upper disturbance crossing the plains tonight may generate a brief
period of light snow or flurries for our northern counties toward
Saturday morning. Not looking for snow accumulation with the
better forcing and snow chances focused north of our area.

.LONG TERM...(Saturday through Thursday)
Issued at 249 AM CST Fri Dec 9 2016

...The Cold Eases this Weekend with Some Low Potential for a Minor
Snowfall Event Sun then Temps Plunge Again as More Arctic Air
Arrives Tue...

Aloft: Low amplitude W or WNW flow will prevail thru Thu. The
problem with this seemingly simple flow is the complexity that
develops from the plethora of subtle shortwave trofs/jet streaks
...any one of which could produce some minor light snow or flurries
given sufficient moisture. In addition...model agreement is usually
low in these situations. So suffice to say fcst confidence is below
average. The good news is any periods of snow should be minor or
even insignificant. The most noticeable/highest confidence trof will
be Sun.

Surface: Cyclonic return flow will be in progress Sat with weakening
arctic high pres N and E of the region. An inverted trof will move
thru Sun morning as weak leeside low pres organizes and eventually
heads into the mid MS Vly...S and then E of the fcst area. Small
high pres forms over KS Sun night and rapidly departs to the E Mon.
Meanwhile...the next arctic front will be plunging S and will cross
the fcst area Mon eve. Arctic high pres builds in Tue-Wed. Return
flow will develop and strengthen Thu as the high departs into the
Ern USA. Another arctic cold front will surge S and cross the fcst
area in the Fri-Sat timeframe.

A few sensible wx highlights...

Sat: a shield of light snow (-SN) will develop over SD down into the
Sandhills around daybreak. The Srn fringe of this may make it as far
S as Neb Hwy 92 during the morning some flurries or a
couple hrs of -SN. It won`t amount to anything.

The cold eases Sat...but temps will still be a few degs colder than

Sun: Lots of uncertainty. Another batch of -SN is possible...but
models are all over the place with QPF and have mostly light amts.
The GFS and EC runs have been consistently on the light side...
probably due to their inability to saturate the 800-600 mb layer.
This period needs to be watch as it could overproduce. The NAM was a
wet outlier with last Sat`s snow event...and it was right. The
12Z/18Z/00Z NAM runs each bring a swath of 1-4" into parts of the
fcst area...but the 06Z came in dry.

Just as with investing in the stock market...past performance is no
guarantee of future results. The NAM persistent cannot be ignored...
but without other models on-board (including its own 06Z run)`s
tough to bite on just the NAM.

Because of the varying model depictions of RH...automated ptypes
were too messy/complicated. So coordinated with neighboring offices
to keep the fcst more simple rain/snow. Poor model QPF consistency
has also lowered snow amts in the fcst. WPC guidance also came in
significantly lower than yesterday`s day shift.

Mon: Temps could bust svrl degs too cool. We are seeing a lot of
temp guidance suggesting highs in the 40s and low 50s.

Mon night: Becoming windy behind arctic cold front. Coordinated with
neighboring offices to increase winds to consensus of MOS...but
believe they`re still not high enough.

Tue-Thu: Other various opportunities for a few flurries or a little
-SN...but most of the time will be dry. Bitter cold re-invades.


.AVIATION...(For the 06Z KGRI/KEAR TAFS through 06Z Friday night)
Issued at 1135 PM CST Thu Dec 8 2016

Surface high pressure across the central plains will shift east
today allowing for return flow of southerly winds. Look for cloud
cover to increase the next 24 hours, with heights at VFR levels
initially but look for low cloud cover to move in during the
afternoon and evening around MFVR heights.





LONG TERM...Kelley
AVIATION...Fay is the U.S. government's official web portal to all federal, state and local government web resources and services.