Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 221122

Area Forecast Discussion
National Weather Service North Platte NE
522 AM CST Wed Feb 22 2017

Issued at 352 AM CST Wed Feb 22 2017

At 09z...Surface low pressure extended south from Northern Plains
southward through the Central High Plains. Temperatures ranged from
31 at Ogallala and 29 at North Platte where winds were nearly calm,
to 50 at O`Neill, with a northwest wind at 10 mph. Skies remained
mostly clear to partly cloudy throughout western Nebraska.


.SHORT TERM...(Today and tonight)
Issued at 352 AM CST Wed Feb 22 2017

Today...An upper trough across British Columbia currently extends
south across Northern California. The southern end of this trough
Will move across Nevada. Further east across the Central Plains,
surface low pressure will deepen across southeast Colorado. A
surface low currently across central South Dakota moves quickly east
into Wisconsin by this evening, which will cause northwest winds to
increase to 10 to 20 mph across western Nebraska. One last day of
mild temperatures, with most areas reaching the lower to mid 60s,
but ranging from 56 at Gordon to 70 at Stockville.

Tonight...The winter storm system discussed the past several days
will begin to affect the western Sandhills tonight. Isentropic
upglide will increase dramatically overnight, with 120mb of lift
shown at the 295 and 300K sfcs. Condensation pressure deficits fall
below 5mb across Sheridan and Cherry County. Colder air will be
drawn southward, to support all snow as precip type in Sheridan and
Cherry county and pop increasing to 80 percent. New snowfall amounts
from a 1/2 inch up to 2 inches. A chance for rain or a rain snow mix
across much of the remainder of forecast area toward 12z. Northeast
winds increase to 10 to 15 mph. The 500mb low will advance into
northern Utah and southwest Wyoming as the 700mb low deepens over
south central Wyoming. Models indicate a weak coupled jet structure,
which will aid in upper level divergence across the area late
tonight. A winter storm watch begins 06z tonight as previously

.LONG TERM...(Thursday through Tuesday)
Issued at 352 AM CST Wed Feb 22 2017

Thursday through Friday...Main forecast concern is the upcoming
Winter Storm. Confidence is moderate that heavy snow will fall
across our northern Sandhills with the greatest potential across the
northwest forecast area including the towns of Gordon and Valentine.
This area is the most favorable for moderate to heavy snow most of
the day looking at BUFKIT forecast soundings. This northwest
quadrant is also the most favorable for precipitation type to start
off as all snow and remain all snow for the duration of the event as
temperatures will remain below freezing. Large scale ascent with a
coupled jet across the region along with good frontogenetic lift
especially in the dendritic growth zone are ingredients for moderate
to heavy snowfall...confidence is moderate that 10 to 15 inches will
fall across the northwest forecast area.

The challenge for this forecast period is for the southern part of
the forecast area where a lot of uncertainty still exist. The timing
of the changeover from rain to snow is still uncertain as even a
degree or two difference warmer will keep rain lingering around
longer thus creating the changeover to snow later and drastically
decreasing snow amounts. That being said the same holds true if it
is a degree or two colder the changeover to snow will be sooner and
snowfall amounts will be greater...however at this time not
expecting heavy amounts of snow across the southern forecast area
and have kept those counties out of the Winter Storm Watch but will
continue to monitor.

Saturday through Monday...temperatures will remain cool with highs
mostly in the 30s across the northern forecast area as fresh snow
pack will keep temperatures cool. Across the southern forecast area
temperatures will warm into the 40s and 50s by Monday.


.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 519 AM CST Wed Feb 22 2017

VFR conditions today into this evening. Later tonight, a storm
system will begin to affect western Nebraska. IFR ceilings and
visibility from snow will move into the northwest sandhills after


Issued at 352 AM CST Wed Feb 22 2017

Elevated fire weather conditions will exist this afternoon,
especially across the southwestern half of the area. Northwest winds
increase to 10 to 15 mph with a few gusts to 25 mph as temperatures
warm into the 60s most areas. Minimum relative humidity will fall to
the 16 to 20 percent range across zones 204, 206, 210 and 219.

An approaching winter storm will end the recent fire weather
concerns for the next several days across north central Nebraska.


Winter Storm Watch from late tonight through Friday afternoon
for NEZ004-094.

Winter Storm Watch from Thursday morning through Friday
afternoon for NEZ005>010-022>029-035>037.



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