Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 301455 AAA
AFDLBF

Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
855 AM CST Wed Nov 30 2016

.UPDATE...
Issued at 855 AM CST Wed Nov 30 2016

Radar...sfc observations...webcams and reports from observers
suggest the threat of hazardous winter weather across Sheridan and
Cherry counties has ended. The winter weather advisory will be
allowed to expire at 15z.

&&

.SHORT TERM...(Today and tonight)
Issued at 332 AM CST Wed Nov 30 2016

The main sensible weather concerns are snowfall potential across the
Pine Ridge and far northwestern Sandhills, snowfall chances
elsewhere, and winds. The main highlights in the short term period
include: the ongoing winter weather advisory for Sheridan and
western Cherry counties, strong winds today, and below normal high
temperatures.

A broad mid-level trough that`s over the central CONUS with a closed
low now over the Upper Mississippi Valley will be lifting
northeastward the next 24 hrs to extend across eastern Ontario and
the Great Lakes. Meanwhile, a short wave ridge west of the longwave
trough currently from the Sierras into the northern Intermountain
West will be flattening today as it moves eastward in the Great
Basin. The surface low associated with the current system impacting
the region has been gradually filling in the last 24-hrs and has a
central pressure of about 998 mb presently near the Twin Cities. The
surface low pressure system will accelerate eastward into far
southeastern Ontario by the end of today.

The winter weather advisory was extended to 15Z this morning based
on upstream weather/latest trends and recent hi-res guidance. It is
expected that light snow will continue over the advisory area,
specifically across the Pine Ridge and far northwestern Sandhills.
KIEN at 2 AM CST near the SD/NE border is reporting light snow and
1SM visibility under light winds that suggests a light accumulation
rate. Moisture should be sufficient this morning and will be
combined with downstream convergence in the lee of the Black Hills
under northwesterly flow and upslope snow enhancement along the Pine
Ridge. As such, additional accumulations up to one inch is expected
in the narrow corridor defined above, while farther away scant
accumulations are expected south of highway 20. Otherwise, another
breezy day is on tap across western and north central NEB, albeit
compared to the last two days gusts are not anticipated to be as
strong. Upper levels winds are expected to mix down to the surface
via momentum transfer. Gusts are expected to peak between 25-30 kts,
approaching almost 35 kts in portions of southwest NEB and the north
central Sandhills. Overnight, winds will lessen more compared to the
previous nights as the aforementioned surface low advances east and
the pressure gradient magnitude relaxes. Lastly, another cool day is
in store for the region with highs expected to be 2-8 degrees below
normal. Near normal lows overnight.

.LONG TERM...(Thursday through Tuesday)
Issued at 332 AM CST Wed Nov 30 2016

The large upper level low pressure system that has been influencing
the weather the last several days, will shift east into eastern
portions of Canada by Thursday. Weak upper level ridging will build
across the area ahead of the next system poised to dive through the
Rockies and into the southern plains Saturday into Sunday. The upper
level ridging will bring warmer temperatures back to the area by the
weekend, with H850mb temperatures rising to around 0C Saturday and
possibly 5C on Sunday. This should support highs of 40 to 45
degrees Saturday and 45 to 50 Sunday.

Next week is looking unsettled and turning much colder. It still
appears that the region will experience the first Arctic outbreak,
as a polar airmass is funneled south into the much of the central
and eastern portions of the country. Models also continue to
advertise upper level energy diving southeast from the Gulf of
Alaska into the northern Rockies and eventually the central and
northern plains. It is unclear how the upper trough will unfold as
it moves into plains, but one development in tonight`s models runs
would be more phasing and interaction with the northern stream. This
keeps the trough progressive and open, with no strong winter storm
development. This will have to be monitored closely, as previous
model runs were advertising a closed low and a strong winter storm
across the region. For now will keep a chance of snow for Tuesday as
the upper trough approaches, along with a dramatic drop in
temperatures with highs only in the 20s.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 550 AM CST Wed Nov 30 2016

Latest satellite imagery and surface plot depicts low-end VFR
ceilings (less than 7 kft) across much of western and north
central NEB. Currently there are some MVFR clouds underneath,
more so upstream, as such portions of the forecast area may be
observing ceilings of lower flight category. A few sites are
reporting MVFR visibility attributable to light snow/blowing snow,
mainly across northern NEB. A storm system in the Upper
Mississippi Valley will continue to impact the region today. Windy
conditions are expected again today across the entire forecast
area with gusts up to 25-30 kts, approaching almost 35 kts in
portions of southwest NEB and the north central Sandhills. Also,
light snow showers or flurries can be expected across the
northern-third of the forecast area today. Tonight, no additional
precipitation is anticipated and lighter winds are expected as the
system moves east. Otherwise, MVFR ceilings are expected to
prevail from the northern portion of the eastern NEB Panhandle
east across north central NEB today and through early tonight.
Elsewhere, VFR ceilings are expected.


&&

.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

UPDATE...CDC
SHORT TERM...Taylor
LONG TERM...ET
AVIATION...ET


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