High Wind in Nebraska, January 13 to 15, 2021

Area Forecast Discussion
National Weather Service North Platte NE
542 PM CST Wed Jan 13 2021

.SYNOPSIS...
Issued at 400 PM CST Wed Jan 13 2021

H5 analysis this morning was highlighted by a closed low
over northern Louisiana, a shortwave over eastern Ontario and a
shortwave south of the Canadian Maritimes. Across the Western CONUS,
high pressure was anchored off the coast of southern California.
North of this feature, a potent shortwave trough of low pressure
extended from southeastern British Columbia into northern Oregon.
This feature shows up well on satellite imagery this afternoon and as
of midday, this feature roughly extended from eastern Alberta into
northern Montana. Very strong surface low pressure in association
with this trough was noted over southwestern Saskatchewan AT 2 PM CT
with a pressure of 883 mb noted. Trailing south of this low, a cold
front extended across northwestern Montana. A surface trough of low
pressure extended south of the low and was situated along the
western borders of the Dakotas, as well as the Nebraska Panhandle.
Winds west of the trough were very strong, especially over eastern
Montana into eastern Wyoming and the far western Nebraska
Panhandle. Over the past hour, some gusts topped 70 MPH in central
Montana and were approaching 60 MPH in eastern Montana and eastern
Wyoming. Across western and north central Nebraska, skies were
mostly cloudy underneath of shroud of high cloudiness. Temperatures
at 2 PM CT ranged from 49 at Gordon, to 60 at North Platte and
Broken Bow.

&&

.SHORT TERM...(This evening through Friday)
Issued at 400 PM CST Wed Jan 13 2021

The main forecasting issues in the near term deal with high wind
potential, precipitation chances tonight, and then again on
Thursday night-early Friday. The before mentioned H5 trough, will
close off over southern Saskatchewan this evening. The trailing
trough of low pressure, now extending into the northern high
plains, will force a cold front through the forecast area this
evening. The short range models, most notably the HRRR, have this
front approaching the NW forecast area around 02z this evening,
pushing it through the forecast area by 06z. Very gusty winds will
occur behind the front. Forecast sounding data, as well as the
HRRR 2m wind gust product, indicate a 1-2 hour window behind the
front with wind gusts to around 60 MPH. Based on what is occurring
upstream, this looks like a good forecast ATTM. Winds will
slacken somewhat overnight into Thursday morning. Winds will then
rapidly increase Thursday afternoon as H850-H700 lapse rates
approach 9-10C/KM. Forecast soundings from the GFS look down right
nasty for the forecast area Thursday afternoon. At 3 PM CT in
Thedford tomorrow, GFS Bufkit sounding winds are 60 KTS at the
bottom of the mixed layer and 73 KTS at the top of the mixed
layer. Winds are 50 KTS only 400 FT AGL at Thedford. With lapse
rates that steep, we should have no problem hitting 60 MPH for
wind gusts tomorrow afternoon and wouldn't be surprised if we
eclipse 65 MPH for wind gusts tomorrow afternoon, especially in
open areas. With sunset Thursday, winds will slacken off slightly
in the evening. Overnight, as the H5 low dives south into eastern
Iowa, a shortwave trough on the northwestern periphery of the low
will approach northeastern and north central Nebraska. This will
force a secondary cold front through the area Thursday night into
Friday morning. Winds will increase once again with this front.
The latest 18z HRRR which runs out through 18z Friday, has 2m wind
gusts in the 50 to 55 KT range Friday morning. These winds begin
to diminish midday Friday. With strong forecast confidence in
winds and wind speeds with this system, upgraded the high wind
watch to a warning with this forecast package. I did start the
high wind warning earlier based on the quicker frontal timing
tonight.

With respect to precipitation chances with this system. They will
come in two episodes. The first will be along and post frontal this
evening into the early overnight hours. The second will be in
association with the arctic front Thursday night into Friday
morning. For tonight, the models continue advertise strong lift from
north central into eastern portions of the forecast area. The timing
of the greatest lift will be along and immediately behind the front,
which favors this evening. Looking at forecast soundings, most
precipitation this evening will be liquid. There is a tight 1-3 hour
window in the northwest where some snow could mix in with rain
before changing over to all snow. This area is generally over
western Cherry and Sheridan counties. The 12z NAM this morning, had
a nice band of heavier precipitation across far ne Sheridan into
western Cherry county with QPF's approaching 0.4 inches. This was
very similar to yesterday's NAM12 forecast. However, this band is
not found in the GFS, HRRR and WARW solns and was treated as an
outlier soln. That being said, the highest QPF's tonight will be
over the northeastern forecast area and have painted the highest
pops in these areas. Again with most of the lift this evening and
temperatures being too warm, not expecting any snow accumulations.

On Thursday night and Friday morning, light snow is expected to
develop over the northeastern forecast area along the arctic frontal
boundary. There continues to be weak lift noted across northeastern
Nebraska during this period and the airmass should be saturated
given the degree of cold air advection. QPF's were increased in
these areas with this package, in step with higher QPF's noted in
this mornings GFS and NAM12 runs. That being said, with the
increased QPF's, snowfall will increase as well. Combine the light
snow with very strong winds, and we could see some potential
blizzard conditions in the northeast. Went ahead and inserted a
mention of blowing snow in these areas, as snowfall was increased to
a half to an inch. We will need to monitor forecast trends closely
in these areas as we could see blizzard conditions if enough snow
falls. FWIW, the CIPS 2 hour blizzard product this morning increased
to 20 to 30 percent for blizzard conditions Friday morning in our ne
forecast area. This was an increase from 10 to 15 percent with
yesterday's run.

.LONG TERM...(Friday through Wednesday)
Issued at 400 PM CST Wed Jan 13 2021

The next chance for precipitation will arrive Monday into Tuesday
as a mid level trough of low pressure carves a path across the
central and northern plains. So far, this appears to be limited in
its precipitation potential. For Saturday, Sunday, and Wednesday,
dry conditions are forecast for now. Highs in the outer periods
will be seasonal with readings in the upper 30s to lower 40s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 540 PM CST Wed Jan 13 2021

Gusty northwesterly winds associated with the passage of a cold
front are the main concern over the next 24 hours for western and
north central Nebraska. Winds will increase through the evening
before midnight with gusts up to 50 knots possible. Skies will
become overcast at this time with the possibility of rain showers
in northern Nebraska and the Sandhills, including KVTN, KGRN, and
KTIF. Skies will become less cloudy tomorrow morning and
afternoon, but wind gusts between 35 and 50 knots will continue.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
High Wind Warning from 9 PM CST /8 PM MST/ this evening to 6 PM
CST /5 PM MST/ Friday for NEZ004>010-022>029-035>038-056>059-
069>071-094.

&&

SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Buttler
AVIATION...Meltzer

Hazardous Weather Outlook
National Weather Service North Platte NE
239 PM CST Wed Jan 13 2021

NEZ004>010-022>029-035>038-056>059-069>071-094-142045-
Sheridan-Eastern Cherry-Keya Paha-Boyd-Brown-Rock-Holt-Garden-
Grant-Hooker-Thomas-Blaine-Loup-Garfield-Wheeler-Arthur-McPherson-
Logan-Custer-Deuel-Keith-Perkins-Lincoln-Chase-Hayes-Frontier-
Western Cherry-
239 PM CST Wed Jan 13 2021 /139 PM MST Wed Jan 13 2021/

This Hazardous Weather Outlook is for portions of western and
north central Nebraska.

.DAY ONE...TONIGHT.

A High Wind Warning remains in effect beginning 9PM CT tonight
for all of western and north central Nebraska. Northwest winds
gusting near 60 mph are expected tonight.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

A High Wind Warning remains in effect for all of western and
north central Nebraska through Friday. Extremely strong
northwesterly winds will result in gusts around 65 mph. Strongest
winds are expected Thursday afternoon. Strong winds could result
in power outages and travel difficulties for lightweight and high
profile vehicles.

In addition, light snow is possible across portions of north
central Nebraska late Thursday night into Friday morning. Areas
of blowing and drifting snow as well as reduced visibilities could
lead to near blizzard conditions.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed through tonight.

&&

Get your weather, hydrological, and climate information at
http://www.weather.gov/northplatte