Special Weather Statement, NWS North Platte, NE

Area Forecast Discussion
National Weather Service North Platte NE
635 PM CDT Thu May 20 2021

.SHORT TERM...(This evening through Friday night)
Issued at 248 PM CDT Thu May 20 2021

 The short term focus is again isolated thunderstorms.

Currently at upper levels, the eastern US is dominated by a large
area of high pressure, while the eastern US is broadly defined by an
area of low pressure, centered over NorCal. This leaves the Central
Plains in between the 2 systems. Given the location of the CWA in
the middle, it is left in resultant gusty southeasterly flow, which
is advecting Gulf moisture into Nebraska primarily at low levels,
but also throughout the atmospheric column. As such, seeing around
1" of precipitable water available, which is ample moisture for
potential precip this evening.

At the surface a low pressure system and stationary front just off
to the west in WY. This provides the basis for storms tonight as
some light FGEN at 850mb will provide the lift, primarily over the
panhandle, to kick off precipitation. As with the previous
discussion, models have continued to back off on widespread precip
in the CWA, and have created greater confidence in only isolated
showers. Similarly, most, if not all, severe storms are expected to
stay to our west as that is where the most of the forcing, unstable
lapse rates and MLCAPE are located. Additionally, west and north
central Nebraska has pretty good capping to help bar storms from
becoming severe. Expecting the biggest threat to be strong winds.

The showers are expected to dissipate allowing for a brief lull
during the day tomorrow. Flow will remain gusty with sustained
winds up to 20mph, and gusts up to 40 mph out of the southeast.
With 850 temps around 23 degrees, but some low to mid level clouds
limiting, expecting highs to reach into the mid 80s across the
region.

There will be another chance for thunderstorms again tomorrow
evening as another stationary front provides lift over the panhandle
and northern Sandhills. There is a chance again tomorrow for severe
weather, again with the greatest threat to the west of the CWA.
MLCAPE reaches up to 2000J/kg and lapse rates near 7-8C/km, but is
met with the stable capping, so continuing to monitor the threat.

.LONG TERM...(Saturday through Thursday)
Issued at 248 PM CDT Thu May 20 2021

Into the long term, upper levels will still be defined by high
pressure to the east, and low pressure to the west of Nebraska. The
low to the west looks to move slowly eastward and reach the CWA by
Sunday afternoon. It will drag an accompanying cold front through
the western half of Nebraska Sunday evening. FGEN at both 700 and
850mb will provide enough lift to kick off showers and possible
thunderstorms along the boundary. The severe threat is currently
uncertain, but locally heavy rainfall is possible as PWAT values
near 1.5". Additionally, as the system approaches, gusty winds are
in store again Sunday as forecast soundings show near 30 mph winds
possible at the sfc.

In the wake of this upper level low, the Plains will be left in a
region of upper level ridging through at least Friday. This flow
should bring a few days of reprieve from the non-stop shower chances
...until Wednesday night when chances for precipitation return
again.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 630 PM CDT Thu May 20 2021

VFR conditions expected to prevail into the overnight hours before
low stratus expands early tomorrow morning. This low stratus will
lead to a period of MVFR/locally IFR for portions of central and
north central Nebraska. Confidence in IFR CIGs at VTN/LBF remains
low, and will defer possible inclusion to later forecasts.
Southerly LLWS develops overnight near 2000ft AGL before
diminishing near sunrise. Winds will remain southerly at around
15kts with gusts approaching 30kts through tomorrow evening.

&&

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

SHORT TERM...NMJ/Sinclair
LONG TERM...NMJ/Sinclair
AVIATION...Brown

Hazardous Weather Outlook
National Weather Service North Platte NE
304 PM CDT Thu May 20 2021

NEZ004>010-022>029-035>038-056>059-069>071-094-212015-
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-
304 PM CDT Thu May 20 2021 /204 PM MDT Thu May 20 2021/

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

Isolated showers or thunderstorms are possible this afternoon
mainly east of Highway 183.

Also, isolated thunderstorms will be possible across the eastern
panhandle and far western Nebraska this evening. A strong or
severe thunderstorm with large hail, damaging wind and heavy rain
will be possible in the eastern panhandle.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

A few strong and perhaps a severe thunderstorm will be possible
Friday afternoon and evening across western Nebraska. Additional
chances for thunderstorms will continue through the weekend.
Later forecasts will better define any severe weather potential.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will likely not be needed through tonight.

&&

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

Roberg

Special Weather Statement
National Weather Service North Platte NE
853 PM MDT Thu May 20 2021

NEZ004-022-210330-
Sheridan NE-Garden NE-
853 PM MDT Thu May 20 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN GARDEN AND
SOUTHWESTERN SHERIDAN COUNTIES UNTIL 930 PM MDT...

At 852 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Alliance to 9 miles northwest of Lisco.
Movement was northeast at 30 mph.

Half inch hail and winds in excess of 40 mph will be possible with
these storms.

Locations impacted include...
Antioch, Crescent Lake National Wildlife Refuge, Patterson Lake,
Smith Lake State Wildlife Management Area, Snow Lake, Richardson
Lake, Miles Lake, Mumper, Wickson Lake, Diamond Lake, Lakeside,
Herman Lake, Krause Lake and Tralnor Lake.

This includes the following highways...
 Highway 250 between mile markers 1 and 30.
 Highway 2 between mile markers 96 and 113.

LAT...LON 4247 10244 4167 10230 4155 10263 4174 10264
      4177 10268 4200 10268 4201 10270 4209 10270
      4210 10274 4235 10275
TIME...MOT...LOC 0252Z 235DEG 26KT 4207 10292 4158 10277

Snively