Severe Thunderstorm Warning 229, NWS North Platte, NE

Area Forecast Discussion
National Weather Service North Platte NE
1229 AM CDT Wed Aug 21 2019

.SHORT TERM...(This evening through Wednesday night)
Issued at 258 PM CDT Tue Aug 20 2019

The primary forecast challenges through tomorrow deal with
thunderstorms and a modest cooldown. A cold front is currently
draped across the Sandhills and will be the focus for convective
development through tonight. High temps tomorrow will likely be
limited to the 70s.

Generally followed a blend of the more aggressive CAMs for precip
potential and timing, mainly the NAMnest and HREF. The environment
is definitely favorable for organized convection with a forcing
mechanism nearby, abundant instability, and some deep layer shear.
Highs near 90 this afternoon coupled with dew points in the 60s to
lower 70s and nearly dry adiabatic lapse rates in the mid levels are
resulting in MLCAPE values of 3000+ j/kg. Forecast soundings suggest
keeping at least 1000+ j/kg of MUCAPE into the nocturnal hours while
the low level jet develops. Veering winds in the lowest 3km may
support supercells upon convective initiation (early evening),
leading to a large hail threat. Can't completely rule out a tornado,
but the limiting factor may be widespread supportive shear. Deep
layer shear ranges from 20 to 40 kts across the CWA and 0-3km shear
from 5 to 20 kts. The mean cloud layer wind and storm motion almost
mirrors the front position overnight, which will likely turn the
focus to a linear system or at least multicell clusters. Forecast
DCAPE values of 1000+ j/kg also favor damaging wind potential. Will
also need to monitor the torrential rainfall threat. Seasonably high
PWAT values coupled with relatively low storm motion and forecast
convective mode may result in a swath of 1" rain totals (and locally
higher). Many locations are reeling with a very wet summer and are
still saturated from storms days ago. Remnants of the potential MCS
should exit the forecast area by 18z Wednesday, but lingering post
frontal thunderstorms will affect western Nebraska through the
afternoon. Temperature-wise, trended cooler with max temps for
Wednesday with lower/mid 70s in the Sandhills where cloud cover will
be thickest and upper 70s elsewhere.

.LONG TERM...(Thursday through Tuesday)
Issued at 258 PM CDT Tue Aug 20 2019

Over the next several days, Nebraska lies on the periphery of the
upper ridge centered over the Desert Southwest and longwave
trough digging into the Northern Plains. Near the surface, passing
frontal boundaries provide the focus for periodic thunderstorms
to keep the overall wet pattern alive. Clouds/precip coupled with
seasonably cool H85 temps around 15C (or lower) will maintain
highs in the 70s for Thursday. Weak WAA in the low levels on
Friday and then a warm front lifting north on Saturday will
rebound temps into the 80s for the weekend.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1228 AM CDT Wed Aug 21 2019

Showers and thunderstorms will be the main aviation story over the
next day. Strong to severe storms are possible tonight before
weakening around 10Z to 12Z. Rain showers and embedded weak
thunderstorms will then continue throughout the day Wednesday.
Strong and erratic winds along with hail and heavy rain are possible
tonight. Some light patchy fog is also possible on Wednesday as the
lower atmosphere becomes saturated.

&&

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

SHORT TERM...Snively
LONG TERM...Snively
AVIATION...Kulik

Hazardous Weather Outlook
National Weather Service North Platte NE
1205 AM CDT Wed Aug 21 2019

NEZ004>010-022>029-035>038-056>059-069>071-094-220515-
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-
1205 AM CDT Wed Aug 21 2019 /1105 PM MDT Tue Aug 20 2019/

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

.DAY ONE...OVERNIGHT.

Severe thunderstorms are possible overnight. The threat area is
south of a line from Chambers to Gordon. Large hail, strong winds,
and locally heavy rainfall will be possible.

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

A few thunderstorms will remain possible Wednesday through
Thursday. Severe storms are not expected.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated overnight.

&&

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

Special Weather Statement
National Weather Service North Platte NE
1218 AM CDT Wed Aug 21 2019

NEZ025>027-037-038-059-210600-
Loup NE-Custer NE-Thomas NE-Blaine NE-Lincoln NE-Logan NE-
1218 AM CDT Wed Aug 21 2019

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN LOUP...NORTHEASTERN
LINCOLN...EASTERN LOGAN...NORTHERN CUSTER...SOUTHERN BLAINE AND
SOUTHEASTERN THOMAS COUNTIES UNTIL 100 AM CDT...

At 1217 AM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Gandy to near Broken Bow to near Mason
City. Movement was north at 20 mph.

Nickel size hail will be possible with these storms.

Locations impacted include...
Broken Bow, Arnold, Sargent, Ansley, Merna, Anselmo, Comstock,
Berwyn, Gandy, Victoria Springs State Recreation Area, Weissert,
Westerville, Lillian, Logan, Milburn, Highway 83 crossing The Dismal
River, Milburn Diversion Dam State Wildlife Management Area,
Walworth, Shanklin Bluff and Tarboz Lake.

This includes the following highways...
 Highway 183 between mile markers 88 and 116.
 Highway 2 between mile markers 242 and 297, and near mile marker
304.
 Highway 92 between mile markers 235 and 308.
 Highway 83 between mile markers 114 and 133.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

A Severe Thunderstorm Watch remains in effect until 600 AM CDT for
central, southwestern, north central and west central Nebraska.

LAT...LON 4137 9966 4138 10047 4178 10057 4178 9967
      4160 9921 4120 9921
TIME...MOT...LOC 0517Z 179DEG 16KT 4145 10038 4144 9967 4127 9923

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