Hail in Nebraska, June 30, 2020

Area Forecast Discussion
National Weather Service North Platte NE
610 PM CDT Tue Jun 30 2020

.SHORT TERM...(This evening through Wednesday night)
Issued at 321 PM CDT Tue Jun 30 2020

The forecast is following the short term model blend for likely
thunderstorm chances this evening east of highway 83 throughout
ncntl Nebraska. This is a little west of the previous forecast and
is based on post frontal thunderstorms forming in addition to
storms developing along a cold front which is slowing up across
cntl Nebraska this afternoon. Storm activity should last about 6
hours and exit ncntl Nebraska to the east around midnight tonight.
The rest of the forecast Wednesday and Wednesday night is dry as
a result of Pacific high pressure building through the region.

The models and latest SPC analysis indicate 4000-5000J/KG of MLCAPE
across ncntl Nebraska this afternoon. A belt of increasing winds
aloft across ern WY/Colo will move in this evening supporting
deep storm development but the directional shear appears limited.
This would seem to support splitting storms and competing
updrafts. SPC suggested supercells at the onset of storm
development evolving into a more linear mode as the MCS shifts
east later this evening. Both the NAM and RAP model soundings show
moisture deepening along the nearly stationary front. The
deepening moisture should weaken the cap by 22z-00z this
aftn/evening.

.LONG TERM...(Thursday through Tuesday)
Issued at 321 PM CDT Tue Jun 30 2020

An upper level ridge of subtropical high pressure centered over
the nrn Gulf of Mexico this morning will build north through Texas
and into Nebraska this week. The GFS and ECM both show an
attendant plume of subtropical moisture moving north with the
ridge. The result is a more moist environment supporting what
appears to be ordinary thunderstorm development across Nebraska.
The new forecast has more scattered thunderstorm chances Thursday
through Tuesday. Winds aloft should remain fairly weak at less
than 15kt. A modest increase in winds aloft is possible next
Tuesday as the ridge weakens with the approach of a nrn stream
disturbance.

The temperature forecast is for highs in the 90s Thursday and
beyond. This is consistent with h700mb around 11C. Steady south
winds are in place associated with a broad area of weak low pressure
forming across the cntl and nrn Plains.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 610 PM CDT Tue Jun 30 2020

Scattered thunderstorms will move through north central Nebraska
this evening (mainly from KBBW to KONL), resulting in tempo visby
and cig drops, along with gusty erratic winds. Otherwise, VFR
will continue through the forecast period. Gusty winds are the
main aviation weather concern, primarily through sunset tonight
(northwesterly) and again tomorrow afternoon (southerly).

&&

.HYDROLOGY...
Issued at 321 PM CDT Tue Jun 30 2020

Radar shows the cold front slowing up across ncntl Nebraska and
the rapid refresh models are pooling moisture behind this front.
Precipitable water will exceed 1.5 inches at the onset of
scattered thunderstorms early this evening. Storm cover should
expand throughout ncntl Nebraska this evening.

The deep southerly flow aloft and elevated CAPE of 2500J/KG shown in
the RAP and NAM models should support splitting storms and perhaps
some HP echo training. The RAP and HRRR are showing signs of a
expansive area significant rainfall with locally heavy rainfall
totals of 1.5 and 2.5 inches. The locally heavy rainfall would
probably lead to flooding in some areas. The Flood Watch in effect
across Holt and Boyd counties has been expanded south and west to
include Custer county and areas north to the South Dakota border.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 5 AM CDT Wednesday for NEZ006>010-026>029-038.

&&

SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Snively
HYDROLOGY...CDC

Hazardous Weather Outlook
National Weather Service North Platte NE
320 PM CDT Tue Jun 30 2020

NEZ004>010-022>029-035>038-056>059-069>071-094-012030-
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-
320 PM CDT Tue Jun 30 2020 /220 PM MDT Tue Jun 30 2020/

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

.DAY ONE...TONIGHT.

Strong to severe storms are possible this afternoon and evening over
portions of north central Nebraska. The main area of concern is east
of Highway 83. Large hail, damaging winds, and locally heavy
rainfall though an isolated tornado cannot be ruled out through
early evening.

Any thunderstorm will be capable of moderate to heavy downpours and
combined with the threat for training thunderstorms, rainfall
amounts of 1-2" are likely with localized amounts of up to 4"
possible. A Flood Watch is in effect for portions of central and
north central Nebraska tonight.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

Thunderstorms are possible daily from Thursday through Monday. At
this time, the threat for severe storms is low.

High heat combined with high humidity will allow heat index values
to climb into the upper 90s for Friday and Saturday.

.SPOTTER INFORMATION STATEMENT...

Please relay any information about observed severe weather to the
NWS.

&&

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

Meltzer/Jurgensen

Special Weather Statement
National Weather Service North Platte NE
754 PM CDT Tue Jun 30 2020

NEZ038-010145-
Custer NE-
754 PM CDT Tue Jun 30 2020

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN CUSTER COUNTY UNTIL
845 PM CDT...

At 754 PM CDT, Doppler radar was tracking a strong thunderstorm near
Eddyville, or 18 miles northeast of Lexington, moving northeast at 25
mph.

Nickel size hail and wind gusts up to 50 mph will be possible with
this storm.

Locations impacted include...
Ansley, Mason City, Buckeye, Block Hill Basin, Burr Oak, Gavin
Siding, Intersection of Highway 183 and Cumro Road and Cumro.

This includes the following highways...
 Highway 183 between mile markers 73 and 95.
 Highway 2 between mile markers 289 and 307.
 Highway 92 between mile markers 300 and 308.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm 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 100 AM CDT for
central Nebraska.

LAT...LON 4104 9925 4104 9935 4105 9966 4139 9945
      4129 9920 4107 9920 4105 9921
TIME...MOT...LOC 0054Z 210DEG 22KT 4101 9955

CDC