Hail in Nebraska, August 10, 2020

Area Forecast Discussion
National Weather Service North Platte NE
357 AM CDT Mon Aug 10 2020

.SHORT TERM...(Today through Tuesday)
Issued at 357 AM CDT Mon Aug 10 2020

The main forecast challenges to start the week revolve mainly around
precip chances and thunder. The first round is being monitored
across the far north this morning, the next tomorrow afternoon with
a warm front, and another Wednesday ahead of a dryline.

This morning... As of 08z, convection is underway just across the
border in SoDak ahead of a rather stout shortwave. Fgen centered
around H7 appears to be the primary forcing mechanism with a surface
high drifting onto the northern Plains and no low level jet in play.
Some of the near term model guidance suggests further development in
far northern Neb, while others keep most of the activity north and
east of the forecast area. Continued chc PoP for areas along and
north of Hwy 20 through the morning, which appears to be a safe
approach. IR imagery showed rapidly cooling cloud tops around KONL,
so will continue to monitor for additional storms. The wave quickly
scoots east, taking the lift and moisture convergence with it. Have
all PoP out of north central Neb by 18z.

This afternoon and evening... Can't completely rule out a couple
rain showers far north central on the back side of the shortwave,
but confidence is too low to include PoP. Broad isentropic upglide
remains at 315K, roughly corresponding to 650-700mb. However,
moisture is beginning to thin out, especially in the lower levels.
Thinking fair conditions should be the main story despite easterly
surface flow and CAA aloft. Forecast soundings keep instability to a
minimum with dew points dropping into the 40s northwest and 50s
elsewhere. Strong CAA is noted at H85 with temps a good 8 to 10C
cooler than yesterday. Went with the middle of the road approach for
max temps, which seemed to line up well with MAV guidance. Forecast
highs range from mid 70s north central to lower 80s panhandle and
far SW. This will feel like a big change after heat index values
reached the upper 90s yesterday.

Tonight... Included a small area of schc PoP far northwest Neb,
mainly near the Pine Ridge. Weak fgen at H5-7 ahead of the next
shortwave couples with a surface front beginning to emerge from the
Rockies. Moisture slowly starts to recover as dew points rise back
into the 50s in the panhandle under southerly return flow. However,
any development should be isolated at best as most of the forcing
remains well west and moisture as a whole is still rather scarce.
Overall, partly to mostly clear skies are expected with lows
generally in the upper 50s.

Tuesday... Southerly flow strengthens and H85 temps warm again into
the mid 20s C. A surface warm front is progged to cross the forecast
area throughout the day, resulting in summerlike conditions in the
west (highs around 90F) and somewhat cooler east (mid 80s). The
front will provide sufficient forcing to fire off some thunderstorms
late afternoon into the evening, while an impulse at H7 will add
some support aloft. Moisture advection is strong yet again as dew
points reach the mid/upper 60s for much of the area. There should be
ample instability, however soundings suggest it will be elevated
with a strong cap holding until well into the evening. Confidence in
coverage and potential increases after 00z.

.LONG TERM...(Tuesday night through Sunday)
Issued at 357 AM CDT Mon Aug 10 2020

Wednesday and beyond... A broad upper ridge remains parked over the
southern Plains while a trough nudges into the northern Plains. This
setup keeps Nebraska in quasi-zonal flow aloft. Depending on the
strength of any waves rounding the upper trough and any surface
features, this pattern could be suitable for periodic thunder
chances. Perhaps the best potential comes Wednesday afternoon and
evening along a progressive dryline. Very high CAPE, modest deep
layer shear, and steep mid level lapse rates would support strong to
severe storms should any develop. Persistent southerly flow at H85
will help keep temperatures seasonably warm to slightly above
normal through the period.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1128 PM CDT Sun Aug 9 2020

For the KLBF terminal: Expect mainly clear skies overnight with
few to scattered coverage of clouds ranging from 20000 to 25000 FT
AGL. For the KVTN terminal: Skies will be mostly clear overnight,
however, there is a small threat for isolated showers and
thunderstorms to impact the terminal from 07z to 11z overnight.
Will handle this with a tempo group with some broken 10000 FT AGL
ceilings. Skies will remain partly cloudy to mostly clear on
Monday with a few clouds at 20000 to 25000 FT AGL.

&&

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

SHORT TERM...Snively
LONG TERM...Snively
AVIATION...Buttler

Hazardous Weather Outlook
National Weather Service North Platte NE
428 AM CDT Mon Aug 10 2020

NEZ004>010-022>029-035>038-056>059-069>071-094-110930-
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-
428 AM CDT Mon Aug 10 2020 /328 AM MDT Mon Aug 10 2020/

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

.DAY ONE...TODAY AND TONIGHT.

Isolated thunderstorms will be possible over northern Nebraska
through 7 AM CT. At this time, the threat for severe storms is
low.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

Thunderstorm chances continue Tuesday through Saturday. The
severe potential remains low at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed through tonight.

&&

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