Damaging Winds and High Wind in Nebraska, July 13 to 14, 2020

AREA FORECAST DISCUSSION
National Weather Service Hastings NE
626 PM CDT Mon Jul 13 2020

.SHORT TERM...(This evening through Tuesday)
Issued at 226 PM CDT Mon Jul 13 2020

Main concern in the short-term is the threat for severe storms this
evening. A few thunderstorms are already starting to bubble up
over the Nebraska panhandle, and these are expected to become more
numerous later this afternoon, especially in the vicinity of the cold
front draped across the Sandhills. SBCAPE in this area is around
4000J/kg, which will initially support threat for large hail, but
CAMs agree that these storms will evolve into more of a wind
threat as they organize into one or more cold-pool driven
clusters. Even so, there is certainly some uncertainty on how far
south and east the severe threat extends. Some models, especially
the HRRR, appear to weaken updrafts rather quickly as storms
enter central Nebraska. There may be a couple factors leading to
this. The first may be increased inhibition farther south and
east, and the second may be lackluster wind shear for overnight
MCS maintenance.

All that being said, the bottom line is that we should still be
prepared for the possibility of damaging wind, particularly for
locations northwest of a line from Cambridge to Grand Island to
Fullerton. Unfortunately, this certainly won't be a widespread
rainfall producer. Rainfall amounts are looking pretty meager on the
latest HRRR runs. Many locations, especially south of I-80, will
stay dry or mostly dry.

A few showers or thunderstorms could linger into the morning hours
of Tuesday, but I expect it to be primarily dry. More notably, the
cold front will sweep through the area Tuesday morning ushering in
northerly winds and significantly cooler, drier air. The latest
model blend also hints strongly at some stratus building in behind
the front as well. Given this stratus and the timing of the front,
we will likely end up with a very large spread in temperatures.
Northern zones may only reach the low 70s, while the far south could
reach the low 90s just ahead of the front around midday.

.LONG TERM...(Tuesday night through Monday)
Issued at 226 PM CDT Mon Jul 13 2020

Despite the drier post-frontal airmass, chances for rain and
thunderstorms return Tuesday evening and overnight as a compact wave
rounds the base of the upper trough and we move into the right-
entrance region of a 100kt upper level jet. In fact, we could end up
with more widespread precip with this event than this evening. SPC
has kept the entire area in a marginal risk during this timeframe,
which seems reasonable given the RAP showing around 3000J/kg of CAPE
and 30kts of bulk shear.

Mild temperatures continue on Wednesday as surface high pressure
slides southward into the area. This should also quell any chance
for thunderstorms Wednesday or Wednesday night.

We will start to see warmth and moisture return on Thursday, and a
few thunderstorms are possible again Thursday evening and overnight.

The warmup continues Friday and Saturday, with highs expected to
push well into the 90s to low 100s by Saturday. Most areas will
have heat index values of at least 100 degrees, and some could top
105, especially on Saturday. Heat headlines will need to be
considered later this week. Despite the increasing heat/humidity,
700mb temperatures around 16C should keep us effectively capped
and dry during this period. A shortwave approaching from the NW
CONUS is then anticipated to bring the next chances for storms,
and possibly a minor cooldown in the Sunday or Monday timeframe.

&&

.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday)
Issued at 624 PM CDT Mon Jul 13 2020

Thunderstorms will be moving in from the west during the evening.
KEAR will have better chances for thunderstorms than KGRI. MVFR
ceilings are expected behind a cold front that moves through late
tonight/early Tuesday morning.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

SHORT TERM...Mangels
LONG TERM...Mangels
AVIATION...JCB

Hazardous Weather Outlook
National Weather Service Hastings NE
235 PM CDT Mon Jul 13 2020

KSZ005>007-017>019-NEZ039>041-046>049-060>064-072>077-082>087-
141200-
Phillips-Smith-Jewell-Rooks-Osborne-Mitchell-Valley-Greeley-Nance-
Sherman-Howard-Merrick-Polk-Dawson-Buffalo-Hall-Hamilton-York-
Gosper-Phelps-Kearney-Adams-Clay-Fillmore-Furnas-Harlan-Franklin-
Webster-Nuckolls-Thayer-
235 PM CDT Mon Jul 13 2020

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

.DAY ONE...This Afternoon and Tonight.

Scattered thunderstorms are expected to approach the Highway 283
corridor around 8pm. Activity will continue to spread east and
northeast through the evening and into the overnight. Severe
weather is possible across the entire outlook area, though the
greatest risk for severe thunderstorms, including damaging wind
gusts of 60 to 70mph, will be northwest of a line from Fullerton
to Grand Island to Cambridge. Large hail looks to be a lesser
threat, but can't be ruled out. The risk for severe weather will
decrease after midnight.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Lingering thunderstorms should exit the area Tuesday morning.
Additional thunderstorms are in the forecast for Tuesday night.
Some of these may be strong to marginally severe south of
Interstate 80, with large hail the main concern.

Thunderstorms will again be possible Thursday and Sunday, but it
is too soon to determine severe weather potential.

Hot temperatures will expand across the entire area Friday
through Sunday. Heat indices of 100 to 105 degrees are currently
forecast. Please stay tuned to later forecasts as a Heat Advisory
may be need for portions of the outlook area.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will may be needed between 7pm and 1am
tonight.

&&

More information may be obtained at the following web page:
   https://www.weather.gov/hastings