Tornadoes and Hail in Nebraska, October 3, 2023

AREA FORECAST DISCUSSION
National Weather Service Hastings NE
256 PM CDT Tue Oct 3 2023

.DISCUSSION...(This evening through Tuesday)
Issued at 256 PM CDT Tue Oct 3 2023

Key Messages:

* Severe weather risk in the first 6-7 hours of the forecast is
  foremost key message.

* Increasing likelihood of freezing/sub-freezing temperatures
  Saturday morning (coldest morning), which seems to be a bit
  colder and more widespread in recent model runs.

* After tonight...and aside from a trace/passing showers rain
  event early Friday,the forecast is dry.

Satellite imagery clearing depicts a sharp short wave lifting into
east central Colorado at this time. Ahead of the wave,
thunderstorms have fired, albeit maybe a bit farther west that
expected. While the dynamics are there, instability has been
marginal due to limited low level moisture. Dewpoints are not
terrible for October 3rd, but when combined with lots of cloud
cover the previous six hours, instability has been somewhat
limited. Shear is strong and possibly a touch too strong.
Nonetheless, a severe thunderstorm is posted for western areas
through 8 pm, and this reasonable as the strong upper dynamics
move into that region of best instability profile. Eventually a
more organized line type structure will develop and the line will
translate more west to east than the current rapidly northeast
movement of individual thunderstorms. Overall tornado risk is
somewhat higher than climatology obviously, but shear profiles do
favor more straight-line hodographs and thus straight-line winds
rather than tornadoes, and so the main focus is hail and wind
gusts.

Eventually, the clusters of storms will organize into a line
structure by 5-6-7pm and move east. With strong dynamics
the push of the storms should be quickly east in the early
evening with localized wind gusts/hail possible. However, once
the sun goes down this time of year (about 7:15 pm), it can be
hard to sustain intense convection, especially given seemingly
lacking instability to start with. All of the storms should clear
the eastern/southeast forecast area by about 9 pm with rapid
clearing thereafter.

Looking ahead...after several days of temperatures averaging
nearly 20 degrees above normal, the next few days are at or below
normal before warming returns.

Wednesday brings a nice day to the region, with surface high
pressure quickly moving into the area by afternoon. Temperatures
will be much closer to normal for early October. Another quick
moving, but dry front, will rapidly move through early Thursday
and shift winds to the northwest and keep temperatures at or
slightly below seasonal normals. A bit more cloud cover will linger
in the morning but should give way to afternoon sunshine.

The main cold push is the strong front which trails its way
across the area late Thursday night/early Friday morning. This is
the coldest air of the fall season with gusty northwest winds all
day Friday. The European model is pretty aggressive with at least
some showers accompanying the front, but other models not so
much. The small chance for showers late Thursday night and Friday
morning is primarily reflective of the European models output to
be honest, as the GFS/CMC are mostly dry. right now, whatever
falls, if anything, should be light and remain a very limited, if
not dry event.

Its the temperatures that matter behind the front.
Models/guidance seems to be hedging colder, thanks to the surface
ridge axis forecast to settle right across the forecast Saturday
morning. Freeze potential (32 degrees or less) for much of the
forecast is looking higher, with even some hard freeze potential
(28 degrees) in the favored cold areas around Lexington, Ord and
Greeley. About the only area currently forecast to escape a freeze
are parts of Mitchell, Jewell and Osborne counties. However, we
have seen valleys across north central Kansas easily getting
colder than expected in years past, so I am not sure any part of
the area is out of the woods for a freeze. Bottom line is late
Friday night and Saturday is a solid frost/freeze headline
timeframe at this point.

Saturday night will be another chilly night (30s) but not as cold
in general. We will reevaluate the need for frost/freeze
headlines for Saturday night/early Sunday after seeing how the
previous night pans out.

After that, its upper level ridging and dry conditions. Ensembles
point toward above normal temperatures, and once again really
quite pleasant for the time of year. Winds will also drop off
again and actually look pretty light Sunday through Tuesday.

&&

.AVIATION...(For the 18Z KGRI/KEAR TAFS through 18Z Wednesday)
Issued at 1229 PM CDT Tue Oct 3 2023

The main challenge for the forecast is within the first 9 hours.
Some showers moving through the KGRI now will pass east and
leave a break for a couple hours, before more widespread
thunderstorms develop in advance of an approaching shortwave
in Colorado. Included a prevailing thunderstorms for the late
afternoon hours for both locations, before a cold front
moves through and sweeps things east by early evening. The
front/storms will exit Kearney first and Grand Island about
an hour later. Some MVFR ceilings and visibilities are expected
with the afternoon precipitation for 3-4 hours due to the fairly
widespread coverage expected.

Once the actual thunderstorms/front clears both airports,
VFR conditions are expected overnight with only passing high
clouds and westerly winds.

&&

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

DISCUSSION...NOAA/NWS/Moritz
AVIATION...NOAA/NWS/Moritz

Hazardous Weather Outlook...CORRECTED
National Weather Service Hastings NE
156 PM CDT Tue Oct 3 2023

KSZ005>007-017>019-NEZ039>041-046>049-060>064-072>077-082>087-
041200-
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-
156 PM CDT Tue Oct 3 2023

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

.DAY ONE...This Afternoon and Tonight.

A severe thunderstorm watch is posted for parts of south central
Nebraska and north central Kansas until 8 pm, and includes areas
generally along and west of a line from Greeley Nebraska, to Red
Cloud, to Osborne Kansas.

Thunderstorms will increase in coverage across most of the
area this afternoon. Through 6 pm, severe thunderstorms capable
of large hail to the size of tennis balls and damaging
thunderstorm winds will be possible, especially in the watch area.
An isolated tornado can't be ruled out either. The thunderstorms
this afternoon should generally move northeast at speeds up to 45
mph.

Between 5 and 7 pm, thunderstorms will become more organized
into a line and move from west to east across the area. The
main hazard with the line will be wind gusts in excess of 60 mph,
though there will still be some risk for quarter to half dollar
size hail into the early evening hours.

All of the storms will move east and out of the area by 10 pm
tonight.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Sub-freezing temperatures are looking more likely Friday night
into Saturday morning across a good portion of the area. Lows
should easily dip into the lower 30s across much of the area, with
some locations west and north of Grand Island possibly dropping
into the upper 20s. This could harm outdoor vegetation and damage
unprotected hoses and sprinklers.

Saturday night and early Sunday morning is expected to be a bit
warmer, but areas of frost are possible again as temperatures dip
to the mid 30s.

.SPOTTER INFORMATION STATEMENT...

Reports of severe weather and rainfall will be greatly
appreciated.

&&

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

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