Flash Flooding and Hail in Nebraska, April 25 to 26, 2024

Area Forecast Discussion
National Weather Service Hastings NE
617 PM CDT Thu Apr 25 2024

.KEY MESSAGES...

- High confidence in a widespread strong to severe thunderstorm
  event across much of the forecast area this evening/tonight.
  Many areas will see over 1 inch of rain, with localized 2 to
  3 inch amounts.

- Primary severe weather threat this evening/tonight will be
  golf ball sized hail and thunderstorm wind gusts to around 70
  mph primarily along and south of I-80. There will also be an
  isolated tornado threat mainly in our southwest (Phillips,
  Rooks, Osborne Counties in Kansas).

- Upper low will be slow to exit the area on Friday and thus
  another round of severe thunderstorms are possible Friday,
  mainly between 11 AM and 4 PM across our east and northeastern
  areas, including the possibility for isolated tornadoes in
  addition to hail and winds.

- Expect a general lull in precipitation chances Friday night
  into at least the first half of the daytime Saturday.
  Thunderstorm chances will increase late Saturday afternoon
  into the evening, with more high end severe weather possible,
  especially from the Tri-Cities and points to the south and
  southeast.

- Areas of frost are possible Sunday night, mainly to the
  northwest of the Tri-Cities as we cool down behind the
  departing storm system.

&&

.DISCUSSION...
Issued at 318 PM CDT Thu Apr 25 2024

This Evening/Tonight (Severe Weather)...

The warm front will gradually lift north and could make it into
our far southwestern counties (Rooks, Osborne, Phillips) by
around or just after sunset. The tornado threat will be limited
to areas in close proximity to this warm front across our far
southeastern zones where storms may become surface based.

Thunderstorms will quickly develop southwest of our forecast
area late this afternoon and then track east northeast into our
southwestern areas primarily after 7 PM. These storms will then
continue to track across our forecast area bringing possible
severe weather and likely heavy rain at times through the late
night/early morning hours. There is some question as to where
the southern most extent of the line of thunderstorms will set
up. All of south central Nebraska is pretty much expected to
get in on these thunderstorms tonight, but it is more
questionable how far south they will extend into north central
Kansas. But even Kansas rain chances are 70-80 percent with near
100 percent rain chances across south central Nebraska.

Added the possibility for locally heavy rainfall including
localized flash flooding to our forecast as thunderstorms could
train over the same locations tonight. Although surface based
instability/CAPE is lacking, there is plenty of MUCAPE at over
2,000 J/KG ahead of these thunderstorms tonight, especially
along and south of I-80. Therefore, large hail is certainly
possible and can also not rule out some stronger wind gusts
making it to the ground behind bowing lines of thunderstorms.

Friday (Severe Thunderstorms East and Northeast)...

The upper low is slow to exit the area and as it slows down from
previous runs we have seen the SPC severe outlook expand further
and further back to the west on Friday to include more of our
forecast area with higher threat levels. There is a concern for
tornadoes near the low across our eastern and northeastern zones
as the warm front lifts north during the late morning and early
afternoon hours. There will be little to no CIN in close
proximity to the low, so thunderstorms could redevelop very
quickly around noon or shortly thereafter. I would not be
surprised to see the future severe outlooks bring the Friday
tornado potential even further west into our forecast area.
Eventually the surface winds will turn southwest by later in
the afternoon as the low lifts northeast and the severe weather
threat will pass off to our east and northeast. Greatest severe
weather threat across our northeastern zones will be between
noon-4 PM.

Saturday (Another Severe Weather Threat)...

The next upper low is quick to eject into high plains by
Saturday afternoon/evening. The main question will center around
where the warm front sets up, but current indications are that
the warm front will be located somewhere across the southern
half of our forecast area. The atmosphere will again be very
unstable along with strong wind shear. All forms of severe
weather including tornadoes will be possible in the warm sector
northward to around the warm front. Large hail will be the
primary severe weather threat north of the warm front. The
forecast may certainly change as this is a few days away, but
keep an eye on where that warm front sets up Saturday afternoon.

Sunday into Sunday Night (Cooling back/frost?)...

We will cool down behind the departing storm system. Some
showers and thunderstorms could linger into Sunday, but the
main concern will be possible frost northwestern areas as we
clear out Sunday night.

Monday through Wednesday (Warming back up)...

Great weather returns with most locations seeing highs back into
the 70s. There are some small rain chances (20-30%) Tuesday
afternoon through Wednesday, but not looking like a big deal at
this point.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 607 PM CDT Thu Apr 25 2024

Active weather period for both Grand Island and Kearney as
the first of a couple of strong upper level systems crosses
the area in the next 24 hours.

Current expectations are IFR ceilings settling in for the
night as showers and thunderstorms become more widespread
by mid/late evening at both airports. Expect visibility
reductions in rain/fog as well. The core of the heavier
precipitation will fall through about 1-2 AM tonight but
then diminish intensity, though linger through the overnight
hours. A break in precipitation is expected through the
morning hours Friday, but the upper low will trigger
showers and thunderstorms (moreso at Grand Island for
thunderstorms) by midday. MVFR conditions are forecast
for most of the daytime hours Friday.

Strong low level jet tonight suggests some potential for
non-convective low-level wind shear. However, stronger
surface winds are expected to persist as well and thus
have not included low-level wind shear at this time.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.

&&

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

Hazardous Weather Outlook
National Weather Service Hastings NE
415 PM CDT Thu Apr 25 2024

KSZ005>007-017>019-NEZ039>041-046>049-060>064-072>077-082>087-
262115-
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-
415 PM CDT Thu Apr 25 2024

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

.DAY ONE...Tonight.

Scattered thunderstorms are forecast to develop just southwest of
the outlook area across northwestern Kansas late this afternoon,
then shift east northeast with time this evening. The
thunderstorms are most likely to move into our north central
Kansas and far southwestern Nebraska counties after 6 or 7 PM.
Large hail up to golf ball size, damaging wind gusts to 70 mph,
and a tornado or two are possible. The primary tornado threat
across our outlook area will be focused across Rooks, Phillips,
and Osborne Counties in Kansas, while the large hail and damaging
wind threat will extend well to the northeast into south central
Nebraska. Localized heavy rainfall and areas of flash flooding
will also be possible late this evening through tonight.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

The main upper level disturbance will only slowly shift through
the outlook area on Friday, so another round of strong to severe
thunderstorms will be possible, especially if development occurs
as early as late morning or early afternoon. Large hail, damaging
wind gusts, and a few tornadoes will all be possible from late
morning through late afternoon. Areas from around and to the east
and northeast of the Tri-Cities have the greatest risk.

Additional off and on thunderstorms are possible late Saturday
afternoon into Sunday, and again Tuesday evening into Wednesday.
Severe weather chances continue into Saturday, particularly for
areas around and to the east and south of the Tri-Cities.

Non-thunderstorm south to southwest wind gusts of 40 to 45 MPH
will be possible Friday afternoon, particularly for areas along
and south of the Platte River.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report any instances of severe weather
that may develop today and tonight.

&&

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

Wesely

Special Weather Statement
National Weather Service Hastings NE
643 PM CDT Thu Apr 25 2024

NEZ072-082-260030-
Gosper NE-Furnas NE-
643 PM CDT Thu Apr 25 2024

...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN GOSPER AND WESTERN
FURNAS COUNTIES THROUGH 730 PM CDT...

At 642 PM CDT, Doppler radar was tracking a strong thunderstorm near
Lebanon, or 20 miles east of McCook, moving north at 40 mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

This strong thunderstorm will be near...
  Cambridge around 655 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4035 10010 4044 10009 4044 9995 4007 10007
      4006 10019 4035 10020
TIME...MOT...LOC 2342Z 198DEG 36KT 4013 10025

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

Rossi

Special Weather Statement
National Weather Service Hastings NE
659 PM CDT Thu Apr 25 2024

NEZ060-072-260045-
Dawson NE-Gosper NE-
659 PM CDT Thu Apr 25 2024

...STRONG THUNDERSTORMS WILL IMPACT WESTERN GOSPER AND WESTERN DAWSON
COUNTIES THROUGH 745 PM CDT...

At 659 PM CDT, Doppler radar was tracking a cluster of strong
thunderstorms near Stockville, or 14 miles southeast of Curtis,
moving northeast at 40 mph.

HAZARD...Wind gusts up to 50 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

This storm will remain over mainly rural areas of western Gosper and
western Dawson Counties, including the following locations... Farnam.

This includes Interstate 80 between mile markers 209 and 232.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4104 10022 4105 9970 4042 9996 4042 10009
      4044 10009 4044 9998 4070 9998 4070 10022
TIME...MOT...LOC 2359Z 208DEG 36KT 4046 10035

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH

Rossi