Hail in Nebraska, April 28, 2025

Area Forecast Discussion
National Weather Service Omaha/Valley NE
Issued by National Weather Service Hastings NE
353 PM CDT Mon Apr 28 2025

.KEY MESSAGES...

- Severe weather remains possible along a dry line, ahead of a
  strong cold front, and primarily southeast of the Omaha metro
  area through 8 PM where an enhanced risk exists. If storms
  develop, they would be capable of very large hail, damaging
  winds, and isolated tornadoes.

- Red Flag Warning is in effect from Lincoln and points to the
  west and southwest through 8 PM, behind the dry line, where
  precipitation is unlikely to occur.

- There's an additional risk for severe storms early this
  evening mainly through 8 PM across northeast NE along the
  cold front, with hail up to one inch and winds up to 60 mph
  possible.

&&

.DISCUSSION...
Issued at 251 PM CDT Mon Apr 28 2025

Severe Weather Threat...
At 3 PM the dry line was located from around Decatur...to
Fremont...to Lincoln...to Beatrice and was sliding east.
Dewpoints just ahead of this dry line were still in the 60s to
even around 70 across portions of western Iowa. Dewpoints
quickly fall behind the dry line and were already down to around
40 degrees in York and points west into central Nebraska.

Dry Line (Southeastern CWA Severe Threat)...
Towering CU at 3 PM indicate that thunderstorms could begin to
fire along this dry line at any point over the next few hours.
Forecast models differ widely on how extensive convection will
be along the dry line and how quickly it will form. The 18Z NAM
NEST is one of the most aggressive models with afternoon
convection along the dry line and probably too aggressive, but
even the NAM NEST holds off on the most significant convection
until the dry line is located over the Richardson/Nemaha County
area northeast into Shenandoah and Red Oak IA. The 19Z HRRR is
less aggressive with dry line convection and holds off until
after 6 PM mainly in that same area from Richardson County
northeast towards Red Oak. Thunderstorms are far from certain
and in fact our POPs for most of eastern Nebraska are generally
around or less than 20 percent ahead of the dry line until you
get down into the Nemaha/Richardson County area up to Red Oak
where we see POPs climb to closer to 50 percent.

Although it may be difficult to get storms to form, once they
form and get established they could quickly become severe with
high end severe weather possible, especially large hail
(baseball size), damaging winds (60-75 mph), and even tornadoes.
We are expecting MLCAPE values to around 3000 J/KG with 0-6KM
deep layer shear values over 55 kts, which is all very favorable
for high end severe weather. However, the hodographs are not
perfectly curved and have a bit of a kink in them, which is less
than ideal for tornadoes along with the somewhat veering
surface winds (south southwest surface winds). That could limit
the overall tornado threat, but not completely negate it as we
are still expecting 0-1 km low level shear values around or
better than 20 kts and effective low level helicity values of
around 200 m2/s2. Again the greatest threat for higher end
severe weather is across our southeastern most counties.

Cold Front and Severe Threat Northeast Nebraska...
The forcing is pretty strong along the cold front across
northeastern Nebraska and most forecast models generate
at least scattered thunderstorms across our far northeastern
zones through 8 or 9 PM. The environment is still supportive
for severe storms in this area, but not as impressive as ahead
of the dry line. MLCAPE values along the cold front in our
northeast are around 1000 J/KG. At this point it seems like we
would be looking at the lower end severe potential with these
northeastern CWA storms of quarters and 60 mph winds.

Tuesday and Wednesday...
It will be much cooler behind the cold front with highs mainly
in the 60s, but with the winds getting lighter through the day.
Warm air advection aloft Tuesday night will bring a return to
shower and thunderstorm chances especially after midnight with
those precipitation chances lingering into Wednesday. Best
chances for appreciable rainfall of greater than 0.25 inches
will be across southern and southeastern zones. Wednesday will
remain cooler with the clouds and possible rain, once again
highs in the 60s.

Thursday through Sunday...
Temperatures warm back up into the 70s with rain chances mainly
lingering in our southeast on Thursday and then again ahead of
the next storm system perhaps as early as Sunday. But we do
expect several dry days in there with upper level ridging
Friday and Saturday.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1243 PM CDT Mon Apr 28 2025

The chance for thunderstorms at our TAF sites is rather low and
for the most part below 20 percent, thus am not including
mention of thunderstorms in the TAF at this point in time. The
probability for thunderstorms will increase as you head north of
KOFK and southeast of KLNK and KOMA. Although we can not rule
out a brief thunderstorm at any of our TAF sites this evening,
the more likely scenario is that we will have the dry slot move
through before thunderstorms can develop. Scattered to broken
low clouds over the area this afternoon will eventually give way
to clear skies behind the front later this afternoon/evening.
The winds will veer with time this afternoon and evening as the
front approaches and then become northwesterly behind the cold
front tonight.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Red Flag Warning until 8 PM CDT this evening for NEZ050-065-
     066-078-088.
IA...None.

&&

DISCUSSION...WESELY
AVIATION...WESELY

Hazardous Weather Outlook
National Weather Service Omaha/Valley NE
Issued by National Weather Service Hastings NE
146 PM CDT Mon Apr 28 2025

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-290900-
Monona-Harrison-Shelby-Pottawattamie-Mills-Montgomery-Fremont-
Page-Knox-Cedar-Thurston-Antelope-Pierce-Wayne-Boone-Madison-
Stanton-Cuming-Burt-Platte-Colfax-Dodge-Washington-Butler-
Saunders-Douglas-Sarpy-Seward-Lancaster-Cass-Otoe-Saline-
Jefferson-Gage-Johnson-Nemaha-Pawnee-Richardson-
146 PM CDT Mon Apr 28 2025

This Hazardous Weather Outlook is for portions of southwest
Iowa...west central Iowa...east central Nebraska...northeast
Nebraska and southeast Nebraska.

.DAY ONE...This Afternoon and Tonight

Isolated to scattered severe thunderstorms are possible this
afternoon through 8 PM, especially along and east of a line from
Sioux City to Lincoln as a dry line moves into the area.
Destructive hail up to three inches in diameter, damaging winds,
and isolated tornadoes are all possible.

Another smaller area of severe potential could materialize this
evening across northeast Nebraska as the cold front moves into the
region. Locally damaging winds and hail to quarter size would be
the main hazards in this area 5 PM to 8 PM.

In addition, extreme fire conditions could develop behind the dry
line this afternoon, west and and southwest of Lincoln. In this
area, a red flag warning will be in effect through 8 PM, due to a
combination of very warm temperatures, low humidity, and gusty
south southwest winds.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

If storms develop, spotter activation could be needed this
afternoon/evening.

Wesely