Special Weather Statement, NWS Omaha, NE

Area Forecast Discussion
National Weather Service Omaha/Valley NE
631 PM CDT Thu Aug 12 2021

...Updated Aviation Forecast Discussion...

.DISCUSSION...
Issued at 307 PM CDT Thu Aug 12 2021

A look at satellite imagery this afternoon shows a line of
convection south of the Nebraska/Kansas border along a front that
has been producing sub-severe wind and hail and areas of
flooding. GOES Cloud Phase Distinction products show some cumulus
trying to develop just north of the border in the lowest 2 tiers
of counties in southeastern Nebraska that could serve as the area
with the highest chances for any remaining convection this
afternoon. CAMs have struggled with the storms to the south all
morning, and their presence of these storms has likely overturned
much of the instability in that relative area. That convection
along with the cirrus wafting northward has reduced the overall
storm chances this afternoon and evening. Another aspect of the
forecast that was affected by the action to the south was the heat
in far southeastern Nebraska, where temperatures at KFNB have
only achieved 87 degrees this morning before falling back to the
lower 80's. CAMs have been showing signals for some elevated
convection this evening, beginning just south of a line from York
to Clarinda after 06z that marches towards the NE/KS border into
early Friday morning. With how poorly the CAMs handled convection
earlier today, questions arise in terms of the extent of the
overnight chances but they are there nevertheless along a gradient
of elevated instability.

Going forward into Friday through the weekend, a sharp change from
the regular 90+ degree heat that we have seen across the area is
expected. Highs are expected to largely stay in the low-to-mid
80's, and will make for a wonderful weekend of weather for the
area. Passing shortwaves in the northwesterly flow could trigger
some sporadic rain and storm chances through the weekend, but
severe weather is not expected.

Monday through Wednesday is expected to feature a change in the
upper pattern as the ridge over the western CONUS gradually
deamplifies ahead of a somewhat deep trough that reaches the
ID/MT/WY region Wednesday. Ensemble situational awareness tables
indicate that the southerly winds ahead of the trough could be
rather gusty, and could indicate some increasing temperature trend
as well. An uncertain feature that models aren't agreeing upon is
a shortwave trough that dips southeast from Wyoming Monday, and
makes it to eastern Kansas by Wednesday. If this feature pans out,
it could serve as a source for shower and storm chances ahead of
the approaching trough.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 631 PM CDT Thu Aug 12 2021

VFR conditions expected to prevail with northeast to east winds
remaining light through most of the period. Earlier indications of
potential shower and thunderstorm development overnight near KLNK
are still there, but latest trends have kept activity farther
south. Therefore, keeping a dry TAF at this time, but can't
completely rule out a stray shower/storm sneaking in and leading
to brief MVFR conditions somewhere in the 8 to 11Z window.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&

DISCUSSION...Petersen
AVIATION...CA

Hazardous Weather Outlook
National Weather Service Omaha/Valley NE
358 PM CDT Thu Aug 12 2021

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-131100-
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-
358 PM CDT Thu Aug 12 2021

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

.DAY ONE...Tonight and Friday

Thunderstorms are possible overnight into early Friday morning
south of a line from Seward to Clarinda. Severe activity with
these storms is not expected at this time.

.DAYS TWO THROUGH SEVEN...Friday night through Thursday

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation should not be needed.

Special Weather Statement
National Weather Service Omaha/Valley Nebraska
937 PM CDT Thu Aug 12 2021

NEZ078-088-130300-
Jefferson NE-Saline NE-
937 PM CDT Thu Aug 12 2021

...A strong thunderstorm will impact portions of northwestern
Jefferson and southwestern Saline Counties through 1000 PM CDT...

At 936 PM CDT, Doppler radar was tracking a strong thunderstorm 6
miles northeast of Alexandria, or 31 miles west of Beatrice, moving
east at 25 mph.

HAZARD...Winds in excess of 30 mph and penny size hail.

SOURCE...Radar indicated.

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

This strong thunderstorm will be near...
  Western around 950 PM CDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4042 9737 4042 9720 4024 9718 4024 9737
TIME...MOT...LOC 0236Z 267DEG 23KT 4034 9734

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...30 MPH

DeWald

Special Weather Statement
National Weather Service Omaha/Valley Nebraska
953 PM CDT Thu Aug 12 2021

NEZ078-088-089-130400-
Jefferson NE-Gage NE-Saline NE-
953 PM CDT Thu Aug 12 2021

...Strong thunderstorms will impact portions of northern Jefferson,
southern Saline and northern Gage Counties through 1100 PM CDT...

At 953 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 4 miles northwest of Pickrell to 6 miles west
of Plymouth to Alexandria. Movement was east at 25 mph.

HAZARD...Winds in excess of 40 mph and penny size hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Beatrice, Fairbury, Wilber, De Witt, Cortland, Plymouth, Western,
Clatonia, Pickrell, Adams, Daykin, Jansen, Tobias, Swanton, Harbine,
Swan Creek Wildlife Management Area, Alexandria State Recreation Area
and Cub Creek Recreational Area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4043 9737 4052 9691 4052 9646 4035 9647
      4021 9686 4011 9737
TIME...MOT...LOC 0253Z 262DEG 22KT 4040 9680 4032 9711 4023 9740

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

CA