Flash Flood and Heavy Rain in Nebraska, July 21, 2025

Area Forecast Discussion
National Weather Service Omaha/Valley NE
634 AM CDT Mon Jul 21 2025

.KEY MESSAGES...

- Considerable uncertainty exists in thunderstorm potential
  again today and tonight. Where thunderstorms occur, locally
  strong wind gusts and/or heavy rain are possible.

- Dangerous heat develops Monday through Wednesday, with heat
  indices up to 100-109.

&&

.DISCUSSION...
Issued at 300 AM CDT Mon Jul 21 2025

Today through Wednesday...

A few supercells surged over north central Nebraska overnight,
but eventually lost their steam as they made it into northeast
Nebraska. Temperatures remained warm, only dropping into the mid
to upper 70s by 2 AM.

An upper ridge will begin to build over the Mississippi River valley
region today, bringing high pressure and moist southerly low level
flow over the Central Plains. Temperatures will push into the upper
80s and low 90s today. The hot temperatures combined with dewpoints
in the mid to upper 70s will push heat indices up to 100-105. **A
Heat Advisory will remain in effect for most of eastern Nebraska and
western Iowa from noon until 8 PM today.

Temperatures will warm a few more degrees, into the mid to upper 90s
Tuesday and Wednesday, ahead of an approaching cold front. This will
draw heat index values up to 100-110, which will likely necessitate
additional Heat headlines in the coming days.

The high pressure over the region should help maintain the capping
inversion, limiting precipitation throughout the day. That being
said, latest CAM runs have tried to blow up convection over the
southern half of the area this afternoon. Confidence is low that
this particular scenario will actually occur, but given ample
instability over the region, it looks worthy of 15-20% PoPs, just
in case that cap does break. Additionally, an increasing low
level jet could drive a few showers and storms through the area
during the evening and overnight hours, leading to more Slight
chance PoPs tonight. A better chance for precipitation will
arrive with the passage of the cold front Wednesday evening and
overnight, when a few strong to severe storms could be possible.

Thursday through Next Weekend...

Additional 20-40% PoPs will remain in the forecast as the surface
boundary lingers in the region through the end of the week.  Highs
will remain warm, yet seasonable behind the front, reaching into the
upper 80s and low 90s Thursday through Friday.

Ridging is forecast to amplify over the central CONUS next weekend,
potentially leading to another round of intense summer heat.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 629 AM CDT Mon Jul 21 2025

A deck of low-level stratus clouds and patchy fog is bringing
MVFR to patchy LIFR conditions across western Iowa into extreme
eastern Nebraska. Conditions will gradually improve through the
morning with VFR conditions returning to all terminals by
16-18Z. Winds will remain out of the south- southeast at 8-12
kts. A thunderstorm complex may develop (20% chance) across
southeast Nebraska from 7/21 20Z - 7/22 02Z, potentially
impacting KOMA and KLNK. However, confidence is low in
thunderstorm coverage and evolution at this time so this
potential has not been included in the current TAF issuance.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Heat Advisory from noon today to 8 PM CDT this evening for
     NEZ011-012-015>018-030>034-042>045-050>053-065>068-078-
     088>093.
IA...Heat Advisory from noon today to 8 PM CDT this evening for
     IAZ055-069-079-080-090-091.

&&

DISCUSSION...KG
AVIATION...Wood

Hazardous Weather Outlook
National Weather Service Omaha/Valley NE
342 AM CDT Mon Jul 21 2025

IAZ043-055-056-069-079-080-090-091-NEZ011-012-015>018-030>034-
042>045-050>053-065>068-078-088>093-212245-
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-
342 AM CDT Mon Jul 21 2025

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

.DAY ONE...Today and Tonight

A Heat Advisory is in effect for this afternoon and evening when
heat indices will reach 100-109.

Considerable uncertainty exists in thunderstorm potential
again today and tonight. The best chance for locally strong wind
gusts and/or heavy rain will be between 2PM to 10 PM this evening.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Dangerous heat continues through Wednesday, with heat indices up
to 100-109.

Another round of dangerous heat looks possible next weekend.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected.