149
FXUS63 KOAX 151103
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
603 AM CDT Tue Jul 15 2025

.KEY MESSAGES...

- There is a 50-80% chance of storms mainly after 5 PM today,
  with a 15-40% chance of severe storms, highest in northeast
  Nebraska. The primary threats are damaging winds and localized
  flooding, but some hail and a brief tornado are also
  possible as storms first develop.

- Additional rounds of storms will continue Wednesday into early
  Thursday, and again Friday evening into the weekend. Severe
  weather will be possible at times, with the threat of flooding
  increasing with each successive round.

- Cooler on Thursday with highs in the lower to mid 70s, but we
  quickly warm back up with 80s Friday and mid 80s to lower 90s
  for the weekend into next week.

&&

.DISCUSSION...
Issued at 344 AM CDT Tue Jul 15 2025

Very quiet early this morning as we remained under the western
periphery of upper level ridging while some debris cloud cover
from decaying convection well off to our northwest was pushing
through. Temperatures as of 3 AM were in the upper 60s to mid
70s.

The main story today will be severe weather chances this
afternoon into this evening and possibly into the very early
morning hours of Wednesday. Features of note early this morning
were a surface cold front slowly pushing south of the ND/SD
border, a lee cyclone over eastern WY, and some shortwave energy
moving east through MT/ID/WY. The front will continue southward
today approaching the NE/SD border by this afternoon with the
shortwave pushing into the NE panhandle around the same time.
Meanwhile, the surface low will meander southward into CO with
the main result of that being the low level jet/moisture
transport tonight pointing into central and southeast NE as
opposed to SD. Ahead of these features today, expect a warm,
humid, and unstable airmass to develop with temperatures in the
upper 80s to mid 90s and dewpoints in the upper 60s to lower 70s
combining with steep mid-level lapse rates to lead to SBCAPE
values of 2000-3000+ J/kg across central into northeast NE.

As the front and shortwave push in, expect thunderstorm
development in north-central NE into south-central SD in roughly
the 2-4 PM timeframe. Initial cells will pose some hail threat,
but lack of deep layer shear will keep things a bit
disorganized and strong forcing will lead to an MCS development
not long after storm initiation. As a result, expect a quick
transition to a damaging wind and heavy rain/localized flooding
threat. The big question will be how far southeast does the
primary wind threat extend, as 0-3 km shear in the 20-25 kt
range won`t be enough to keep the storms from becoming outflow
dominant. In addition, instability really tapers off as you move
into southeast NE, so would expect an overall weakening trend
anyway, though moisture transport pointing into the area should
keep things going for a bit. Regarding the heavy
rainfall/flooding threat, guidance is in decent agreement that
storms should move through pretty quickly, and precipitable
water values of 1.50-1.75" and warm cloud depths around 3500 m
don`t exactly scream high end flooding threat. However, they`ll
still be decently efficient rain-producing storms and given
fairly saturated soils, it wouldn`t take much training to lead
to some localized flooding. Finally, should mention that there
is a small tornado threat (2% chance per SPC outlook), but this
would likely be confined to the areas where storms first go up
and before they become outflow dominant, so for us, the most
likely area would be in northeast NE, with the threat likely
significantly dropping off as storms push southeast.

Expect some lingering storms into early Wednesday as CAMs
depict an MCV feature pushing into northwest IA while the
surface front remains in the forecast area. The big question
continues to be how far south the front is able to make it
Wednesday, with guidance still somewhat split on keeping it in
the forecast area and pushing it into KS/MO. Wherever it sets
up, expect storm re-development Wednesday afternoon/evening with
guidance suggesting a another very unstable airmass near and
south of the boundary. For what it`s worth, HREF guidance
suggests about a 60% chance the front is south of I-80, and I
tend to lean toward farther south solutions with precip likely
helping it to push farther south, but still enough model spread
that it`s definitely worth keeping an eye on. Wherever storms do
occur, expect mainly a damaging wind and heavy rain/flooding
threat, with probably a higher risk of training thunderstorms in
this particular setup.

Precip looks to come to an end early in the day Thursday as
surface high pressure builds in. Behind the front, temperatures
will struggle to get out of the mid-70s, which is more in line
with a late September day than mid-July. However, the cooler
weather will be short-lived as surface high pressure quickly
pushes off to the east Thursday night and southerly flow returns
Friday, with the surface boundary pushing back north as a warm
front. Expect highs back in the 80s Friday with mid 80s to lower
90s for the weekend and into early next week. We`ll also
continue to see on and off storm chances as various bits of
shortwave energy push through and interact with the boundary.
Basically, we have a 20-40% chance of storms each day Friday
through next Tuesday, with evening and overnights currently
favored. However, still quite a bit of spread and lots of
details to work out between now and then. There will likely be
some occasional severe weather chances in there as well,
especially for flooding given potential repeated rounds, but
current machine learning algorithms only suggest about a 5%
chance any given day, likely owing to the model spread.

&&

.AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/...
Issued at 602 AM CDT Tue Jul 15 2025

VFR conditions expected with south winds around 10 kts (some 20+
kt gusts at OFK) and some passing clouds around 5000-7000 ft
during the day. A line of storms will then move in this evening,
potentially bringing severe wind gusts, especially in northeast
Nebraska, including OFK. Still some questions on timing and how
far southeast storms will make it, with some guidance suggesting
OMA and LNK barely get anything, but tend to think there will at
least be some storms around. Winds will shift to northwesterly
behind storms with MVFR ceilings moving into OFK, but likely
staying north of OMA and LNK through 12Z.

&&

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

&&

$$

DISCUSSION...CA
AVIATION...CA