993
FXUS63 KOAX 221734
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1234 PM CDT Tue Apr 22 2025

.KEY MESSAGES...

- There will be a few showers possible today, with a strong to
  severe storm or two possible in far southeast NE and southwest
  IA by evening.

- Expect several additional chances for thunderstorms Wednesday
  through Friday, and again by late Sunday.

&&

.DISCUSSION...
Issued at 259 AM CDT Tue Apr 22 2025

Early Tuesday morning, a convective complex that brought a
multi-county-long strip of severe hail to the local area late
Monday evening, was moving east across central and eastern
Iowa. A cool front extended from west central Iowa to near
Fremont, and then northeast. This front was dropping southeast
and should be in far southern NE/IA by mid morning where it will
stall out. There area few light showers north of the front in
south central NE, but are generally struggling to reach the
ground. There is a slight chance for a shower amidst the general
frontal zone over the southern area today, but most any
meaningful precip should wait until late in the day or
overnight. The stalled frontal zone over the area will provide a
focus for boundary layer convergence. It will be weak, but
persistent. There are also indications of a weak disturbance
moving along the front and into the local area by late
afternoon. This may be just the extra bit of lift needed to
initiation thunderstorms in the frontal zone, probably near and
south of a Fairbury to Red Cloud line after 4 PM. It does
appear that a high LFC and some dry air in the boundary layer
may overall be inhospitable to an organized severe threat.
However, if storms develop and persist, one or two could
organize and become strong given sufficient deep layer shear
and modest instability. Any severe weather would likely be in
the from of localized damaging winds, or perhaps a bit of hail.

A weak low level jet will develop late tonight, with some
moisture transport aloft into the forecast area. Models are
currently very limited in terms of precip production late
tonight, but forecast soundings indicate the presence of
uncapped elevated instability, and while large scale forcing is
limited, zones of convergence on the LLJ may be sufficient lift
for convection to initiate. If storms do develop, there would be
sufficient instability and effective shear to support a hail
threat, mainly very late tonight.

Getting into Wednesday, a compact short wave trough will bring a
more focused zone for ascent across the southern half of the
forecast area. Thunderstorm coverage will increase, especially
over southern NE and IA. Then throughout the day and through
Thursday night, the front will act as a loose focus for
multiple rounds of thunderstorms as several weak short wave
impulses move overhead with speed divergence aloft and varying
degrees of convergence in the lower levels. Overall instability
will be limited with an abundance of clouds and convective
overturning, but the scattered rain and storms will eventually
overspread the entire forecast area. The rain is unlikely to be
constant, but off-and-on for a prolonged period, possibly
leading to more than an inch of rain for a good chunk of the
area, and probably exceeding two inches in some locations south
of I-80. The likelihood of flooding issues is pretty darn low,
but there is a bit of potential with multiple rounds of
convection expected. The severe threat will be on the low- but-
non- zero side as any intermittent periods of sunshine or
heating will quickly destabilize...but shear profiles are pretty
unimpressive at times.

Ensemble guidance is in pretty solid agreement that the front
will push through the entire forecast area on Friday, possibly
drying the area out for a bit before the western CONUS low
deepens again later in the weekend. This deepening trough will
lift a warm front and LLJ into our area again with storm chances
increasing as early as late Saturday. Sunday and Monday, and
perhaps into Tuesday, are showing signs of severe weather
potential with strengthening mid and upper flow over
increasingly rich Gulf moisture in much of the Plains. The
overall severe potential will depend on timing/location of
surface fronts, but pattern recognition and an ingredients based
approach point to severe potential on some/all of these days.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1234 PM CDT Tue Apr 22 2025

VFR conditions favored through much of the period with passing
mid level clouds. Winds will generally remain below 10 kts, out
of the northeast to start, but eventually easterly to
southeasterly at OMA and LNK. Could see a few showers and storms
this evening/overnight, but they should remain south and east of
TAF sites. Additional showers and isolated storms are expected
to develop toward mid morning, near and southeast of an OMA/LNK
line. For now just included -SHRA with MVFR ceilings, but may
eventually need -TSRA.

&&

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

&&

$$

DISCUSSION...Barjenbruch
AVIATION...CA/Petersen