068
FXUS63 KOAX 152225
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
525 PM CDT Sun Sep 15 2024

.KEY MESSAGES...

- Temperatures are expected to remain above-normal through the
  work week with highs in the 80s.

- A 20-30% chance of showers and thunderstorms tonight into
  Monday morning, and Monday night into Tuesday morning.

- More widespread showers and thunderstorms are possible
  (40-60%) Tuesday night into Wednesday morning, and Friday
  through Saturday.

&&

.DISCUSSION...
Issued at 259 PM CDT Sun Sep 15 2024

Tonight and Monday:

A subtle shortwave trough over UT as of early afternoon will
translate into the northern High Plains tonight. The low-level
mass response to that feature will be reflected in the
development of a nocturnal low-level jet (LLJ) across the
central Plains. Warm thermal and moisture advections occurring
along the LLJ axis are expected to contribute to the development
of a north-south band of widely showers and thunderstorms
(20-30% PoPs) across our western counties toward daybreak
Monday. That convection is expected to decrease in areal
coverage while slowly shifting east through the morning. In
general, precipitation should be relatively light. However,
localized 0.25" amounts appear possible.

Convective cloud debris will likely linger through the morning
with decreasing cloudiness by afternoon. Highs may end up a tad
cooler than today with readings in the mid to upper 80s.

Monday night and Tuesday:

A nocturnal LLJ is forecast to develop again Monday night from
the central High Plains into the eastern Dakotas and western MN.
A number of the 12z models indicate QPF on the eastern edge of
the LLJ, across northeast NE late Monday night into Tuesday
morning. Accordingly, 20-30% PoPs will be maintained in the
forecast to account for that scenario. Clouds cloud linger a
bit longer on Tuesday (compared to Monday) with highs in the low
to mid 80s.

Tuesday night through Thursday night:

The 12z models are in reasonably good agreement in suggesting
that a vigorous shortwave trough will overspread the northern
and central Plains Tuesday night into Wednesday morning. Forcing
for ascent attendant to that feature is expected to foster a
north-south band of showers and thunderstorms that will move
into eastern NE late Tuesday night into Wednesday morning
(40-60% PoPs). It appears we will see a fairly widespread
rainfall event for eastern NE with localized 0.5+" amounts
possible. The models suggest that the showers and thunderstorms
will weaken/dissipate while moving into western IA, so both PoPs
and precipitation amounts are lower there. That being said,
there is a model signal for the redevelopment of showers and
thunderstorms (30% PoPs) Wednesday night for areas including
western IA.

A low-amplitude shortwave trough is forecast to traverse the
northern Plains on Thursday with the glancing influence of that
feature supporting 20-30% chance of showers and thunderstorms.

Severe-weather potential remains somewhat uncertain during this
time frame with machine-learning guidance indicating broad
areas of 5% probabilities.

Daytime highs will remain above normal with readings in the 80s.

Friday and Saturday:

Another prominent mid-level trough will progress from the
Interior West into the central and southern Rockies with
prevailing southwesterly flow regime present downstream across
the mid MO Valley. In the low levels, the models indicate a
surface front stalling in the general area, which will enhance
shower and thunderstorm potential (40-60% PoPs) during this
time frame. There will probably be some severe-weather threat;
the extent of which remains uncertain.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 522 PM CDT Sun Sep 15 2024

VFR conditions persist over the next 24 hours. Confidence is
growing for a chance of showers / thunder at KOFK around 12-15Z
Monday morning (30%). Have chosen not to include in this TAF
issuance, but on this trajectory it will be added with the 06Z
TAFs later tonight.

Otherwise, expect southerly flow to continue through the TAF
period with Monday bringing occasional gusts of up to 25 knots.

&&

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

&&

$$

DISCUSSION...Mead
AVIATION...Nicolaisen