762
FXUS63 KOAX 031724
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1224 PM CDT Wed Jul 3 2024

.KEY MESSAGES...

- Multiple rounds of showers and thunderstorms could affect the
  region from this evening into Thursday afternoon. Some severe
  weather is possible with the primary hazards being isolated
  occurrences of large hail and/or damaging winds. Heavy-rain
  potential appears lower than recent events.

- Pleasant weather is expected Thursday evening.

- Thunderstorm potential increases again Saturday afternoon into
  Saturday night with some severe weather appearing possible.

- Daytime temperatures to remain near or below seasonal normals.

&&

.DISCUSSION...
Issued at 419 AM CDT Wed Jul 3 2024

.Today and Tonight:

The mid-level pattern will be characterized by broad, cyclonic
flow from the northern Rockies through the Great Lakes with an
embedded shortwave trough tracking from the lee of the Canadian
Rockies into the northern Plains by Thursday morning. In the low
levels, a weakening surface high will quickly build through the
mid MO Valley early today ahead of an inverted trough/front
that will advance through western portions of the Dakotas and
Nebraska tonight.

Clear skies and light winds associated with the surface high
have resulted patchy fog development early this morning, and
some expansion of the fog is possible through daybreak.
Thereafter, weak warm advection on the backside of the high will
contribute to an increase in clouds today with some models
suggesting the potential for a few light showers across portions
of southeast NE this afternoon. Highs today will be in the low
to mid 80s.

By late this afternoon into tonight, increasing height
falls/forcing for ascent preceding the above-mentioned shortwave
trough is forecast to contribute to the development of one or
two thunderstorm complexes over western and central NE into
southern/western SD. Latest CAM data suggest that the initial
wave of thunderstorms could move into portions of northeast NE
by as early as 5 or 6 PM amidst an environment supportive of
isolated occurrences of large hail and/or locally strong wind
gusts. Subsequent weakening of that initial thunderstorm complex
is forecast as it continues east into the area during the
overnight hours. By late tonight into Monday morning, a second
thunderstorm complex could move into our area from the west with
a similar potential for damaging winds and hail.

In regard to heavy rainfall potential, the 03/00z HREF
indicates really low probabilities (<10%) of >1" 6-hr rainfall
in our area with other metrics such as probability-matched-mean
fields indicating the better potential to our west. The HREF
signal is in general agreement with other CAMs outside of that
ensemble system and the parameterized-convection models. In
short, the heavy-rain threat currently appears lower than the
previous couple of events we`ve experienced.


.Thursday and Thursday night:

The above-mentioned shortwave trough is forecast to intensify over
the northern Plains into upper MS Valley with a belt of
unseasonably strong mid and high-level winds developing to the
immediate south across the central Plains into mid MS Valley. At
the surface, an area of low pressure will develop through
eastern NE and western IA during the morning with a trailing
cold front advancing east through our area during the late
morning and afternoon hours. While renewed thunderstorm
development is possible along the front, early-day clouds and
lingering precipitation coupled with the early passage of the
front through the area casts uncertainty on the extent of any
severe weather threat owing to instability concerns.

Clouds should begin to decrease from west-to-east Thursday
afternoon with below-normal highs in the mid 70s to low 80s.

By evening, pleasant conditions are expected for 4th of July
activities with temperatures in the 60s to low 70s, partly to
mostly clear skies, and northwest winds of generally less than
10 mph.


.Friday:

A deep-layer cyclone will move from the upper Midwest into the
Great Lakes with breezy northwest winds (especially in the
morning) expected on the backside of the system across our
area. Highs will remain below normal; in the mid 70s to low 80s.
An isolated shower or two possible, especially over portions of
northeast NE into west-central IA.


.This Weekend:

The 03/00z global models are in reasonably good agreement in
suggesting that a shortwave trough will progress through the
northern and central Plains on Saturday into Saturday night,
ahead of another disturbance following the same track on Sunday.
The former system will interact with a moist and unstable air
mass, supporting a chance of showers and thunderstorms Saturday
afternoon into Saturday night. Some severe weather appears
possible. Precipitation chances are more uncertain on Sunday in
association with the second mid-level system. Highs are forecast
to be in the 80s both days.


.Early Next Week:

The models maintain an amplified mid-level trough from Hudson
Bay into the MS Valley early next week with the best
precipitation chances residing to our east. Daytime highs are
expected to remain in the 80s.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1219 PM CDT Wed Jul 3 2024

VFR conditions at TAF issuance. Thunderstorms will be possible
at all three locations, at KOFK 04/02-05z, KLNK 05-08z, and KOMA
05-09z. Showers could be possible after the thunderstorms, with
MVFR ceilings developing by 15z at KOFK/KLNK, and KOMA by 17z
toward the end of the TAF.

&&

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

&&

$$

DISCUSSION...Mead
AVIATION...DeWald