FXUS63 KOAX 240820
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
320 AM CDT Wed Apr 24 2024

.KEY MESSAGES...

- Several rounds of showers and thunderstorms are expected,
  beginning Thursday and continuing through the weekend. 

- Some severe weather is possible, especially during the 
  afternoon and evening hours on Friday, Saturday, and perhaps 
  Sunday. 

- Flooding will also become an increasing concern due to
  the potential for repeated thunderstorm activity over the 
  same areas. 

&&

.DISCUSSION...
Issued at 320 AM CDT Wed Apr 24 2024

.Today and Tonight:

A surface ridge axis extending from the Dakotas into central NE
early this morning will shift east through the mid-MO Valley
today as a lee trough deepens along the High Plains. Low to 
midlevel warm advection developing to the west of the ridge axis
has fostered a broken band of elevated showers from southeast 
WY into central KS. And, latest guidance indicates that 
precipitation regime will spread east, eventually reaching our 
area by late morning into this afternoon. However, forecast 
soundings depict a considerable amount of dry air in the lowest
10 kft, and the current expectation is that most of the 
precipitation will evaporate prior to reaching the ground. 
At the least, we will see an increase in cloud cover today with
highs in the mid to upper 60s. Winds will be considerably 
weaker today than in previous days with a light east or
northeast breeze this morning becoming southeast at 5 to 10 mph
by this afternoon.

Warm advection will further strengthen tonight with isolated
showers possible, especially across portions of southeast NE and
southwest IA. 


.Thursday and Thursday night:

A vigorous shortwave trough will move into the central and
southern Rockies Thursday before advancing into the adjacent
High Plains Thursday night. In the low levels, a surface low
will deepen over eastern CO before developing into southwest NE
by Friday morning. Meanwhile, an associated warm front will lift
north through KS Thursday and into southern NE Thursday night.
In response to these developments, a southerly low-level jet
will develop over the central and southern Plains, which in 
turn will enhance the transport of heat and moisture into the 
mid-MO Valley, especially Thursday night. That destabilization 
process will lead to increasing shower and thunderstorm chances 
Thursday within a zone of modest warm advection occurring to the
north of the surface warm front. 

Showers and thunderstorms are expected to become widespread
Thursday night with the arrival of stronger forcing for ascent
occurring downstream from the midlevel trough. While the 
greatest severe weather threat is expected to remain to the 
southwest of our area Thursday afternoon and evening, forecast 
soundings indicate a moderately unstable air mass developing above
a shallow stable layer, which may support isolated occurrences 
of severe hail. Localized flooding also is a concern, especially
in areas of training storms.


.Friday and Friday night:

The 00z global models are in good agreement in suggesting that a
vertically stacked low pressure system will develop from western
into central or eastern NE on Friday before pivoting northeast
of the area Friday night. Showers and thunderstorms may be
ongoing Friday morning; however, the northward advection of the
system dry slot should allow for cloud breaks and resultant air
mass destabilization by afternoon ahead of a Pacific front 
approaching the area from the west. As a result, additional
thunderstorms are expected to develop during the afternoon and
evening hours within an environment supportive of all severe
weather hazards, including flooding. The models indicate that
convective activity eventually moving northeast of the area
later Friday night in tandem with the low pressure system.

The forecast will indicate highs in the 70s on Friday, though
those numbers could end up lower in areas of persistent clouds
and precipitation. 


.Saturday and Saturday night:

It appears that a surface boundary will stall across the area on
Saturday with a break in shower and thunderstorm chances during
the morning into early afternoon. High temperatures will range
from the 60s over northeast NE to 70s or even low 80s south of
the front in southeast NE and southwest IA. Later Saturday
afternoon into Saturday night, another significant midlevel
trough will pivot across the southern into central Plains. In
the low levels, a surface low will deepen while developing from
western into n-central KS with the above-mentioned boundary 
lifting north through our area as a warm front. Thunderstorms
are expected to develop by late afternoon into evening, along 
and south of the surface front with all severe weather hazards 
again possible.

Showers and thunderstorms are likely to continue overnight
Saturday with an increased risk for flooding given the 
anticipated, earlier rounds of thunderstorms.


.Sunday and Sunday night:

The models have slowed the progression of the midlevel trough
and associated surface low through the area Sunday, and now it
appears that a severe weather threat could materialize during
the afternoon into evening hours, especially over w