FXUS63 KOAX 261124
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
624 AM CDT Fri Apr 26 2024

.KEY MESSAGES...

- Several rounds of showers and thunderstorms are expected
  through the weekend. 

- Severe weather appears likely (>80% chance) during the 
  afternoon and evening hours on both Friday, Saturday, and 
  perhaps Sunday. 

- Flash flooding is also a concern due to the potential for 
  repeated thunderstorm activity over the same areas.

&&

.DISCUSSION...
Issued at 319 AM CDT Fri Apr 26 2024

Today...
 
Multiple rounds of showers and thunderstorms traversed 
eastern Nebraska and southwest Iowa overnight, fueled by a 
robust southerly low-level jet. Heavy rain with these storms 
required the issuance of a handful of flood advisories over 
parts of northeast Nebraska.

Despite the dreary start to the day, expect clouds to begin to thin 
across parts of southeast Nebraska by early Friday afternoon. 
Moderate instability will blossom in this region, ahead of an 
approaching dry line. Strong bulk shear vectors of 40-55kts are
possible across much of the forecast area late Friday morning 
and into the early afternoon, as a low pressure system begins to
move through northeast Nebraska. Supercells will become the 
most likely storm mode Friday afternoon. Given the steep lapse 
rates, and robust low level jet. Very large hail will be the 
primary threat, along with a few tornadoes (some of which may be
strong). Heavy rain and strong winds would also be possible 
with any supercell that forms. The current CAM solutions have 
storms developing around 2 PM and moving out of southwest Iowa 
around 8 PM. One potentially limiting factor to the Friday 
afternoon/evening event would be how far north the narrow 
channel of sufficient instability reaches. Even the latest model
solutions vary on how much clearing and atmospheric recovery we
will see after noon today. However, it is clear that any 
supercells that do become established will be capable of 
producing damage. 

Friday Night through Saturday...

Once the rain shuts down Friday evening, the remainder of the night 
Friday night into Saturday morning looks quiet, especially for those 
participating in outdoor activities Saturday morning.
However, that break will be short-lived as another round of severe 
weather potential develops Saturday afternoon by 4 PM and beyond, as 
a frontal boundary from the first system is reinvigorated by the 
next closed low moving out of the Rockies. This allows widespread 
showers/storms to redevelop across the region Saturday night, with 
the next round of severe storms possible along/south of Interstate 
80. Once again, all modes of severe storms would be possible, 
including another round of supercells with potential tornadoes and 
very large hail. Given the multiple rounds of storms Saturday night, 
compounded with the rainfall we received overnight tonight and will 
receive this evening, we will have to keep a close watch on flooding 
potential with an increasing risk for flash flooding. 

Sunday and Beyond...

Another round of storms will close out our weekend on Sunday, as the 
second low pressure system passes through the forecast area. While 
the best chance for more well-developed/stronger storms will likely 
remain off to our east, the passage of the surface low through the 
heart of our CWA brings concerns for a few low-topped supercells 
with tornadic potential. 

We finally receive a break from the active weather pattern on 
Monday and into early next week, with just a few minor showers 
and storms possible Tuesday and Wednesday. Temperatures will 
generally top out in the 70s next week, with a few locations 
reaching the low 80s on Tuesday.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 624 AM CDT Fri Apr 26 2024

Expect some lingering showers and a few storms early in the 
period. These will give way to MVFR to IFR ceilings and 20 to 30
kt southeasterly wind gusts into early afternoon. There may be 
a brief break in the clouds, followed by additional storm 
development, with potential for severe storms. Confidence in 
storm strength and exact timing at a given TAF site is fairly 
low, especially with some signs of earlier spotty development, 
breaks in the main line, and lingering storms following the 
primary line. That said, the main line should last 1-2 hrs at a 
given location with potential for large hail, damaging winds, 
and even a tornado. Behind the storms, expect VFR conditions 
with clouds gradually scattering out and winds weakening and 
becoming more southwesterly to westerly.


&&

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

&&

$$

DISCUSSION...KG
AVIATION...CA