763
FXUS63 KOAX 012334
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
634 PM CDT Sat Jun 1 2024

.KEY MESSAGES...

- Daily storm chances starting by this evening and lasting
  through at least Tuesday.

- Increasing chances for a strong wind storm moving into the
  area after 9 PM tomorrow.

- The highest chances for strong to severe storms are on Sunday
  and Tuesday, but confidence is low on exact timing and how
  widespread the severe weather threat will be.

- Slightly warmer through next week with highs in the upper 70s
  and 80s.

&&

.DISCUSSION...
Issued at 413 PM CDT Sat Jun 1 2024

Tonight through Tomorrow:

Water vapor imagery this afternoon features largely zonal flow with
ridging in place centered over New England while several shortwaves
litter the remaining CONUS, including a  more potent one moving
farther into the Ohio River Valley. Looking closer at a recent
surface analysis, upper 50s to 60s dewpoints continue to linger in
Nebraska and Iowa with a drier airmass on the northern side of a
very weak boundary at the NE/SD border. Light northerly are in
place currently with highs being realized in the upper 70s to
low 80s, with a few patches of cirrus left over from morning
convection in western and central Nebraska. After sunset, low-
level wind speeds associated with the nocturnal jet are expected
to pick up largely over western and central Nebraska, with jet
nosing and shortwave PVA allowing for instability rooted at 700
mb to be realized. Latest runs of the CAMs move this activity
into northeastern Nebraska after 1 AM before pushing it off to
the east by mid-tomorrow morning.

By tomorrow afternoon, strong warm air advection and moisture
transport will be in full force in the forecast area. CAMs have been
divided on producing storms after 1 PM across eastern Nebraska,
owing most of the uncertainty on weaker shear, and limited moisture
to fight the cap. Sufficient instability and shear are in place
so that if scattered storm activity develops, quarter-sized
hail is a possibility through 6 PM. The main concern of the day
comes later in the form of what is expected to be a large
bowing MCS that progresses out of convection starting in the
Panhandle. Earlier runs of the extended CAMs have been showing
impressive low-level and surface wind fields and has warranted
an increase to an Enhanced Risk (level 3 out of 5) just into
northeast Nebraska. While this system is expected to move into
our area, weaker shear and increased capping will limit its
severity as it moves east. The main concern continues to be the
damaging winds, with quarter-sized hail possible and heavy rains
falling on saturated soils (especially in northeast NE).

Monday and Tuesday:

Monday and Tuesday are expected to continue the active trend
precipitation-wise, with continued shortwaves moving through the
zonal flow. Machine-learning storm outlooks for day 3 and 4 continue
to clip southeast Nebraska and Iowa with Tuesday holding our best
chances for stronger storms. Driven by better shear and a stronger
front, more focus for ascent will sweep through Tuesday afternoon
and evening with scattered storms in central Nebraska expected
to form a larger line of showers and storms by the time it
reaches Iowa.

Wednesday and Beyond:

For the rest of the week, the main upper jet moves south and becomes
northwesterly, guarding eastern Nebraska and Iowa from any of
the good moisture to the south. Despite the northwesterly flow,
highs are still able to old healthily into the lower 80s, making
for a really nice stretch of weather to be outside in going in
to the weekend.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 635 PM CDT Sat Jun 1 2024

Quiet weather leaves TAFs in the VFR category for tonight with
variable winds generally at 5 knots or less. Expect these winds
to develop a SSE flow after sunrise Sunday morning with gusts of
20-25 knots.

Have continued to keep TAFs dry for now with a scattered
t-storms possible between midnight and 6am working from west to
east. Location and timing is more uncertain than normal with
some model solutions keeping things nearly dry. Will not add
RA/TS into TAFs until things become clearer.

Late Sunday night brings more confidence in thunderstorms
working through the area from northwest to southeast.

&&

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

&&

$$

DISCUSSION...Petersen
AVIATION...Nicolaisen