844
FXUS63 KOAX 010811
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
311 AM CDT Sat Jun 1 2024

.KEY MESSAGES...

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

- 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 311 AM CDT Sat Jun 1 2024

Pretty quiet early this morning with radar showing only some
light lingering returns in our area following our day of heavy
rain. To our west, a few storms were going up over in the NE
panhandle on the nose of some weak low level moisture transport.
CAMs suggest they will push east through the morning and
gradually weaken, though a few pieces of guidance suggest they
could make it to portions of northeast NE by late morning
through mid-afternoon. Shouldn`t amount to much more than a
brief downpour and some lightning if they make it (probably a
10-15% chance).

Additional storms are expected to approach from the west late
this evening into early Sunday, but once again should weaken as
they push east, with most guidance in good agreement that
instability quickly tapers off in our forecast area. That said,
it is worth noting that a few pieces of guidance (various
GEFS/EPS members and the 01.00Z NAM) give us a little more
instability and suggest the storms organize into an MCS and push
through Sunday morning on the nose of strong moisture
transport. Then during the day Sunday, the general idea is that
we`ll see strengthening southerly flow/moisture ahead of a
surface low in eastern CO and some shortwave energy progged to
move along the NE/SD border. This looks to usher in a warm,
moist, unstable airmass with MUCAPE values of 2000-3000 J/kg
ahead of a cold front approaching from the northwest, suggesting
we`ll see a line of strong to severe storms late Sunday
afternoon/evening. However, there`s quite a bit of spread on
just how much shower and storm activity we`ll see during the
day, likely in large part owing to differences in cap strength.
This will play a large role in how the evening severe weather
threat plays out, with any daytime storms likely greatly
reducing instability ahead of the approaching front. In fact, if
storms do get going during the daytime hours, a few could be
strong to severe, though deep layer shear does look to be on the
weak side (25-30 kts), suggesting they could be a little
disorganized. So bottom line, we`re highly confident we`ll see
thunderstorms at some point on Sunday (70-90% chance), but lots
of questions remain on exact timing and the overall severe
weather threat. Less storms during the day would mean a much
stronger line of storms for the evening. More storms during the
day would mean a more prolonged strong to severe storm threat,
but maybe a little lower end when it comes to coverage and
strength of severe storms. Flooding is probably the severe
weather threat we have the highest confidence in seeing simply
due to the recent heavy rainfall and additional rounds of storms
in an environment with precipitable water values progged to be
hovering around 1.50 inches.

Additional storms would be possible Monday with a decent amount
of instability remaining in place over at least the southern
half of the area and some moisture transport continuing to point
into the region. Tuesday looks to be our next best chance for
severe weather, with a very similar setup to that of Sunday as
we could see some daytime showers and storms ahead of an
approaching cold front that could bring another line of strong
to severe storms Tuesday evening.

Behind that front, model consensus is that surface high
pressure builds in and keeps us mostly dry, though there are
some hints that a few bits of weak shortwave energy slide
through the northwesterly flow aloft and bring us additional
shower and storm chances through the latter half of the work
week. However, at this time those chances appear to be 10% or
less. Otherwise, expect seasonable temperatures for the start of
meteorological summer, with upper 70s to mid 80s on tap through
next week (though daytime showers and storms could lead to
cooler highs on a couple days).

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1012 PM CDT Fri May 31 2024

Rain has moved off to the east for the night and we`re starting
to see low clouds spread across eastern Nebraska. Patches of
MVFR cigs are expanding, with MVFR cigs expected at all the
terminals later tonight, possibly lowering to IFR as well. Winds
are light generally out of the southeast but will be turning
northwesterly later tonight. We`ll see cigs slowly improve as
cigs break up Saturday morning with winds shifting to
northeasterly, easterly, then southeasterly again by Saturday
afternoon.

&&

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

&&

$$

DISCUSSION...CA
AVIATION...McCoy