-- Discussion containing changed information from previous version are highlighted. --
942
FXUS63 KOAX 151643
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
1143 AM CDT Sat Jun 15 2024

.KEY MESSAGES...

- Non severe thunderstorms early this morning, then an
  additional chance of strong and possibly severe thunderstorms
  this afternoon. All modes of severe weather would be possible
  from 4 pm through midnight, mainly along and south of a
  Columbus to Sioux City line.

- Very hot temperatures expected Sunday and Monday with
  afternoon heat index values 98 to 103 each day.

- Daily storm chances exist at least somewhere in our coverage
  area every day from Sunday night through next week, and
  especially north of Interstate 80. Each round of storms will
  have potential for some severe weather and locally heavy
  rains.

&&

.DISCUSSION...
Issued at 357 AM CDT Sat Jun 15 2024

A line of non severe thunderstorms is currently moving through
eastern NE early this morning. Wind gusts have ranged from 40 to
55 mph along with some small hail. This line will continue to
push into western IA before daybreak, with an hour or two of
stratiform rain trailing behind the main line. The rain will end
from west to east with the bulk of it over by 10 am. Then
there will be a few hour break from late morning through early
afternoon, and while most areas will remain dry during this
time, there could still be a spotty shower here or there.

Meanwhile, we will be waiting for the main shortwave to move off
the front range of the Rockies, which will fire strong and
possibly severe storms this afternoon. The CAMs honestly provide
varying locations for the convective development this
afternoon, but the consensus seems to indicate the best severe
threat along and south of a line from Columbus, NE to Sioux
City, IA. There should be enough recovery time to allow the
atmosphere to destabilize before this happens, and when storms
develop, they could be quite strong with supercells possible,
with all modes of severe weather possible. SPC has placed the
area in a slight risk for severe storms, with a 15% chance of
wind and hail, and a 5% chance of for an isolated tornado. WPC
has also placed eastern NE and southwest IA in the area for
excessive heavy rainfall since this area will receive heavy
rainfall this morning. Again though, confidence is somewhat low
where the axis of storms develop. The severe storm threat could
begin by 4 pm and linger through midnight. Any storms that
develop will continue to push east and be east of the forecast
area by daybreak Sunday. Before the severe storms arrive late
this afternoon, high temperatures should the middle to upper
80s, and could even reach the lower 90s along the KS/NE border.

And then hot weather is expected to develop Sunday with mostly
sunny skies and high temperatures in the middle to upper 90s.
Combined with dewpoints in the upper 60s, this will create
afternoon heat index values from 98 to 103, and major heat risk.
These values are just below official heat advisory criteria, but
those with outdoor plans should plan accordingly and stay well
hydrated with water and seek the shade whenever possible.
Southerly winds at 15 to 25 mph will help, but it will be the
hottest day of the year so far.

Storm chances come again Sunday night, mainly north of
Interstate 80, with a marginal risk of both severe storms and
excessive heavy rainfall.

Monday brings continued small storm chances north of I80, but
realistically, it could even be north of our forecast area. It
will be another hot day with high temperatures once again in
the lower to middle 90s, and heat index values 97 to 102. Due to
the prolonged heat, the heat risk will remain elevated, but
again, heat index values remain just below heat advisory
criteria. And rain chances continue north of I80 Monday night,
but again, based on newer models, any storms could also be
north of the area.

Another front moves into the region on Tuesday, which brings
more thunderstorms, and another chance for severe storms along
with heavy rainfall. And storm chances continue every day for
the remainder of the week. Highs Tuesday in the upper 80s to
lower 90s, but that front could bring cooler temperatures in the
upper 70s to upper 80s for Wednesday, but warming back up to the
upper 80s to lower 90s again by the end of the week.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
-- Changed Discussion --
Issued at 1137 AM CDT Sat Jun 15 2024

A patch of MVFR ceilings around KOFK is expected to improve to
VFR by 20Z. Strong southerly winds sustained at 15 to 25 kts
with gusts up 35 kts will continue through a majority of the
forecast period. Strong to severe thunderstorms are expected to
develop in eastern Nebraska later this afternoon before moving
east into western Iowa. Model guidance is currently showing
high uncertainty in the timing and coverage of these storms.
Confidence is increased that storms will impact KOMA this
afternoon and likely KLNK too. Current impacts appear in the
21-00Z timeframe for KLNK and 22-03Z for KOMA. Expect these
timeframe to wiggle and shrink a bit as confidence in this
system is gained through the afternoon.
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&&

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

&&

$$

DISCUSSION...DeWald
AVIATION...Wood