-- Discussion containing changed information from previous version are highlighted. --
950
FXUS63 KEAX 121132
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
632 AM CDT Wed Jun 12 2024

.KEY MESSAGES...

- Hot and muggy conditions expected starting today and
  continuing tomorrow. Heat index values Thursday eclipse 100F.

- Strong to severe storms are possible Thursday evening. Large
  to giant hail and damaging winds are the primary concerns.
  The atmospheric setup looks quite volatile with potentials
  ranging from isolated quickly maturing storms to no storm
  development.

- Showers and thunderstorms continue through the weekend. Some
  strong to severe storms are possible; however, the environment
  does not look as potent as Thursday evening.

- Hot and humid conditions look to continue as the summer
  solstice approaches next week.

&&

.DISCUSSION...
Issued at 339 AM CDT Wed Jun 12 2024

Summer is upon us as we are 8 days away from the summer solstice,
but also as large scale high pressures build across the central
CONUS opening up southerly flow spreading hot and muggy conditions
throughout. While 500mb flow remains northwesterly, two lower level
highs build across the Gulf and northern Rockies respectively.
Southerly flow along the western side of the Gulf high funnels warm
air and moisture into the region. This manifests itself today with
highs reaching into the 90s for the first time this year. Dew points
also begin there ascent; fortunately, antecedent drier air means that
dew points have a farther way to climb than temperatures. This
results in Wednesday being warm and a bit muggy; however, somewhat
comfortable compared to Thursday.

Continued compression as the northern and southern highs converge
accelerates and shifts the axis of southerly flow straight into NW
MO. This vaults temperatures into the mid to upper 90s with dew
points cresting 70F. This brings uncomfortably muggy conditions with
heat index values from 100-105 for much of the region. But wait,
there`s more! As the dueling highs converge, the northern high drags
along a cold front, which when supported by NW upper level flow and
accompanying shortwave enables it to push into NW MO. The atmosphere
ahead of this front looks to be very complex yielding a volatile, yet
uncertain forecast. Warm air and substantial moisture advection
yields an incredibly unstable atmosphere with MUCAPE ranging
between 3000-6000 J/kg with mid level lapse rates in excess of 8
C/km. However, low level convective variables are meager with many
indicies sitting at or below minimum thresholds of concern. That
said, the potent nature of the atmosphere Thursday evening should
not be understated. Storm development will be highly dependent on
the kinematic interactions with the front as well as how well the
CAP holds up. Models guidance so far has been fairly pessimistic
with storm development; however, members have been suggesting the
potential for several discrete cells and sparse storm complexes. Any
updrafts that develop will have a chance to tap into the more
favorable environment becoming strong to severe. With the high
instability and steep lapse rates, large to giant hail is plausible
(2-4"+); damaging winds are also a possibility. PWAT values above
1.5" result in plenty of water vapor to condense into hailstones as
well as heavy rainfall. Fortunately, with the weakened low level
variables, the tornado threat looks low at this time. Again, this is
a very volatile setup. If the front comes in weaker and the CAP
stronger, storms may not form at all; however, if a storm is able to
form, it has the chance to become very strong quite quickly.

With sunset on Thursday, one of the nudgers for storm development
(i.e. the sun) disappears calming things down for Friday. Embedded
upper level shortwaves may create some isolated showers and
thunderstorms south of I-70. However, the southern high fights back
with a warm front lifting across the region Friday night into
Saturday bringing continued chances for showers and thunderstorm
during the evening and overnight hours. Substantial instability
across west central MO brings some isolated chances for strong to
severe storms across Linn (KS), Bates, and Henry counties Friday
evening, but overnight storms are expected to be sub-severe with the
exception of some heavy rainfall which could create some localized
flooding concerns given the above average rainfall of recent weeks.
Showers and thunderstorms continue into Saturday as multiple upper
level shortwaves pass through the region. Unfortunately, this will
do little to quell the heat as overall atmospheric flow remains SSW.
Most likely, rain will bring a brief respite before the sun comes
back creating even muggier conditions. This is the first signal that
the summertime pattern is establishing itself.

Long term global guidance puts a strong Bermuda high across the SE
CONUS. This continues the advection hot and muggy air into the
central CONUS. Highs look to remain in the 90s for the foreseeable
future. The good news is the region finds itself along the edge of
the high which features many embedded shortwaves creating a "ring of
fire" setup. Intermittent waves of showers and thunderstorms are
expected as they traverse the outside of the large high pressure. So
at the very least we look to continue getting precipitation and hold
of the seasonal bake for a little while.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
-- Changed Discussion --
Issued at 627 AM CDT Wed Jun 12 2024

VFR conditions are expected to prevail through the period with
only a few passing high clouds late tonight. Light southerly
winds this morning should increase to 12 knots with gusts to 20
knots by early afternoon before relaxing once more by 1z this
evening.
-- End Changed Discussion --

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...None.
KS...None.

&&

$$

DISCUSSION...Pesel
AVIATION...BMW