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422
FXUS63 KEAX 240802
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
302 AM CDT Mon Jun 24 2024

.KEY MESSAGES...

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- Heat Advisory This Afternoon Through Tuesday Evening

- Scattered Strong/Severe Storms Possible Late Monday / Early Tuesday

- Showers and Thunderstorms Tuesday Afternoon/Evening; A Few Severe
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.DISCUSSION...
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Issued at 302 AM CDT Mon Jun 24 2024

Mid-level ridge continues to amplify today but a few short-wave
perturbations are working their way around it ejecting out of the
Rockies. As of this morning, surface anticyclone is centered over
the lower Missouri River Valley and will slowly move eastward this
afternoon. Surface pressure falls in response to dCVA over the Front
Range will start extending into the eastern Plains this afternoon
and enhance low-level southerly flow. This will increase theta-e
advection through the afternoon and bolster temperatures in the
upper 90s across most of the forecast area with the exception our
furthest northeastern counties. With dewpoints steadily climbing from
the upper 60s into the lower 70s, expecting heat index values to
range anywhere from 103 to 108F from eastern Kansas into Central
Missouri this afternoon. Therefore, have maintained the heat
advisory and added Randolph County, Missouri to it. Throughout the
afternoon there will not be much in the way of forcing but with a
warm moist destabilizing boundary layer cannot rule out a few isolated
airmass showers/storms developing during peak heating this
afternoon. However these should not last very long as the lack of
shear should prevent any organization. Heading into the late evening
hours, the first mid-level short-wave approaches the lower Missouri
River Valley and will provide subtle H5 height falls to disrupt the
amplifying ridge. Coarser resolution model guidance and their
respective ensembles have not been painting overly high
probabilities for precipitation during the evening and overnight
hours, but recent CAM trends have been hinting at convection
development especially north of Hwy. 36. While the boundary layer
will have plenty of moisture advection this afternoon, flow above to
850mb to around 700mb will be more southwesterly and may help to
reinforce an EML providing steeper mid-level lapse rates (RAP
soundings showing around 8.4 C/km), which when present over a moist
boundary layer that destabilizes through the day would yield a
decent degree of instability, and mixing could help to erode the
cap. As the LLJ kicks in, perhaps increased convergence with
approaching mid-level vort max could force a few showers. Overall
deep layer shear will be rather weak with this first short-wave
moving through overnight into Tuesday morning which limits
organization potential, but robust thermodynamics may support a few
isolated stronger updrafts that eventually tap into the low-level
jet and drag momentum downward, resulting in some wind gusts. The
NAMNest and NSSL-WRF seem to paint a vigorous MCS moving through the
early hours. While the mid-level vort max could have some decent
strength to it, not sure if low-level kinematics will support
something as strong as those two CAMs are suggesting. The scattered
activity of the HRRR may be closer to what is realized, but could
still produce some stronger wind gusts. One important note on the
heat for late tonight and Tuesday morning, is that lows will not
drop much. More areas will see lows in the upper 70s, and western
counties including the KC Metro may struggle to drop below 80
degrees by Tuesday morning, which could augment heat related impacts
with the lack of overnight relief.

Later Tuesday morning into the early afternoon, the stronger short-
wave axis moves into the Ozarks, but a secondary vort-max develops
across the lower Missouri River Valley in response to a stronger mid-
level short-wave moving into the Upper Midwest and helps create a
corridor of surface pressure falls into the forecast area. The
northern system will push a cold front further south into Iowa and
will increase convergence into our area. This convergence will push
on a high theta-e boundary layer Tuesday late morning through much
of the afternoon that will likely result in more shower and storm
development. The deep-layer shear for Tuesday afternoon may be
questionable, if the stronger short-wave from Monday Night stalls a
bit over the Ozarks, the back-end of it may help provide some deep
layer shear that could support organization of storms, and result in
a marginally severe hail and continued wind gusts. However, if that
wave moves too far and the mid-level flow is weak, the updrafts will
mainly be buoyancy driven and could still result in some downburst
wind gusts but struggle to organize and survive. Tuesday evening,
cold front will start to sink further south but may stall with more
short-wave activity over the Front Range forcing H5 height rises
downstream across the lower Missouri River Valley. The cold front
would be needed for convergence strong enough to continue robust
rainfall into Tuesday Evening, as there may not be much in the way
of mid-level support. The boundary layer will likely be unstable
enough to support buoyant parcels heading into the evening, and will
also need to monitor potential for lingering outflow boundaries if
any downburst convection occurs earlier in the morning. Right now,
most CAMs are focusing stronger development Tuesday evening in Iowa,
as this is where the cold front lingers. GEFS and other synoptic
scale ensemble suites are hinting at this trend too, with decreases
in probabilities for 0.10 inches of QPF during the late evening
hours of Tuesday. Once the Tuesday morning convection is complete,
this may make it easier to determine what happens Tuesday Night.
Overnight into Wednesday morning, cold front progresses southward
and should bring move convection into our area. A few strong to
severe storms could also occur within this cluster, but confidence
remains low at this time. As for Tuesday temperatures, expecting a
long enough break in precipitation for temperatures to climb back
into the mid 90s across most of the area with dewpoints still in
upper 60s and lower 70s. This will continue to yield heat index
values Tuesday afternoon between 100-105, and thus have extended the
heat advisory through Tuesday evening. Will note though that if
precipitation is more widespread lingers later into the afternoon,
this could cut into high temperatures. Current NBM members do
demonstrate larger inner-quartile spread for temperatures Tuesday
afternoon, which slightly decreases confidence in heat index values
when compared to the forecast for Monday.

By Wednesday, cold front moves through the area and brings
temperatures into the 80s. Weak mid-level height rises should bring
a break from precipitation potential for a little bit, but another
short-wave is expected to bring shower chances Thursday and Friday,
and more activity is expected next weekend with increasing ensemble
probabilities for accumulating rainfall. Temperatures may climb back
into the 90s, but there is a large degree of uncertainty, mainly
due to the multiple opportunities for rainfall through the end of
next week.
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.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1200 AM CDT Mon Jun 24 2024

VFR ceilings and visibilities remain during the TAF period.
Expecting a wind shift out of the southwest by the morning
tomorrow, with the introduction of some higher level clouds
towards the far northeast. As such, electing to keep KIXD in SKC
for the morning. Gusty winds up to 20 kts expected by the
afternoon with mixing, but should calm going into the evening.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
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MO...Heat Advisory from noon today to 8 PM CDT Tuesday for
     MOZ001>006-011>015-020>023-028>033-037>040-043>046-053-
     054.
KS...Heat Advisory from noon today to 8 PM CDT Tuesday for KSZ025-
     057-060-102>105.
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&&

$$

DISCUSSION...Krull
AVIATION...Krull