177
FXUS63 KEAX 291156
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
656 AM CDT Sun Jun 29 2025

.KEY MESSAGES...

* Warm to hot and humid conditions continue today.
  - Heat Index values mainly mid 90s to low 100s deg F

* This Morning: Scattered non-severe thunderstorms will move across
  the area, likely dissipating through the morning. Non-severe (<58
  mph) wind gusts and brief heavy rain may be possible.

* Today and Tonight: There is a SLIGHT RISK for severe thunderstorms
  this evening and into the overnight hours. Primary risks remain
  damaging winds and locally heavy rainfall.

* Early Work Week: A bit cooler and less humid.

&&

.DISCUSSION...
Issued at 330 AM CDT Sun Jun 29 2025

While the large scale/big picture synoptic pattern has seen little
change and remains on track, the devil is in the details. And the
details are ... messy ... to put it nicely.

Predominantly weak zonal flow remains dominant over the region with
the jet stream remaining displaced northward toward the US-Canada
border and northward. Shortwave trough/disturbance has moved off the
Canadian Rockies and into the Northern Plains and surface high
building in on its heels too has pushed a cool front across the
Northern Plains. As expected, robust convection has initiated
along/ahead of this surface boundary during the evening and
overnight hours. More towards the immediate area, scattered weak/non-
severe convection too has begun to blossom early this morning (~2am)
in response to broad isentropic lift associated with a modest LLJ.
With table set, the short term (24-36) hr forecast remains
remarkably uncertain/low-confidence, though that tends to be the
hallmark of this sort of summer flow pattern. Let`s break the
forecast down into individual pieces...

Ongoing LLJ convection: This activity over eastern Kansas and
central Missouri respectively is largely according to forecast, if
not a couple hours early compared to recent HRRR and other recent
CAM guidance. As such, this tends to be the highest confidence
portion of the next 24 to 36 hrs. Expect this activity to slowly
glide eastward and expand in coverage over the coming few hours,
primarily affecting eastern Kansas and western to central Missouri.
Initially modest PWats around 1.5 are expected to increase in
response to the LLJ induced moisture transport, pushing towards 2
inches this morning. With virtually nil vertical wind shear and weak
steering flow, this activity will act much like air mass
thunderstorms in that individual updrafts will be relatively short
lived. As LLJ wanes mid-late morning, so too should coverage of this
activity. Any "stronger" clusters that are able to produce outflow,
may allow convection to linger into the afternoon over central to
eastern Missouri. Brief heavy rainfall and non-severe wind gusts
would be primary results.

Existing Northern Plains convection: The reason to mention this is
that its evolution may/will carry large ramifications for local
strong/severe potential later this evening and night. As has already
been alluded to, CAM guidance has been and continues to be
relatively all over the map. Recent HRRR for example has recently
depicted existing Nebraska/South Dakota convection as drifting
eastward and staying away from Missouri/Kansas. However,
current/ongoing convection is not acting as such, instead drifting
SE as a marginally strong/severe MCS, generally following existing
broad ML/MUCAPE gradient. This is likely attributed to the weak
easterly steering flow and its inability to more directly influence
the convection. The 00z HRRR and some of the older MPAS/RRFS runs
have better depicted what is ongoing. Should we buy into the latter,
this would potentially push into and track across the area this
morning, and begin to call into question recovery for latter
potential convection. Something to continue to keep a close eye
on...

This afternoon and evening/night convection potential: An unusually
uncertain forecast resides here due to potential convective
evolution(s) mentioned above, resulting in a wide range of
possibilities. Current reality tends to suggest the existing
Nebraska MCS to more closely reflect 00z HRRR/MPAS/RRFS/NSSL-WRF
progressions versus more recent HRRR cycles. As such, worked over
atmosphere and lingering cloud cover could severely hamper the
extreme CAPE scenario that had been mentioned in previous AFDs,
especially with only weak/modest southerly return flow to re-prime
conditions. Do think this may be the current most likely scenario
and as such would limit the strong/severe potential this
evening/night. It would not necessarily eliminate convection, but
would begin to take the higher end wind scenarios off the table.
Conversely, if the MCS peters out before reaching the area and the
LLJ activity does not linger, >3500-4000 J/kg CAPE may remain in
play across the area and keep the existing SPC Slight more in
play. Primary threat would remain strong/damaging winds in that
scenario. Want to reiterate the uncertainty in evolution and the
importance of the next couple/few hours to how this evening may
play out.

Heat: Lesser concern overall here, but uncertainty certainly
carries to the temperature/humidity/heat index portion of the
forecast as well. Hottest scenario would be the Nebraska MCS not
arriving and LLJ activity not lingering, allowing maximal diurnal
heating and heat index values to approach lower 100s in/around
eastern Kansas/western Missouri, and especially within the KC Urban
Heat Island.

Work Week: Frontal boundary moves across the area late overnight
tonight and brings about modest temperature and humidity relief.
Expect temperatures to ease back a handful of degrees into the mid
80s and dew points gradually falling back into the lower 60s early
week. Upper level pattern then begins to take on more amplified
stance, with some degree of ridging over the Central CONUS by mid-
late week, allowing southerly flow to return and push temperatures
and dew points back towards the lower 90s and lower 70s
respectively.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 630 AM CDT Sun Jun 29 2025

Scattered thunderstorms MVFR conditions expected to continue
through the 14z time period 14z time period there may be a
potential with extending past the 14z with the thunderstorms
coming from OAX moving southward. Estimated distance speed will
be through KSTJ past 14z and if it remains intact. Its moving
about 45 mph and main concern is if there will be more -SHRA
across KMCI, KMKC from 14-16z with more cloud cover than
represented in TAFs. Thus there could be chances but not enough
for Prob30 group. The big question is if this remains across
the area depending through morning with the -SHRA or cloud cover
behind which will play into the activity later tonight. For now
kept TAFs evening thunderstorms potentially developing after 02z
with greatest impact TSRA between 06z-09z for TAF sites. Again
this development and strength will depend on the this morning
but currently expecting.


&&

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

&&

$$

DISCUSSION...Curtis
AVIATION...WFO EAX