004
FXUS63 KEAX 160006
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
706 PM CDT Sun Jun 15 2025

...00z Aviation Update...

.KEY MESSAGES...

- Chances for showers and thunderstorms have significantly
  decreased today. Some chances (10-20%) remain across far
  northern MO and southern into west central MO.

- Confidence is increasing in chances for strong thunderstorms
  Tuesday into early Wednesday. Heavy rain, damaging winds, and
  hail the primary hazards.

- Growing confidence in the potential for hazardous heat toward
  the end of the week.

&&

.DISCUSSION...
Issued at 255 PM CDT Sun Jun 15 2025

Visible satellite showed multiple decaying mesoscale convective
systems across the central CONUS this morning. This has sent
numerous cold pools and outflow boundaries across the region. So
far, capping has kept these gust fronts from initiating any
convection and it is likely that this cold outflow will stabilize
lower layers and dissipate keeping much of the region dry today. The
two spots of precipitation are from a mesoscale convective vortex
working along the I-44 corridor with the northern fringe of showers
just creeping into our CWA. Another decaying MCS across IA could
bring some passing showers across far northern MO later this
afternoon. CAM guidance really struggled resolving the multiple
mesoscale convective systems and their associated cold pool
interaction leading to a plethora of results from expansive popcorn
convection to none at all. Observations and satellite images trend
toward the later which we have no complaints.

A more substantial opportunity for precipitation comes starting late
Monday through the day Tuesday. A shortwave trough across the
central CONUS teams up with a leeward wave and the LLJ developing a
large MCS over Nebraska. This system tracks across the Central
Plains through the day Tuesday.  As it does so, the LLJ pivots to a
more SW to NE orientation which advects large amounts of warm air
and moisture into the region. This pushes heat indicies toward 100F
for the first time this year and also lifts a warm front toward the
US-36 corridor. This sets up a two phase convective event for the
region. The first is the potential for prolonged rainfall across
northern MO primarily north of US-36, but areas north of I-70 have
the potential to see prolonged rainfall. The residual MCS fueled by
a reinvigorated LLJ and warm front during the afternoon creates an
expansive area of rain. PWATs exceeding 2 inches suggest the
potential for very heavy rainfall.
With the complex paralleling the warm front, training storms and
torrential downpours create a favorable environment for flooding,
both flash and river.

The second phase of this event is more convective. As the LLJ pushes
the warm from north, an extensive warm sector develops across MO
south of US-36. This pushes CAPE values toward 3000-5000 J/kg. Shear
starts Tuesday relatively marginal, but becomes more favorable as
upper level CVA pushes into the region. Subsequently early lapse
rates exceed 8 C/km giving the potential for substantial lift. Cold
frontogenesis to the west acts as the coercion mechanism to initiate
convection. Environmental variable like these clearly display the
potential for strong to severe storms Tuesday; however, the critical
missing factor is timing and location. Deterministic models are still
struggling to resolve the cold frontogenesis with some presenting a
rather weak gradient. Others develop the front so far west, that is
does not have the time to tap into the favorable environment until
after sunset when the environment becomes less sustainable (note:
not unfavorable). This westward shift in frontogenesis may yield two
results. The first is storms fail to form down the cold front. This
is somewhat unlikely as thunderstorms are likely to form along the
front a some point, but the later in the day they form, the less of
a chance for discrete, more volatile storms. The second is that the
MCS talked about earlier expands along the front bringing a line of
damaging winds and potentially large hail through the overnight.
This second solution is becoming the more likely scenario across
model guidance.

There are yet two more curve balls that could affect the outcome.
First is the track of the storm. Most guidance forms the front
toward the US-36 corridor and storms follow it through northern MO.
The ECMWF shifts things southward putting the front along the I-70
corridor. If this were to happen, much of northern MO including the
KC metro could see prolonged heavy rainfall and flooding quickly
becomes the largest concern. The severe potential remains, but is
likewise shifted southward. It would not be unfathomable for an area
like the 435 loop to get flooding rain across the north side and
damaging winds and hail across the south. The second kink is the
potential for discrete convection in the warm sector ahead of any
line which could pose more significant severe hazards. At the
moment, this does not look likely given the relatively uniform flow
across the warm sector and the lack of any apparent lifting
mechanism. We will have to see if the CAMs suggest any potential
when they come into range. There remains much uncertainty,
especially in the CAMs, because of the scattered cold pools from
multiple mesoscale convective systems around the region Sunday
resulting in rather chaotic outputs which get translated into
future forecast hours.

Regardless of all the different branches the forecast can take.
Confidence is growing in the potential for a impactful complex of
showers and thunderstorms Tuesday into early Wednesday. The primary
threats remain heavy rainfall and damaging winds. Hail and an
isolated tornado cannot be ruled out and will heavily depend on the
mesoscale evolution of the system.

Once the system moves out of the region, southerly low level flow
dominates the central CONUS. Warm air and humidity advect into the
region lifting temperatures toward the end of the week into the 90s.
Heat index values approach 100F towards the end of the week bringing
our first exposure to multiple days of near 100 head indicies. While
this may not necessarily meet the thresholds of extreme heat, it is
prudent to prepare and take steps to mitigate heat exposure as we
approach the core of the summer season.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 703 PM CDT Sun Jun 15 2025

VFR conditions expected to prevail across the TAF sites this
period. Best chances for any shower or storm activity to remain
outside of TAF sites and more toward the Iowa-Missouri border
and toward southern Missouri respectively. Otherwise, another
night of partly to mostly clear skies and light winds may allow
for some patchy fog to develop, primarily in prone areas. This
could potentially affect KSTJ/KMKC given their locations in
relation to the Missouri River, but have left out any prevailing
mentions at this point in time.

&&

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

&&

$$

DISCUSSION...Pesel
AVIATION...Curtis