024
FXUS63 KEAX 071119
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
619 AM CDT Mon Jul 7 2025

...Updated 12z Aviation...

.KEY MESSAGES...

- Storms Possible Monday Afternoon; Low Confidence In Evolution

- Strong Thunderstorm Complex Over Nebraska May Move Across The
  Area Late Monday Night; Showers Likely, Severe Threat Uncertain

- Additional Shower/Storms Much of This Week; Tuesday Activity and
  Strength Heavily Dependent on Monday Night Activity

&&

.DISCUSSION...
Issued at 326 AM CDT Mon Jul 7 2025

Clear skies and weak winds has led to the development of fog across
portions of eastern Kansas and Missouri, especially along river
valleys, creeks, and other low lying areas. This should mix out by
sunrise.

Multiple mid-level vort maxima continue to travel across the Central
CONUS in a generally westerly to northwesterly flow regime, driven
by strong anti-cyclone over the desert southwest. This will continue
a cycle of mid-level lift, followed by subsidence. Near surface
layer remains fairly moist, with dewpoints holding steady in the
upper 60s to lower 70s across most of the forecast area. A transient
thermal boundary has stalled along the Interstate 70 corridor
overnight, likely a result from the stronger convection that
occurred Sunday evening across the Ozarks. A few observations prior
to 06z showed some stronger moisture pooling, but as the overnight
hours have progressed, the temperature gradient has largely eroded.
Surface and 925mb theta-e analysis indicates that something is still
there. However, the overnight hours saw a subtle H5 ridge move
through, which clearer skies quite a bit on both sides of this
thermal boundary. This is making the mesoscale setup for Monday
afternoon quite uncertain, and is one of two main factors
contributing to low confidence in precipitation chances for the
first 24-30 hours of this forecast period. Without well defined
cloud cover on either side of this thermal boundary, its hard to see
substantial differential heating reestablish its strength today,
thinking most of the area should see temperatures in the upper 80s
to lower 90s, with dewpoints holding steady in the upper 60s to
lower 70s. A few of the 00z CAMs have depicted storm initiation
along this remnant thermal boundary, some starting in far
northwestern Missouri, and some right over the Kansas City metro.
Most of this appears to be tied to peak heating, and would expect
destabilization throughout the afternoon given current satellite
trends. Will have to keep an eye on cirrus advection from the cloud
cover over the High Plains. Diurnal heating of a moist boundary
layer should generate a cumulus field by the mid to late afternoon
hours. With respect to showers or storms developing will depend on
the timing of the mid-level vort maxima moving through. If this
lines up with the nearly 2000 J/kg SBCAPE, as depicted in the 00z
HREF, a cluster of multicells likely develop. The favorable spot
would seem to be along the MO-KS state line, though the instability
axis could extend pretty far eastward into Central Missouri. With
higher instability, a few stronger storms certainly cannot be ruled
out as a the mid-level wave moves through, but RAP and HRRR
soundings are not showing as robust of an inverted-v sounding and
evaporational cooling potential as we had seen last week. Therefore,
if the cumulus field is able to initiate deep convection, would
expect the severe threat to be relatively limited, wind gusts
perhaps around 40 to 50 MPH. The stronger deep layer shear remains
progged over the Central Kansas and Central Nebraska, thus that is
where better storm organization likely occurs Monday late afternoon.
Once we are past peak heating this evening, CAMs remain relatively
dry, and would expect a break from isolated convection if it
develops.

Attention then turns activity over Nebraska, where stronger H5
height falls, better surface convergence and stronger dCVA aligns
with a strong instability axis, along with a greater deep layer
shear. By evening, storms over Nebraska congeal, and CAMs along with
other ensemble suites are favoring development of an MCS. CAMs so
far have been favoring an area of expansive showers moving into
northwest Missouri around 06z this evening, then moving east-
southeast overnight into Tuesday morning. The HRRR specifically
decays the stronger convection by the time it reaches most of the
forecast area. And based on the background environment, would make
sense as the wind shear drastically decreases as this MCS would exit
the Central Plains. Therefore, would anticipate decaying shower
activity overnight. The big question, how healthy would the cold
pool of the system be as gets to our area. If the MCS maintains
itself for longer, there is the potential to see severe wind gusts
across portions eastern Kansas to central Missouri, and this
morning`s SPC SWODY1 marginal risk highlights this. From analysis
this morning, this is a lower probability outcome. And the
antecedent mesoscale parameters from the Monday morning remnant
boundary and any daytime convection will also play a role. For now,
will maintain likely POPs (55-60%) in our northwest with decaying
convection, with slight chance POPs further south and southeast. We
may not have overly high confidence in showers/storms overnight
until we see how convection over Nebraska evolves.

Tuesday, another mid-level short-wave moves through, and likely will
see another day of stronger destabilization as this lift moves
through. However, the early morning convection throws a big question
mark on how the boundary layer recovers. With decaying convection,
odds are favorable for an outflow boundary, perhaps multiple, to be
present across eastern Kansas to Central Missouri. These will
probably provide most of the focus for redevelopment on Tuesday.
Strong differential heating along these boundaries would likely be
the main driver of any kind of severe wind threat. 06z CAMs that
have started to come in are indicating stronger storm development
for across Central Missouri after 22z on Tuesday. If Tuesday morning
convection pushes southeast and stabilizes the boundary layer, the
storms and severe threat could push eastward out of our area on
Tuesday.

Beyond Tuesday, we will continue to see short-waves traverse the
region that will bring additional shower and thunderstorm
opportunities. Mid to upper-level flow will still remain fairly
weak, limiting deep layer shear. Storm strength will largely be tied
to the degree of destabilization and what kind of lapse rates can be
achieved. Ensembles are likely spreading out low end precipitation
chances over too broad of a time period, but given the varying
propagation speeds of any of these waves, makes it hard to be
certain. Friday into Saturday will finally bring a large scale
pattern change to the area, as a strong PV anomaly sends a more
robust long wave trough toward the Central CONUS and breaks down the
desert southwest ridge. This will provide more moisture transport
back to the area, while destabilization could still be robust, but
provide better deep layer shear.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 616 AM CDT Mon Jul 7 2025

Expecting fog for another hour or so along the Missouri River
Valley. This will keep visibility under 1SM at STJ through at
least 13z, perhaps goes until 14z. VFR cloud bases expected for
most of the afternoon, cumulus field likely develops this
afternoon. Potential for isolated shower/storm activity from
eastern Kansas into Central Missouri, will place PROB30 in TAF
sites for this potential. Late tonight, organized system out of
Nebraska will move southeast and begin to decay, bringing shower
activity to far northwest Missouri. At this time, uncertain if
this will reach STJ and the KC Metro terminals, thus will not
place in the 12z TAFs. Will continue to watch high resolution
model trends through the day.

&&

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

&&

$$

DISCUSSION...Krull
AVIATION...Krull