170
FXUS63 KEAX 091737
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
1237 PM CDT Wed Jul 9 2025

...18z Aviation Update...

.KEY MESSAGES...

- Mostly Dry Today; Potential For Short-Lived Pop Up Showers

- More Organized Shower/Storm Activity Overnight and Thursday Morning

- Strong to Severe Storms Possible Friday Evening

&&

.DISCUSSION...
Issued at 410 AM CDT Wed Jul 9 2025

594+dam high remains centered over the desert southwest with subtle
short-wave troughs continuing to traverse the west-northwest flow
across the Central Plains. The MSLP field over the Missouri River
Valley has been homogeneous, with clear skies from the low-amplitude
ridge axis that passed through yesterday. Winds have been weak,
which has allowed radiational cooling of a boundary layer with
dewpoints in the upper 60s to lower 70s. This had led to the
development of fog across portions of the forecast area overnight.
Expecting clear skies to start the morning. Diurnal heating today
should quickly destabilize the boundary layer, and some CAMs are
showing a decent depth of mixing even with the higher water vapor
content. By the afternoon should see cumulus field develop, and
there is some potential a brief shower could develop. Dewpoint
depressions though throughout much of the troposphere are quite
high, especially in lower portions of the boundary layer. Therefore,
may make it difficult for hydrometeors to actually reach the
surface, perhaps some potential for virga to be spotted. For now,
will maintain a dry forecast for Wednesday afternoon. This may need
to be adjusted though as we watch the boundary layer evolve through
the day. A weak short-wave trough is expected to eject across the
Plains, downstream from the broad anticyclone over the desert
southwest. This will produce just enough dCVA to generate lift and
surface pressure falls from the Front Range across much of the
Central Plains. RAP and HRRR analysis suggest areas east of the
Kansas Flint Hills to western Missouri will see surface pressure
falls starting after 00z, along with subtle H5 height falls as the
weak mid-level vort maxima moves through. CAMs have been spread in
how the central and high Plains destabilize this afternoon with an
EML present, and therefore has presented a lot of spread in
projected CAPE values into the lower Missouri River Valley. HREF
Mean MUCAPE values are still above 1000 J/kg past 00z this evening,
but will point out that some CAMs have very little meaningful CAPE,
as some bring in a strong EML that completely caps the environment
with an inversion at 700mb. With the forcing over the Central Plains
and rapid destabilization, would expect some shower and storm
activity to develop across Kansas and Nebraska, then move eastward
along with the next mid-level short-wave. The HRRR has been
conservative with storm coverage as this moves eastward, while the
NAM and NAMNest maintain enough moisture to keep more widespread
convection moving into Central Missouri overnight into Thursday
Morning (and the FV3 CAM output just seems too robust for synoptic
setup). In the forecast, have placed slight chance to chance POPs
(15-35%) to areas just west of Hwy. 63, mainly reflecting where HREF
indicates enough CAPE along the axis of potential convergence. RAP
and HRRR have been depicting better wind shear moving eastward that
if there is convection could help to organize it. DCAPE will be
quite high, along with larger theta-e deficits between the surface
and 700mb, lending potential for severe winds with stronger storms.
The 06z SPC SWODY1 outlook highlights this potential with a marginal
risk that clips portions of the forecast area mainly along the MO-KS
stateline. It is possible for activity to continue past 12z into
Thursday Morning, and if the axis of convergence is still present
with enough wind shear, may maintain a wind threat into Thursday.
Another potential outcome into Thursday morning could be remnant
outflow boundary and differential heating that reinvigorates
convection Thursday morning. By Thursday late morning to early
afternoon, this activity will either move eastward or dissipate if
it becomes disconnected from the parent weak-shortwave.

Late Thursday evening into early Friday morning, stronger PV anomaly
moves inland along the western CONUS, promoting deeper troughing
that should either de-amplify the strong ridge over the desert
southwest or result in a pattern that forces it to retrograde. More
robust dCVA and lift occurs from the Intermountain West to the Front
Range, and kicks off surface cyclogenesis of a more well-defined
cyclone, that should also result in well-defined baroclinic zones.
Stronger flow along these zones should increase deep layer shear,
above a higher theta-e airmass that been in place for nearly an
entire week across the area. The strong H5 height falls and surface
pressure troughing is progged to extend into the lower Missouri
River Valley by Friday evening, and ensemble suites have been
showing an uptick in precipitation probabilities Friday Night into
Saturday. This setup should be favorable for organized convection
resulting in strong to severe storms. If the stronger mid-level vort
max gets forced northward, the stronger/severe storm potential could
end up shifting northward toward the Upper Midwest and western Great
Lakes Region. But we still should be able to realize a few rounds of
needed showers for much of the region. Once we see what happens to
the anticyclone over the desert southwest, we should be able to
better pinpoint severe storm potential on Friday. For the remainder
of the forecast period, deterministic guidance has been depicting a
decent belt of westerlies across the northern Plains but with
several short-wave perturbations that sink southward toward our area
that will present more shower and storm opportunities. None of these
features though over are overly large or deep, and you can see that
in the ensemble output, as precipitation probabilities of 15-30% for
measurable QPF are continuous and spread out over a longer time
range through next week. Expecting to maintain temperatures
generally in the upper 80s and lower 90s through next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1235 PM CDT Wed Jul 9 2025

Quiet, VFR conditions largely expected to prevail through the
TAF period. Exception may be in the overnight/early morning time
frame as a cluster of storms may be moving out of Nebraska and
toward the area/TAF sites. Confidence in this scenario remains
fairly limited, so have opted for PROB30 mentions for this
possibility. Otherwise, S/SSW winds remain light today, under 10
kts, then pick up late in the period in the 10 to 15 kt range
and gusts approaching 20kts.

&&

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

&&

$$

DISCUSSION...Krull
AVIATION...Curtis