057
FXUS63 KEAX 170006
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
706 PM CDT Fri May 16 2025

.KEY MESSAGES...

* Quiet, very pleasant Saturday

* Active pattern ramps up Sunday, continues into Wednesday

  - Strong to severe storms possible each of Sunday
    night/overnight, Monday, and Tuesday.
    - Greatest severe storm chances currently appear Monday

  - Multiple rounds of moderate to heavy rainfall may lead to
    overland and river flooding concerns.

&&

.DISCUSSION...
Issued at 236 PM CDT Fri May 16 2025

After a few elevated showers this morning passed through NE Missouri
and into Iowa, skies largely cleared out behind a passing compact
shortwave and gave way to a pretty comfortable day across the area.
With surface boundary, primarily a dry line, situated over SE
Missouri, dew points remained abundantly pleasant, in the 40s
to low 50s deg F and aided in keeping skies mostly clear. Some
mid-higher level cloud cover wrapping around the closed low over
Minnesota arrived this afternoon over NW/N Missouri, but should
stay largely relegated north of I-70, if not Highway 36, and
more scattered in nature. Main, if any, consequence there is
slightly cooler highs in the upper 70s vs lower 80s elsewhere.
Of greater note though, breezy conditions across the area,
especially N/NW where surface pressure gradient is strongest.
Deep boundary layer mixing has too aided in periodic wind gusts
into the low to mid 30s mph, which will continue into the early
if not mid-evening hours before some easing. Pressure gradient
remains tight enough overnight to for sustained winds
greater than 10mph along/north of I-70 and occasional gusts
to the upper teens/20mph before further easing Saturday
morning. Still expected to see fair degree of nocturnal cooling
with amply dry air and CAA ongoing, upper 40s/low 50s low temps
Saturday morning. Saturday itself remains expected to be a
fantastic day by virtually all standards with surface high
influence keeping skies clear and easing winds, comfortable dew
points, and forecast highs largely in the 70s.

As we work into Sunday, little has changed with regard to the
expected large scale pattern transition to a much more active
stance. First western CONUS mid-upper shortwave digs toward/into the
desert SW, pushing ridging/height rises across the central CONUS and
inducing Lee cyclogenesis over the southern High Plains and Colorado
Front Range. Locally, this will see a warm front begin to march
northward Sunday and the beginnings of a prolonged period of strong
theta-e/WAA/moisture advection (really however you want to reference
it). Expectation remains for showers and non-severe thunderstorms to
be associated with this northward marching warm front Sunday. While
there are ingredients in place for potential stronger/severe storm
or two Sunday afternoon/evening, fair amount of capping and storm
motions parallel to the frontal boundary limit potential. Instead,
if boundary is slow to work northward, training activity may prime
the pump, so to speak, for future hydrologic threats with additional
rounds of activity expected thru Tuesday. Current synoptic guidance
depictions suggest warm front to only reach around I-70/Highway 36
corridors during the daytime/early evening hours. By the latter
evening and into the overnight, initial western CONUS mid-upper wave
attempts to work off the Rockies, deepening and pushing associated
surface low eastward toward the CO/NE/KS shared border area.
Increasing wind fields and overall lift/dynamics will yield
explosive convection and likely severe/supercellular activity. While
well westward, this activity too is expected to grow upscale into an
MCS and may affect the forecast area during the late evening and
overnight hours. Potential MUCAPE depictions >1500 J/kg and strong
wind fields may yield a continuing/ongoing wind threat, but is
anticipated to be on a weakening trend as it outruns stronger
instability. This `could` be the first hydrologic threat potential
depending on overlap over greatest preceding Sunday rainfall
amounts. GFS/GEFS is notably further N/NE with this Sunday/Sunday
night activity vs the Euro and its ensemble, something to watch.

Deterministic and ensemble guidance continues to depict a secondary
shortwave dropping into the desert SW by Monday. As it does so, it
prevents initial/leading shortwave from completely ejecting into the
Plains. Instead pulling it back westward and instigating Fujiwara-
like action. This will keep warm/moist southerly flow ongoing over
the area and continue to moisten up the region. PWats >1.70" are
widely depicted among guidance by Monday, which would put it well
above 90th percentile via SPC Sounding Climatology page for TOP and
toward maximums for this time of the year. With some eastward
movement of the broader western trough and negative tilt, dynamics
become such that Monday afternoon/evening remains the forecast
area`s best opportunity for severe storms during this active
stretch. The broader details within the warm sector, SB/MUCAPE >2500
J/kg, 0-6km bulk shear >40-50kts, moderate to steep mid level lapse
rates, warm front and dry line boundaries nearby, LCLs <1 km all
suggest all modes of severe weather may be in play. Certainly large
(possibly very large) hail and damaging winds. Tornadic activity may
be a bit more suspect and dependent on warm frontal boundary to
enhance low level rotation in otherwise questionable hodographs
within the warm sector. GFS/GEFS and Euro oriented AI/Machine
Learning/Analogues continue highlight Monday with our greatest
potential, though of note they have ticked upward over the western
forecast area with regards to Sunday night/overnight. Hydrologic
threat potentially builds during this time frame should areas that
see moderate to heavy rainfall be similar to previous opportunities
from Sunday and Sunday overnight. Bolstered by efficient rainfall
potential with warm cloud layer depths approaching 4km and GFS/Euro
ensembles and NBM all broadly depict 50th to 90th percentile QPF
spreads of roughly 1.75" to 4" thru Monday overnight. Take away too
being the potential for locally greater rainfall amounts given
convective nature that is difficult to grasp within synoptic models.
With some of the question into overlapping moderate/heavy rainfall,
WPC EROs continue to depict Slight risks over the Days 3-5 (Sun-Tue)
time frames. Details continue to hash out, but certainly no reason
to let guard down for Monday afternoon/evening at this point in
time.

A strong/severe threat lingers into Tuesday as the western
trough/dueling shortwaves gradually work into the central to
northern High Plains. Much may depend on how Monday shakes out with
regards to lingering boundaries, cloud cover, etc as a good portion
of the area appears poised to remain within the warm sector.
However, this is also where guidance begins to diverge in its
handling of the mid-upper low evolution and track, let alone surface
details. Risk does appear to slide eastward overall though, limiting
chances for western forecast area (incl KC Metro) to see third day
of strong/severe threat.

Large scale pattern evolution through the early-mid week time frame
does also take on an Omega block appearance, further slowing down
the exit and drying out of the region. As the western portion of the
block continues to gradually drift eastward, consensus is for it to
undercut mid-upper level ridging and become absorbed and aide in the
retrograde and development/re-development of a closed mid-upper low
system over the Great Lakes. This will eventually push a cold
frontal boundary and drier air through the region, but possibly not
before an additional few showers pass with front. This too likely
pushes temperatures well below normal for a day or two, possibly
into upper 50s/60s

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 702 PM CDT Fri May 16 2025

VFR conditions are expected to persist through the period under
mostly clear skies. Gusty westerly winds will relax a bit by
around 2z tonight, but gusts to 20 to 25 knots will likely
persist through 6z, with gusts up to 20 knots continuing through
the overnight and Saturday morning hours. Winds should become
northwesterly and relax to around 10 knots by around 18z
Saturday.

&&

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

&&

$$

DISCUSSION...Curtis
AVIATION...BMW