786
FXUS63 KEAX 290458
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
1158 PM CDT Sat Jun 28 2025

.KEY MESSAGES...

- There is a slight risk of severe thunderstorms across much of
  the area Sunday and Sunday night. Damaging winds and heavy
  rainfall are the primary threats. There is low, but not zero,
  potential (less than 10 percent) for significant severe wind
  gusts (gusts 75 mph or greater) with the strongest storms.

- Hot and humid conditions will continue on Sunday. Heat indices
  exceeding 100 degrees are likely (>60 percent chance) in far
  eastern Kansas and far western Missouri.

- After a drier and slightly cooler period early in the work
  week, hotter and more humid conditions are expected to return
  by Independence Day.

&&

.DISCUSSION...
Issued at 204 PM CDT Sat Jun 28 2025

A fairly typical summer upper-air pattern is in place across
the conterminous U.S. today, with faster flow confined to the
far northern portion of the country. A perturbation is ejecting
eastward from the northern Rockies to the northern Plains today,
which should yield a good convective episode for the Dakotas
and Minnesota tonight. There is some question regarding how far
south any convection will develop and move through overnight,
with some of the latest MPAS convection-allowing models (CAMs)
suggesting a mesoscale convective system (MCS) may approach or
even move through our area late tonight into Sunday morning (in
a weakened, primarily sub-severe state). The 18z HRRR continues
with prior longer-range simulations without such a convective
evolution. Instead, scattered convection initiates via lift from
the nocturnal low-level jet (LLJ) somewhere in eastern Kansas
or Missouri (generally after 2 or 3 am), lingering through mid-
morning before the LLJ wanes.

Whatever the storm evolution, there are some immediate
forecasting implications as a result. (1) The temperature/heat-
index forecast tomorrow is lower-confidence, owing to any
lingering effects of cloud cover and early-morning
precipitation. However, even if the convection remains for most
of the morning, it will not take much late-June sunshine to
warm/destabilize the area quickly. Currently, think there is
potential for portions of eastern Kansas and far western
Missouri to reach the mid 90s (with heat indices in the low to
mid 100s). Did contemplate issuing a heat advisory tomorrow for
the KC metro (and this still may happen), but currently,
confidence is too low to meet heat-index thresholds in a
widespread area (105+ degrees).

(2) What effects will there be on subsequent convection on
Sunday? CAMs provide a veritable cornucopia of solutions. One
option: Isolated to scattered convection during the afternoon
(if early-morning convection dissipates sufficiently fast). Such
convection would be slow-moving, producing torrential downpours
before dissipating in pulse-like fashion. An isolated
microburst would be possible with such convection, but
widespread severe chances would be low. A second option: Little
in the way of afternoon/diurnally-driven convection, but
instead an organized band/cluster of storms developing closer to
a front approaching from the north during the evening and
overnight. Given this option, considerable to extreme
instability would be present (CAPE >4000 J/kg), with
thermodynamic profiles very favorable for severe wind gusts
should organized cold pools develop. The SPC has upgraded our
region to a slight risk for just this potential scenario (as
modeled by the HRRR, RRFS, and some of the MPAS members). A
third option: Some flavor of both options 1 and 2, with unclear
impacts on the evening/overnight MCS if the afternoon scattered
storms develop. The bottom line here is that the forecast for
Sunday and Sunday night has a lot of uncertainty, but there is
an increasing signal for severe wind gusts with organized storms
Sunday evening/night (generally after 7 pm) given a favorable
ambient environment and approaching forcing from a northwest-
flow-type shortwave trough moving into the northern Plains (and
attendant cold front).

Given very high PWs in the central Plains, heavy rainfall
remains a threat with any vigorous convection that develops. The
scattered/diurnally-driven storms on Sunday would be slow-
moving but would also likely be of the pulse variety (so would
not last much more than 30-45 minutes in a given location),
mitigating a more substantial heavy rain threat. The MCS would
certainly be capable of producing excessive rainfall rates, but
would also likely be quite progressive, mitigating a more
widespread flash flood threat. As a result, think the potential
overall is too low for a flood watch at this time.

With storms expected to move through Sunday night, the hot and
humid conditions this weekend will give way to slightly cooler
and drier weather early this coming week. Upstream ridge
amplification will ensure the drier period Monday through
Wednesday, with the ridge axis remaining well west of the area
(keeping us on the "cool" side of the overall ridge). Highs will
generally be in the mid to upper 80s, and lows will be in the
60s.

Late in the week, the ridge axis will approach the area,
allowing for warmer temperatures to creep back into the region.
Additionally, with increased moisture and closer proximity to
glancing shortwave troughs (mostly to our north and west), the
storm potential will slowly increase (though will be far from
high; generally less than 25% Thursday and Friday). There are
some indications that the next front will approach the area by
next weekend, but model variability is high by that time. The
higher-confidence aspect of the forecast is a return to
hotter/more humid conditions for Independence Day.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1148 PM CDT Sat Jun 28 2025

Scattered thunderstorms initiated by warm air advection are
expected to develop towards 09Z across eastern KS. These
thunderstorms are expected to build towards the KC metro, and
have included tempos in the 11-14Z time frame. There is a
question about how far north these storms build, so only have a
prob30 for the KSTJ terminal. Thereafter, the forecast becomes
very muddy with the potential for additional thunderstorms, but
timing is VERY uncertain. Will need to keep an eye on the
thunderstorms organizing over eastern SD as of 05Z. For now,
left mention of thunderstorms out of the TAFs after 14Z.

&&

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

&&

$$

DISCUSSION...CMS
AVIATION...BT