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755
FXUS63 KEAX 201720
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
1220 PM CDT Fri Sep 20 2024

...Updated 18z Aviation...

.KEY MESSAGES...

* Quiet, warm/hot today - though less humid for most

* Active period of shower/storm opportunities Friday overnight
  through Sunday

  - Welcome widespread rainfall, especially Sat night into Sun
  - Possible flash flood threat, low severe threat

* Cooler late weekend into next week - Highs mid 60s to 70s

&&

.DISCUSSION...
Issued at 406 AM CDT Fri Sep 20 2024

Storm activity from earlier Thursday lingered into the overnight
across northern Missouri as a cold front sagged in from Iowa and
Nebraska. Without much oomph from the front or other lifting
mechanisms, storm activity followed a persistent downward trend.
Lingering convection over north-central to northeast Missouri
continues early this morning, and should continue to follow a
general downward trend in strength and coverage before largely
subsiding by sunrise.

Today will be quiet through the daytime hours, though another warm
to hot one for many. While a frontal boundary will continue to sag
in from the north, it will largely bring about lower dewpoints
versus appreciably cooler air temperatures. So in that regard, the
sensible weather change will be less humid conditions behind/north
of the front. Expectations remain for the front to stall around
central Missouri, just a bit south of the I-70 corridor. Expect
highs to top out in the upper 80s to low 90s, with elevated heat
index values held at bay with the reduced dewpoints/humidity.

Late tonight/overnight, shower/storms return to the area as a SW
CONUS shortwave trough begins to slide eastward into/across the
lower Rockies. This will help increase SW flow and pushes of theta-e
advection into the region. Storm chances will be best around/north
of the previously mentioned frontal boundary, where isentropic lift
will be strongest. Threat for strong to severe storms remains
minimal within a highly elevated and unsupportive effective shear
environment. A few enhanced wind gusts may be possible though with
the elevated nature and dry low to mid levels. As multiple rounds of
showers/storms are likely, enhanced wind threat should gradually
reduce as low-mid levels moisten from previous rounds of
showers/storms. General area of activity may drift northward into
Saturday as the bounday attempts to lift northward as a weak warm
front. Antecedent dry conditions reduce the overall risk for water
issues through Saturday, but may set up some areas for potential
issues with the next wave of activity...

By overnight Saturday into Sunday, activity in the area further
increases as the SW CONUS shortwave trough crosses the Rockies.
During this time, a northern steam shortwave trough will have swept
across southern Canadian Plains and its associated surface low and
cold front pushed southward into portions of northern Kansas and
Missouri. Ongoing and enhanced mid-level SW flow will continue to
provide broad theta-e advection/isentropic lift overriding the
front. With appearance of similar location to previous rounds and
continued PWats of around 2 inches, there may be a threat for flash
flooding for areas that see heaviest rainfall amounts. Though,
overall dry antecedent conditions of late, and some dependence on
rainfall location and amounts Fri night into Sat, keep risk on the
lower end at this time. Threat for any strong to severe to remains
low too within an increasingly unsupportive environment as lapse
rates (and by virtue CAPE) dwindle and a marginal to poor effective
shear environment.

Beyond Sunday/into next week, drier and cooler fall conditions
settle in for a few days as highs fall into the mid 60s to 70s.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
-- Changed Discussion --
Issued at 1218 PM CDT Fri Sep 20 2024

Mostly clear conditions expected the rest of afternoon through
early evening. Thunderstorms may develop over Kansas late this
evening and arrive near the terminals around 08z. A break is
expected from this first wave, but additional showers are
expected later Saturday morning and will last through much of
the day. Most ceilings will be VFR. If a heavy rainfall shower
occurs directly over the terminal, we may see low-end MVFR to
IFR visibility for a brief period of time.
-- End Changed Discussion --

&&

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

&&

$$

DISCUSSION...Curtis
AVIATION...Krull