518
FXUS63 KEAX 191929
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
229 PM CDT Sun May 19 2024

.KEY MESSAGES...

- A line of thunderstorms capable of producing severe wind gusts
  will likely move through the region late this evening into
  early tomorrow morning.

- There will be a conditional threat for strong to severe
  storms tomorrow afternoon and evening.

- Enhanced risk for severe thunderstorms on Tuesday, with all
  severe hazards (large hail, damaging wind gusts, and a few
  tornadoes) possible.

&&

.DISCUSSION...
Issued at 210 PM CDT Sun May 19 2024

A broad area of west to southwesterly flow remains over much of the
central CONUS downstream of a synoptic trough over the Intermountain
West. Meanwhile, water vapor imagery shows a shortwave trough over
northern AZ and NM, with this expected to move east
northeastward with an associated mid level jet max nosing into
the central High Plains. This will help initiate storms this
afternoon across far SE Colorado, SW Kansas, and the OK
Panhandle in vicinity of a surface low and accompanying
southward extending dryline. As these storms move east
northeast, they should grow upscale into a quick moving MCS
capable of producing widespread severe winds, traversing from SW
Kansas all the way into eastern Kansas. As the MCS approaches
our far eastern Kansas counties by around 10 pm, they should be
entering into a slightly less favorable convective environment.
However, most recent CAM guidance does suggest a large bowing
squall line capable of producing severe criteria wind gusts
moving through the KC metro in the 10 pm to midnight time frame,
with this continuing to move eastward through Missouri into the
early morning hours, with the damaging wind gust threat
diminishing the further east it progresses. 0-3 km bulk shear
vectors could also perhaps support some embedded QLCS
mesovortices, especially if bowing segments allow for a more
favorable orientation of the shear vector with respect to the
line itself. The severe threat should be over by around 2 am,
but areas of stratiform precipitation may linger for a bit
longer. With the overall progressive nature of the MCS, hydro
concerns should be relatively low tonight.

Severe chances for Monday is still very much uncertain. New
convection may initiate over the area by early to mid morning
tomorrow and continue into the early afternoon hours, but these do
not appear to pose much of a severe threat. However, another
shortwave trough should eject out of the Front Range and into
the Plains tomorrow afternoon, deepening the the surface low
over Kansas and enhancing low level southerly flow, bringing in
upper 60s dewpoints. By late Monday afternoon, model soundings
suggest up to 2000 J/kg of ML CAPE over the region with
sufficient shear to support organized updrafts. That being said,
forcing for ascent will be lacking. It is possible that storms
could initiate along a remnant outflow boundary or a
differential heating boundary of some sort. If any storm does
manage to initiate, it will have the capability to become severe
with large hail and damaging winds. CAMs suggest a large MCS
developing over SE Nebraska by late tomorrow night as better
forcing arrives, and moving eastward into southern Iowa into the
early morning hours of Tuesday. It is possible that this could
clip portions of northern Missouri, but best chances should stay
north of the MO/IA border.

Tuesday afternoon/evening remains our most favorable set up for
severe weather across the region as a stronger shortwave trough
moves into the Plains with a belt of 80 knot WSW winds at 500
mb overspreading the region. At the surface, the low should
deepen and further approach the area, creating surface pressure
falls and backing surface winds, yielding even better low level
moisture advection into the region. By mid afternoon, our
region will be in a very warm, moist warm sector with ML CAPE
values at 3000 J/kg or above with very steep mid level lapse
rates. Given the aforementioned band of 80 knot mid level winds,
deep layer wind shear will be very strong. This pairing of
large instability and deep layer shear will support supercells.
Low level wind shear and hodographs will also support a tornado
threat, especially if surface winds can back enough to out of
the SE. While supercells will be possible out in the open warm
sector earlier on in the event, storms will likely quickly grow
upscale into linear storm modes later in the afternoon/evening
given the strong forcing and advancing cold front. At this
point, damaging wind gusts would likely be the primary hazard,
especially if any bowing segments develop.

The cold front should clear the region to the east by late Tuesday
night into early Wednesday morning, with precipitation exiting with
it. High temperatures for Wednesday should be much cooler (mid
70s) behind the cold front, but temperatures should rebound back
to the lower 80s by Thursday and continuing into the weekend.
Chances for showers and storms return for Thursday night into
Saturday morning.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1239 PM CDT Sun May 19 2024

Currently VFR at all terminals under mostly clear skies with
southerly winds around 10 knots. These conditions should
generally persist through the afternoon and early evening hours.
A squall line is likely to impact the terminals around 4z
tonight, with moderate rain lowering visibility to around 3SM.
This squall line will also bring gusty WSW winds, with the
initial surge of winds on the leading edge of the line
potentially as strong as 50 knots. Storms and breezy winds may
linger through around 6z, with some light rain potentially
lingering through around 10z. Guidance suggests the potential
for additional shower development in the 13z to 17z time
window, especially in the vicinity of STJ.

&&

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

&&

$$

DISCUSSION...BMW
AVIATION...BMW