954
FXUS63 KEAX 150616
AFDEAX

Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
Issued by National Weather Service Louisville KY
116 AM CDT Thu Aug 15 2024

.KEY MESSAGES...

- Strong to severe storms possible this evening into the
  overnight.

- Additional storms, some strong to severe, are possible
  Thursday.

&&

.UPDATE...
Issued at 109 AM CDT Thu Aug 15 2024

After collaboration with SPC and TOP, have allowed Severe
Thunderstorm Watch 622 to expire on time at 1am CDT. Line of
storms currently crossing Franklin and Anderson counties in
northeast Kansas may still pose a wind threat as it pushes east
into the EAX CWA and western Missouri, but thus far the
strongest wind signatures have remained aloft, with peak winds
at UKL only around 37 mph. Can`t completely rule out the
possibility of a warning or two south of Kansas City during the
06-09Z time frame, but it appears that most storms will be more
SPS-level.

Issued at 1051 PM CDT Wed Aug 14 2024

 Line of strong to severe storms continues to push through a
corridor of maximized MUCAPE showing up on plan view analysis
and ACARS sounding out of MCI. Sounding does show a very
shallow stable layer, CIN has increased regionwide as we
progress deeper into the nighttime hours, and radar shows the
storms west of the KC metro becoming largely outflow dominated.
Still, gusts recently reached 59mph at the Topeka NWS office and
warnings are being issued downstream ahead of a bowing segment
coming in to Leavenworth County in a localized maximum of steep
mid level lapse rates and DCAPE 1300-1400 J/kg. These storms
may threaten the Kansas City metro, especially along and north
of Interstate 70.

Though the storms may lose some of their punch as they cross
northern Missouri, as has already been seen in the storms from
St Joseph northward, a severe threat will persist for a few more
hours and Severe Thunderstorm Watch 622 has been expanded about
two rows of counties eastward per collaboration with SPC. At
this time it appears unlikely that the watch will need to be
extended in time beyond 06Z, but will continue to monitor.

Issued at 836 PM CDT Wed Aug 14 2024

An elongated broken band of strong to severe storms continue to
advance eastward this evening across central and eastern Kansas.
Storms are already advancing into our far NW CWA (Atchison
County) but this activity has been sub-severe and will likely
continue to weaken with eastward extent.

Farther south, a mixture of linear segments and supercellular
structures are being observed north of Manhattan/Topeka Kansas.
Reports of hail and even a tornado have been observed with these
storms.

Overall environment for surface based storms becomes less
favorable with eastward extent as SPC Mesoanalysis shows a
fairly strong MLCIN gradient near and east of the KS/MO borders.
Still, modest deep layer shear and elevated instability will
keep an organized storm threat going for the areas within the
Severe Thunderstorm Watch.

Issued at 701 PM CDT Wed Aug 14 2024

Heat index values have dropped below criteria levels so the heat
advisory has been allowed to expire on time.

Issued at 557 PM CDT Wed Aug 14 2024

Severe Thunderstorm Watch 622 has been issued for northwestern
portions of the region. Strong to severe storms have already
formed in portions of central Kansas and this activity will
gradually slide eastward through the remaining evening and
overnight hours.

&&

.DISCUSSION...
Issued at 316 PM CDT Wed Aug 14 2024

Earlier convection has pushed into central and southeastern
Missouri, with plenty of debris clouds limiting temperatures to the
upper 70s and lower 80s so far, but a very warm and moist air mass
lurks across SE Kansas and SW Missouri. PWAT values exceed 1.5
inches across eastern Kansas and there`s an axis of 2" across
central Missouri. Expect a modest northward surge of the warmer and
oppressively humid air mass during the late afternoon hours, so the
Heat Advisory conditions could still be realized especially in and
south of the KC Metro.

Hi-res models suggest the effective boundary over central Kansas and
SE Nebraska will light up this evening between 00-02Z, with some
initial supercell structures possible. Steepening mid-level lapse
rates will support large hail, and there`s a brief window for a
tornado threat, mainly north and west of St Joseph, before storms
congeal into a MCS that will trek across northern Missouri
overnight. Wind threat could continue as impressive DCAPE surges
north ahead of the incoming system, fading as you get farther south
and east of the I-35 corridor.

Renewed SVR threat on Thursday will depend on how quickly the
atmosphere recovers from overnight storms. Multiple disturbances in
the flow aloft could interact with a sfc cold front, and any
convection that does develop will feed off the instability and 30-40
kt of deep-layer shear. Will be another window of opportunity for
supercells and attendant tornado and hail threats, with damaging
winds as the primary threat to continue as storms organize.

By Friday a post-frontal NW flow takes over, with a modestly less
humid air mass building in. Still enough cyclonic curvature in the
upper flow to allow for some destabilization, so we can`t rule out
more storms late in the day Friday.

A stretch of mostly dry weather begins on Saturday and continues
well into next week as an upper trof pushes east into the Great
Lakes and upper ridging amplifies along the Rockies. Sfc high
pressure will retreat from the Upper Midwest into the Great Lakes,
maintaining low-level easterly flow, which will result in near-
normal temperatures and seasonably muggy dewpoints. Convection on
the periphery of the high should remain focused over central
portions of Nebraska and Kansas and dive almost due south, leaving
western Missouri and northeast Kansas high and dry.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1210 AM CDT Thu Aug 15 2024

Line of strong convection from earlier this evening has moved
through the TAF sites and is weakening as it crosses northern
Missouri. Additional convection has developed from Kansas City
and Topeka southwestward, but this activity is more isolated and
much less robust. Will account for the possibility of TSRA in
the first hour of the new TAF period at MCI/MKC. Chances are
lower at IXD, and STJ should be done by TAF issuance time
(though will need to keep an eye on small thunderstorm north of
TOP at the time  of this writing).

This afternoon a cold front will pass through the region. There
will be plenty of instability and moisture ahead of the
boundary, suggesting the possibility of thunderstorm
development. However, most model progs show very little in the
way of convection at or near the TAF sites, possibly due to
capping showing up in soundings. Better chances of storms may be
just to the east of the TAF sites. So, at this time will leave
TSRA out of the forecast, but will need to consider it in
future forecasts.

&&

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

&&

$$

UPDATE...WFO Louisville/13
DISCUSSION...WFO Louisville
AVIATION...WFO Louisville/13