Area Forecast Discussion
Issued by NWS Springfield, MO

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433
FXUS63 KSGF 260102 AAA
AFDSGF

Area Forecast Discussion...UPDATED
National Weather Service Springfield MO
802 PM CDT Sat May 25 2024

.KEY MESSAGES...

- Slight (2 of 5) to Moderate (4 of 5) Risk for severe
  thunderstorms late tonight into Sunday morning (between 11 pm
  - 7 am). Damaging winds up to 80 mph and hail up to baseballs
  are the primary potential severe weather hazards. There is
  also a conditional risk for a few tornadoes.

- Flood Watch in effect tonight for the entire area. Repeating
  thunderstorms could produce 1-3 inches of rainfall.

- Slight (2 of 5) to Enhanced (3 of 5) Risk for severe
  thunderstorms on Sunday afternoon and evening. Primary hazards
  are damaging winds up to 70 mph and large hail up to golf
  balls.

&&

.MESOSCALE...
Issued at 800 PM CDT Sat May 25 2024

Severe thunderstorms are ongoing as planned across Kansas and
Oklahoma with the most significant concentration south of
Wichita into northern Oklahoma. These storms have already
produced baseball size hail, damaging winds and at least one
tornado. The 00z KSGF sounding data revealed a vastly different
airmass than 12 hours ago with significant destabilization
having occurred. Surface temps in the 80s and dewpoints in the
upper 60s have returned to the area with ML CAPE values being
measured at 2300j/kg with very little cap remaining (21j/kg
CIN). MU CAPE values were an impressive 3900j/kg therefore the
airmass is primed. 0-6km wind shear was 50kts however the low
level shear was weak. This will change overnight as the llj
increases. Mid level lapse rates were also steep with a max of
8.6C/km measured in between 700-500mb.

Latest high res guidance continues to indicate that these
supercell storms will continue moving east this evening towards
southeast Kansas with additional storms developing further north
in Kansas. A low level jet is currently in the process of
increasing across Oklahoma and this will nose into Kansas as
well. This will increase the low level helicity therefore the
tornado threat may begin to increase across Kansas/Oklahoma over
the next few hours. An additional cluster of storms also looks
to form further north, across north central to northeast Kansas.
As storms move into our southeast Kansas counties (generally
after 11pm), storms may begin to congeal into a cluster(s) of
storms (either line segments or supercells). These cluster(s)
still look to produce large hail up to the size of baseballs,
damaging winds of 60-80mph and even a strong tornado.

These supercell storms then look to move into western Missouri
however a few trends are noted in most recent high res models.
One being that the storms that eventually form further north
(between Wichita and Kansas City) may actually congeal into a
strong enough cold pool to begin pushing southeast into the area
after 2-3am. With a 50kt llj this could create a northwest to
southeast oriented backbuilding line of storms. It is hard to
pinpoint where this may occur but if it does then this would
increase the flash flooding threat substantially. Last few HRRR
runs show this with a few pockets of 3-5 inches of rainfall
wherever storms move over the same areas. We will need to
monitor this threat closely overnight. This back building line
of storms would still pose a risk for large hail, damaging winds
and tornadoes. This cluster or line of storms could persist
through the 5-7am timeframe. Therefore a messy convective mode
looks likely overnight and given the amount of people outdoors
it will be imperative people have multiple ways of receiving
warnings and having a way to get indoors.

We are planning a special balloon launch in the 4-6z timeframe
to get another look at the local atmosphere ahead of the storms.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 255 PM CDT Sat May 25 2024

This Afternoon-Evening: A warm front is lifting north through
the area this afternoon ahead of the next approaching shortwave
trough. Ahead of this next system late tonight into Sunday, a
rather dry and warm afternoon is unfolding. Highs will range
from lower to middle 80s across the area, with dewpoints
climbing into the middle to upper 60s, near 70 as the front warm
front lifts into central Missouri. Expectations are for the area
to remain capped through the afternoon and evening. This has
been well captured by the guidance. Supercell thunderstorms will
develop west of the area across the Southern/Central Plains,
with a Moderate Risk (4 of 5) draped across this area.

Tonight: By tonight, the atmosphere becomes primed for
development of severe thunderstorms. A brief overview of the
environment, depicts instability around 2000 to 4000 J/kg in
the vicinity of 0-6 km deep layer shear of 35 to 40 knots. Both
deep layer and low-level shear will be on the increase into
tonight. Additionally, a low-level jet around 45 to 50 knots
builds into the area tonight, which will further amplify low-
level flow into the region. This will correspond to strong mid-
level flow around 500 mb. SPC highlights a Moderate Risk (4 of
5) into southeast Kansas and southwest Missouri. Further east,
Enhanced (3 of 5) to Slight (2 of 5) risk exists into Missouri.

Ongoing supercell thunderstorms to the west will slowly slide
into the area, generally after midnight for portions of far
southeast Kansas and along the Missouri/Arkansas border.
Supercell coverage may not be widespread, though the activity
that is present will likely be intense. Initial thought is that
activity will remain semi- discrete in nature for areas along
and west of Interstate 49. Hazards in this area include
destructive damaging wind gusts up to 80 mph, large hail up
baseballs, and a strong tornado or two. The tornado environment
is characterized by sufficient 0-1 km shear around 25 to 30
knots and SRH values around 250 to 300 m2/s2. With winds
slightly backed out of southeast and low LCLs, mature supercells
may be able to tap into a favorable low-level environment.
However, a tornado outbreak is not expected at this time as the
window for tornadic development in short-lived before the
activity grows upscale. Additionally, steep mid-level lapse
rates and ample instability through the hail growth zone
supports large hail. Large Hail Parameter paints a picture of
values greater 20. As thunderstorms push further east towards
Highway 65 in the early morning hours, the transition from
supercells into line segments is expected. The primary hazard
will become damaging wind gusts up to 80 mph, with less focus on
large hail. As for tornadoes, 0-3 km shear around 25 knots from
the west- southwest, would support a few brief and weaker
tornadoes where the segments are able to become balanced along
the UDCZ and bowing structures exist. CAMs suggest this line of
thunderstorms to persist into central and south central
Missouri, towards sunrise Sunday morning. Damaging wind gusts of
60 to 70 mph will be the primary risk with a gradual
"weakening" trend east of Highway 65, though some guidance
suggests otherwise. This will need to be monitored closely with
radar and mesoscale trends. There is an additional concern for
localized heavy rainfall and flooding across the area. HREF
highlights a few corridors, particularly across west central
into central Missouri of 1 to 3 inches or more in short periods
of time where thunderstorms train over the same areas. Pinning
down these exact locations in subjective in nature, but the
general consensus is that the conditions are favorable for
heavy rainfall with efficient rainfall rates to produce flash
flooding. Additionally, there may be some backbuilding in the
vicinity of the warm front and nose of the low-level jet into
this area. A Flood Watch has been issued for late tonight (1 AM
Sunday) through Sunday evening (7 PM) to account for this
increasing potential.

Sunday: The overnight MCS complex will be ongoing Sunday morning
across portions of central and south central MO. How the
overnight MCS evolves through Sunday morning will play a key
role in the potential for additional strong to severe
thunderstorms Sunday afternoon and evening along the trailing
cold front. If thunderstorms are able to redevelop, the
atmosphere will be supportive of large hail up to golf balls and
damaging wind gusts up to 70 mph. The area of greatest risk
extends from central into south central Missouri where an
Enhanced (3 of 5) Risk exists.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Issued at 255 PM CDT Sat May 25 2024

(From Previous AFD) Upper level wave will push through on
Sunday night with a drier air mass moving into the area. This
should clear the convection to the southeast of the area with
temperatures dipping into the upper 50s to low 60s.

An upper low in Canada will drop southeast into the Great Lakes
region early in the week bringing more of a northwesterly flow
aloft to the area. The best moisture axis should remain over the
deep south into the southern plains with precipitation chances
fairly low for the first half of the work week.

An upper level ridge will begin to push into the area on
Thursday with moisture beginning to increase over the western
CWA by late in the week. Temperatures in the long term period
look to remain seasonal for this time of year.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 609 PM CDT Sat May 25 2024

Confidence is high that thunderstorms, some severe, will move
into the TAF sites closer to 06z. These storms may linger for
several hours at SGF, perhaps into 12z. Damaging winds are
likely if these storms move through the sites. Winds outside of
storms will be out of the south to southeast with increasing
gusts overnight. A brief period of MVFR ceilings may prevail in
the morning with VFR then expected for the rest of Sunday. There
is a 30 percent chance of thunderstorms in the afternoon at SGF
and BBG however confidence is too low to include at this time.
Winds will gradually turn southwesterly during the day with
increasing gusts. Low level wind shear is likely overnight at
the sites.

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
KS...Flood Watch from 1 AM CDT Sunday through Sunday evening for
     KSZ073-097-101.
MO...Flood Watch from 1 AM CDT Sunday through Sunday evening for
     MOZ055>058-066>071-077>083-088>098-101>106.

&&

$$

MESOSCALE...Burchfield
SHORT TERM...Perez
LONG TERM...Perez
AVIATION...Burchfield