-- Discussion containing changed information from previous version are highlighted. --
890
FXUS63 KSGF 221529
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
1029 AM CDT Wed May 22 2024

.KEY MESSAGES...

- Marginal (1/5) to Slight (2/5) risk for a few isolated strong
  to severe thunderstorms late this morning through the early
  evening across southern Missouri. Primary hazards are hail to
  the size of golf balls and damaging wind gusts up to 60 mph.

- An additional Marginal (1/5) to Slight (2/5) risk on Thursday
  into Friday morning for a few strong to severe thunderstorms.

- Daily shower and thunderstorm chances ahead Friday through
  Memorial Day. The highest chances (50-70%) are with a system
  late Saturday into Sunday, with the potential for additional
  severe weather and localized flash flooding. All day washouts
  are not expected at this time.

&&

.UPDATE...
-- Changed Discussion --
Issued at 1027 AM CDT Wed May 22 2024

An ill-defined shortwave moving eastward across eastern OK/NW
AR this morning while the cold front associated with yesterday`s
severe weather has struggled to pass the Boston Mountains in
northwest Arkansas extending into the MO Bootheel.

The atmosphere south of the front in northern Arkansas remains
very unstable...with supercells riding the instability axis as
they move eastward/south of the forecast area this morning. See
SPC`s SWOMCD #889 for additional detail.

Farther north MUCAPEs to 2000 J/KG along the Arkansas border
into southeast Kansas have yielded a few stronger but elevated storms
with hail to the size of pennies.

Confidence is high that the scattered thunderstorms will
continue into the early afternoon...with better coverage of
stronger storms along the Arkansas border into south central MO
as the shortwave progresses eastward. Storm coverage will
diminish northward toward/a bit north of I-44.
-- End Changed Discussion --

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 230 AM CDT Wed May 22 2024

Through Tonight: A few isolated showers and thunderstorms
continue to dissipate across south central Missouri. The
associated frontal boundary from Tuesday evening has slowed
into southern Missouri, with the expectation of the front to
slide into northern Arkansas through the early morning. This
front and areas just north of it will be the focus for
additional development of isolated showers and thunderstorms by
mid to late morning. Recent hi-res guidance would suggest the
extent of coverage to be limited to areas along and south of
Interstate 44, with the highest chances (50-70%) along the
Missouri/Arkansas border through the afternoon. The environment
late this morning into the afternoon will be characterized by
0-6km deep layer shear around 40-50 knots and sufficient
instability with MUCAPE around 1500-2000 J/kg. Being on the
north side of the frontal boundary, activity will be elevated in
nature. However, the evolution of the storm mode remains messy
and there is a lack of any strong forcing; with a subtle
shortwave to the south of the area. The latest CAM trends
suggest scattered thunderstorms, potentially congealing into
multi-cell clusters. Given the recent trends, SPC has backed off
with the Day 1 Severe Weather Outlook. A Marginal Risk (1/5)
extends from Pittsburg, KS to Osage Beach, MO and south, with a
sliver of Slight Risk (2/5) into south central MO through the
West Plains area. Primary hazards will be hail up the size of
quarters and damaging wind gusts up to 60 mph in the strongest
thunderstorms. If a thunderstorm takes on an elevated supercell
structure, hail size would be up to golf balls. However,
widespread severe weather is not expected at this time with this
system. Additionally, efficient rainfall rates will support
heavy downpours and a quick 0.25 to 0.50 inch of rainfall in
localized areas. Any flash flooding would be limited to flood
prone areas and sensitive waterways. Some locations may remain
completely dry through this evening. Much cooler this afternoon
with highs in the lower to middle 70s behind the frontal
passage. Rain chances (30-50%) linger through tonight with the
potential for additional scattered showers and a few non-severe
thunderstorms across southern Missouri.

Thursday: On Thursday, a warm front will lift back north through
the area. This will support the return of warmer temperatures
and additional low-level moisture. This is characterized by
high temperatures in the upper 70s to near 80 and dewpoints
into the middle to upper 60s. In general, forcing remains weak
through Thursday afternoon in the warm sector. Thus, current
PoPs will hold around 20-40% through Thursday afternoon and
evening with most locations remaining dry. However, the
environment would support a strong to severe thunderstorm if
development occurs. The Marginal (1/5) to Slight (2/5) Severe
Risk remain rather conditional at this time across the area
through Thursday evening. By Thursday night, guidance depicts the
approach of a shortwave and a developing 30 to 40 low- level
jet. Potential ongoing convection across northeast Oklahoma may
build into southeast Kansas and southwest Missouri into
Thursday night, which would support a potential MCS as upscale
growth occurs into the overnight/early Friday morning. This
potential MCS will need to be assessed closer in future forecast
updates.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 230 AM CDT Wed May 22 2024

Friday: A potential overnight MCS from Thursday night may be
ongoing Friday morning across the area. There would likely be a
weakening trend into the morning hours as it lifts
east/northeast through the area, though some redevelopment may
occur across central Missouri into Friday afternoon. This
scenario is reflected in the current PoPs forecast. Otherwise,
some dry time can be expected into Friday evening as we enter
into Memorial Day Weekend. Highs in the lower 80s.

Saturday-Sunday: A break in the active pattern lingers through
Saturday morning and afternoon. Highs this weekend reach into
the lower to middle 80s. By Saturday evening, a stronger
shortwave and associated low pressure system lift out of
Plains. Early indications suggest this system will feature much
stronger dynamics. The presence of ample instability and shear
may support the development of strong to severe thunderstorms
overnight Saturday into Sunday. However, there remains some
differences among the ensembles on the exact timing and
evolution of this system. SPC highlights portions of the area
with a 15% risk to account for this potential. Additionally,
this system may pose the risk for excessive rainfall and
localized flash flooding. Stay tuned for additional updates into
the weekend.

Next Week: For Memorial Day, rain chances (10-30%) linger
across the area. However an all day washout is not expected with
activity more isolated to scattered in nature as a front slides
through the region. By next Tuesday, ensemble guidance suggests
the longwave trough shifts east of the central CONUS. A bit
cooler with the pattern shift with highs in the middle 70s on
Tuesday. An upper level ridge builds over the region late in the
forecast period, supporting a potential stretch of drier
weather into late May.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 550 AM CDT Wed May 22 2024

Clouds build back into the region this morning ahead of the next
system bringing isolated shower and thunderstorm chances to the
area. Expect a few isolated showers and thunderstorms through
the afternoon into the evening, primarily across southern
Missouri. Confidence remains low on the extent of coverage, and
thus rain chances have been depicted in the TAFs as PROB30
groups. Instances of MVFR to IFR flight conditions may occur
within heavy showers or thunderstorms. Additional low rain
chances (20-40%) linger through tonight. More widespread MVFR
ceilings may build into the area late in the TAF period on
Thursday morning. Winds remain light around 5 knots out of the
northeast to east.

&&

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

&&

$$

UPDATE...Runnels
SHORT TERM...Perez
LONG TERM...Perez
AVIATION...Perez