809
FXUS63 KSGF 070025
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
725 PM CDT Mon May 6 2024

.KEY MESSAGES...

- Severe thunderstorms are likely tonight with the highest risk
  areas along and west of Highway 65. Primary hazard is damaging
  wind gusts of 70 to 80 mph. Additional hazards include
  frequent lightning, a few short- lived tornadoes and half
  dollar sized hail. Severe storms will move into the area after
  9pm and continue overnight.

- Localized flooding is also a concern tonight across southeast
  Kansas and western Missouri where localized pockets of 1-2
  inches of rain will occur.

- Additional strong to severe thunderstorms on Wednesday. Exact
  hazards remains in question, but very large hail, damaging,
  and a conditional tornado threat are all in play. SPC has a hatched
  Enhanced Risk (3/5) for most of the area.

&&

.MESOSCALE...
Issued at 725 PM CDT Mon May 6 2024

Storms have developed across a front across central Kansas and
Oklahoma this evening. This activity will continue to move east
this evening into tonight as an upper level trough moves east
into the plains. The high res models continue to be in good
agreement that these storms developing into a line and move
into the far western portions of the area by 11pm then moving
east across the area through the overnight hours exiting the
area to the east by early Tuesday. Damaging winds of 60 to 80
mph winds remain the main threat with these line of storms
especially along and east of Highway 65. Low level shear will
also support a brief tornado risk within the line of storms with
any surges to the east/northeast. Locally heavy rainfall and
localized flooding will also be possible with the best potential
across far southern Missouri. A few of the stronger updrafts
will be capable of hail up to the size of half dollars.

Storms have developed across north central Kansas into Nebraska
early this evening with another area of storms across central
Oklahoma into south central Kansas. The activity across northern
Kansas and Nebraska are forming into line segments and should
continue to move off to the northeast. The storms across
central Oklahoma into south central Kansas are currently
supercells in nature, but a cold pool should develop with these
storms as they move east which should allow these storms to
form into a line.

Once the storms across Oklahoma and southern Kansas form into a
line they will move off the east/northeast at 30 to 40kts. An
unstable air mass will be in place across the area with 1500 to
2200 J/kg of MLCAPE in place west of Highway 65, with values of
1200 to 1700 J/kg to the east overnight. Damaging straight line
winds will occur with the line of segments with gusts up to
80mph possible with the bowing segments. The 00Z SGF sounding
is showing down draft CAPES over 1000 J/kg which is also
supports strong down drafts. Low level shear will also increase
tonight. 0-3KM shear vectors are currently at 26kt across the
area and should increase to around 40kt to the northeast across
of the line of storms. This will support a QLCS tornado risk
with the line of storms with surges in the line to the
northeast.

There are some indications that the the southern part of the
line of storms will become outflow dominate across southern
MO/northern Arkansas and the outflow become parallel with the
0-3km shear vectors and could lead to the potential for some
training of storms and a localized flooding risk tonight. Will
have to watch exactly where this will form.

The storms will push east to the I-49 corridor by 9 to 11 PM to
the Highway 65 corridor by 12 to 2 AM, then to Highway 63 by 2
to 4 AM and the main line of storms should push east of the area
by 6AM, though some linger storms could occur across south
central Missouri until closer to 8 AM. Again damaging straight
line winds will be the main risk across the entire area with
wind gusts up to 80 mph possible and a few short lived tornadoes
mainly along and west of Highway 65. Hail up to half dollars
and localized flash flooding will also be possible tonight.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 100 PM CDT Mon May 6 2024

Current Conditions and Synoptic Pattern: Water vapor and upper
air analysis shows a strong upper level shortwave trough across
Wyoming and Colorado with a 120kt upper level jet across Arizona
and New Mexico. Surface low pressure continues to deepen across
South Dakota with a secondary low across Kansas. A warm front
was in the process of lifting north through the area at this
time. A dry line was located across western Kansas and western
Oklahoma with storms already initiating across northern Kansas.
12z KSGF sounding showed a stable airmass in place (north of the
warm front) however soundings south of the warm front measured a
moist and unstable airmass. Visible satellite showed breaks
in the clouds across the area which should allow the warm front
to continue lifting north. A few showers were occuring however
many areas were dry with temps in the upper 60s to lower 70s.
Dewpoints were also creeping up into the lower 60s.

This Afternoon through early evening (1pm-8pm): The warm front
will continue lifting north through the area and temps will
continue warming up into the 70s which will increase
instability. While a few showers and even a thunderstorm may
develop, upper level forcing will still be to the west therefore
many areas will remain dry. All eyes will be on developing
supercells in a High Risk severe environment across southern
Kansas and northern Oklahoma. These storms will begin to evolve
into a line with time.

Tonight (After 9pm): High res ensembles continue to be in good
agreement that a line of severe storms will approach far
southeast Kansas in that 9-10pm timeframe. RAP forecast
soundings across southeast Kansas and western Missouri indicate
around 1500j/kg of ML CAPE (potentially up to 2000j/kg) with
40kts of 0-6km shear (this will increase further with time). The
120kt 300mb jet will be nosing into the area tonight. Also of
note is that 1.4-1.5in PW values which indicates a very moist
airmass. All this leads to high confidence that storms will
remain severe as they approach the area. Given the expected
linear mode and high instability/shear combo, damaging winds of
60-80mph will be the most likely risk as highlighted in the SPC
Moderate/Enhanced risk areas. That being said, any bowing
segments to the east- northeast or northeast could cause brief
tornadoes. We believe that the threat for supercells and
significant tornadoes will remain just west of the area however
if storms were slower to morph into a line then this expectation
would change. Southeast Kansas will need to closely monitor
storm mode tonight. The hail threat looks lower with this
system given the linear mode however hail up to the size of half
dollars will be possible.

As the line moves further east (between I-49 and Highway 65),
the damaging wind threat (60-80mph winds) and brief tornado
threat will continue. Latest RAP sounding for Springfield
between 11pm-1am still shows 1000-1500j/kg of ML CAPE with 40kts
of shear. PW values are also in the 1.4-1.5in range which
supports heavy rainfall rates.

While it does look like storms will gradually weaken as they
move east of Highway 65, the instability/shear combo will
remain high enough to keep the damaging wind/brief tornado
threat going however perhaps not as high a threat as areas
further west. In general, the line of storms will likely be
clearing the area by 5-7am.

Overall a busy overnight period is expected with the increasing
potential for widespread damaging winds. We will continue to
heavily message safety information for this night time severe
event.

Contemplated a Flood Watch for areas west of Springfield tonight
however given the progressive nature of this line, flooding will
remain localized and brief. 12z HREF does show a few pockets of
1-2 inches of rainfall across far southeast Kansas therefore we
will be monitoring this risk.

Tuesday: The airmass will likely be worked over from overnight
storms and combined with mid level height rises we should see
low precip chances (less than 20 percent). Winds will turn
southwesterly during the day with skies clearing and temps
reaching the upper 70s.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 100 PM CDT Mon May 6 2024

Wednesday: Another shortwave trough will move through the
southern Plains with a surface front moving through the area
during the afternoon or early evening. Strong instability will
be available with the NBM mean showing between 2000-2500j/kg of
surface based CAPE along and southeast of the I-44 corridor.
This instability and unidirectional shear could produce
supercell thunderstorms and the area is in a Enhanced Risk on
Wednesday. There still remains uncertainty with frontal timing
and since we are not in the window of time yet for the high res
guidance it is urged to stay up on the forecast for Wednesday.

Thursday into the Weekend: The overall trend during this time
period is drier conditions and cooler temps. This is likely due
to a pattern shift with northwest flow aloft causing north
surface winds. Friday looks to be the coolest day with highs in
the 60s in many locations.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 532 PM CDT Mon May 6 2024

Gusty southeasterly winds will continue this evening, some MVFR
ceilings could occur, but mainly VFR conditions will occur. A
few isolated showers and maybe a thunderstorms may be possible
this evening but most locations will remain dry through 9PM.

Storms have developed across central Oklahoma and Kansas early
this evening. These storms will continue to move east and
developing into a line or lines of storms. This activity will
move into the area western portions of the area late this
evening and through the rest of the area overnight. These storms
will have the potential for damaging winds, frequent lightning
and brief heavy rain. IFR to LIFR conditions will occur with the
storms. The storms will move east from west to east overnight
into early Tuesday morning. Winds will turn to more
southwesterly behind the storms and remain gusty on Tuesday.

&&

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

&&

$$

MESOSCALE...
SHORT TERM...Burchfield
LONG TERM...Burchfield
AVIATION...Wise