813
FXUS63 KSGF 061813
AFDSGF

Area Forecast Discussion
National Weather Service Springfield MO
113 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.

&&

.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 SUNDAY/...
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 TUESDAY/...
Issued at 100 PM CDT Mon May 6 2024

MVFR ceilings will continue at SGF and BBG for a few more hours
this afternoon however a return to VFR ceilings should occur
with time. While a few rain showers will be possible this
afternoon, the more hazardous time period will be after 9pm as a
line of thunderstorms moves in from the west. These storms will
bring the potential for damaging winds and frequent lightning
along with a reduction in flight categories. Outside of
thunderstorms, southerly winds will continue with gusts of
25-30kts outside of the storms. A brief period of low level wind
shear will likely occur before the storms arrive overnight. Winds
will turn more southwesterly on Tuesday with drier conditions
and VFR ceilings.


&&

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

&&

$$

SHORT TERM...Burchfield
LONG TERM...Burchfield
AVIATION...Burchfield