106
ACUS02 KWNS 011732
SWODY2
SPC AC 011730

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1230 PM CDT Sat Jun 01 2024

Valid 021200Z - 031200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF NEBRASKA AND NORTHERN KANSAS...

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
WEST TEXAS...

...SUMMARY...
Severe thunderstorms producing severe gusts, some greater than 75
mph, are possible across parts of Nebraska and northern Kansas
Sunday afternoon into evening. Additional severe storms producing
strong gusts and large hail are possible across the broader
central/northern Plains vicinity. Very large hail to baseball size
is also possible across parts of west Texas.

...Northern/Central Plains...

A subtle upper shortwave trough will shift east across the region on
Sunday. Surface cyclogenesis will remain modest as upper height
falls are not forecast to be very strong. Nevertheless, a weak
surface low over the western Dakotas will shift east/northeast
toward western Ontario through the period. As this occurs, a
trailing cold front will develop eastward across the Dakotas and NE
from late afternoon into the nighttime hours. South/southeasterly
low-level flow will transport generally low to mid 60s F dewpoints
northward across NE and the central/eastern Dakotas into parts of MN
and IA, with somewhat higher dewpoints into KS and MO. A plume of
steep midlevel lapse rates will overspread the region, with
southeast ND being the northern extent of those steeper lapse rates.
This will aid in strong destabilization across SD/NE/KS during the
afternoon/evening, with forecast MLCAPE values climbing into the
2000-3000 J/kg range (somewhat lower over ND).

Initial convection is expected to develop over west-central ND by
early afternoon, with some warm advection storms possible closer to
the Red River during the morning. Additional storm development
across SD/NE/northeast CO will be a bit later in the afternoon as
stronger capping will need to be eroded. Initial cells will pose a
risk of large hail and damaging gusts. With time, linear forcing
imposed by the eastward-advancing cold front should support upscale
development, especially as a low-level jet increases toward evening.
A more potent line/MCS may develop over southern SD/NE/northern KS
where overall instability and kinematics will be better compared to
further north. Point forecast soundings from CAMs guidance indicate
at least a 60-70 kt rear-inflow jet, suggesting a strong and
well-organized system. As a result, wind probabilities have been
increased and an Enhanced risk (level 3 of 5) has been introduced
for parts of the area.

...Southern Plains to TX/LA coast...

Some uncertainty exists concerning possible ongoing convection
across parts of OK and/or northwest TX Sunday morning. Regardless of
whether convection is continuing from the Day 1/Sat overnight
period, outflow will likely exist over this area, along with a
quasi-warm front within southeasterly low-level flow. Heating along
this boundary and dewpoints into the 70s F will support strong
instability. Forcing for ascent will remain weak, but isolated to
scattered thunderstorms are expected to develop into southeast TX
and the LA coast vicinity as either new convection and/or
reinvigorated morning storms. Strong gusts will be the main concern
with this activity.

Confidence is greater in isolated to widely scattered storms
developing near a dryline extending southward from the OK/TX
Panhandle into southwest TX. Vertically veering wind profiles with
40+ kt effective shear magnitudes will support high-based
supercells. Elongated/straight hodographs amid very steep midlevel
lapse rates and 2500-4000 J/kg MLCAPE suggest large to very large
hail will be possible. Strong outflow winds also are expected with
this activity.

...OH/TN Valleys into the Southeast...

Northeastward progression of a weakening shortwave trough and
associated surface low will aid in thunderstorm development across
the OH Valley. Airmass destabilization is also anticipated across
much of the Southeast, with scattered afternoon thunderstorm
development likely. Weak shear should mitigate overall storm
strength in both areas.

..Leitman.. 06/01/2024

$$