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Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0720 AM CDT Sun Jun 05 2022

Valid 051300Z - 061200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS WESTERN NE TO
NORTHERN/CENTRAL OK...

...SUMMARY...
Significant severe thunderstorms producing very large hail, intense
damaging winds, and a few tornadoes are possible across parts of
Oklahoma, Kansas, and Nebraska from late afternoon through tonight.

...OK/KS/NE...
Although alluded to as a possibility in the 06Z outlook, confidence
is too low to warrant an upgrade to a cat 4/MDT risk. Worst-case
scenario could still support a derecho occurring this evening into
the overnight somewhere in the region.

A progressive MCS, which produced mainly strong wind gusts and a few
measured severe early this morning, continues across far southeast
KS and north-central to northeast OK. This MCS has not been terribly
well-simulated by most CAM guidance, with the 00Z HRW-NSSL closest
to reality. It's MCV will seemingly shift into the Ozark Plateau.
Deep convection along its southwest flank may not entirely decay as
low-level warm theta-e advection persists atop the convective
outflow, a scenario supported by the HRW-NSSL. A farther south
evolution of convective outflow would clearly suppress
destabilization in eastern OK that is advertised by the bulk of
guidance. Regardless of where convective outflow ultimately ends up,
a very unstable air mass is expected to its west centered on western
OK. Very steep mid-level lapse rates of 8.5-9 C/km will overspread
upper 60s boundary-layer dew points to yield large buoyancy with
MLCAPE in excess of 3000 J/kg. Modified air mass recovery is
expected in the wake of the outflow across western parts of KS/NE.

Guidance differs substantially with the degree of convective
development near the outflow/dryline intersection centered around
northwest OK. The HRW-NSSL, 00Z HRW-ARW, and 06Z NAM-NEST all
suggest convection will develop around early evening near this
intersection and along the cool side of the remnant outflow boundary
into south-central KS as the low-level jet intensifies. This
scenario would yield quick upscale growth and probable forward
propagation south-southeast along the MLCAPE gradient. The 06Z HRRR
and subsequent runs indicate no sustained deep convection occurring
in the OK/KS border area during this time frame, despite having
uncapped forecast soundings. The overall intensity and coverage of
the severe threat with southern/eastern extent in OK will be
modulated based on how far south/west this morning's MCS affects
instability, and whether an MCS can develop during the evening
versus overnight.

A more probable convective signal exists along the lee
trough/dryline across western NE to the KS/CO border. Robust
boundary-layer heating to the west of the dryline will remove MLCIN
for late afternoon scattered thunderstorm development. Several
initial supercells in this regime will have the potential for
significant severe hail given such steep mid-level lapse rates.
Consolidating cold pools will likely yield upscale growth into a
maturing MCS towards south-central NE and central KS during the
evening. The overall intensity/coverage of the severe wind threat
with this MCS will be modulated by whether a separate MCS will be
simultaneously ongoing in far southern KS and OK. If the latter does
not develop, a more favorable regime for significant severe wind
gusts would be possible across central KS and then shifting into
northern OK overnight.

...Interior Northwest...
Within the left exit region of an intense upper jet centered on
northern CA and southern OR, scattered thunderstorms are expected
this afternoon from eastern OR across ID into a portion of western
MT. Elongated, straight-line hodographs will encourage a few
splitting supercells. However, buoyancy will likely remain weak with
moderate mid-level lapse rates and below-normal surface
temperatures. This suggests that isolated severe hail will be the
primary hazard, with locally strong wind gusts a secondary threat.

..Grams/Broyles.. 06/05/2022