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000
ACUS02 KWNS 120555
SWODY2
SPC AC 120554

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1254 AM CDT Fri Apr 12 2024

Valid 131200Z - 141200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN CENTRAL OR...

...SUMMARY...
Isolated severe hail is possible across central Oregon between about
2 to 8 PM MDT on Saturday.

...OR...
An amplified mid/upper low just off the central CA coast will dampen
as it gradually wobbles inland near the Bay Area into the Central
Valley by early Sunday. The initially meridional and fast mid-level
jet east of the low will weaken somewhat as it flattens to a
southwesterly orientation across south CA into the eastern Great
Basin. Mid-level flow will become more backed and subside somewhat
across the Northwest relative to Friday. But within the exit region
of the mid-level jet, inland surface cyclogenesis will occur in the
northwest NV/southeast OR vicinity. To the north of this cyclone,
moderate elongation of the hodograph is anticipated with a
sufficient wind profile to sustain a supercell or two. 00Z CAMs are
fairly consistent with this signal across the central OR vicinity.
Despite MLCAPE holding at or below 500 J/kg, isolated severe hail
will be possible from mid-afternoon to early evening.

...Great Lakes...
Poleward low-level moisture return from the western Gulf will become
more pervasive across the central states on Saturday as a surface
anticyclone drifts east in the northeast Gulf. This will occur
beneath an increasingly broad elevated mixed layer. By Saturday
night, strengthening low-level warm theta-e advection should yield
at least isolated, highly elevated convection across northern WI and
parts of MI. Available CAM guidance in this time frame is generally
more sparse with coverage relative to convectively parameterized
guidance. It seems likely that bulk of elevated convection will
remain north-northeast of capping from the elevated mixed layer
until perhaps close to the end of the period. MUCAPE should largely
remain weak with only modest effective shear in the cloud-bearing
layer. Small hail is possible with overall thunder probabilities
from 10-20 percent.

...Central Great Plains...
Guidance is consistent with indicating a minor mid-level impulse
drifting east from the southern Rockies into KS/NE on Saturday,
impinging on the full latitude mid-level ridge across the Great
Plains. Rather deeply mixed thermodynamic profiles with LCL heights
approaching 600 mb are expected within the modified moisture return
ahead of a weak surface trough/dryline. 00Z CAMs outside of the HRRR
are fairly consistent in simulating convective development with the
HRW-FV3 the most aggressive of the HREF members. MLCAPE should be
meager at most, but a locally strong gust from the high-based,
low-topped convection is possible given such large DCAPE.

..Grams.. 04/12/2024

$$