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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



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