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ACUS01 KWNS 140057

SWODY1

SPC AC 140056



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

0756 PM CDT Sat Apr 13 2024



Valid 140100Z - 141200Z



...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS EVENING

ACROSS PARTS OF SOUTH CENTRAL OREGON...



...SUMMARY...

Isolated strong thunderstorm development remains possible into this

evening across parts of south central Oregon, to the north and east

of the Klamath Falls vicinity, posing at least some risk for severe

wind and hail.



...01Z Update...



...Southern Oregon...

As a deep surface low migrates northward to the lee of the northern

Sierra Nevada, forcing for ascent, aided by downstream low-level

warm advection, may maintain vigorous thunderstorm development to

the north and east of the Klamath Falls vicinity into the 02-04Z

time frame.  Based on latest objective analysis, at least a small

pocket of moderate boundary-layer instability persists across this

region, in the presence of marginally sufficient shear for

occasional supercell structures posing at least some risk for severe

hail and wind.



...Great Lakes...

In advance of a digging low-amplitude short wave trough and

associated developing surface low, models suggest that warm

advection along a strengthening frontal zone may contribute to weak

destabilization tonight.  Forecast soundings suggest that moisture

return within and/or above elevated mixed-layer air emanating from

the northern Great Plains will be sufficient to support convection

capable of producing lightning, which may commence across northern

Wisconsin/adjacent upper Michigan by 04-05Z, before spreading

east-southeastward overnight.  Although southwesterly to westerly

wind fields are forecast to strengthen in excess of 50 kts in the

dry sub-cloud air, potential for downward mixing of this momentum to

the surface will tend to be inhibited by a near-surface inversion

layer.  This will remain more pronounced with eastward extent across

northern lower Michigan toward the eastern Lake Erie/western Lake

Ontario vicinity, but occasional gusts approaching severe limits

might not entirely be out of the question.



...Black Hills vicinity into mid Missouri Valley...

In advance of a developing, southward advancing cold front,

a seasonably warm and deeply-mixed boundary-layer became

sufficiently unstable to support widely scattered weak thunderstorm

activity late this afternoon.  This continues in spots, but appears

to be diminishing with the loss of daytime heating, and thunderstorm

probabilities will be maintained at less than 10 percent through the

remainder of the period.



..Kerr.. 04/14/2024



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