SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0143 PM CST Wed Dec 09 2020 Valid 092000Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Isolated thunderstorms will be possible late tonight into early Thursday across southern Arizona. ...20Z Update... No change needed to the previous forecast. Isolated lightning is still possible later tonight/early tomorrow morning ahead of an upper low across southern AZ. ..Mosier.. 12/09/2020 .PREV DISCUSSION... /ISSUED 1016 AM CST Wed Dec 09 2020/ ...Southern AZ... A cutoff upper low west of Baja CA will evolve into an open wave as it ejects towards the AZ/Sonora border area by early Thursday. Substantial moistening around 700 mb within the warm conveyor downstream will contribute to an increase in rain showers tonight, initially across southeast AZ. Isolated thunderstorms will also be possible, and more probable across southwest AZ along the periphery of the elevated moisture return, where mid-level lapse rates will be steeper closer to the upper low. 12z forecast soundings from the RAP/NAM suggest limited buoyancy should be present atop an initially very dry sub-cloud layer, which would support overnight convection with minimal rainfall.
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