SPC Dec 22, 2023 2000 UTC Day 1 Convective Outlook

[NorthGeorgiaWX]

SPC 2000Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0148 PM CST Fri Dec 22 2023

Valid 222000Z - 231200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTHERN ARIZONA AND INTERIOR SOUTHERN CALIFORNIA...

...SUMMARY...
Isolated hail and gusty winds remain possible this afternoon and
evening across parts of southern Arizona and vicinity.

...20Z Update...
No changes have been made to the Marginal Risk. The potential for
isolated hail and gusty winds continues with any robust convection
that can move from northwest Mexico into southern AZ this afternoon
and evening.

..Gleason.. 12/22/2023

.PREV DISCUSSION... /ISSUED 1022 AM CST Fri Dec 22 2023/

...Southwest US...
Morning water vapor loop shows a compact upper-low off the coast to
the southwest of San Diego, CA.  A 70+ knot mid-level jet max is
rotating around the base of the low, and will overspread northwest
Mexico and into southern AZ tonight.  Widespread clouds and
scattered precipitation will limit heating/destabilization in most
parts of AZ today.  However, visible imagery shows broken cloud
cover over southern CA just ahead of the upper low.  Steep mid-level
lapse rates and cold temperatures aloft may result in sufficient
CAPE for a few robust updrafts this afternoon.  CAM guidance
suggests the main area of concern is along and east of the Colorado
River valley.  A few storms may produce hail and gusty wind in this
region this afternoon.

Other strong storms may form in the low-level warm-advection zone
and beneath the strong winds aloft across southeast AZ after dark. 
This area will see very little daytime heating or destabilization,
but stronger vertical shear profiles and sufficient CAPE could
encourage an organized storm or two capable of gusty winds.

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