Valid 252000Z – 261200Z
…NO SEVERE THUNDERSTORM AREAS FORECAST…
Isolated thunderstorms will be possible through tonight along and
near the coast of central/southern California. Severe thunderstorms
are not expected.
Aside from a few deeper showers over southeast AZ, where one or two
lightning strikes have been noted, the greatest risk for
thunderstorms remains near the immediate coast of central and
southern CA. Scattered deep convection is concentrated within exit
region of digging mid-level jet and this activity should spread
south later this evening. No appreciable changes to the 1630z
outlook are warranted.
.PREV DISCUSSION… /ISSUED 1027 AM CST Wed Dec 25 2019/
Much of the previous forecast remains on track. A well-defined
mid-level shortwave trough, embedded within larger scale cyclonic
flow, will continue to propagate southeast towards the southern
California coastline during the period. Deep-layer ascent associated
with the shortwave aloft, combined with the cooling of
temperatures/steepening of mid-level lapse rates in the 700-500 mb
layer, will continue to increase near the southern California
coastline, coincident with low-level moisture advection. As such,
isolated thunderstorm development is expected to increase,
particularly through the late afternoon into the overnight hours.
Severe thunderstorms are not expected, though the steepening lapse
rates may promote some small hail and wind gusts.