SPC 1300Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0643 AM CST Fri Jan 08 2021

Valid 081300Z - 091200Z

...NO THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Thunder potential appears minimal over the U.S. mainland.

...Synopsis/Discussion...
Low-level frontal passage -- associated with the cyclone analyzed at
11Z offshore Cape Fear -- will leave behind a boundary layer too dry
and/or stable for overland thunderstorms east of the Rockies. 
However, brief thunder (below unconditional criteria) cannot be
ruled out over or near the Outer Banks today, in association with a
greater convective potential offshore near the northeastward-
ejecting, occluding surface low.  The associated mid/upper cyclone 
-- now covering most of KY/TN and portions of adjoining states --
will move offshore from NC around 06Z. 

In the Northwest, a negatively tilted trough was apparent in
moisture-channel imagery from near Cape Mendocino northwestward
across the Pacific, offshore from OR/WA.  This perturbation should
move quickly eastward/inland through the remainder of the morning. 
The most vorticity-laden southern portion of this feature should
pivot southeastward across the northern Great Basin and intensify
late in the period, becoming a strong shortwave trough and nearly a
closed cyclone over southern UT by 12Z.  Very isolated lightning 
cannot be ruled out over or west of the Cascades for another couple
hours until the large-scale midlevel ascent and cooling aloft shift
inland over unfavorably dry/cold air.  However, the potential
appears too isolated and brief for unconditional thunder
probabilities at or above 10%.

..Edwards.. 01/08/2021

Read more
There’s more click here.