Friday morning update (11am)

Friday morning update

(11am)

As of 11am Friday, multiple bands of showers and thunderstorms were noted just offshore, 

with dozens of lightning strikes having been detected through the morning, and seemingly increasing in frequency. 

Cloud tops appear to be warming, though, with these bands, 

indicating they're likely weakening. 

New convection is developing behind, between, and ahead of these older bands though, and expect the newer storms will re-invigorate ongoing convection or takeover themselves as new complete bands. 

MUCAPE values in the 200 – 500 j/kg are widespread offshore supporting this convection in combination with deep subtropical moisture and lift from the upper-level low situated about 350 miles off the CA/OR coast. 

These offshore bands and the low’s cold front will continue to progress eastward through the afternoon, 

inland into northern California, with the cold front expected to slide through during the evening.

Visible satellite, radar, and weather conditions displayed via METARs, from 11:10am.

A continued warm and moist southerly flow ahead of the front will stream up into the region through the day, which combined with cooling temperatures well aloft will promote increasing instability inland.

HRRR indicates sufficient conditions to allow CAPE values to rise in excess of 700 – 800 j/kg across portions of the valley and delta this afternoon,

which combined with increasing lift and moisture through early to mid-evening may allow shower/thunderstorm development to occur ahead of the offshore bands, and if not ahead, directly along the bands that work their way onshore.

Most high resolution models do indicate that at least a few thunderstorms are possible during the afternoon and evening, but coverage and location is iffy.

In general, given increasingly strong mid-level flow ahead of the low/trough, any thunderstorms, especially if a line of storms form, gusty winds and very heavy rainfall would be the most likely impacts, but if clearing occurs for a while ahead of the bands, stronger storms could be possible.