The Central Coast kicked off the week with a lot of daytime highs in the mid to upper 70s but this won't last long. Tuesday still looks like a reasonably warm day with the interior getting into the 70s and some coastal valleys but onshore flow will resume for beaches and near coastal valleys ensuring mostly 60s for daytime highs.
The weather gets much more interesting on Wednesday. A strong onshore push early should deliver some low clouds and potentially some sprinkles early in the day but it is really Wednesday afternoon evening and overnight when rainfall becomes heavy thunderstorms are possible and the winds crank up significantly.
This storm Wednesday into Thursday is an atmospheric river which means it is fueled by a long stretch of subtropical moisture that originates in the central Pacific.
An atmospheric river means that the storm system moving into the area will be well supplied with moisture and instability. This will mean rainfall rates between 1/4 to 3/4 of an inch per hour at times especially if thunderstorms develop.
The moisture stream itself will provide a significant amount of potential accumulation.
Our forecast is for between 1/2 of an inch of rain in the deep interior to up to three inches at the coast. There will be some wind-prone areas with south-faces that see potentially more than 4 inches of rain.
Snow levels start quite high, around 7000 feet but descend to about 5500 feet Thursday. At the highest levels, we will see some accumulating snowfall in combination with the expected high winds. For the Central Coast, there isn't a lot of real estate at those levels but some type of a winter storm warning is possible.
Winds will be quite strong out of the south-southwest Wednesday night into Thursday with some gusts 30 to 40 mph and perhaps even stronger at higher elevations in the Santa Barbara County mountains.
As of this writing, there are no current advisories but a wind advisory is something we might see for Wednesday night into Thursday.
The Storm Prediction Center has identified coastal California as having a chance of thunderstorms Wednesday night into Thursday. Thunderstorms do have the potential for brief heavy downpours lightning and hail.
And this isn't the only game in town, another storm is likely Sunday into Monday. The overall pattern looks cold and unsettled starting at the midpoint this week and extending into next week.
