Good morning Central Coast! The storm that we have been talking about all week is nearly here.
Let's dive right in!
The morning is going to be off to a mild start, a little dense fog is expected as the onshore winds continue to bring more cloud cover in.
Temps will still be mild (for the start of Wednesday at least) with highs once again in the mid 60s for most communities with added cloud cover.
By early afternoon the rain will begin, starting light but as the evening goes on and the cold front presses onshore rain will become much heavier and begin our major area of concern.
This evening into the overnight hours strong southerly winds will combine with a plume of moisture to bring thunderstorm and heavy rain. Accumulations 1/4 to 1/2 of an inch per hour is possible at times. That is enough for flooding, plus as it is overnight visibility of flooded areas is a concern. Take extreme caution if you will be on the roads overnight into Thursday early morning.
The band of rain will push east through the overnight hours. The Santa Barbara County southcoast and E/W facing ridges will see the worst of this with several hours of that very heavy rain.
As the worst of this passes east skies will clear (at least partially) for Thursday morning's commute.
Even once the main system has passed through scattered showers and isolated thunderstorms are expected through Thursday, Friday and Saturday.
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.
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. The Weather Prediction Center has identified the area in a risk for excessive rainfall Wednesday into Thursday as well.
As expected, wind advisories have been issued for the Central Coast and a high wind warning for the Santa Barbara County higher elevations. High winds will be sustained 30-40 mph with gusts up to 60 mph.
High surf is expected. 7-10ft Wednesday but building to 14-18ft Thursday for the west-facing Central Coast. The SB Southcoast will see some 8-12ft break. Advisories last until Saturday evening.
This system is categorized as an atmospheric river. 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 1/2 of an inch per hour at times especially if thunderstorms develop. The moisture stream itself will provide a significant amount of potential accumulation.
Atmospheric rivers are categorized on a 1 to 5 scale. For this first storm tonight into Wednesday it is a category 1/5, our second strong storm is expected to be more intense and with a longer duration, placing it as a 2/5 AR system.
Our forecast remains for 1/2 of an inch of rain in the deep interior 2 up to 3 inches of rain at the coast. There will be some wind-prone areas with S faces that see potentially more than 4 inches of rain from this system. That is enough for flooding and potential mudslides in fragile slopes.
And this isn't the only big storm on the way, another storm is likely Sunday into Monday.
This second system could deliver another 1-4” of rain. This means cumulative rainfall between now and this time next week could be 2-7+”. Here is a look at the potential cumulative rain.
That’s a lot of rain potential and historically when we get that much rain there will be some local issues handling all that water.
With the potentially serious nature of the forecast, knowing where to get alerts and what to do in an emergency situation is of the utmost importance. Here are direct links to the county offices of emergency services.
For San Luis Obispo County (click the link below)
READYSLO.org (click for redirect)
For Santa Barbara County (click the link below)
READYSBC.org (click for redirect)
Have a wonderful day Central Coast, stay weather aware through the forecast!
