How this story works: Updates will be inserted at the top. As you go further down you'll see more forecast information. It is long and detailed in an attempt to answer all your questions and fully prepare you.
Update from KSBY Daybreak Meteorologist Vivian Rennie: Monday 4:15 a.m.
The *Flash Flood Warning* has been expanded to include Santa Barbara, Goleta, Isla Vista, Montecito, Carpenteria and the associated communities. Debris flows, mud slides and flooding through 10:30 a.m. 1-2" more inches of rain are expected this morning. Take extreme caution.
Update from KSBY Daybreak Meteorologist Vivian Rennie: Monday 2:10 a.m.
A *Flash Flood Warning* has been issued for most of Santa Barbara County through 10:30 a.m.
Mud and debris flows are likely this morning and well as significant pooling of water on roadways. On top of the rain already accumulated 3-4 more inches of rain is expected as we head into the morning. Take caution and do not travel. This includes Santa Maria, Lompoc, the Santa Ynez Valley, Vandenberg and all of the Santa Ynez Mountains. At this point this does not include cities along the SB County South Coast but similar conditions are expected.
Update from KSBY Chief Meteorologist Dave Hovde: Sunday 12:34am
SLO County now has a Flood Advisory in place until 7:30am. Locally moderate to heavy rain has fallen producing some areas of water on roadways and in low-lying locations.
Significant rainfall has come down since 11:30pm
Up to 3" has fallen in parts of SLO county and up to 4" has fallen in Santa Barbara County. .50-1.5" across the coastal valleys is common as of 12:33am
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Update from KSBY Chief Meteorologist Dave Hovde: Sunday 10:43pm
The surf advisory has been upgraded to a high surf warning into later Tuesday:
I also think it is important to note that modeling is showing a pretty significant gap between this first
part of the storm, and the second part.
From tomorrow, sometime after sunup, to later Tuesday afternoon or early evening, the Central Coast might not see much rain. Tuesday late evening into Wednesday morning the upper low passes over which will turn moderate activity back on:
Update from KSBY Chief Meteorologist Dave Hovde: Sunday 8:15pm
We have our first Flood Advisory for Santa Barbara County through the overnight. This means urban and small stream flooding is likely in the advisory area.
Update from KSBY Chief Meteorologist Dave Hovde: Sunday 7:20pm
The rain has started here on the Central Coast. The Lompoc area was one of the first places to see moderate rainfall and between Lompoc and Point Conception about an inch has fallen as of 7:15pm. Downtown Santa Barbara has about .75". Most of the Central Coast is still near .10". It is still quite early in the forecast.
I've attached the 6pm weathercast to this story.
Also, and I mentioned this earlier, the concerns about convective rainfall have increased. This means more brief downpours, thunderstorms, and localized winds are higher.
Honestly, now we are more or less in the waiting game. We have to see what the storm really does. I think all the preparations have been made and the advisories activated.
Update from KSBY Chief Meteorologist Dave Hovde: Sunday 2:00pm
I just finished attending the National Weather Service afternoon briefing on the storm. No significant change to the forecast. We are still expecting significant rainfall to begin later this afternoon. The first wave of rain looks significant with .50-1"/Hr. rainfall rates possible. The concern based on recent modeling is that the storm appears more convective. This means it will likely feature more downpours and has the potential to produce thunderstorms. Check out the timing and intensity chart, It indicates this initial segment of the storm could be the strongest:
*Also new.. The Salinas River in Paso Robles has a chance to hit monitoring stage. This is short of flood stage but indicates a good amount of water is expected to enter the system.
This is the latest rainfall outlook. It does trim back some of the potential in the SLO county northcoast hills, but it still calls for very significant rainfall across Santa Barbara County and in the mountains some high accumulations are still possible there. This chart is for the entirety of the storm into early Wednesday:
Weather Service also notes, as I did earlier today, that the storm will likely get a lull after the first part of the storm but again things should pick up Tuesday:
Update from KSBY Chief Meteorologist Dave Hovde: Sunday 11:00am
Rain looks to begin this afternoon (though a few light showers could precede more significant rain):
Models this morning like some of the heaviest rain later today into Monday morning then being more scattered thru Tuesday. Some models backed a little on Central Coast rainfall totals but still hit the Santa Barbara Southcoast hard. I still think a 1-4" range for the Central Coast is good with 2-5" for the Stouhcoast and 4-8" in the Southcoast hills. The biggest disagreement is about the SLO County north coast hills. I think it is best to prepare for the higher amounts but that may not verify. I'll update as new modeling comes in during the day:
Update from KSBY Chief Meteorologist Dave Hovde: Sunday 9:25am
We are still going to be using this story for the forecast and storm updates. I will be extensively editing this later to remove some older information as I add new information near the top.
This morning models are taking a slightly different view of the system. Most models are coming in a little lighter and further south with the heavier rains. That said, I don't think there is any reason to back off from the existing forecast. New modeling is still coming in. And the changes I am talking about are subtle. Heavy rain is still expected, flooding, surf and winds are all still significant concerns.
I discuss this in a new forecast video this morning which is at the top of this article.
The satellite picture this morning shows the clear comma shape of the storm off the California coast. It is still an atmospheric river storm. It has been judged as a 1 on a scale of 1 to 5. But this is a multi-day system which means the moisture is around for a long time.
The satellite did show some lightning in the larger storm. Thunderstorms are possible today, Monday, and Tuesday as the system moves through. This means there is a chance of downpours, rainfall rates up to or exceeding 1"/hour at times, hail, winds, waterspouts and even small tornadoes. This will not be the emphasis of the activity but it is possible.
Modeling this morning still shows rainfall starting again this afternoon, and once it starts rain will be pretty consistent into Monday morning. After that, it looks to be more scattered thru Tuesday into Wednesday morning.
We have seen a good bit of rain in the last week, so the ground is saturated. Some reservoirs are near the top, so some spilling is possible.
Interior areas might see less than an inch of rain but most of the area is still in the 1-5" rainfall range with mountains and foothills potentially getting 4-8".
The advisory picture has not changed:
Flood watch
Wind advisory
Wind warning
High surf advisory
Coastal Flood advisory
Details on all those advisories are included below.
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Update from KSBY Chief Meteorologist Dave Hovde: Saturday 5:15pm
SLO County has seen a good amount of rain as of 5:15pm. .25-.50" with less inland. Santa Barbara County has seen less thus far:
I'll include some graphics from the NWS briefing this afternoon. They are in line with prior forecasts, but it never hurts to get a fresh update:
Update from KSBY Chief Meteorologist Dave Hovde: Saturday 2:38pm
The SLO County north coast has already picked up a quick .25-.50" of rain. The rest of SLO county has lighter amounts so far while much of Santa Barbara county has yet to see much significant from this first of two systems for the weekend. This is the much weaker of the two:
If you have been watching me this week, I have been expecting wind advisories to be posted when the larger system drew closer. A wind advisory and high wind warning have been issued. Here is what you need to know about those:
Update from KSBY Chief Meteorologist Dave Hovde: Saturday 12:00pm
There are some updates to tell you about. The Weather Prediction Center has upgraded their Excessive Rainfall Outlook for the storm. For Santa Barbara County it is an elevation to "moderate" risk Monday and Tuesday. This means 40-70% chance of excessive rainfall:
Here is a look at the timing of the first (smaller) rain event this afternoon before the larger event begins later Sunday"
The radar is active and that line of rainfall will move from NW to SE across the area this afternoon into this evening.
Modeling coming in today continues to reinforce the outlook for heavier rain potential, rates, and accumulations:
The Weather Prediction Center's outlook for 1-7 day accumulated rainfall is in line with our forecast and modeling:
The atmospheric river still looks on track to play a significant role in fueling the Sunday-Wednesday morning rainfall"
Here is a mid-range model view of the storm thru Wednesday:
The advisory situation has not changed. Our key advisory is for flood potential. There are other advisories for coastal flooding and high surf and the details of those can be found further down this story:
Update from KSBY Chief Meteorologist Dave Hovde: Saturday 10:00am
I've attached a new forecast discussion video to the top of this story. I have looked at the latest modeling this morning and don't see a reason to significantly adjust the forecast. If anything, the new information gives additional confidence to the forecast presented here.
The Central Coast is expected to get hit with some significant rain potential later this weekend into early Wednesday. The larger storm Sunday through Wednesday is preceded by a smaller system Saturday into early Sunday:
• Front moving over San Luis Obispo and Santa Barbara Counties
• Totals up to 0.5", and locally up to 1 inch across the SW-facing mountain slopes
After that, there is not much of a break until the larger storm arrives Sunday PM-Wednesday. That storm is an atmospheric river storm:
Cumulatively 2-5” of rain is possible in the region into early Wednesday with 4-8” possible in mountains, and wind-facing slopes.
Large surf from multiple directions is also in the forecast with surf advisories going into place Saturday through Tuesday for the larger storm. Some coastal flooding is also possible at times of high tide.
A Coastal Flood Advisory is in effect for early Sunday AM and Tuesday AM
There is a Flood Advisory in effect from Sunday PM into Wednesday. Here is a list of potential impacts from the larger storm system:
• Risk of significant flooding in urban areas, especially over roads and other low-lying areas
• Risk for mudslides over vulnerable hills and rockslides on canyon roads
•Debris flow potential in recent burn areas
• Dangerous high flows in rivers and especially in streams, with a moderate potential for overflowing banks; increased need for swift water rescues
• Dangerous lightning, strong erratic winds, and heavy downpours are possible with thunderstorms, though that risk is only about 10-20%.
• Rainfall rates 0.50 to 1.0 inch per hour will be possible near any heavier showers or thunderstorms that form
• Additional threat of high intensity 1 in/hour rain rates, as well as high 3–6-hour rates due to possible convective and orographic enhancement
• Peak gusts: 20-40 mph in most areas, except 40-60 mph in the foothills and mountains
• South to southeast wind direction
• Strongest over San Luis Obispo and Santa Barbara Counties, but likely weaker than the most recent event(Feb. 3-6)
• Gusty and locally damaging winds with a moderate risk of downed trees and powerlines with some power outages likely
• Hazardous driving conditions with strong cross winds and road debris
