Update at 9:31pm from Meteorologist Dave Hovde:
The severe thunderstorm warning for parts of Santa Barbara County has been allowed to expire. There still is a line of strong rain and wind but it is no longer considered to be severe at this point. There is still a flood advisory for SLO County until 11 and until 2am in Santa Barbara County for areas of flooding in flood-prone and low-lying areas.
Update at 9:00pm from Meteorologist Dave Hovde:
A Special Marine Warning has been issued for the East Santa Barbara Channel, outer waters including the Channel Islands, and waters from Point Sal to Santa Cruz Island until 10:00 PM PDT. At 8:54 PM PDT, severe thunderstorms capable of producing waterspouts were located along a line extending from 12 nautical miles east of Point Conception to 10 nautical miles south of San Miguel Island, and are moving eastward at 20 knots. These storms present the hazards of waterspouts, wind gusts of 34 knots or greater, and small hail. Waterspouts can easily overturn boats and create locally hazardous seas, while small craft could be damaged in briefly higher winds and suddenly higher waves. Mariners near West Point Santa Cruz Island, Goleta Point, San Miguel Island, and Santa Rosa Island should move to safe harbor immediately.
Update at 8:25pm from Meteorologist Dave Hovde:
Update at 8:03 p.m. from Meteorologist Dave Hovde:
A Severe Thunderstorm Warning has been issued for much of western and central Santa Barbara County until 9:30 p.m.
At 8 p.m., showers capable of producing damaging wind gusts were located along a line extending from 6 miles east of Nipomo to 9 miles northwest of Point Conception and are moving eastward at 25 mph.
These storms threaten wind gusts up to 60 mph, which can cause damage to roofs, siding, and trees. Residents in the affected area should take immediate precautions to protect themselves and their property.
This is a developing story. Check back later for updates.
___
Update at 7:43 p.m. from Meteorologist Dave Hovde:
A Flood Advisory is in effect for much of Santa Barbara County, including the Lake Fire Burn Scar, until 2 AM PDT Thursday. Doppler radar indicates heavy rain from showers and thunderstorms is increasing across the region, leading to expected minor flooding in low-lying and poor drainage areas. There is also a risk of minor landslides, including rockslides and mudslides, and minor debris flows in and around the Lake Fire Burn Scar. Residents in areas such as Santa Maria, Santa Barbara, Lompoc, and surrounding communities should exercise caution, especially when encountering flooded roads, and remember to never drive through flooded areas. Be particularly vigilant at night when recognizing flood dangers is more difficult.
___
Update at 7:36 p.m. from Meteorologist Dave Hovde:
The marine warnings have now extended into the Santa Barbara Channel and a warning is active until 9pm for the strong storms, severe at times, capable of producing downpours, strong winds, hail and waterspouts.
Radar is showing the leading edge of the main band of precipitation moving into NW Santa Barbara county as of 7:36 p.m.
Heavy rainfall is possible across Santa Barbara County until midnight before activity becomes more scattered but even those scattered cells will be capable of higher rainfall rates and isolated thunderstorms.
___
Update 7:16 p.m. from Meteorologist Dave Hovde:
___
Update: 6:37 p.m. from Meteorologist Dave Hovde:
There is a special weather statement until 7:15 p.m. for southern SLO and northwest Santa Barbara counties. A line of strong storms capable of producing thunderstorms, high winds, waterspouts, hail and small tornadoes is possible in the statement area.
There is also a new Areal (area) Flood Advisory until 11 p.m. Excessive rainfall is possible which can produce low-lying and poor drainage areas. Water over roadways is also a possibility.
————from the original story—————-
The Central Coast is preparing for a significant storm system that will bring periods of heavy rain, mountain snow, gusty winds, and much colder temperatures through Friday.
While light warm frontal rain fell on the Central Coast and Southcoast this afternoon, the main event is still to come this afternoon and tonight.
Today's Precursor
The light rain observed this afternoon is due to a weak, warm frontal boundary moving across the region. This is a precursor to the main cold front that will blast through the area between now and midnight.
The atmosphere is primed for heavier precipitation, as indicated by increasing precipitable water values, suggesting a moisture-rich environment.
The Main Event
A fast-moving cold front will sweep through the region overnight, bringing the most intense rainfall. This system packs a significant punch, with a possibility of exceeding debris flow thresholds in the foothills and mountains. The rapid approach of the front, combined with ample moisture, will lead to high rainfall rates.
The high rainfall rates, exceeding 0.50 inch/hour and potentially reaching 0.75 inch/hour, combined with recent burn scars in SoCal, create a significant risk of debris flows. The rapid influx of water can destabilize the soil, leading to mudslides and debris flows.
Thursday's Mixed Bag
Thursday will bring a mix of weather conditions, including rapidly lowering snow levels, increasing air mass instability with isolated thunderstorms, and periods of no rain with some sunshine. The cold air mass aloft, combined with a diffluent flow pattern, will create conditions favorable for instability and potential thunderstorms. Snow levels will drop significantly, potentially reaching 2500-3000 feet, making travel over mountain passes hazardous.
Why the Rapid Snow Level Drop?
The cold front will usher in a much colder air mass, leading to a rapid drop in snow levels. This, combined with strong winds, will create blizzard-like conditions in the mountains.
Windy Conditions
A low-level jet stream will bring strong winds to the region, with High Wind Warnings and Wind Advisories in effect. The strong pressure gradient associated with the approaching cold front will generate these powerful winds.
Why the Strong Winds?
The approaching cold front will create a strong pressure gradient, leading to powerful winds, especially in the interior valleys and mountains. The low-level jet stream will further enhance these winds.
Other advisories
High surf 10-13ft. with dangerous rip is likely thru Friday evening.
High elevations in the SB County Mountains could see up to a foot of snow, but the snow levels do drop down to around 3k feet by Friday, so lower-level snow is also likely.
The flood watch for the Southcoast is for higher rainfall totals and rainfall rate,s which could cause localized flooding.
Looking Ahead
Another weak and cold storm system will move through the region between Friday and Saturday, bringing another chance of light rainfall. High pressure will then establish over the weekend, bringing a drying trend. Another storm system is expected early next week, bringing the potential for colder temperatures and gusty winds, particularly to northern areas.
