The weather begins transitioning toward a cooler and wetter pattern on Friday.
The ridge will move east, allowing a powerful storm system currently impacting the Pacific Northwest to shift southward. Onshore flow will develop later in the day, increasing cloud cover across the Central Coast.
Rain Timing:
- A slight chance of rain will emerge Friday afternoon in northwest San Luis Obispo County.
- Temperatures will cool with onshore flow.
Long Term (Saturday - Tuesday):
Weekend Storm System:
This weekend will feature the Central Coast’s first major storm of the season, bringing cooler temperatures, widespread cloud cover, and periods of rain. The storm will be driven by a strong jet stream and a moisture plume with high precipitable water values (1.25 to 1.35 inches), though the system lacks consistent southerly flow that typically enhances rainfall totals.
Rain Timing:
The storm will bring two main frontal waves:
First Wave: Arriving Friday evening into Saturday, with lighter rainfall, but 1"+ potential exists for the SLO County north coast.
Second Wave: Expected late Sunday into Monday, potentially stronger with better upslope flow, leading to higher rainfall amounts in mountain and foothill areas.
Rainfall Amounts (for both events combined):
- North of Point Conception:
- Northwest San Luis Obispo County: 2 to 3 inches possible.
- Other areas: 0.75 to 1.5 inches.
- South of Point Conception:
- Coastal and valley areas: 0.75 to 1.5 inches.
- Enhanced rainfall possible along south-facing slopes of the Santa Ynez Mountains.
Ensemble models suggest variability, with some showing totals as high as 2–4 inches, especially in isolated areas, though these scenarios remain less likely.
Temperatures:
The storm will bring a noticeable drop in temperatures:
Highs will generally remain in the upper 50s to mid-60s through the weekend and into early next week.
Snow Potential:
This is a warm system, so snow levels will remain above 7,000 feet through the weekend. As colder air filters in Monday and beyond, snow levels may drop to 5,000–6,000 feet, but precipitation will likely taper by then, minimizing snow impacts.
Looking Ahead:
There’s a chance of a third, colder storm arriving late next Tuesday or Wednesday, potentially bringing lower snow levels and additional rain. However, not all models are seeing this possibility.
