Tracking a high impact storm, bringing torrential rainfall into the weekend.
The atmosphere remains unstable today but theres only a slight chance for showers to develop and its likely they would evolve in the northern counties or in higher terrain. Onshore flow strengthens so temperatures cool off a few degrees and highs will be below average and into the middle to upper 50s and low 60s. It will be a rather mundane day with breezy winds at times. Overnight lows will be cooler and most of the area will dip down into the upper 30s and lower 40s.
Winds pick up Saturday morning, especially near the South Coast. Winds may be up to advisory thresholds but other than gusty conditions the first half of Saturday will be calm and cooler but that trend quickly disappears as a high impact storm arrives by the afternoon. Models now indicate the atmospheric river is approaching and will bring rain earlier than originally thought. By Saturday afternoon it appears a warm front will arrive. With typical warm fronts, lesser rain is expected, but due to the setup and presence of the atmospheric river, this particular warm front will bring heavier rain to the entire area. The main concern is that this system is set up to stall south of Point Conception, meaning heavy rain for extended periods of time. With the already saturated soil, there is a strong possibility of flash flooding and mudslides and it is imperative that you prepare now. These are potentially life threatening conditions and the possibility of flood evacuations are very high. Start prepping an evacuation kit, think about where to park your car and utilize the most recent forecasts.
Sunday shows the heaviest amounts of rainfall being dropped and data indicates that the area wont see a break from moderate to heavy showers until Monday afternoon. The storm continues to produce extremely heavy amounts of precipitation while winds increase to advisory and possibly High Wind Warning status. Some models show 50mph sustained winds (which is extremely abnormal).Downed trees and power lines are likely and its advised to stay indoors and avoid travel at all costs. Rainfall amounts look to be particularly hard to nail down, as some models indicate less than others. With the most recent data, the south facing beaches and Ventura County will be impacted the most. The lighter side of the rainfall range appears to be 3-6 inches. If we take into account the Wednesday storm, which was much weaker and still easily dumped 3 inches, its safe to say these lighter amounts are not accurately depicting what could happen. We cannot rule out the factors of winds, topography and orographic lifting which could bring these rain totals to amounts never before seen, upwards of 6-10 inches. Of course forecasts can change a lot in only a few days, but even if this storm was to shift north or south by a hundred miles, it will still develop to be the most impactful of the season so far.
