Heavy rain, and even snow, will overtake the West Coast as we head into the weekend and the beginning of next week. This system, which is known as an Atmospheric River, has the potential to trigger landslides, mudslides, flash flooding, debris flows, and even travel delays and cancellations.
This atmospheric river will fuel the heavy rain as a strong storm moves into the Pacific Coast on Thursday and will continue through Saturday. The heaviest amounts of rain will occur in Northern California during Friday.
This system is part of a surge of tropical moisture that extends near Hawaii, and that is the reason that this system will impact the West Coast so much. This air isn’t usually near our latitude, so it will have a larger impact. This type of weather pattern will definitely enhance looming threats such as flash flooding and landslides. Areas that were affected by wildfires this year will be especially vulnerable to flooding and debris flows since the water cannot penetrate the scorched ground.
As for rainfall totals, 2-3 inches is expected in northern California and western Oregon. This also includes the Bay Area, which has been completely dry throughout the whole month of January. This is the first time that San Francisco has had no rain in January since weather trackers began taking records in 1850. In the farthest north portion of California, the rainfall amounts may exceed 5 inches from Thursday into Saturday.
Flight delays and cancellations may be possible at San Francisco International Airport on Friday due to low clouds and excessive rainfall that is predicted to be associated with the storm. Even motorists can expect slower travel on the ground as the rain begins to mix with oil buildup on roadways, as this will more than likely create some slicker than normal conditions.
A second storm will make its way into the West Coast on Sunday and will extend into Monday; this storm will dump some heavy rain along the coast of California and Oregon. This rain follows a very dry season for many locations, and this is the first significant rainfall event for Northern California since the middle of December.
The most important resource to fill the reservoirs and water supply for California during drought is the snowpack from the mountains. It is imperative to take a look at snowpack levels when analyzing the impact that the storms may have on the drought situation. Unfortunately, mountain snow isn’t very likely to be included in the list with these upcoming storms. Snow levels will be quite high because of the warm subtropical flow, and it will exceed 8,000 most of the time. This means that too much rain in some places isn’t necessarily a good thing; because it won’t be of any help in trying to put down a snowpack.
Check with your local weather resource for more information!