Heavy Rain, Mountain Snow Events Target Northern California; Flood Watches Issued

Quincy Vagell
Published: January 16,2016
After an already wet first two weeks of January, another round of storm systems will impact California into the new week ahead. This time, the most generous rain and mountain snow will target the northern part of the state along with the Pacific Northwest, where January has gotten off to a much drier start.
Some of the heavy rain may lead to flash flooding, as NOAA's National Weather Service has posted flood watches for portions of northwestern California into southwestern Oregon, in effect through early Monday.
The active southern branch of the jet stream over the region is associated with the strong El Niño pattern. It will transport atmospheric moisture, at times via a so-called atmospheric river, toward California.
(MORE: El Niño Has Peaked...Now What?)
The wettest in the series of storms could bring rainfall heavy enough to lead to flooding concerns from Sunday into Monday morning. Meanwhile, the Cascades and Sierra are in line for several feet of snow over the next several days from the weather pattern.

Flood Watches and Warnings

The snow is great news for area ski resorts, and it's also great news for the long-term drought still entrenched over most of California.
Snow water content across the Sierra Nevada is essentially normal, sitting at 101 percent of average for this time of year as of Wednesday, according to the California Department of Water Resources. On the same date in 2015, that number was just 37 percent.
The snow cover itself is a substantial move in the right direction for drought relief, as snowmelt later in the season plays a big role with replenishing reservoirs and water tables in California. The region is in a much better position now than it was 12 months ago.
Recent weeks have already seen a gradual lessening of drought conditions over parts of the West Coast, but more than two-thirds of California remains in extreme to exceptional drought as of Jan. 12, according to the U.S. Drought Monitor.

Current Radar and Satellite

Here is a look at how the next several days are expected to evolve.

Sunday Through Early Monday

A potent, moisture-rich storm system will plow into the West Coast on Sunday into Monday. It is this moisture that could potentially produce some localized flash flooding.

Forecast Next 3 Days

Widespread moderate to heavy rain reaches Northern California and southwestern Oregon during the day Sunday, persisting into part of the day on Monday. An additional 3 to 5 inches of rain is possible throughout the area from this wave of moisture alone.
The heavier rainfall rates will raise the risk of flooding during this period, though the extent of the risk will depend on exactly how much rain falls and how quickly it does so. It's possible that a persistent band of rain may stall over northern California for a time, which would also raise the risk of flooding, particularly in the foothills.
(INTERACTIVE: Flood Alerts)
Gusty, onshore winds are also expected with this system. The National Weather Service has posted high surf advisories for much of the coastline from Northern California to Washington.
Much of this area is also under a wind advisory, while the Cascades in southern Oregon have high wind warnings in effect. Those locations under warnings may see wind gusts approach 80 mph through Sunday evening.

Tuesday and Wednesday

After a brief break for some of the region, another round of rain and snow will impact the region late Tuesday into Wednesday morning, then again late in the week.

Forecast Rain and Snow Through Wednesday

Meanwhile, substantial snowfall totals of 1 to 2 feet with locally higher amounts will plaster much of the Sierra and the Cascades. Some of the highest snowfall amounts by early next week in these areas could easily eclipse 3 feet.
Total rainfall amounts may exceed 6 inches along the coast of southwest Oregon and northwest California as well as northern portions of the Sacramento Valley.
To put it into perspective, Redding, California, may receive up to 5 inches of rain over the next week. While that may seem like an excessive amount of rain, January is typically their wettest month of the calendar year, averaging just over 6 inches of rain.
Farther north, similar rainfall amounts are forecast for Crescent City along the northwest California coast. January is typically an even wetter month at that location, picking up an average of more than 10 inches a rain. This is a sharp contrast to the minuscule 1.73 inches of rain reported at Crescent City in January 2015.

Pacific Ocean Satellite, Pressure and Winds

Given the overall pattern across the Northern Hemisphere and longer-range forecasts from the computer weather models, the West Coast could see this stormy setup continue into the latter portion of January.
Check back with weather.com for the latest forecasts and information.

Late Week Snowfall Reports

Northstar at Tahoe in California reported 18 inches of new snowfall as of Friday morning. Near Incline Village, Nevada, 15 inches of snow was reported.
Some locally heavy snow advanced as far east as the central Rockies, as 12 inches of new snow was reported at Tower, Colorado on Friday.
MORE: Western Storms Slam California - January 2016