We’ve already had two big events like this so far this year, now forecasts show a clear pattern of a heavily moisture laden “atmospheric river” taking aim directly onto the Oroville Dam watershed over the next week. Accumulated precipitation forecasts show that the Lake Orovile watershed will score a direct hit with the maximum amount of precipitation over the next 10 days (see graphic near bottom of this article).
Above: Computer forecast models indicate a powerful jet stream will continuously pound California over the next ten days and bring copious amounts of moisture from off of the Pacific Ocean into the state. This 10-day loop of predicted upper-level winds at 250 mb are in 6-hour increments from today until Thursday, February 23rd; maps courtesy tropicaltidbits.com, NOAA/EMC (GFS)
Meteorologist Paul Dorian of Vencore Weather writes:
There have been many occasions in the past in which floods have followed droughts in California and this recent time period is yet another example. In California, incredible amounts of rain have piled up in recent weeks across low-lying areas of the state, mountains of snow have accumulated in the higher elevations of the Sierra Nevada Mountains – and more is on the way. After a couple days with a break in the action, another storm is likely to arrive in northern California by later Wednesday and continue into Thursday and then a second storm looks like it will slam the entire state by early this weekend.
After a lengthy drought, California has been battered by potentially record-setting rain, with the Northern California region getting 228 per cent more than its normal rainfall for this time of year. The average annual rainfall of about 50 inches had already been overtaken with 68 inches in 2017 alone and another 6+ inches is possible over the next week-to-ten days. The latest computer model forecast of upper-level winds for the next ten days (Monday, 2/13 to Thursday, 2/23) does not hold out much hope for any significant drying in California. Powerful winds in the upper atmosphere (at 250 mb) will continuously pound California and bring copious amounts of moisture from the Pacific Ocean into the state. The total precipitation forecast map by NOAA for the next 7 days indicates more significant rainfall (and snowfall) is likely throughout the state.
The long-term forecast has rainfall totals withing the watershed that are showing the exact spot where Lake Oroville watershed is located will get 11.62 inches of rain over the next 10 days, the most accumulated rainfall in the entire western USA: