A strong winter storm is possible late in the coming week that could produce a significant amount of rain and snow in the Sierra, northeast California and western Nevada, according to the latest from the National Weather Service in Reno.
In the weather service image above, the model shows moderate to strong atmospheric river reaching the California coast by Thursday. Here’s some information, forecaster confidence, for the potential upcoming event.
Timing – medium to high. The models agree in a storm system moving into the Sierra and western Nevada Wednesday Night to Friday, but there are differences in how quickly this system moves through the region.
Rain/Snow – medium to high. Models agree this system is likely to produce rain and snow sometime between Wednesday Night and Friday. However differences in timing of the system reduces confidence on when and where the heaviest rain and snow occurs in the Sierra, and how much precipitation reaches western Nevada.
Gusty winds – medium to high. Gusty winds occur with almost every winter storm moving into the Sierra and western Nevada. This far out the strength of the winds is in question. Peak gusts in the lower elevations could stay below 45 mph or be as high as 70 mph.
Snow Levels – low to medium. Snow levels should remain below 8000 feet, but models have trended warmer with this system over the last couple days. This reduces confidence in how quickly snow levels drop to 6000 to 7000 feet.
Snow Totals – low to medium. Medium confidence in significant snow accumulations in the Sierra above 8000 feet. Below 8000 feet, confidence in snow totals is low due to the timing differences in the models and how much cold air is pulled into the system from the Gulf of Alaska. Typically less snow accumulates below 7000 feet, if the precipitation occurs during the day.
The latest guidance shows the heaviest precipitation may occur during the day on Thursday, with snow levels ranging from 7000 to 8000 feet.
