Last week, computer weather forecast models were hinting at the possibility of a weather system pattern change that could result in significant precipitation for California and the West Coast. While tenuous then, the predictions are firming up now, and it looks like there will be a significant shift in the jet stream, which will put California squarely in the middle of the storm track.
The main impact with this change will be gusty south to west winds, especially today & Monday. There could also be some showers mid to late-week for the northern mountains.
AccuWeather has been more aggressive with their forecast, saying:
A round of heavy rain, mountain snow and gusty winds will impact the Western U.S. at the end of the week, most notably Oregon and California, which will face the worst impacts.
The combination of these strong winds and surge of moisture will lead to a rather potent storm system for Oregon and northern and central California late Thursday through Saturday.
Very strong winds are expected with gusts up to 70 mph along the north-central California coast to the Washington coast. These winds will be able to cause damage. Wind gusts of 50 to 60 mph are likely elsewhere across Oregon, Nevada, and northern California.
Rainfall amounts of 3 to 6 inches are expected across the Coastal Range and foothills of the Cascades and Sierra Nevada. This, plus additional water from melting snow in the mountains, will lead to quick stream and river rises and possible flooding in some locations.
While snow levels initially will be high, they will fall through Saturday. The heaviest snow will occur across the Sierra where a few feet will fall by Saturday.
Their model suggests a strong low of the NW coast of California, that will cause a “pineapple express” type river of moisture event from the southwest:
Precipitation Forecast Models from the National Weather Service have been less aggressive, suggesting no significant inland and Sierra mountain precipitation for Northern California. This graphic shows forecast rainfall totals for the week ahead:
It is too early to tell who will be right, but one thing is for sure, if California experiences what AccuWeather is forecasting, we will likely see an end to the fires, but the beginning of mudslides and huge debris runoff into rivers in burn scar areas.
via Watts Up With That?
September 13, 2020 at 12:41PM