Colder storms hitting California connected to Arctic Air in Northern Canada

FRESNO, Calif. (KFSN) -- After a very slow start to the rain and snow season in Central California, things are picking up at a fast pace.

The last several storms were significant rainmakers for the Valley and snowmakers for the Sierra and Foothills.

"We no longer have a ridge pattern over us and the flow of air is now out of the north and the northwest. And that air easily moves southward into California," said Kevin Durfee, Meteorologist with the National Weather Service in Hanford.

Durfee explained that the colder storms that hit the Central Valley and much of California were produced from Artic air in Northern Canada.

He pointed out that was a separate event from the Polar Vortex that hit the east coast.

"It is up in the Yuko territory and that air the longer it stays bottled up the more brutal it is when it comes southward," said Durfee.

Snow levels in the foothills dropped down to 1,000 feet and helped produce a solid for the Sierra.

As of Wednesday the Southern Sierra snowpack is at 137% of normal. State wide at 130%.

But now the concern from Wednesday's storm is a melting snowpack.

This storm is pulling up moisture from the south through the atmospheric river.

"There is a fair amount of snowpack below six thousand feet in elevation and there are no reservoirs other than Friant Dam and the San Joaquin River basin that can capture that run off," said Duane Stroup, Bureau of Reclamation.

Stroup said the Bureau of Reclamation began releasing water out Friant Dam on Monday to contractors along the Friant-Kern Canal and the Madera Canal.

Millerton Lake is at 85 % of capacity. The early release is necessary to prepare for more storms for the rest of winter and into the spring.

"So if they can take water now we are letting them take water. If we don't let them take water it increases the chances of a release from Millerton Lake that would have the potential to cause flooding downstream," said Stroup.
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