Substantial Snow Returning to the Pacific Northwest

During even the strongest El Nino years there is often a period at the tail end of winter when the atmospheric circulation associated with El Nino collapses.

When the atmosphere adjusts to considerably more solar radiation over the northern latitudes the "lock" of the tropical Pacific is lost.

This re-adjustment will likely occur next week, leaving the door open to cool wet flow over our region.

This means lots of mountain snow and even the chance of flakes near sea level.

Let me show you!

The forecast for total snowfall through 1 PM Friday is hardly impressive, with a few inches in the mountains.  Yawn.

By 1 PM Sunday, the totals in the north Cascades and southern BC are healthier, reaching nearly a foot in favored locations.

Fast forward to 1 PM Tuesday, and the Washington Cascades and Olympics have gained several feet.  Considerable lowland snow is evident.

And by 10 PM Wednesday, February 29th. some mountain areas have gained 4 feet and parts of the western Washington lowlands have a thin veneer of snow.

So what is going on? 

 Examining the situation at around 18,000 ft (500 hPa) this morning, a strong trough of low pressure is found off the California coast. This is the kind of pattern that has been dominant over the last few months.

Fast forward to the end of the week (Sunday evening) and a very strong trough of low pressure is moving in.   Classic snow producer for the NW.

But the shocker is the prediction for March 1 (below).  Very cold, powerful trough off our coast.  Very wet, very cold, and very snowy.

All of this is a bit far out in time to be sure, but most of the solutions of ensemble forecast systems, in which the model is run many times with slight changes, produces similar predictions.  You may not want to put away your winter gear quite yet.

Keep tuned.