Wednesday, November 28, 2012

Major Storm Pounds the West Coast - and Will Continue thru the Weekend...

A strong storm system is pounding the central and northern Pacific coast of the U.S. and adjacent portions of southwest Canada today.  Heavy rain and mountain snow are being buffeted by 30-40 mph sustained winds and gusts in excess of 60 mph, creating extremely hazardous conditions.

In California, the heaviest rains are currently falling from San Francisco, Northward to near Redding and Eureka:

Rainfall amounts through Friday will average 3-6 inches across the region, with amounts in excess of 6-8 inches possible in some areas:

Unfortunately, this is only the first installment in a series of systems that will continue to produce widespread precipitation through the weekend, with rainfall amounts in excess of 12 inches likely in many areas:

Snow levels across the Sierra-Nevada range are currently 7,000-7,500 feet or greater, with very heavy snows likely to continue in the higher elevations.

In the wind and wave department, conditions are already bad and are about to become worse.  The chart below shows peak wind gusts (as gathered by the National Weather Service (NWS) in San Francisco) so far today:

Wave heights offshore along the central and northern California coast are averaging about 15 feet, and rising.  The following graph shows increasing wave heights at Point Reyes, CA, off of the coast West of San Francisco, with recent values just under 15 feet:

Wave heights will likely exceed 20 feet at times, especially during periods of stronger onshore winds.  High surf and flood watches and/or warnings are in effect across the region, as shown in purple on the image below:

Low level winds are forecast to become particularly strong along the northern California and southern Oregon coasts later tonight and on Thursday, with the high resolution NAM computer model forecasting widespread winds in excess of 70 mph (darker orange and red shaded areas on the image below):

We'll continue to monitor this situation with additional updates forthcoming over the next few days...

For more information from 'The Original Weather Blog', including shorter, more frequent posts during rapidly changing weather events, please be sure to follow Rob on facebook and twitter:
If you are in need of highly customized, site specific weather forecasts and/or storm warnings for your business, school or event, be sure visit my professional webpage at


Anonymous said...

How about a forecast for AGU-attending folk next week?

Rob White said...


Thanks for the comment/question. I'm assuming you mean the AGU Fall Meeting in San Francisco that begins on Monday...

The worst of the weather will peak this weekend, with widespread flooding possible. If you have flights/travel plans into the SFO area on Friday, Saturday or Sunday, plan on significant delays and/or cancellations. I'd delay travel until Monday if possible...

After Sunday, the weather looks to quiet down for much of next week. Some passing showers are possible especially on Wednesday. Temperatures will be in the 60s.

Thanks for reading!

Astrosymm said...

West Coast Storm, Japan Tunnel Collapse, Cambodia Dam Collapse, Russia Snowstorm of Dec 1, 2012 all related to Mayan Astronomical Symmetric Pattern which persists this Fall. Check
for Extratropical Storms, Solar, Mayan or Earthquakes Page to see Heliocentric or Geocentric Diagrams.