Storm passing the Bay Area Sunday March 20 9:30AM

Huge lingering Cut-Off Low.

by Mike Godsey, Oct. 7
Several days ago this Cut-Off Low pinched off from the upper level winds that loop around the globe as alternative southward extending upper troughs and northward extending upper ridges.
Below you can see the huge counter-clockwise spinning Cut-Off Low over California and Nevada. This pesky low at 18,000 ft. is blocking the regular progression of weather from west to east.
It is also keeping the Central Valley cool so the pressure gradient has been very weak the last few days. Worse it has also kept the North Pacific High's surface NW winds west of the ocean buoys.
Prize! Win a free night at the best Gorge view and Mt. Hood view rental house only 10 minutes from 5 launch sites by answering these question correctly:
1. Why do Cut-Off Lows linger so long in one location?
2. Why is it so difficult to forecast there movement?
3. Why is it that sometimes Cut-Off Lows make great wind but sometimes like this one they make poor wind.
Mail your answers to:
mike@iwindsurf.com

Note the ripples streaming off the end to the Pt. Reyes Peninsula. These are created by the NW winds just aloft. If they reach the bay this afternoon we will see gusty low to near mid 20's wind.

No, not again!

by Mike Godsey,
August 17
Spawned by the endless pacific upper trough at 18K feet a second Cut-Off Low brings a return to southerly flow and a deep marine layer.
Looking at the animation of the upper level winds you can see the counter-clockwise spinning spinning winds of the Cut-Off Low well to the west of California yesterday afternoon. This allowed the NW flow to reach the bay helping many sites.
But as the animation continues notice the Cut-Off Low hitting the coast near the Oregon border. Notice how this positioning brings southerly winds over the Bay Area. Through a complex process this deepens the marine layer clouds and enhances southerly flow at the surface.
My guess is that Mark Twain made his famous quote about San Francisco in a summer like this one.