Western USA Weather Forums: Western USA Weather Forums

With all of the talk of a strong La Nina meaning runaway zonal flow, I thought I would take a look at what the strongest Ninas of all time brought for the NW. The 4 strongest Ninas of the 20th century are almost certainly 1916, 1955, 1973, and 1988. There is a lot of edbate whether 1916 was stronger than 1973 or not, but they were both extreme. The interesting thing is 3 of the 4 winters (1916-17, 1955-56, 1988-89) featured very cold and snowy weather at times. Even the weakest winter of the 4 featured a period of respecatably cold weather for the first week of Janauary which could have easily been something much more. It's just one of those freakish things that it didn't. At any rate very strong Ninas do have a good history of having extreme blocking episodes at some point during the winter over the Eastern Pacific and Gulf of Alaska. A lot of reason for optimism.

The two maps posted below speak volumes to the potential we have. The first is a composite temperature map of the 4 winters, and the second one is a one week 500mb composite for early Jan 1974. I would take my chances with that pattern any day of the week!

EDIT: The maps don't want to go in that order.

We will likely see many records this year

Record-setting rain for Metro area

"PORTLAND, Ore. -- It didn't take long for the unofficial start of fall to arrive.
The day after Labor Day brought record rain levels to the Metro area.
A total of 1.55 inches of rain fell in Portland Tuesday, making it the rainiest September 7 in recorded history. It was also the fifth-wettest September day of all time.
The hourly rainfall was even more impressive. At PDX Airport, the official measuring station for Portland, 1.03 inches of rain fell in the hour between 8 and 9 p.m., setting the all-time record for an hour of rainfall.
Tuesday was also the wettest day on record since June 6. It has also been the coldest summer on record in 17 years.

KGW Meteorologist Rod Hill promised that some sun breaks were on the way following Tuesday's dump.
Thursday will bring possible sun breaks and Friday holds promise of a dry day with afternoon sunshine, according to Hill."

http://www.kgw.com/n...-102395079.html

Has anyone here done any investigation on frequency/intensity of windstorms and flooding events during strong vs weak La Ninas...or even if they have more to do with the EPO?

My gut feel is that strong La Ninas would feature more in the way of snow and cold as opposed to more flooding/windstorms, but I don't have anything quantitative to base that on.

Just received the monthly PDO update from Nate. Looks like -1.27 for August. I think there will be some surprised faces on this post. I thought sure it would be lower. Just like I said about the ONI, "I will take it!"

Steve

http://www.theweathe..._Forecast/22752

SCWXA, UJEAS Project -- The UJEAS is a system developed by the Southern California Weather Authority. The system stands for Upper Jet Extended Analog System, in-which it takes the current state of the atmosphere and spins it ahead a full month in hopes to get a long range pattern outlook.

The UJEAS was hit with a virus in February 2010 and a lot of data was lost. Over the Summer I've worked on the project and it is ready for testing.

For September of 2010 it shows the upper level jet staying mainly across Canada. There are numerous cold storms up there, however not many of them will come down.