Monday, August 31, 2009

Back to Work.....

It has been a few weeks since my last post. I was on vacation & figured since there wasn't any weather to talk about, other than monitoring El Nino, I would take a vacation from blogging before the weather gets busy. I took a trip to the East Coast & had a chance to surf some of the swell from hurricane Bill last weekend. Growing up on the East Coast, hurricanes passing by in the summer was equivalent to big powder dumps here in the Sierra.

Since I last posted there has not been much to talk about weatherwise here in the Sierra. For those of you who missed my winter outlook please refer back to my July 19th posting. There will be a storm passing to our North this weekend which will keep temps in the 60's.

As of today's El Nino update from NOAA there is not much change. SST's (Sea Surface Temps) in all region are averaging between .7 - .9 above average which is where they have been all summer. The sub-surface temps in the Eastern Equatorial Pacific have declined & the SOI has gone strongly positive the past 2 days, although the 30 & 90 day avg. is still negative. The heat index has also declined. There is however a Kelvin Wave, which is an area of warm water shifting from the West Pacific to the East Pacific currently. Winds have been back & forth between Westerly & Easterly along the Equator.

All of this data indicates a flat-lined El Nino or even hints of a possible weakening for the moment. The models all still show the El Nino strengthening thru the fall & peaking in December before declining. About 1/3 of the models show El Nino staying weak & 2/3 have it going moderate. The change is that now models don't show it getting to the strong category. I mentioned my thoughts on this back when the models were going crazy with a strong El Nino. With all the cold water in the Pacific & the lack of warm water under the surface I really don't see how it would happen. It seems that as time goes on the models have to keep readjusting downward in the near & long term.

The current ONI for May, June, July, is .6 above avg. That is the first 3 month running avg. above .5 which is the threshold for official El Nino conditions. Now we need that to happen 4 more months in a row for an official full fledged El Nino which should happen by the end of Nov. Our go to year of 51-52 for this year peaked at an ONI of .8 which is a weak El Nino. Don't forget we are 50/50 above & below avg. for precip in winters of a weak & moderate El Nino. Refer to the July 19th posting for my thoughts on why I think this could be an above avg. winter.

August re-cap coming later this week. A preview, dry & cold, we're running over 4 degrees below avg. this month with one more day to go. Also, keep checking, the sun had no spots for 51 days in a row until today when a small spot appeared. That falls one day short of tying the record for this minimum from last summer. We are 80% of the year with no spots, well on our way to breaking the record for the number 2 spot this century set last year & we still have a chance at breaking the record set in 1913 of 311 days. We can only have spots 3 or less days the rest of the year to break that though. Look for some reaction in the climate, especially if this continues. BA


Anonymous said...

When does California officially begin it's water year?

BA said...

October 1st.