Another El Nino on the way?

[Glen Romine]

The recently released forecast from the Climate Prediction Center is now suggesting that the El Nino condition is starting to appear.

http://www.cpc.ncep.noaa.gov/products/anal...sory/index.html (http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/index.html)

The forecast gives a 50-50 chance for El Nino conditions to be present within 3 months.

Glen

[Geoff Boyle]

I was wondering if we were due for another one.

[Howard Robinson]

Its ENSO!!!!

ROFL :) just thought I would throw that in.

But yea, we are due for one. Its going to be a wild winter!

[rdale]

"The forecast gives a 50-50 chance for El Nino conditions to be present within 3 months."

But I think they went on to say there's only a 10% chance of the 50-50...

[Glen Romine]

Its ENSO!!!!


Maybe you are just thowing this out there, but if this is meant to be a terminology correction, actually ENSO can be either an El Nino or a La Nina event - it is just the term for an anomoly, regardless of the sign.

http://www.pmel.noaa.gov/tao/proj_over/ensodefs.html

Glen

[Shyanna Busch]

What kind of weather events can El Nino cause? I don't really know too much about it.

[Bridget Beddow]

I can't remember a whole lot about El Nino but if I'm not mistaken, it does cause a tremendous amount of rainfall/mudslides in South America. And then there was an issue with coral reefs in the Pacific as the change in the water temperature causes the coral reefs to die.

I could be wrong, though - just remembering something from the Discover Channel.

[Glen Romine]

The impacts a generally global - but not all events follow the rules. Here is a simplified graphic I found:

http://www.pmel.noaa.gov/tao/elnino/gif/winter.gif

So, generally for the US impacts, temperatures are warmer than typical in Alaska - which always leads to below normal temperatures (not shown) in the Great Lakes region as upper level flow is predominantly from the northwest in the plains states when it is warmer than usual in Alaska. Also, the southern jet stream is generally much more active, bringing more strong Pacific cyclones further south than typical, and leads to an active pattern along the Gulf coastal states. The active Gulf coast convection often limits the number of times Gulf moisture penetrates into the northern plains and Great Lakes region, leading to below normal precipitation in those areas. The summer following El Nino typically has fewer tropical cyclones as well.

Glen

[GPhillips]

Impacts on U.S. temperature and precipitation of past relatively strong ENSO events can be found at:

http://www.cpc.ncep.noaa.gov/products/moni...onnections.html (http://www.cpc.ncep.noaa.gov/products/monitoring_and_data/ENSO_connections.html)

Weaker ENSO events are not as strongly correlated with U.S. temperature and precipitation anomalies. The correlation of ENSO to specific temperature and precip anomalies is greatest in the Northern Hemisphere cool season.

[Jamie Lahowetz]

El Nino is an amazing thing. Its strange how an oscolation in water temperature could cause so much globally. If this El Nino does happen then it could affect next years chase season, maybe.

Just some info links:
http://www.cpc.noaa.gov/products/analysis_...enso_cycle.html (http://www.cpc.noaa.gov/products/analysis_monitoring/ensocycle/enso_cycle.html)
http://www.cpc.noaa.gov/products/analysis_...77-present.html (http://www.cpc.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears_1877-present.html)
http://www.coaps.fsu.edu/lib/booklet/

[John Cameron]

Originally posted by rdale

But I think they went on to say there's only a 10% chance of the 50-50...

sounds like something i've said during a weathercast......you know.....I like to be to the point! :wink:

[Cstok]

Last big El Nino 1998 here in S. Cal we had a crazy winter. Warmer than usual, and much higher total rainfall amounts.

One interesting thing to note is that while the El Nino effects more of the equatorial waters (I think), even here in S. Cal, I believe, I can see the effects in the water temps. I have surfed for about 20 years and every time we have an El Nino the water temps generally are a degree or two warmer than usual. For instance right now the water temps are around 71 degrees, and have been for a while (with slight dips due to upwelling from infrequent blustery onshore wind days). That is fairly warm for S. Cal... it does get to that temp almost every (late) summer, but it seems to stay there for a longer period of time, with less fluctuations, during el ninos.

As for severe weather, I do remember reading a study that suggested that the number of significant outbreaks on the plains is less, and the action shifts somewhat to the east.

[Tim Vasquez]

This is all discussed in my Storm Chasing Handbook. Some salient points about an El Nino (ENSO) event:

- ENSO is correlated with a dominant southern jet stream branch in the US, which increases the incidence of precip/storms along the Gulf Coast.

- There is unquantified, empirical speculation that Great Plains chase prospects are good during an ENSO start, poor during ENSO, and very bad coming out of ENSO. Not to say that severe weather doesn't occur, but the incidence may be less.

- There is no definitive correlation yet established between ENSO and Great Plains tornado numbers.

- Overall the cause and effect is very indirect -- Pacific temperature anomalies are just one of many factors influencing prevailing patterns in the central US, and do not cause individual events.

Of course it is hard to say whether the El Nino forecast will pan out, much less what phase we would be in by spring.

Tim