ENSO Updates

General Weather Discussions and Analysis

Re: ENSO Updates

Postby Ptarmigan » Wed Mar 21, 2012 3:33 pm

This Week's ENSO
Niño 4 = -0.6ºC
Niño 3.4 = -0.6ºC
Niño 3 = -0.4ºC
Niño 1+2 = 0.3ºC

Average
-0.325ºC or -0.3ºC

Last Week's ENSO
Niño 4 = -0.8ºC
Niño 3.4 = -0.6ºC
Niño 3 = -0.2ºC
Niño 1+2 = 0.4ºC

Average
-0.3ºC

Highlights
• La Niña has weakened across the tropical Pacific Ocean.*
• Equatorial sea surface temperatures (SST) remain at least 0.5°C below average in the central Pacific, and near average in the eastern Pacific Ocean.
• Atmospheric circulation anomalies remain largely consistent with La Niña.
• La Niña is expected to transition to ENSO-neutral conditions by the end of April 2012.

http://www.cpc.ncep.noaa.gov/products/a ... ts-web.pdf
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Re: ENSO Updates

Postby Ptarmigan » Tue Mar 27, 2012 4:51 pm

This Week's ENSO
Niño 4 -0.4ºC
Niño 3.4 -0.5ºC
Niño 3 -0.1ºC
Niño 1+2 0.5ºC

Average
-0.125ºC or -0.1ºC

Last Week's ENSO
Niño 4 = -0.6ºC
Niño 3.4 = -0.6ºC
Niño 3 = -0.4ºC
Niño 1+2 = 0.3ºC

Average
-0.325ºC or -0.3ºC

http://www.cpc.ncep.noaa.gov/products/a ... ts-web.pdf
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Re: ENSO Updates

Postby Ptarmigan » Tue Mar 27, 2012 4:51 pm

The 2011–12 La Niña reaches its end
http://www.bom.gov.au/climate/enso/

The 2011–12 La Niña event has ended, with key indicators returning to neutral (neither El Niño nor La Niña) levels. Climate models surveyed by the Bureau of Meteorology suggest that neutral conditions will persist until at least early winter.

Key Pacific Ocean indicators are now at neutral levels, with values similar to those last seen in August 2011. Likewise, atmospheric indicators such as cloudiness, trade winds and the Southern Oscillation Index (SOI) have also returned to near-normal values for this time of year. Despite the 2011–12 La Niña not commencing until far later than normal (spring), the decline has been fairly typical of past events, with a peak in January and a return to neutral conditions during autumn.

The demise of the La Niña does not mean the risk of wet conditions (or tropical cyclones) over Australia has ended. While sea surface temperatures around the continent remain warmer than normal and the tropical wet season is active, there remains a risk of above average rainfall over Australia.

The Indian Ocean Dipole (IOD) has limited influence on Australian rainfall from December through to April. Neutral IOD conditions are forecast for the southern hemisphere winter.
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Re: ENSO Updates

Postby MontgomeryCoWx » Tue Apr 03, 2012 9:52 am

The latest weekly SST departures as of April 2nd are:
Niño 4 -0.5ºC
Niño 3.4 -0.2ºC
Niño 3 0.3ºC
Niño 1+2 0.9ºC
Team #NeverSummer
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Re: ENSO Updates

Postby Ptarmigan » Wed Apr 04, 2012 9:04 pm

Thanks MontgomeryCoWx for posting the latest ENSO data.

This Week's ENSO
Niño 4 -0.5ºC
Niño 3.4 -0.2ºC
Niño 3 0.3ºC
Niño 1+2 0.9ºC

Average
0.125ºC or 0.1ºC


Last Week's ENSO
Niño 4 -0.4ºC
Niño 3.4 -0.5ºC
Niño 3 -0.1ºC
Niño 1+2 0.5ºC

Average
-0.125ºC or -0.1ºC

We are now Neutral.

http://www.cpc.ncep.noaa.gov/products/a ... ts-web.pdf
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Re: ENSO Updates

Postby wxman57 » Thu Apr 05, 2012 9:55 am

Not neutral yet. JFM average was -0.7. Still La Nina:

http://www.cpc.ncep.noaa.gov/products/a ... ears.shtml

The graphic at the Top is the weekly values, which have moved into the neutral range. But it's the 3-month average that determines the status, not the current value. The bottom graphic is a plot I made of the ENSO from 1950-2012 (3 month averages).
Attachments
Weekly ENSO Values.gif
ENSO 1950-2012.gif
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Re: ENSO Updates

Postby Ptarmigan » Thu Apr 05, 2012 10:02 am

wxman57 wrote:Not neutral yet. JFM average was -0.7. Still La Nina:

http://www.cpc.ncep.noaa.gov/products/a ... ears.shtml

Here's a plot I made of the ENSO from 1950-2012:


That is for Region 3.4.
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Re: ENSO Updates

Postby unome » Thu Apr 05, 2012 4:54 pm

from pg 20 of the latest update:

Oceanic Niño Index (ONI)

•The ONI is based on SST departures from average in the Niño 3.4 region, and is a principal measure for monitoring, assessing, and predicting ENSO.

•Defined as the three-month running-mean SST departures in the Niño 3.4 region. Departures are based on a set of improved homogeneous historical SST analyses (Extended Reconstructed SST – ERSST.v3b). The SST reconstruction methodology is described in Smith et al., 2008, J. Climate, vol. 21, 2283-2296.)

•Used to place current events into a historical perspective

•NOAA’s operational definitions of El Niño and La Niña are keyed to the ONI index.


from NOAAWatch, updated April 5th:

Image


from: http://www.cpc.ncep.noaa.gov/products/a ... ears.shtml

Jan Feb Mar: -0.7
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Re: ENSO Updates

Postby Ptarmigan » Mon Apr 09, 2012 10:36 pm

This Week's ENSO
Niño 4 -0.4ºC
Niño 3.4 -0.3ºC
Niño 3 0.3ºC
Niño 1+2 0.5ºC

Last Week's ENSO
Niño 4 -0.5ºC
Niño 3.4 -0.2ºC
Niño 3 0.3ºC
Niño 1+2 0.9ºC

http://www.cpc.ncep.noaa.gov/products/a ... ts-web.pdf


How the global climate is progressing right now.

Global Ocean Monitoring: Recent Evolution, Current Status, and Predictions
http://www.cpc.ncep.noaa.gov/products/G ... urrent.pdf
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Re: ENSO Updates

Postby Ptarmigan » Wed Apr 18, 2012 8:24 pm

This Week's ENSO
Niño 4 -0.2ºC
Niño 3.4 -0.3ºC
Niño 3 0.5ºC
Niño 1+2 1.9ºC

Last Week's ENSO
Niño 4 -0.4ºC
Niño 3.4 -0.3ºC
Niño 3 0.3ºC
Niño 1+2 0.5ºC

Trending away from La Nina and likely heading into El Nino.

• A transition from La Niña to ENSO-neutral is underway.
• Equatorial sea surface temperatures (SST) remain near 0.5°C below average in the central Pacific, and above average in the eastern Pacific Ocean.
• Atmospheric circulation anomalies remain mostly consistent with La Niña, but have weakened in recent weeks.
• La Niña is expected to transition to ENSO-neutral conditions during April 2012.

http://www.cpc.ncep.noaa.gov/products/a ... ts-web.pdf
Last edited by Ptarmigan on Wed Apr 18, 2012 8:26 pm, edited 2 times in total.
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