NOAA April update of ENSO=Transition to Neutral ENSO

[cycloneye]

EL NIÑO/SOUTHERN OSCILLATION (ENSO)
DIAGNOSTIC DISCUSSION
issued by
CLIMATE PREDICTION CENTER/NCEP
April 7, 2005

Synopsis: A transition fromweak warm-episode (El Niño conditions to ENSO-neutral conditions is expected to continue during the next three months.

Sea surface temperature (SST) anomalies increased in the Niño 3.4 and Niño 3 regions during March 2005 (Fig. 1), while positive SST anomalies [greater than +0.5°C (~0.9°F)] persisted in the Niño 4 region. By the end of the month, positive equatorial SST anomalies greater than +0.5°C (~0.9°F) extended from Indonesia eastward to 115°W (Fig. 2). Cloudiness and precipitation returned to near average over Indonesia , while the enhanced precipitation, observed over the central tropical Pacific in February, weakened and drier-than-average conditions developed over that region (Fig. 3).

The increase in SST anomalies and upper-ocean heat content (Fig. 4) in the east-central equatorial Pacific during the last half of March was associated with an eastward-propagating oceanic Kelvin wave (downwelling phase). This wave is stronger than those that have occurred in recent months in association with MJO activity. Surface and subsurface ocean temperatures are expected to increase along the west coast of South America (Ecuador and northern Peru) during April. However, substantial cooling in the upper ocean has occurred in the wake (upwelling phase) of this Kelvin wave, accompanied by a strengthening of the easterly winds over the central and western equatorial Pacific during March. This cooling is expected to propagate eastward, eventually reaching the eastern equatorial Pacific during May. Thus, the effects of the expected warming along the west coast of South America during April should be brief.

A majority of the statistical and coupled model forecasts indicate that a transition from weak warm- episode (El Niño) conditions to ENSO-neutral conditions will continue during the next three months, and that ENSO-neutral conditions will likely prevail during the northern summer.



http://www.cpc.ncep.noaa.gov/products/a ... _advisory/

Ok now we have the Australians who say El NINO will develop and CPC,NCEP say the contrary.MWatkins,Derek and other experts about this what is the real truth of what will happen.?

My personnal opinion is that I am with the NOAA discussion.

[MWatkins]

The biggest difference between the 1997 and 2005 wave (see previous post on that) is the amount of cool water present in front of and behind the Kelvin wave this year, and the trailing area of cool water appears to be the biggest difference between the AUS and USA intrepretations of what will unfold.



Unfortunately...there is no skillful way to tell which scenario is correct. We just don't know enough about ENSO to know. Seems to me the biggest questions are:

1. Like X-y-No pointed in the other thread, what impact will the cool water in front of the kelvin wave have? Will it moderate temps some?

(other thread: http://www.storm2k.org/phpbb2/viewtopic.php?t=60379)

2. Will the warming that will occur (no question about it) this month touch of a reversal of the trades in the eastern Pacific? If so...will it last? If the trades flip and go westerly...especially if this all happens in conjunction with the newest MJO pulse on the way...a warm regime could take hold even if water temps moderate some next month.

Looks like we have a pretty good game here that probably won't get settled until the end of May.

Dr. Landsea expressed some concern that the warm regime may win out...but also expressed that we just don't know enough about the process to make a call either way. It's kind of like having a strong opinion on a coin flip. You can have a feeling that the coin will land heads...but it's still a 50/50 deal.

It gives us something to watch here in April though.

MW

[cycloneye]

The biggest difference between the 1997 and 2005 wave (see previous post on that) is the amount of cool water present in front of and behind the Kelvin wave this year, and the trailing area of cool water appears to be the biggest difference between the AUS and USA intrepretations of what will unfold.



Unfortunately...there is no skillful way to tell which scenario is correct. We just don't know enough about ENSO to know. Seems to me the biggest questions are:

1. Like X-y-No pointed in the other thread, what impact will the cool water in front of the kelvin wave have? Will it moderate temps some?

(other thread: http://www.storm2k.org/phpbb2/viewtopic.php?t=60379)

2. Will the warming that will occur (no question about it) this month touch of a reversal of the trades in the eastern Pacific? If so...will it last? If the trades flip and go westerly...especially if this all happens in conjunction with the newest MJO pulse on the way...a warm regime could take hold even if water temps moderate some next month.

Looks like we have a pretty good game here that probably won't get settled until the end of May.

Dr. Landsea expressed some concern that the warm regime may win out...but also expressed that we just don't know enough about the process to make a call either way. It's kind of like having a strong opinion on a coin flip. You can have a feeling that the coin will land heads...but it's still a 50/50 deal.

It gives us something to watch here in April though.

MW

Agreed Mike it is a 50/50 proposition right now as it can go both ways.The only thing to do is to watch how all evolves in the next couple of months to see on which side of the fence ENSO goes.

[x-y-no]

Got to agree with NOAA here, since it's pretty much what I've been saying.

[LarryWx]

I still think that even if there is an El Nino this summer, it will be a weak one. Through my research of the last 55 seasons, I've found that the difference between a weak El Nino and a neutral one has been minimal as far as the average number of storms is concerned. I believe it will be either neutral or a weak El Nino and either would likely result in a similar number of storms imo.

[cycloneye]

The question becomes about the difference between what the Aussies are saying and what NOAA is saying.Why they discuss the same subject about ENSO in a different way one saying el Nino has a high probability while the other say No El Nino but Neutral? Both agencies talk about the same Kelvin Wave but then they differ on the effects it may cause.These differences tend to confuse some who may not know much about ENSO.

[Scorpion]

Finally some good news after a few days of discouraging ideas.

[Typhoon_Willie]

what developes in around May then. It should prove to be interesting!

[Derek Ortt]

there's an MJO behind the Kelvin wave, which will likely bring about enhanced westerlies.

I would place the value of the CPC nino forecasts as less than the paper they are written on

[Anonymous]

Isnt the severe weather and flooding rains in Fla during our dry season a sign of El Nino? If this is any indication, I would hate to see our summer and the rainy season if El Nino develops... Sounds like Fla is better off getting the hurricanes like 2004 than having an El Nino summer with flooding rains and tornadoes IMHO.

[donsutherland1]

Cycloneye,

It's a somewhat close call, but I believe neutral ENSO conditions will develop and hold for the summer (June-August). Generally, in 2/3 cases (top 15 matches) where the MEI and ENSO regional anomalies over the past 6 months were similar to those of 2004-05, neutral conditions prevailed during the summer. Of concern is that the closest MEI match is 1993, which had El Niño conditions for the summer.

I don't believe the Australian idea and CPC's idea are in much conflict. The Australians seem to be suggesting the possible arrival of an El Niño late in the summer or during the fall:

Despite the moderating of some indicators, the chance of a basin-wide El Niño occurring later this year remains higher than normal...

The Bureau of Meteorology's POAMA model has included these, and it has listed the chance of Pacific ocean warming above El Niño thresholds during the late southern winter and spring 2004 to above 50%, which is around double the long-term average for this time of year.

CPC states:

A majority of the statistical and coupled model forecasts indicate that a transition from weak warm- episode (El Niño) conditions to ENSO-neutral conditions will continue during the next three months, and that ENSO-neutral conditions will likely prevail during the northern summer.

[Aquawind]

there's an MJO behind the Kelvin wave, which will likely bring about enhanced westerlies.

I would place the value of the CPC nino forecasts as less than the paper they are written on

Yep.. The Current MJO is stronger than the MJO that helped create the current Kelvin and the easterlies in the PAC have weakened in the last five days..Westerlies have developed with the MJO as well.. This is a power point presentation that is excellent.. Microsoft's free power point viewer works great with it.. and it looks like the update is weekly..whether it translates into a strong Kelvin is still up in the air..lol

http://www.cpc.ncep.noaa.gov/products/p ... update.ppt


http://www.cpc.ncep.noaa.gov/products/p ... ml#outlook

Very important 2 months ahead.

Paul

[cycloneye]

there's an MJO behind the Kelvin wave, which will likely bring about enhanced westerlies.

I would place the value of the CPC nino forecasts as less than the paper they are written on

Yep.. The Current MJO is stronger than the MJO that helped create the current Kelvin and the easterlies in the PAC have weakened in the last five days..Westerlies have developed with the MJO as well.. This is a power point presentation that is excellent.. Microsoft's free power point viewer works great with it.. and it looks like the update is weekly..whether it translates into a strong Kelvin is still up in the air..lol

http://www.cpc.ncep.noaa.gov/products/p ... update.ppt


http://www.cpc.ncep.noaa.gov/products/p ... ml#outlook

Very important 2 months ahead.

Paul

The timing for all of this will be very important to then have el nino by summer or not.