ENSO Updates (2007 thru 2023)

[cycloneye]

Will CPC make El Nino official on the March update of the 5th? The ONI as you said Ntxw is there to make the call in this upcoming update.

[Kingarabian]

Didn't the CPC say that despite the sea water temperatures claiming El-Nino, the atomsphere claims the contrary?

I always thought the definition to declare El-Nino was solely based on SST in the Nino regions.

[Dean_175]

Didn't the CPC say that despite the sea water temperatures claiming El-Nino, the atomsphere claims the contrary?

I always thought the definition to declare El-Nino was solely based on SST in the Nino regions.

They use different criteria for "el nino alert" and an el nino event. "El nino alert" is for an operational declaration. For there to declare an "el nino alert" , there must be both a warm ocean AND an atmospheric response along the equator ( a negative SOI does not count because it is not measured along the equator). This atmospheric response can be indicated by at least some of the following: 1) decreased outgoing longwave radiation near the dateline (indicating increased precipitation there) and increased outgoing longwave radiation from regions like Indonesia (indicating suppressed rainfall there), 2) westerly wind anomalies near the equator (weakened easterlies), 3) a negative ESOI (equatorial southern oscillation index). At the February update, they said that atmospheric conditions in the equatorial Pacific had resembled el nino for the past few weeks- but they didn't declare it yet because they wanted to know the atmospheric conditions persisted to determine if it was ENSO related. So we will see on Thursday's update what happens.

Now when it comes to an "el nino event". That is defined as any period in which the ONI exceeds/meets +0.5 Celsius for 5 consecutive trimonthly periods. It is possible for them to declare an event without them declaring el nino conditions to have been operationally in place. No atmospheric indicators are taken into consideration for the declaration that an el nino event has occurred.

We have ONIs of:

SON: 0.5 C
OND: 0.7 C
NDJ : 0.7 C
and DJF is definitely above 0.5

So we have 4 trimonthlies, as long as March doesn't see too much of a decrease in nino3.4 anomalies- we will almost certainly see a declaration of an official el nino event after March -regardless of how the atmosphere behaves.

[Ntxw]

0.6C this week

[cycloneye]

The weekly CPC update as Ntxw said is at +0.6C and that is up from the past three weeks of +0.5C. ONI remains at +0.7C.

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

[cycloneye]

The Aussies upgrade to El Nino Watch.

Renewed warming in the tropical Pacific Ocean

Issued on 3 March 2015 | Product Code IDCKGEWW00

The Bureau's ENSO Tracker has been upgraded to El Niño WATCH. This is due to a combination of warmer-than-average temperatures in the tropical Pacific Ocean and models showing that further warming is likely in coming months. El Niño WATCH indicates about a 50% chance of El Niño forming in 2015.

The central to western regions of the tropical Pacific Ocean have warmed by 0.2 °C to 0.3 °C over the past fortnight, while monthly sub-surface temperatures were more than 2 °C above average over a large area for February. This is largely the result of weakened trade winds and tropical surface currents in recent weeks. Weakened trade winds are forecast to continue, and this may induce further warming.

All international models surveyed by the Bureau indicate that central tropical Pacific sea surface temperatures (SSTs) are likely to remain warmer than average, but within the neutral range, until at least May. By mid-year, six of the eight models indicate SSTs will exceed El Niño thresholds. However, accuracy of forecasts made at this time are lower than those at other times of the year, and hence some caution should be exercised.

El Niño is often associated with below-average winter–spring rainfall over eastern Australia and above-average daytime temperatures over the southern half of Australia.

http://www.bom.gov.au/climate/enso/

[cycloneye]

The latest model forecasts are bullish for warming by July.

[cycloneye]

Note=I am going to move this ENSO thread to Talking Tropics forum on March 20 when Spring begins but the shadow thread will be left on this Winter forum.

[cycloneye]

Big WWB coming in next few days. Will it trigger a moderate El Nino instead of a weak one?



NHC folks are chimming in.

Eric Blake EricBlake12
Huge westerly wind burst forecast over the next week-- wonder if that could hlep create a real El Nino :

Eric Blake EricBlake12
ToddKimberlain tcrawf_nh If March Nino 3.4 is AOA 0.5, then the 2014-15 event will officially qualify as a weak event, fwiw

[cycloneye]

The always important first thursdays of each month update is upom us and this time is all expectation to see if they pull the trigger and declare officially El Nino.Let's see when the update is released around 9 AM EST says.

[Ntxw]

They better declare it because no reason to believe March won't remain above 0.5C as enso continues to warm. They will have their 5 trimonthly definition by the end of this month.

[cycloneye]

They better declare it because no reason to believe March won't remain above 0.5C as enso continues to warm. They will have their 5 trimonthly definition by the end of this month.

They now have support from the Aussies that upgraded to El Nino Watch.

[Ntxw]

They better declare it because no reason to believe March won't remain above 0.5C as enso continues to warm. They will have their 5 trimonthly definition by the end of this month.

They now have support from the Aussies that upgraded to El Nino Watch.

And this new warm pool will keep it going through Spring. I don't know if we will get a multiyear Nino but it's certainly more possible than say a few months ago.

[cycloneye]

That warm pool has grown in a steady way in the past couple of months.Will it turn like that very large one in April and May of 2014.

[Kingarabian]

In the wake of no declaration, do we have to wait until April?

[cycloneye]

In the wake of no declaration, do we have to wait until April?

Yes if they don't do it in this monthly update.

[xtyphooncyclonex]

Less than two hours left. IMO it is very likely that El Niño will be declared, mainly because DJF ONI may be at 0.6C based on last week's update...

[xtyphooncyclonex]

Wow. Opposite of what they showed in 2014.

[cycloneye]

Yeah,a big change by that model compared to a flat forecast on very weak El Nino to now Moderate by Summer.

[xtyphooncyclonex]

I know it's too early, but the CPC WILL declare it IMO