Why I think a Modoki El Nino is developing.

This will be a quick post showing why I think we're on the cusp of a Modoki El Nino. I've made several slides showing how things currently look and how they have been evolving over the last few months. This will dovetail with my post dealing with my preliminary thoughts on winter 2018-2019. Here are links to them if you want to read them.

Part one 

Part two

The El Nino Southern Oscillation covers a large part of the Pacific equatorial region. It deals with Sea Surface Temperature (SST) anomalies. The area  is divided into four regions.  Nino Regions 1+2 is located in the East Pacific right next to South America, Nino regions 3, 3.4, and 4 sit west of there. The ENSO has two phases, one is called El Nino the other is called La Nina.  El Nino is when Oceanic Nino Index values are greater than or equal to a positive 0.5 C. La Nina is the exact opposite characterized by a ONI less than or equal to negative 0.5 C.

 

There are two types of El Nino: The most common is the classic east based El Nino. Less common is the central based Modoki El Nino. Both of these have an impact on our weather here in the Northeast. I describe how they influence our weather take a look at my preliminary thoughts on winter 2018-2019.  

Why I think an El Nino Modoki is about to occur:

Like most weather outlets I show a lot of images  of surface based SST anomalies. Here is a look at the global SST from Tropical Tidbits.

Here is a look at subsurface SST and other charts showing El Nino data.

 

We've been seeing a lot of changes in SST's in the Atlantic. This is something I've been talking a lot about on my Facebook weather pages; you can find my Facebook page here. Well the Pacific has also been seeing a lot of changes over the last 4 weeks. Looking at the subsurface SST we can see how the water temperatures have migrated from the East Pacific to the Central Pacific.  When we look at the Temperature anomaly chart showing each individual region. We can see Nino region 4 has had above average SST since late April. Nino region 3.4 has been slightly above average for the last 8 weeks or so. Region 3 had above average SST but has cooled and even dropped slightly into the below average range for a week or so, before going back into above average anomalies.  Region 1+2 has been below average since February. But recently it has risen slightly above average.   This could be why some outlets have been confused or hesitant to talk about the Modoki we should see this Fall.

To clear up the confusion we have to once again look at the subsurface SST anomaly charts.  Those red blobs are showing where temperatures are the warmest. The dark red areas are around 3 degrees C above average. Comparing the two subsurface charts we can see how warmest water temperatures were close to Nino region 1+2 and were very close to the surface. But since then this area has cooled while at the same time region 4 has warmed a lot.  The warm blogs in region 4 and 3.4 are below the surface but these should migrate upward and warm the surface even more.  The East Pacific should continue to cool.  This set up would lead to a  Modoki El Nino. We should also see the temperature spike in Nino regions 3 and 1+2 go back below average. We are getting close to the temperature anomaly pattern that should become a Modoki El Nino this Fall, this should extend into and through winter 2018-2019.

Anyway, this is why I'm so animate that we will see a Modoki El Nino.