2023 Atlantic Hurricane Outlook Part Three

 

The 2023 Atlantic Hurricane Season is right around the corner Which is why I’ve been talking about the tropics on my Facebook weather pages. I’ve also released part one and part two of the outlook for 2023.

These previous segments covered things like terms that I will use during the season; They also laid the ground work for Part 3.

Part one can be found here and Part two can be found here.

In my final installment of hurricane outlook series. I will go more into El Nino. More analysis of Sea Surface Temperatures, Make some adjustments to analogues. Take a look at my latest thoughts on the numbers and impacts they could bring. Talk about the Bermuda High, Reexamine the potential hot spots, I will also discuss factors that could make the outlook bust.  

Sea Surface Temperature (SST) anomalies…

 

The latest SST anomalies shown on the map from the NOAA Coral Reef Watch show something very spectacular. Looking at the map we can see that the vast amount of the global oceans is above average to well above average. When I look at the SST record, I couldn't find another year that had the Atlantic so warm during an El Nino. 

In fact the oceanic water near Peru and Ecuador in Nino Region 1+2 are well above Average, and likely record breaking. We also have that warm blob in the western North Pacific.

 We do have some cooler SST in the far Southern Hemisphere. The only other real exception, is that large patch of cool SST off the West Coast up into the Gulf of Alaska. But for the most part the global oceans are above average.   

 Those very warm SST off the West Coast of South America will continue to push west into the Central Equatorial Pacific.

The Atlantic continues to see those above average SST anomalies.  SSTs off the West Coast of Africa out into the MDR across the Central Atlantic are above average. We also have those well above average SST in the Gulf of Mexico (GOM) and off the East Coast.

 The Developing El Nino…

El Nino is looking increasingly likely. This means that the ENSO is in the positive phase. As I said in Part Two, the SOI has switched to negative values. But Nino region 3.4 is still reading in the neutral range. With the Eastern and Central Pacific warming and SOI values decreasing; it can be a strong indication of El Nino development.

The latest weekly Nino region 3.4 index value was +0.4°C, with the easternmost Nino 3 and Nino 1+2 regions at +0.8°C and +2.7°C, respectively.

Looking at the Subsurface water temperatures; we can see they are above average from the International Dateline eastward to the Coast of South America. All of this warm subsurface water is the result of the triple dip La Nina. All that is needed is strong westerly winds to cause upwelling and bring all that warm water to the surface. How much upwelling occurs will be a major player in how strong this El Nino becomes.

Right now, the El Nino looks to start out weak, then it should go into a moderate to strong phase.

This would mean we would see more vertical wind shear during the 2nd half of the Season.

There will be a bit of a lag as the atmosphere resets from ENSO neutral/weak El Nino to moderate too strong. So, the first half of the season could act more La Nina like. 

A few of the models like the Australian are calling for a very strong (super) El Nino.

 Typically during El Nino the Caribbean sees less activity. This is due to increased windshear over that part of the Atlantic Basin. 

The Pacific Decadal Oscillation (PDO)…

Right now, the current index is -3.05 which makes the PDO strongly in the negative phase. As I said in the Summer Outlook, The PDO has a big influence on the ENSO. If the PDO is in the same phase as the ENSO their Associated impact can be amplified. However, if they’re not in the same phase the associated impact can be reduced.

There are signs that the negative PDO has reached its peek and is starting to collapse. If the PDO does become positive, that wouldn't happen until late Summer or more likely during the Fall into Winter.   

So, while El Nino is a typical signal for a quieter tropical season in the Atlantic Basin.  With the PDO in a negative phase, this could allow for a slightly higher number of tropical cyclones in the Atlantic this season, than would be typical for a El Nino season.  

 The Atlantic Multi-Decadal Oscillation (AMO)…

As I’ve already covered, the Atlantic Basin is very warm

The AMO is a cyclical variation of sea surface temperature anomalies over the North Atlantic Ocean that influences weather conditions across the globe, especially North America, Europe and Northern Africa. It typically has a cycle of 50 to 70 years.

 

The positive phase is characterized by warm SSTs over much of the North Atlantic

 

The negative phase is a mirror image with cool surface waters over the North

 

When SSTs are anomalously high (positive phase), hurricane activity in the North Atlantic is increased.

The African Monsoon looks to be very active this season, leading to more tropical waves coming off the West Coast of Africa.   .

Analogues…

These are the years I've decided to use for 2023. The years are the best general match to all the factors going on leading into the 2023 Atlantic hurricane season.

1957, 1965, 1972, 1976, 1982, 1997, 2002, 2009, 2015, 2019

1957

1965

1972

1976

1982

1997

2002

2009

2015

2019

1967 thru 2019

2023

1957 and 1976 are being used because both were El Ninos that came after triple dip La Nina’s.

1972 is the closest match to current global SSTs. 1997 is the second closest match, with 1982 just behind that.

 Based on what I'm seeing there is a good chance this El Nino could be very strong.

The Numbers…

In part two I said this will be a slightly below average to average season, with 10 to 14 named storms 4-7 hurricanes and 1 -2 major hurricanes.  The seasonal ACE looks to be 60-90.

But with the other factors I’ve mentioned in part three. The seasonal activity could end up  above average.

My final numbers are 14-20 named storms, 8-12 hurricanes, 3-5 major hurricanes. The CONUS could see 2-4 landfalls with one of them possibility being major. The ACE would be 100-150.

 Hot Spots and impacts…

A moderate risk for a few Cape Verde systems.

 So, we should see recurving systems out in the Atlantic that head into the North Atlantic.

 But the greatest risk for tropical cyclone development will be in the Gulf of Mexico and off the Southeast Coast. 

The risk of close in tropical cyclone development increases the risk for landfalling tropical Storms and hurricanes along the Gulf Coast and East Coast.

The East Coast is most at risk for Landfalling systems. There is a chance the Middle Atlantic and New England could be impacted.

Florida could very well be in the crosshairs once again this season.

With those very warm water temperatures, there is going to be the risk for rapid intensification.

What Could Go Wrong…

Even though El Nino looks likely, right now the odds are around 60%.  But as we saw in 2014 when a strong El Nino was being forecasted on the models. However unusually strong easterly winds in the summer of 2014 ended up  preventing the warm surface water from shifting eastward as seen in a typical El Nino events and left a reservoir of warm water below the ocean’s surface, resulted in the El Nino failing to really develop. But strong westerly winds along with the very warm pool of water that developed during the winter shifted east, this continued into the Spring and Summer of 2015 and led to the development of the Super El Nino of 2015-2016.  It is possible a similar change in the wind regime or some other unforeseen factor could end up stopping El Nino from developing this year.

The PDO is in an opposite phase from El Nino; this could lead to more of an active Atlantic hurricane season.

The above average SSTs in the Atlantic Basin, could very well help counter the El Nino impacts, at least somewhat.

Other possibilities that could happen with the ENSO

 A)    El Nino Modoki

There is a chance that the central equatorial Pacific namely Nino region 3.4 could warm faster than Nino 1+2, if that warm subsurface water makes it to the surface. I think the chance of this is low, but it can’t be completely ruled out.  There is research that supports the idea that El Nino Modoki’s lead to more hurricanes than usual in the Atlantic Ocean.

 B)    La Nina Modoki

The water temperatures are very warm in Nino region 1+2 off the West Coast of South America. But a closer look at the SST anomalies, show water temperatures are also rising near Indonesia off the province of Papua. This would mean that the SSTs in the central equatorial Pacific are slightly cooler.  That could technically be called a La Nina Modoki. Again this is a lower chance, but I can't discount it.  If this develops, we would be in another La Nina. Which would have a drastic influence on the Atlantic windshear profile. Coupled with those very warm SSTs. It could lead to a very active tropical season in the Atlantic.  

The most recent El Nino Modoki happened in 2019.

 Bermuda High…

We look to see the Bermuda high setup near the Azores and then drift west during the season. As the BH sets up in the western Atlantic in the 2nd half of the season. Helping to direct tropical waves/cyclones toward the US, possibly increasing the landfall risk. But increased windshear that looks to develop during the 2nd half of the season, could help counter at least some of the landfalling threat.

Final Thoughts…

There is no way of knowing the exact number of tropical cyclones are the exact track they will take. I’ve looked at past patterns and compared those to the current pattern. I’ve also looked at what I think the teleconnections are saying as to what could happen. I’ve also looked at return dates based on hurricane historic data. 2023 is going to be a difficult year for long range hurricane outlooks, due to the multitude of conflicting signals. I think the approach I’ve taken is reasonable after looking at all the data.

It is important to take the time to make a plan and also have a hurricane kit to keep your family safe.  

Well, that’s it

If you have any questions regarding this outlook, please feel free to send me a comment here or on my Facebook Weather Page here.

I have to add, The National Hurricane Center has determined that that the nor’easter back in January was actually a subtropical storm. This would make it the first Atlantic cyclone of the 2023 season.  It is being designated as “AL012023.” Since the January storm is considered the first of the season, the next tropical depression that forms will be designated as “tropical depression 2.” If it strengthens into a tropical storm, it will be named Arlene.