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.
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.
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.
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.
A moderate
risk for a few Cape Verde systems.
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
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.
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.
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.
As always, thanks for the thorough analysis. I print it out to reread it several times. A lot of info!!
ReplyDeleteYou're welcome. Thank you for taking the time to read the outlook.
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