Calling for another quite active season with up to 4 major hurricanes

https://www.accuweather.com/en/hurricane/accuweathers-2020-atlantic-hurricane-season-forecast/705233?utm_campaign=AccuWeather&utm_medium=social&utm_source=facebook&utm_content=1585339785

 

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There are some very warm SSTs just off the African coastline in the Equatorial Atlantic Ocean at the moment which is making everything look really good at the moment for an active hurricane season.

Any La Nina which develops in the ENSO region will no doubt help with that and there are some models which are pointing towards that happening as early as the summer.

Having said that though, I'm not convinced that this will actually happen as the SOI Indexes are currently showing the atmosphere to be in an El Nino state in the ENSO region.

Even without a La Nina though, I would still say that the chances of an active hurricane season are looking very promising just now.

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GOM SST anomalies approaching +3/+4c close to the coastline....

Widely +2c across the basin..

There's a lot of angular momentum in the atmosphere to be diminished before the atmosphere can cooperate with any oceanic move toward La Nina.

I believe this is why the model consensus is still for ENSO neutral during the peak season months of Aug-Sep, though La Nina starts to gain favour by Oct so there's some wiggle room there.

Even that, though, can support a busy season if other factors are supportive - as 2005 demonstrated to the extreme.

The SST situation is alarming at face value, but in a number of years past, I've seen the anomalies change substantially between now and July, so persistence is far from a given. That said - there isn't much sign of anything capable of majorly shaking-up the tropical-subtropical weather patterns in the near future; minimal ENSO trend, no sign of a dramatic final warming to the polar vortex (big contrast to 2019), N. Atlantic SSTs not exhibiting any strong dipole or tripole configurations (for the first time in a while!) that might suddenly dissipate in response to the seasonal decline in N. Atlantic storminess.

There's a negative QBO still descending, unusually gradually, toward the lower stratosphere which might serve to encourage some northward displacement of the subtropical highs, which would favour increased tropical cyclone activity - but this is a tenuous link in the summer months especially.

Each month, I produce a set of analogue years for MetSwift, the March update of which also suggest an above-normal season of activity:

https://twitter.com/peacockreports/status/1240032251523588097 

 

A possible wildcard this year is the drop in pollutants due to the widespread lock-down actions taking place. Less reflection and obstruction of sunlight could have some effect where skies are clear - subtropics may be most affected of the ocean regions. The impact should, however, tend to be less than that experienced overland and will in any case be focused in the vicinity of major human population centres... of which there are obviously none in the open ocean.

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