2020 hurricane outlook update

I released my thoughts on the upcoming Atlantic Basin hurricane season on March 23.  Today is the 23^rd of April. So, I wanted to post an update.

The 2020 Atlantic hurricane season starts on June 1^st.  This point in April is a good time to take another look at the key factors, in order to get a better handle on what conditions will be like during the hurricane season.  I will likely post a final update on this year’s hurricane season on May 23^rd.

The predictions from other outlets:

Major weather outlets and universities release hurricane outlooks. Here are the major ones that gather interest.

 

Colorado State University has a prediction of 16 named storms, 8 hurricanes, 4 major hurricanes, with at least one major hurricane making a landfall on the U.S. coastline.

The Weather Channel is predicting 18 named storms, 9 hurricanes, 4 of them becoming major hurricanes.

AccuWeather is predicting 14-18 named storms,7-9 hurricanes, with 2-4 becoming major. They think 2-4 storms could impact the U.S. Coast.

WeatherBELL is predicting 14-20 named storms, 7-11 hurricanes, 3-6 of them major. They also believe the Gulf Coast and East Coast are at a high risk for landfalling tropical systems.

Tropical Storm Risk (TSR) is predicting 15 named storms, 7 hurricanes, and 4 major hurricanes.

University of Arizona is calling for 19 named storms,10 hurricanes, 5 major hurricanes.

North Carolina University is calling for 18-22 named storms, 8-11 hurricanes, and 3-5 major hurricanes.

 

There are two other outlets that I like to look at.  The one from Huston’s Weather Research Center isn’t out yet, or I haven’t been able to find it if it is out. The other is NOAA itself, but they don’t release an outlook until the end of May.

Climate Signals:

Here is a look at the current Sea Surface Temperature (SST) anomalies, as well as SST from past seasons, and precipitation rate patterns for August through October.

The North Atlantic

When we look back at Atlantic Basin hyperactive seasons, we see a similar SST pattern in the Atlantic.

The Gulf of Mexico and Caribbean

The SST’s across the Caribbean and Gulf of Mexico are warmer than average.

Here is a look at the SST anomalies in the Gulf. The Gulf is playing a big part in the highly active severe pattern in April. Those warm waters are going to be a big concern during the hurricane season. One thing to keep in mind, is many times cool springs, lead to early season tropical activity. not saying it will happen, only something to keep in the back of your head.

The Pacific Ocean

The SST anomalies across the Pacific are warm.

ENSO

Earlier this April we had borderline weak El Nino Modoki conditions in place. Since then we have transitioned to neutral conditions. The Indian Ocean Dipole is also neutral. We most likely will stay in neutral territory for the next few months. But, as we get into July and especially August, we very well could be in a weak La Nina, that extends into the late fall.

Madden Julian Oscillation (MJO)

Looking at the subsurface tropical Pacific SST, we see there is a shallow layer of warm water near/at the surface, with a cooler pool of water under it. The warm surface water was west of the Dateline, but now it has shifted near to and a little east of the Dateline.

So far, the analog years I’m using are: 1933, 1952, 1953, 1959, 1995, 1996, 1998, 2005, 2007, and 2017. Most of these seasons saw above average tropical activity in the Atlantic Basin. In fact, many of these seasons ended up being hyperactive. 

When we look back at past years that were active and compare that to the SST anomalies, I’m using for analogs We see the SST pattern is quite similar.

2005 and 2017 were very hyperactive 2017 had 17 named storms and 2005 ended up with 28 named storms.  When we compare SST from those two hyperactive seasons to now, we see very similar SST patterns. In fact, currently the Atlantic main development zone, Gulf, and along the East Coast are warmer than they were in 2005. Something to at least think about.

During November wind anomalies were westerly in the Pacific. From mid-December into mid-March the trade wind anomalies were generally easterly. Then from the end of March to now the wind anomalies have switched to become westerly in the Central Pacific.  This has to do with the MJO and SOI.

In the last two months, negative subsurface temperature anomalies, have extended from the western to eastern Pacific Ocean.

Positive subsurface temperature anomalies reside near the surface, except in the eastern Pacific (100 W-80 W).

Here is the current SOI index numbers and chart.

Once the SOI goes positive the easterly trade winds will increase leading to those cooler subsurface SST to upwell to the surface.

If the MJO keeps rotating through phases 2 and 3 this Summer, that would help promote tropical activity in the Atlantic Basin.

Accumulated Cyclone Energy (ACE):

Ace is used to measure the intensity of a hurricane season as well as individual   tropical cyclones. The higher the number the more active the season and the danger level during the season and the greater the damage potential of individual storms.

The ACE statistics go back to 1851. Many of my analog years saw higher than average ACE. 1933 holds the record for the highest ACE; that being 259. 2005 wasn’t too far behind with an ACE of 250. 2017 ranks 7^th, with an ACE of 223.

An ACE value of 95-105 is considered average in the Atlantic Basin. For this season I'm calling for an ACE well above that.  

Where are my thoughts?

I am forecasting an above average hurricane season due to a combination of either neutral ENSO conditions or La Nina conditions, an active Western African Monsoon, well above average SST and the possibility of lower than average wind shear conditions. The things I’ve just gone over, shows there is a real possibility of a well above average season with close in activity being a real danger this season. This is something that will need to be watched closely.

I still feel there is a high risk for tropical cyclone impacts for places like Cuba, Hispaniola, Bahamas, the East and Gulf Coast. When we look back at the precipitation pattern from those analog and high impact years, we see the pattern is very wet in the Gulf and along the East Coast.  That supports my thoughts on there being a real risk for Coastal areas of the U.S.

I haven’t changed my numbers I released a month ago. You can find them here.

Thanks for reading.