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2021 Atlantic Hurricane Season Tracking Thread


WxWatcher007
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Just following up on yesterday, it’s been really awesome to see so many reach out to inquire about my content, especially in the last year.

I’ve gotten so much better positioning myself and documenting wx. Years ago it was just me and an old camera but now I’m capable of doing so much more. I sometimes wish I had more time to put into it but I know I’m doing a lot already. 

Can’t wait to hit the road again.

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31 minutes ago, H2O said:

Hit the road?  You local chased this one.  It doesn't count if you only went as far as the nearby 7-11 to get "storm surge" :P

I did drive down to RI at the start of the day, but yes, the top 5 river flood was basically down the street :lol: 

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1 hour ago, WxWatcher007 said:

Just following up on yesterday, it’s been really awesome to see so many reach out to inquire about my content, especially in the last year.

I’ve gotten so much better positioning myself and documenting wx. Years ago it was just me and an old camera but now I’m capable of doing so much more. I sometimes wish I had more time to put into it but I know I’m doing a lot already. 

Can’t wait to hit the road again.

Let me know when you want to chase a drought.  Got some good tips on locations.

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10 minutes ago, mappy said:

99L def worth watching. Josh is already sounding alarms. 

Tremendous flood potential for the Western Gulf states, not too mention the wind threat/ storm surge from an extreme Cat 4 or even 5 hurricance. 

 

 p168i.gif?1629889177

 

 

 

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28 minutes ago, WinterWxLuvr said:

I’m changing that to 24 hours

It looks quite good for a disturbance. Everyone knows it's coming, just look at the wording of the outlooks. It's crazy strong for an invest. 

1. A broad area of low pressure is expected to form over the western 
Caribbean Sea during the next day or so from a tropical wave 
currently located north of Colombia.  Environmental conditions are 
forecast to be conducive for development, and a tropical depression 
or tropical storm is likely to form late this week or over the 
weekend.  The system is expected to move northwestward over the 
northwestern Caribbean Sea and near or across the Yucatan Peninsula 
of Mexico on Friday and into the Gulf of Mexico this weekend, where 
conditions are expected to be favorable for additional development.  
Regardless of development, heavy rainfall and flooding will be 
possible through the weekend in portions of Central America and the 
Yucatan Peninsula.  In addition, this system could bring dangerous 
impacts from storm surge, wind, and heavy rainfall to portions of 
the coasts of Louisiana, Texas, and the Mexican state of Tamaulipas 
late this weekend and early next week. However, uncertainty remains 
large since the system has yet to form. Interests in these areas 
should closely monitor the progress of this system and ensure they 
have their hurricane plan in place. An Air Force Reserve 
reconnaissance aircraft is scheduled to investigate the system 
Thursday afternoon, if necessary.
* Formation chance through 48 hours...medium...60 percent.
* Formation chance through 5 days...high...80 percent.
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WxWatcher007 2021 Atlantic Hurricane Peak Season Forecast

I'm a few days late due to the timing of Hurricane/Tropical Storm Henri, but it's time for me to issue my 2021 forecast for the peak of the Atlantic hurricane season. 

In recent years, my outlooks have done very well, and last year's historic season was my best yet. For those that haven't followed these forecasts, I look at the climatological peak of the season, from August 20 to October 20. Of course, with a few days lost we shift August a bit. Last year, we saw an active peak that pushed out a number of major hurricanes in the back end of September and into October and beyond. 

Peak Season Forecast Numbers (August 25-October 20)
Named Storms:  13
Hurricanes: 9
Major Hurricanes: 5

The numbers above are bullish to say the least. Based on this forecast, more than 50% of the hurricanes that develop over the next two months would become majors. We'd likely rival 2005 and 2020 in the number of major hurricanes in a season should this come to pass. 

Let's take a look at why I am so bullish on the peak of the season. 

1. ENSO

First and foremost, ENSO will tell you whether you are likely to see an active season or not. After last year's La Nina, there were significant questions over whether we'd see a slide toward more neutral conditions. 

Officially, ENSO neutral conditions are present, but we are once again marching toward an La Nina. In fact, we are under a La Nina watch. The Nino 3.4 region in particular has slid colder since the end of June, potentially heralding a Nina regime for the peak of the season, especially in atmospheric condition reflection in October. The current neutral state of ENSO and potential for a Nina strongly suggests that an active peak of the hurricane season will present itself in 2021. It is important to note that a bona fide nina is not necessary for this forecast to verify. 

QpZAxYI.png

2. Atlantic Multi-decadal Oscillation (AMO)

What is the AMO? It's another important long term factor in determining potential during a season. A warm AMO is associated with periods of higher activity. We've been in this state for quite some time (hence AMO), and that looks to continue. Combined with the other factors as you will see, it favors activity. The AMO facilitates 1) a wetter West African Monsoon and more robust wave activity, 2) warmer SSTs in the Main Development Region (MDR), and 3) lower vertical wind shear. 

FGyIBiI.jpg

 

3. Sea Surface Temperatures (SSTs) and Tropical Cyclone Heat Potential (TCHP)

The thermal environment over the Atlantic basin is mixed.

First, let's talk SSTs. While they're warm in an absolute sense, from an anomaly standpoint, they're not that impressive.

eFsZPUS.png

9Hx8bjj.png

I think that the relatively lukewarm waters will reduce the potential of an extremely high named storm peak season. I expect a well above average number of named storms as the SSTs are more or less on par with the last 5 years of SSTs, each of which produced above average hurricane seasons. However, as you will see below, SSTs fall well short of the extraordinary warmth we saw in 2020.

I believe that will have an impact on the length of the season post October 20 and the number of named storms (think marginal systems) as we progress into the latter part of the peak. 

giphy.gif?cid=790b7611862ea627b1cefe42b1


On the other hand, what the 2021 basin lacks in quantity it makes up for in quality. This is a very high TCHP environment. As a refresher, TCHP is essential to the development of major hurricanes as it provides systems with deep reservoirs of oceanic heat that allows for the high end intensification of hurricanes.

As you will see below, the TCHP of 2020 was off the charts, but the extent and depth of high TCHP waters in 2021 is greater than all of the other recent active seasons that had significant numbers of major hurricanes, and just as important, the high TCHP levels are in regions that coincide where I believe storms will be focused this peak--the Caribbean, Gulf, and SE coast. 

giphy.gif?cid=790b7611569ed35a63c80485f1

As a result, what we may lose in named storms in the subtropics and MDR we could make up for in hurricanes and major hurricanes. We're already starting to see this come into greater focus with the current disturbance in the Caribbean and to a lesser extent with Elsa, Fred, Grace, and Henri, three of which became hurricanes. 

3. Wind Shear

Let's refer back to ENSO here. One of the biggest reasons neutral to Nina seasons feature higher Atlantic activity is the drop in wind shear that comes with the ENSO state. 

Here's the shear departures in a weak Nino, which we are not expecting. 

Kv47fT0.jpg

Above, the Caribbean is effectively closed for business. That reduces major hurricane potential. 

Here's a warm neutral, which again, we are not expecting. 

vWoWd6z.jpg

Here you see less wind shear near the coast, and less shear in the MDR, including the Caribbean. 

So what do we have this season? With a cool neutral regime that could become a Nina, we have shear that favors an above average season. Once again, the reduced shear is present in places where TCHP is best and more storms are likely to form, and while it may look higher in the Caribbean, there can be sizable differences between an eastern Caribbean (i.e. graveyard) system environment and a western Caribbean system environment. 

WHHacGT.gif

OCD3hVs.gif

K8jq0HF.gif

CNnO1qG.gif

The shear profiles strongly favor the development of more hurricanes and major hurricanes IMO, especially as we reach the climatological nadir of shear in September and October. 

4. MJO/CCKW Timing

The fourth and final factor I'm looking at in a significant way this season is more a stroke of luck (good or bad depending on your perspective). We have an MJO and CCKW regime which will enhance activity in September and likely October. First, the MJO. Let's look at the CFS. 

PdE2GJw.gif

This is a HUGE signal for an active Atlantic. Eric Webb explains it much better than I could ever hope to, but essentially this phase of the MJO in September is prime for AEW (wave) activity through the month and again, even if those waves don't immediately develop they are likely to find more favorable thermodynamic, moisture, and wind shear environments. 

Now that I've tried, here's Eric: 

The active period of the MJO is timed perfectly with the peak of the hurricane season. That means plenty of activity. 

To hammer home the point, here's Phase 4. Image once again courtesy of Eric Webb. NW Caribbean, Gulf, central/eastern MDR, and SE coast.

Homebrew :wub: galore. 

bdZB8p8.jpg

 

So with each of these factors at play I expect a very active peak that has a high level of named storms (though not historically high), hurricanes, and a potentially historic number of major hurricanes. Unlike last season, that had a distribution of high end hurricanes later in the peak (and after lol), I expect high end storms to be distributed throughout the peak, in large part due to the MJO and well-timed CCKWs that provide a boost to waves that are unable to develop in the Atlantic portion of the MDR but find a more favorable environment in the Caribbean and perhaps off the SE Coast. 

My margin for error as it is every year is +/- 1 storm in each category. 

Final Note-Landfall Odds
Last year was historic in the landfall department, with 11 named storms (6 hurricanes/5 tropical storms) making landfall along the US coast. The overwhelming majority made landfall in the Gulf. One hurricane made landfall along the East Coast, Isaias, along the coast of NC. 

This season has already seen 5 US landfalls--Claudette, Danny, Elsa, Fred, and Henri--all tropical storms. 

Although the pattern over the next few weeks may favor recurves of CV waves (as the pattern usually does--few CVs actually develop in the central/eastern MDR and make it to the US), with anomalous ridging favored through the peak and the potential for Caribbean and SE coast homebrew in September and October, I believe we are on the path toward another high to potentially historic landfall season.

For now, the Gulf is favored, but the East Coast cannot let its guard down, especially in late September and October when climo favors SE coast and Caribbean homebrew and troughing in the east. 

sep_1_10_sm.png

sep_11_20_sm.png

sep_21_30_sm.png

oct_1_10_sm.png

oct_11_20_sm.png

 

We'll see what happens.

I do not think there will be a shortage of threats.

Hope you enjoyed reading. :) 

 

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7 hours ago, Chris78 said:

Gfs has been shifting the track further east.  Actually brings the remnants through to our west next week  

LWX AFD from this morning already mentioning it

The forecast for the middle of the week next week is a bit more
uncertain at this time. The National Hurricane Center is monitoring
a tropical disturbance in the Caribbean right now, which may impact
the Gulf Coast this weekend. This system will then come in our
general direction by mid-week. So, will have to monitor any tropical
development in the coming days and see how guidance trends in
regards to any potential impacts for our region. For now though, far
too many questions in the forecast to say anything for certain. For
now, keeping chance POPs in Tue/Wed.

Monitor hurricanes.gov for updates on the tropical weather outlook
in the coming days.
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15 minutes ago, mattie g said:

Are more recent hurricanes more likely to end up with retired names? Like...everyone gets a trophy?

There have certainly been more in recent years but I think that’s a function of hurricanes being stronger and hitting more populated areas. Impactful storms still get left out. Isaías for example last year. 

https://www.wunderground.com/cat6/most-surprising-hurricanes-names-not-get-retired

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