2021 Atlantic Hurricane season

[Prospero]

One year ago today Tropical Storm Eta passed by off the coast of Tampa Bay. It was actually the local highlight of the year for us.

We had over 7 inches of rain in our yard and a few hurricane strength gusts in the middle of the night.

A lucky year for us last year, and this year was another lucky year.

[Scorpion]

Interesting and makes sense. Those pressure wind relationships with Matthew, Irma, and Dorian just did not make sense. Irma was a decent sized hurricane and the SFMR showed 160 kt while it was still 926 mb. Irma was probably likely 145-150 kt, same with Dorian. Matthew was probably 125 kt max.

[Tezeta]

Havahahahahabababavahghahghaaa
 

your legends are false idols

[ncforecaster89]

It’s not a perfect science, so it’s unlikely we’ll ever truly know the exact intensity of storms such as Irma, Michael, and Dorian. 
 

It appears that the SFMR isn’t the most reliable tool/method in determining the strength of these high-end systems.  Although imperfect, flight-level Recon wind obs and dropwindsounde data (especially WL-150 winds) are far more trustworthy for assessing intensity…as a result of long-term application and research.   
 

Given the aforementioned, and the fact the SFMR measurements are the only data supportive of an intensity greater than 145 kt…it’s likely the peak surface winds were closer to 150 kt for Dorian.  The same applies for Irma, albeit it actually had higher 700 mb FLWs in support of a 150 kt intensity.

As well-detailed in the TCR, Michael’s peak intensity was highly likely somewhere in the 140-145 kt range…or about 5-9 kt (6-10mph) below that of Irma and Dorian, respectively.  
 

Edit:  I suspect the NHC will ultimately revise the respective intensities…as a compromise between the adjusted SFMR recalibration results and the Recon data…to arrive at the following:

Dorian: 155 kt

Irma: 150 kt

Michael: 140 kt

[Floydbuster]

https://www.noaa.gov/news-release/active-2021-atlantic-hurricane-season-officially-ends

Hurricane Season 2021 officially over and in the record books. 

 

I think this was a very memorable season, mainly because of the 150 mph landfall of Hurricane Ida along the Louisiana coastline. Those type of Gulf Coast landfalls are rare, despite three in the last few years. (Michael, Laura, Ida)

I think those of us who have been tracking hurricanes for decades know that most seasons are made memorable because of only one or two storms. 2002 had Isidore and Lili. 2003 was Fabian and Isabel. I think there is a generation of storm trackers spoiled by the likes of 2005, or 2020.

Overall, this was a memorable hurricane season. Elsa and Fred could have been slightly more intense, and both could have struck Florida as hurricanes. (Remember the persistent HWRF model showing Fred crossing Biscayne Bay at 90 kt?) but Grace performed beyond expectations. 

I busted with Henri, which I thought would be much more damaging to New England, but thankfully it wasn't.

Ida takes the cake as the storm of the year although (stupid point) I wish it had been named "Hurricane Julian".

Larry and Sam were beautiful but out to sea. I'm still surprised Sam's ACE ended up so high. Very impressive.

Hurricane Nicholas was a nasty little thing but already seems forgotten. 

 

Overall, a memorable season. I still think I myself am partial to the long-tracked threat seasons. Think Frances/Ivan 2004 or Irma 2017.

[StormchaserChuck!]

A few GFS ensembles are showing a tropical storm in the GOM long range.. 

[Roger Smith]

As of now, 2021 ranks tied second lowest with three other years in the ratio of hurricanes to named storms (7 of 21, 0.333) in this century, and is tied 6th lowest all time with six other years (since 1850). Only these years had lower (or equal) ratios of hurricanes to named storms. 

YEAR ___ named __ H _ M ____ Ratio

1895 _____ 6 ______ 2 __ 0 ____ 0.333

1956 ____ 12 ______ 4 __ 1 ____ 0.333

1982 _____ 6 ______ 2 __ 1 ____ 0.333

2002 ____ 12 ______ 4 __ 2 ____ 0.333

2009 _____ 9 ______ 3 __ 2 ____ 0.333

2019 ____ 18 ______ 6 __ 3 ____ 0.333

2021 ____ 21 ______ 7 __ 4 ____ 0.333

1931 ____ 13 ______ 3 __ 1 ____ 0.231

1905 _____ 5 ______ 1 __ 1 ____ 0.200

2013 ____ 14 ______ 2 __ 0 ____ 0.143

1907 _____ 5 ______ 0 __ 0 ____ 0.000

1914 _____ 1 _______ 0 __ 0 ____ 0.000

-------------------------------------------------

One more tropical storm not reaching hurricane status would move 2021 to sixth place alone at 0.318. 

Of the thirteen years with 17 or more named storms, only 2019 joined this list, and the average ratio of hurricanes to named storms in those ten seasons is 0.506

(2020, 14 of 30; 2005, 15 of 28; 1933, 11 of 20; 2010, 12 of 19; 1887 and 1995, 11 of 19; 2012 10 of 19;  2011, 7 of 19; 1969, 12 of 18; 2017, 10 of 17 and 1936, 7 of 17). 

 

On the other hand, 2021 joins this list of seasons where more than half the hurricanes became majors: 

100% _ 1850 (7 of 7)*, 1917, 1930 (2 of 2), 1905 (1 of 1)

 80% _ 1894, 1915 (4 of 5)

 75% _ 1926 (6 of 8) ... 1941 (3 of 4)

71.4% _ 1964 (5 of 7)

66.7% _ 1996, 2004 (6 of 9) ... 1909, 1932, 1948 (4 of 6) ... 1873, 1883, 1900, 1957, 2009 (2 of 3)

62.5% _ 1961, 1999, 2008 (5 of 8)

 60% _ 2017 (6 of 10) ... 1935, 1988 (3 of 5)

57.1% _ 2012, 2016, 2021 (4 of 7)

54.4% _ 1933, 1950 (6 of 11)

50% _ numerous examples incl 2019 (3 of 6), 2020 (7 of 14)

It could be noted then that 2021 produced four major hurricanes out of a smaller number of hurricanes than any years except 1894 (5), 1909 (6), 1915 (5), 1932 (6), 1948 (6). 

____________

* 1850 (7 of 7) is considered less reliable as both a total and a ratio than the other data. 

 

[Prospero]

23 hours ago, Roger Smith said:

As of now, 2021 ranks tied second lowest with three other years in the ratio of hurricanes to named storms (7 of 21, 0.333) in this century, and is tied 6th lowest all time with six other years (since 1850). Only these years had lower (or equal) ratios of hurricanes to named storms. 

YEAR ___ named __ H _ M ____ Ratio

1895 _____ 6 ______ 2 __ 0 ____ 0.333

1956 ____ 12 ______ 4 __ 1 ____ 0.333

1982 _____ 6 ______ 2 __ 1 ____ 0.333

2002 ____ 12 ______ 4 __ 2 ____ 0.333

2009 _____ 9 ______ 3 __ 2 ____ 0.333

2019 ____ 18 ______ 6 __ 3 ____ 0.333

2021 ____ 21 ______ 7 __ 4 ____ 0.333

1931 ____ 13 ______ 3 __ 1 ____ 0.231

1905 _____ 5 ______ 1 __ 1 ____ 0.200

2013 ____ 14 ______ 2 __ 0 ____ 0.143

1907 _____ 5 ______ 0 __ 0 ____ 0.000

1914 _____ 1 _______ 0 __ 0 ____ 0.000

-------------------------------------------------

One more tropical storm not reaching hurricane status would move 2021 to sixth place alone at 0.318. 

Of the thirteen years with 17 or more named storms, only 2019 joined this list, and the average ratio of hurricanes to named storms in those ten seasons is 0.506

(2020, 14 of 30; 2005, 15 of 28; 1933, 11 of 20; 2010, 12 of 19; 1887 and 1995, 11 of 19; 2012 10 of 19;  2011, 7 of 19; 1969, 12 of 18; 2017, 10 of 17 and 1936, 7 of 17). 

 

On the other hand, 2021 joins this list of seasons where more than half the hurricanes became majors: 

100% _ 1850 (7 of 7)*, 1917, 1930 (2 of 2), 1905 (1 of 1)

 80% _ 1894, 1915 (4 of 5)

 75% _ 1926 (6 of 8) ... 1941 (3 of 4)

71.4% _ 1964 (5 of 7)

66.7% _ 1996, 2004 (6 of 9) ... 1909, 1932, 1948 (4 of 6) ... 1873, 1883, 1900, 1957, 2009 (2 of 3)

62.5% _ 1961, 1999, 2008 (5 of 8)

 60% _ 2017 (6 of 10) ... 1935, 1988 (3 of 5)

57.1% _ 2012, 2016, 2021 (4 of 7)

54.4% _ 1933, 1950 (6 of 11)

50% _ numerous examples incl 2019 (3 of 6), 2020 (7 of 14)

It could be noted then that 2021 produced four major hurricanes out of a smaller number of hurricanes than any years except 1894 (5), 1909 (6), 1915 (5), 1932 (6), 1948 (6). 

____________

* 1850 (7 of 7) is considered less reliable as both a total and a ratio than the other data. 

 

There were a few named storms this year that in the past would not even come close. I wonder how the history would pan out if today's technology were in play 20 or 30 years ago.