Technicality of Naming and Season Designation for Dec 31 - Jan 1

[Ryxn]

Let me explain a scenario that has NEVER occurred in the Atlantic basin.

Let's say hypothetically we have Tropical Depression Thirty-Two (32L) form on December 31 at 1800 UTC in the East Central Atlantic near Azores. The year 2021 arrives but the depression has not yet strengthened into a tropical storm.

Another depression forms in the West Central Atlantic but more south on January 1 at 1200 UTC. Since it is now 2021, it is deemed operationally Tropical Depression One (01L). This depression develops faster than the previous year's TD32 and gets the name Ana at 1800 UTC the same day.

And after just over a day as a depression, Tropical Depression Thirty-Two strengthens into a tropical storm at 0000 UTC January 2 but WHAT NAME WOULD IT RECEIVE? Bill or Kappa?

There are arguments for both. Since TD32 formed in 2020, it would be a part of the 2020 season timeline and records however having been named during 2021 it would use 2021's name while STILL being a part of the 2020 season as a depression and a storm.

Or the storm could be considered part of the 2021 season entirely despite having initially formed at the end of 2020 as a depression (Just like Omar of 2020 is considered a September storm despite forming in August as a depression).

Or the storm could still be named Kappa despite having strengthened to a tropical storm in 2021 because Kappa would not cause any name confusion with Ana because it is part of a different list. Kappa would be a part of the 2020 season as a storm but still likely be included in 2021's storm summary like Zeta was in the 2006 storm summary and timeline graphic and Alice (Dec 1954) was in the 1955 storm summary and graphic.

The storm being considered part of BOTH seasons which is my favorite solution. Sorta like below.

Tropical Storm Bill (32L / Redesignated 01L-2 01L)
Formed: December 31, 2020
Dissipated: January 4, 2021 (Remnent Low after January 3)
Highest Winds: 65 mph (100 km/h)
Lowest Pressure: 995 mbar (hPa)

Part of the 2020 and 2021 Atlantic Hurricane Seasons

"Bill was the latest forming tropical depression on record forming at 1800 UTC as Tropical Depression Thirty-Two. It was also the earliest occurring depression (01L) as it persisted into 2021 and was reassigned as 01L from its original 32L for the 2021 season after it strengthened into Bill. When it was named, it became the earliest named storm on record despite forming the year previous."

The storm would be a part of the 2020 Atlantic Hurricane Season but only as a Tropical Depression putting the Atlantic's numbers at 32 Depressions and 30 Tropical Storms. In the timeline chart, it could either be baby blue with Thirty-Two (TD) beside it and end at Jan 1 at midnight. Or be baby blue with Bill (TD) beside it or aqua blue / baby blue with Bill (TS) beside it. In all the "Bill" solutions it would show the graphic terminating at January 5 much like Zeta. I think having it as Thirty-Two (Bill) (TD) with the graphic terminating at the end of January 1, 2021 would work best for me.

The depression that formed on January 1 at 1200 UTC was operationally given the designation of Tropical Depression One but may get changed to 02L when TD32 from 2020 is named to avoid confusion about the 2021 tropical cyclone count. 32L, 01L, 02L for 2021's first three TCs would be confusing. 32L would either be retitled 01L-2 for the 2020 storm database (01L for 2021) or be referred to as both (32L / 01L). The depression that forms after the dissipation of Ana and Bill should be designated Tropical Depression Three (not Two) to avoid confusion. We wouldn't want Claudette forming from Tropical Depression "Two" in late May being the second depression but THIRD storm of the year would we? No it would be TD3 and 03L.

For the 2020 Season, Bill would be seen as below in the Systems section of Wikipedia.

Tropical Depression Thirty-Two (Bill)
---------------------------------------------------------------------------------------------------
Tropical Depression (SSHWS)
---------------------------------------------------------------------------------------------------
Duration: December 31, 2020 - January 1, 2021 (continued in the 2021 season)
---------------------------------------------------------------------------------------------------
Peak Intensity: 65 mph (100 km/h) 995 mbar (hPa)
---------------------------------------------------------------------------------------------------
Main Article: Tropical Storm Bill (2020-21)




End of the 2020 Atlantic Hurricane Season
------‐---------------------‐-------------------------------------------------------------------------
Hurricane Theta | November 12 - 17
---------------------------------------------------------------------------------------‐--------------
Tropical Storm Iota | November 22 - 29
------------------------------------------------------------------‐-----------------------------------
Tropical Depression Thirty-Two (Bill) | December 31
------------------------------------------------------------------------------------------------------
^ Possibly Dec 31, 2020 - Jan 1, 2021



Start of the 2021 Atlantic Hurricane Season
--‐---------------------------------------------------------------------------------------------------
Tropical Storm Bill | December 31, 2020 - January 5, 2021
------------------------------------------------------------------------------------------------------
Tropical Storm Ana | January 1 - 3
-----------------------------------------------------------‐------------------------------------------
Tropical Storm Claudette | May 27 - 30
----------‐-------------------------------------------------------------------------------------------

Just something to think about...

If Omar can be considered a September storm and not an August storm, why couldn't a hypothetical Bill be considered a January 2021 storm of the 2021 season?

If Otto of 2016 can be considered a Pacific storm despite forming in the Atlantic basin, why couldn't the same thing mentioned about Bill occur?

Also fun tidbit, the 1955 Atlantic Hurricane Season which had Hurricane Alice ringing in the new year after forming in 1954, states on Wikipedia that its first system formed on December 30, 1954. It's the only season article to have a date from the previous year for one of "its" systems. Alice was operationally considered to be the first storm of the 1955 season. That is problem why this situation occurred.

https://en.m.wikipedia.org/wiki/1955_At ... ane_season

Any thoughts on this hypothetical scenario?

[BadLarry95]

I imagine that if this happened, it would be like in the EPAC where a depression forms then enters the CPAC, only to get its name from there.

So TD32 forms on 12/31 at 0000 UTC. Struggles for a day or two and becomes a TS on 1/2/21 at 12 UTC. I think it would be TS Ana

[al78]

I think the calendar year is a hard boundary, and which season it belongs too is determined by which year a tropical depression formed. It formed in one of two years, there is no other option. A depression forming on New Year's Eve and intensifying into a tropical storm in January will belong to the prior year's season so will be named next on that list. A depression forming on New Year's day and developing into a tropical storm will be part of year Jaunary's season, so will be given the first name on that list. Whether the second storm was named before the first storm is irrelevant. The storm ID e.g. ALXX2020 or ALxx2021 is determined when the first advisory is issued so if a depression formed on Dec 31st this year, it will be given an ID ALXX2020 where XX will be in the high 20's, say. The depression forming in January 2021 will be given the ID AL012021, so if it was named before the Dec 31st storm, it would be inconsistent for the Dec 31st storm to have a 2020 ID but a 2021 name.

There was one year where there were two Alices, because advisories were first issued for a depression on January 1st, so was given the name ALICE, but post analysis was found to have formed on New Years Eve. Had they correctly started issuing advisories on New Yeays Eve operationally, it wouldn't have had the name ALICE but the next name on the prior year's list.

[snowystar]

TD-9C of 2015 almost ran into the same issue, plus there is also the date line to worry about. See the forecast in:

https://ftp.nhc.noaa.gov/atcf/archive/M ... discus.002

The depression did not developed though, and ended up dissipated on Jan 1 next year.

[HurricaneEdouard]

A similar thing I've thought about is what happens if a tropical storm forms on December 31st but becomes a hurricane in January. Does it count towards the previous season's hurricane totals, or the next, or both? Would it be listed as only a tropical storm for the previous year (just like Cesar-Douglas is listed as a Category 1 for the 1996 Atlantic season even though it peaked as a Category 4 in the East Pacific)?

Another thought: what if a tropical depression forms, or is named as a tropical storm, at, say, midnight January 1st UTC, but it's still December 31st on the NHC's advisory, using, say, Eastern time?

But to answer your question, my recollection of 2005 is that Zeta was going to be named from the 2006 list if it strengthened to a tropical storm on or after January 1st (but the tropical cyclone was operationally named in its first advisory at 1700 UTC on the 30th, with genesis as a tropical depression and strengthening to a tropical storm shunted back a few hours in the tropical cyclone report). So I believe your hypothetical tropical depressions would be named Ana and Bill.

[al78]

A similar thing I've thought about is what happens if a tropical storm forms on December 31st but becomes a hurricane in January. Does it count towards the previous season's hurricane totals, or the next, or both? Would it be listed as only a tropical storm for the previous year (just like Cesar-Douglas is listed as a Category 1 for the 1996 Atlantic season even though it peaked as a Category 4 in the East Pacific)?

It counts towards the previous season's hurricane totals. Crossing into another basin is different, the storm will be counted in both basins as whatever its peak intensity was in each basin.

https://en.wikipedia.org/wiki/1954_Atla ... ane_season
https://en.wikipedia.org/wiki/Hurricane ... ember_1954).
This was only named Alice because it was operationally thought to have formed in January, but when re-analysis established it had formed at the end of December, it was counted as a 1954 hurricane, not a 1955 one, but the 1955 name stayed.

Another thought: what if a tropical depression forms, or is named as a tropical storm, at, say, midnight January 1st UTC, but it's still December 31st on the NHC's advisory, using, say, Eastern time?

The NHC use coordinnated universal time which avoids any ambiguity with time zones.
https://www.nhc.noaa.gov/aboututc.shtml

[NorthieStangl]

This is the reason why I think what I personally term the "hurricane year" should begin on March 1, not synchronized with the calendar year. There was only one recorded storm in both February and March dating back to 1851, making both equally the least active months of all, even though that lone March storm was a hurricane. Compared that to something like 4 recorded storms in January and like 3 in April during that period, it would make sense to restart the name list at the climatological minimum, which would be March 1, which is about 6 months before, and at the same time, also about 6 months after the climatological tropical peak on September 10. But alas, apparently we have to follow the calendar year.

[Ryxn]

This is the reason why I think what I personally term the "hurricane year" should begin on March 1, not synchronized with the calendar year. There was only one recorded storm in both February and March dating back to 1851, making both equally the least active months of all, even though that lone March storm was a hurricane. Compared that to something like 4 recorded storms in January and like 3 in April during that period, it would make sense to restart the name list at the climatological minimum, which would be March 1, which is about 6 months before, and at the same time, also about 6 months after the climatological tropical peak on September 10. But alas, apparently we have to follow the calendar year.

Exactly. IMO any January tropical system has more to do with the previous year than its own year. Take 2016's Pali in the Central Pacific as an example. There was a strong El Niño in 2015 and activity in the Eastern and Central pacific progressed into January. We got Sandra in November, a depression right before the new year and then a Cat 2 hurricane.

The peak of hurricane season is September 10. I think it makes sense to have the year period be March 1 to February 28/29 which is around the opposite of September 10.

The 2015 Pacific Hurricane Season should have been the most active Pacific season with 27 surpassing 1992's 26.

How things are

2015 Pacific Hurricane Season
Tropical Depressions: 31
Tropical Storms: 26
Hurricanes: 16
Major Hurricanes: 11

1992 Pacific Hurricane Season
Tropical Depressions: 30
Tropical Storms: 27
Hurricanes: 16
Major Hurricanes: 10


How things SHOULD be

2015-16 Pacific Hurricane Season RECORD!
Tropical Depressions: 32
Tropical Storms: 27
Hurricanes: 17
Major Hurricanes: 11

1992-93 Pacific Hurricane Season NOT a record, sorry!
Tropical Depressions: 29
Tropical Storms: 26
Hurricanes: 15
Major Hurricanes: 9

LOL

[CrazyC83]

That is definitely a gray area. Having the title 32L would link it to the previous year, so they may apt to name it by the next 2020 name. But, being in 2021, they could just call it Tropical Storm Ana. There's no precedence for such though. Also 00Z January 1 is the start of the new year by NHC and NOAA standards (an issue that came up with SPC watches and MD's on the December 31, 2010 tornado outbreak). Hence, a system forming at 03Z January 1 (i.e. the 10 pm EST advisory) would be a 2021 storm and would be TD 1.

If it became a TS on December 31 but a hurricane in January, it would be a December hurricane added to the 2020 totals.

[Dean_175]

For example: IF that happened this year: Would you have Tropical storm Ana listed in the 2020 season? And then 2021 would officially start with Bill?

[underthwx]

If analysis shows its formation actually occured in 2020, I would have to say it would be assigned a Greek alphabet name, rather than the A storm for 2021...that is how I feel it would be handled...

[Teban54]

This is exactly what happened to the second Hurricane Alice in 1954. It was operationally recognized as a tropical cyclone on January 2, 1955, and thus received the name Alice (back then the same list of names was used every year). However, post-season analysis found that it formed on December 30, 1954.

The storm now counts as part of the 1954 hurricane season and does not count towards 1955 hurricane season's totals. As a result, the 1954 season has two hurricanes named Alice.

[wxman57]

If it reached TS intensity in 2020, it would get a Greek alphabet name. If it was only a depression this year but was named in 2021, it would get the "A" name of 2021.

[Ryxn]

I have a thread for this created in October

viewtopic.php?f=31&t=121442

[AJC3]

I have a thread for this created in October

viewtopic.php?f=31&t=121442

merged...

[wxman57]

Doesn't make any difference what year a system was classified as a depression. When that depression becomes a TS, it takes the next available name on the list for that year. If it was a TD in 2020 but a TS in 2021, it takes the next name available for 2021. If "Ana" was already named for 2021, then it gets named "Bill". TD numbers are meaningless and have no bearing on the future name.