Suptropical Storm 1 (Upgraded in Pre-season Reanalysis)

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Re: ATL: INVEST 90L - Discussion

#121 Postby THC_Scientist » Tue Jan 17, 2023 1:10 am

Don’t see what the fuss is about. Already starting to deteriorate. Not to mention the giant dry slot in the middle of it.
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Re: ATL: INVEST 90L - Discussion

#122 Postby Teban54 » Tue Jan 17, 2023 1:41 am

THC_Scientist wrote:Don’t see what the fuss is about. Already starting to deteriorate. Not to mention the giant dry slot in the middle of it.

It doesn't matter how long it stays as a (sub)tropical storm. As long as it meets all criteria, it should be classified.

Plenty of "shorties" were even shorter lived and/or uglier looking than this.
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Re: ATL: INVEST 90L - Discussion

#123 Postby TheDreamTraveler » Tue Jan 17, 2023 1:46 am

I don't get why this didn't receive a name
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Re: ATL: INVEST 90L - Discussion

#124 Postby TheDreamTraveler » Tue Jan 17, 2023 1:47 am

Jr0d wrote:
Category5Kaiju wrote:So has the NHC developed a new rule for naming storms? Especially off-season? I'm still kind of lost here as I was under the assumption that even if we're in off-season, if there's an Atlantic storm that meets all the criteria for a TS or SS that it would almost certainly be tracked and receive a name?


My amateur opinion is the only reason why its not named is because its the middle of January. The NHC was a bit late classifying as an invest also, I was surprised this did not happen Saturday evening...

I do think post season analysis will upgrade this system to a sub tropical storm


We had Alex a few years ago that formed in January and received a name. There was also hints from the weather models that a subtropical system would form from this days ago so it's not like they had no idea
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Re: ATL: INVEST 90L - Discussion

#125 Postby PavelGaborik10 » Tue Jan 17, 2023 6:30 am

 https://twitter.com/Dylan_Hurleyh2/status/1615310072191524865




Impressive, despite the tops warming she's still attempting to fire off convection and still has an extremely impressive looking center given the context here.

What a cool little system, upgrade or not.
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Re: ATL: INVEST 90L - Discussion

#126 Postby cycloneye » Tue Jan 17, 2023 7:24 am

At 45N still looks relativly good.

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Re: ATL: INVEST 90L - Discussion

#127 Postby Sciencerocks » Tue Jan 17, 2023 7:29 am

A solid case could be made that this is going to make landfall as more tropical then Fiona back in September and probably actually a tropical cyclone landfall. It will be very interesting to read the post season discussion on this system....
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Re: ATL: INVEST 90L - Discussion

#128 Postby cycloneye » Tue Jan 17, 2023 8:04 am

12z best track. I think this will be the last BT as it arrives at Nova Scotia.

AL, 90, 2023011712, , BEST, 0, 453N, 601W, 50, 982, LO


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Re: ATL: INVEST 90L - Discussion

#129 Postby Sciencerocks » Tue Jan 17, 2023 8:29 am

Landfall
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Re: ATL: INVEST 90L - Discussion

#130 Postby InfernoFlameCat » Tue Jan 17, 2023 8:36 am

Wow what a landfall. A tropical system making landfall in Canada!
In January!
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Re: ATL: INVEST 90L - Discussion

#131 Postby wxman57 » Tue Jan 17, 2023 8:38 am

I agree that this appeared to qualify for an upgraded to a subtropical storm with about 50kt wind, so why didn't the NHC upgrade it and start advisories? I've heard two reasons from sources at the NHC.

1. The storm would be a short-lived marine threat and could be handled by standard marine warnings. Its impact on Nova Scotia is considerably less than from the very large low over the area already. Eastern Nova Scotia is reporting a west wind at 15-20 kts as it passes. No big deal. Small storm with minimal impact to shipping.

2. Staffing issues. I heard that a number of forecasters were out on vacation and remaining staff were too busy to issue advisories every 6 hrs with intermediate updates.

I know that one forecaster in the analysis branch started Dvorak estimates on Sunday (1.0 then), but those Dvorak estimates were discontinued Sunday night by the next forecaster.

Clearly, the NHC had determined early on that this would be a minimal threat and that issuing advisories would not be any significant benefit to the general public or shipping. This fits within the NHC's primary goal of public safety. Issuing advisories above the standard marine warnings would not increase public safety. The NHC's goal is not to immediately name everything possible so that the database is always accurate. They can go back and review the storm and decide if it should be added to the data record at the end of the 2023 season.
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Re: ATL: INVEST 90L - Discussion

#132 Postby wxman57 » Tue Jan 17, 2023 8:41 am

InfernoFlameCat wrote:Wow what a landfall. A tropical system making landfall in Canada!
In January!


No, not a TS or even an STS this morning. Just a weak low that isn't producing any significant wind. Check out the observations from a station on the eastern tip of Nova Scotia. Peak wind 270 at 9 kts gusting 16 kts. Just a brief STS yesterday and nearly a remnant low today.

KMTP 171254Z AUTO 27009G16KT 03/M03 A2973 RMK AO1 SLP067 T00331028
KMTP 171154Z AUTO 28007KT 03/M03 A2973 RMK AO1 SLP065 70002 T00331028 10039 20028 51007
KMTP 171054Z AUTO 28008KT 03/M03 A2972 RMK AO1 SLP062 T00331028
KMTP 170954Z AUTO 29008G17KT 03/M03 A2972 RMK AO1 SLP063 T00331028
KMTP 170854Z AUTO 30009G16KT 03/M03 A2971 RMK AO1 SLP059 T00281028 56002
KMTP 170754Z AUTO 30008KT 03/M03 A2971 RMK AO1 SLP060 T00281028
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Re: ATL: INVEST 90L - Discussion

#133 Postby KWT » Tue Jan 17, 2023 10:20 am

Sciencerocks wrote:This is stronger then nicole and more deserving of the hurricane title.

I don't know how anyone could look at that satellite and say polar low? I mean why?


To be fair polar lows can look fantastic.

This system reminds me alot of a medicane, similar presentation with the eyewall and developing from a larger LP with cold air aloft and probably a shallow warm core.

Honestly both this and medicanes should get recognised as such, but sadly they often just get ignored even post season.
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Re: ATL: INVEST 90L - Discussion

#134 Postby cycloneye » Tue Jan 17, 2023 10:25 am

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Re: ATL: INVEST 90L - Discussion

#135 Postby cycloneye » Tue Jan 17, 2023 11:20 am

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Re: ATL: INVEST 90L - Discussion

#136 Postby CyclonicFury » Tue Jan 17, 2023 12:13 pm

It could be over a year before we know if 90L will be retroactively classified as a (S)TC. I don't think the NHC analyzes other possible storms until after the season is over. Not to mention, NHC still has a lot of 2022 TCRs to finish.

I wonder if this is a sign that NHC will refrain from naming short-lived subtropical storms all year, or if this particular case was just left unnamed because of staffing issues. NHC didn't hesitate to name short-lived subtropical storms from 2018-21, just look at Andrea (2019) and Teresa (2021) for examples. NHC did seem more stringient with convective organization last season, wonder if the departure of Ken Graham as NHC director is a reason why.
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Re: ATL: INVEST 90L - Discussion

#137 Postby CrazyC83 » Tue Jan 17, 2023 12:38 pm

It definitely weakened as it moved northward close to Nova Scotia (and over it), but there was still deep convection and even now it's non-frontal. I would estimate it was a 40 kt tropical storm at landfall, although such winds were only over water.
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Re: ATL: INVEST 90L - Discussion

#138 Postby CrazyC83 » Tue Jan 17, 2023 1:00 pm

This is COMPLETELY unofficial, but here is my analysis of the best track:

AL012023, UNNAMED, 11,
20230115, 1200, , LO, 37.3N, 69.7W, 40, 993,
20230115, 1800, , LO, 37.6N, 68.9W, 45, 991,
20230116, 0000, , LO, 37.5N, 68.3W, 45, 990,
20230116, 0600, , TS, 37.2N, 67.2W, 50, 987,
20230116, 1200, , TS, 36.9N, 65.8W, 50, 984,
20230116, 1800, , TS, 37.8N, 63.6W, 55, 982,
20230117, 0000, , TS, 39.8N, 61.8W, 55, 980,
20230117, 0600, , TS, 42.4N, 60.7W, 55, 980,
20230117, 1200, , TS, 45.3N, 60.1W, 45, 983,
20230117, 1305, L, TS, 45.9N, 60.0W, 40, 984,
20230117, 1800, , LO, 48.3N, 59.7W, 35, 988,

* Going by the satellite images, it first developed as an independent system at about 1200Z January 15.

* At first, there was no deep convection, but it started to develop just after 0000Z January 16. Before 0600Z, it had completely been surrounded by such. As it was non-frontal and warm core, I believe it became a tropical cyclone at 0600Z January 16, as a 50 kt tropical storm.

* A subtropical classification could be argued, but I think it was convective enough and there was no real trough impact that tropical is more appropriate.

* Yes, it developed an eye feature and you could argue for T4.0 on Dvorak. However, the cold water meant that it likely did not bring the strongest winds down most effectively. Hence, I estimate the peak intensity was 55 kt. The pressure of 980 mb is based on the Sable Island reading which just missed the core.

* It started to weaken before reaching Nova Scotia, but radar and satellite imagery suggest it was still holding on to deep convection despite the cold water. The temperature did rise by a few degrees as the core moved over land at about 1305Z, which supports a shallow warm core system. For that reason, I think it was borderline on whether to classify as tropical storm or remnant low (it was clearly non-frontal, so extratropical is not appropriate). I went with tropical at landfall, based on the temperature trends. At that point, I think the winds were 40 kt, of which were only over water. (Wreckhouse winds cannot be used for analysis as they are not representative of the true intensity.)

* At 1800Z January 17, I estimate it became a remnant low as the convection decreased, although that was likely while or shortly after crossing Nova Scotia.
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Re: ATL: INVEST 90L - Discussion

#139 Postby wxman57 » Tue Jan 17, 2023 2:31 pm

First appearance by Bones this year:

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Re: ATL: INVEST 90L - Discussion

#140 Postby Teban54 » Tue Jan 17, 2023 2:41 pm

wxman57 wrote:I agree that this appeared to qualify for an upgraded to a subtropical storm with about 50kt wind, so why didn't the NHC upgrade it and start advisories? I've heard two reasons from sources at the NHC.

1. The storm would be a short-lived marine threat and could be handled by standard marine warnings. Its impact on Nova Scotia is considerably less than from the very large low over the area already. Eastern Nova Scotia is reporting a west wind at 15-20 kts as it passes. No big deal. Small storm with minimal impact to shipping.

2. Staffing issues. I heard that a number of forecasters were out on vacation and remaining staff were too busy to issue advisories every 6 hrs with intermediate updates.

I know that one forecaster in the analysis branch started Dvorak estimates on Sunday (1.0 then), but those Dvorak estimates were discontinued Sunday night by the next forecaster.

Clearly, the NHC had determined early on that this would be a minimal threat and that issuing advisories would not be any significant benefit to the general public or shipping. This fits within the NHC's primary goal of public safety. Issuing advisories above the standard marine warnings would not increase public safety. The NHC's goal is not to immediately name everything possible so that the database is always accurate. They can go back and review the storm and decide if it should be added to the data record at the end of the 2023 season.

If that's the case, I wonder why staffing issues didn't stop Alex 2016 from being named.
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