2023 Atlantic Hurricane season

[NorthHillsWx]

This started showing up a few days ago but current storm (Philippe) looks to continue running headfirst in a wall of shear. The trailing wave (91l) actually benefits from this as the predecessor storm creates a break in the shear. The two systems go through a complex interaction, somewhat like a fujiwhara effect, before Philippe becomes a remnant low and the trailing system takes over as the dominant storm. Given the complexity of this interaction, guidance for 91L is all over the place. It seems a quicker weakening of Philippe may ultimately lead to a stronger trailing system. I expect heavy swings in model track guidance over the next couple of days as 91L seems tied to Philippe’s fate both from a track and intensity perspective. If 91L remains weak and not vertically stacked, it may take the southern route and get close to the islands. If it strengthens more, it seems to feel Philippe and get pulled north towards the break in the ridge quicker. Time will tell 

[TheDreamTraveler]

On 9/24/2023 at 5:24 PM, nycwinter said:

i think as of right now idalia will be the only storm to be retired..

Idalia might not have even been a major when it made landfall. It was one of the most hyped up storms I've seen in years that did way less damage than what was forecast due to it rapidly weakening hours before landfall. There really wasn't any widespread catastrophic damage to warrant it being retired. It also helped it hit one of the least populated areas of Florida. I'd be surprised if it got retired.

[Superstorm93]

On 7/5/2023 at 10:38 AM, Superstorm93 said:

The new Euro seasonal model continues to show an exceptionally active remainder of the season. Little skeptical, but it's going to be rather interesting to watch this unfold over the next two months.

I suppose we could rack up some ACE with several long-tracked Cape Verde storms if we have more intra-seasonal forcing than the giant WP standing wave, 

Pretty wild how well some of the seasonal forecast models performed this year. The enhanced activity from the MDR and into the sub-tropics was pretty much nailed from the start of the season. 

[Superstorm93]

On 9/26/2023 at 5:26 AM, TheDreamTraveler said:

Idalia might not have even been a major when it made landfall. It was one of the most hyped up storms I've seen in years that did way less damage than what was forecast due to it rapidly weakening hours before landfall. There really wasn't any widespread catastrophic damage to warrant it being retired. It also helped it hit one of the least populated areas of Florida. I'd be surprised if it got retired.

I mean a rapidly intensifying hurricane in the Gulf deserves some level of hype. We're very lucky with how things panned out and I'd rather have increased awareness that leads to a relatively low death toll than the opposite...

If you want to talk about unnecessary hype then Lee is a storm that was blown way the hell out of proportion. 

[GaWx]

52 minutes ago, Superstorm93 said:

Pretty wild how well some of the seasonal forecast models performed this year. The enhanced activity from the MDR and into the sub-tropics was pretty much nailed from the start of the season. 

Although not at all resembling a typical moderate to strong El Niño in terms of ACE and # of systems, it has resembled El Niño in terms of dominant general tracks due to a weaker than average Bermuda high. Fortunately, only one of six hurricanes to this point made landfall at that strength along with minimal casualties (though any is too many) from the one that did, Idalia.

[MJO812]

This is a change from past runs where the models had Phillipe staying way out to sea.

[olafminesaw]

38 minutes ago, MJO812 said:

This is a change from past runs where the models had Phillipe staying way out to sea.

Really hard to predict track with the system behind it having some influence and possibly Fujiwara effect. A weaker system should come more south though and they are leaning hard on the Euro

[GaWx]

1 hour ago, MJO812 said:

This is a change from past runs where the models had Phillipe staying way out to sea.

There’s very likely not going to be much left of Philippe once getting close to PR if it takes this track instead of recurving. It would pretty much be a nonentity with it sheared to near nothing as this NHC map shows. OTOH, a recurve would keep it going much longer and possibly allow for restrengthening. See the 12Z GFS for example.

[Floydbuster]

As long as Philippe dissipates by the Caribbean and doesn't bring some kind of vorticity into the Northwest Caribbean. 

[Ed, snow and hurricane fan]

Unless something changes Florida looks safe into mid-October from Caribbean systems.  Not only is shear across the Gulf strong per GEFS the entire run, it has a NW component to it.  SW shear could at least ventilate a system lifting into the Gulf.  SW shear didn't impact Ian negatively very much when it entered the Gulf.  But NW shear and dry air should mitigate the risk for a strong Gulf system.

[NorthHillsWx]

As of this writing, the North Atlantic basin has exceeded an ACE value of 123. This is the value typically associated with an “average” season. I do not think many people predicted an above average ACE season, much less with more than a month to go and two active storms. Add in 18 named storms with 3 becoming major hurricanes (all cat 4+) and this has been an extremely active year. For an El Niño season (specifically a strong El Niño) this is absolutely unprecedented. 

[NorthHillsWx]

If you read CSU’s prediction, it was pretty spot on. My only critique to this point is they called for an ACE of 160 with 18 storms. We are well below that with 18 storms due to many weak and short lasting named systems this year. However, their forecast reasoning played out in the face of ENSO and I think it was truly an impressive call, especially to increase their prediction during a period when the basin was completely inactive.

[MattPetrulli]

[MattPetrulli]

 

[Ed, snow and hurricane fan]

Euro weeklies have a small chance something leaks into the S GOMEX from the Pacific, and an even smaller chance of something forming/leaking into the Caribbean.  It seems to be saying season over.  Euro enembles seem to support the slight chance of something weak in the S. GOMEX

 

Or I still think there is a very small chance, below a normal October, for a Florida storm.  First real cold front of the season in Texas is 2 weeks late, but the season is over here.  But temps only in the 70s and undefeated teams playing college football at the State Fair of Texas, the end of another dead Texas season is less depressing to my inner weenie than usual.  That, and with the set up we were lucky to get a Deep South Texas late developer.  Death ridge could have been no season at all.

[Ed, snow and hurricane fan]

Morning HGX discussion mentioned Pacific system, shredded crossing the Sierra Madre, possibly developing into a hybrid low in the Gulf.  Sensible weather for Texas little to none, but I could see a Florida rainstorm in a week.  (1000 mb/40 knot STS type rainstorm)

[NorthHillsWx]

With Philippe continuing (albeit a disorganized mess) the streak of an active Atlantic storm continues. Since August 20, there has not been an advisory cycle without an active system. Further, with models now showing development of the next wave coming off Africa, it will be a race to see if that development occurs prior to Philippe’s extratropical transition. What a streak regardless 

[NorthHillsWx]

As if on cue- Philippe was finally downgraded and the streak is over

[WxWatcher007]

Moving into fall mode now. Aside from Idalia, finally a quiet year with regard to US impacts. Not expecting that to change at this point. 

[Normandy]

That streak might come to an end soon with the BOC system.  Looks like another weak shorty which is on brand for the year

[olafminesaw]

The wind shear over the SE US is incredible. Not sure I've seen values over 100 before.

[Ed, snow and hurricane fan]

CV lemon mid October.  7 days cone of development looks like an August CV lemon.

[Windspeed]

CV lemon mid October.  7 days cone of development looks like an August CV lemon.

Need to watch placement of the ridge. This might actually get driven into the E. Caribbean.

[Windspeed]

GFS is back to CAG/WCARIB shenanigans.

[andyhb]

12z guidance, particularly the Euro, are not painting a pretty picture for 94L regarding the Antilles. MDR upper air pattern is amazingly favorable for it this late in the season in an El Nino year, plenty of heat content/warm SSTs to work with as well.

[Floydbuster]

Wow do those EURO ensembles make Invest 94L a monster hurricane in the Caribbean. 

[GaWx]

Going back to 1950, here are the latest TS+ hits from the east on the Lesser Antilles:

- Alice of 1954 was cat 1 H in Leewards Jan 2 moving WSW:

 https://en.m.wikipedia.org/wiki/Hurricane_Alice_(December_1954)

 

- Tomas of 2010 was 100 mph cat 2 H in Windwards Oct 30:

https://en.m.wikipedia.org/wiki/Hurricane_Tomas

 

- Helena of 1963 was TS in Leewards Oct 26-7:

*During El Nino*

https://www.meteo-tropicale.fr/en/detail-du-systeme-meteo/?Storm=AL091963

 

- Jose of 1999 was cat 1 H in Leewards Oct 20:

https://en.m.wikipedia.org/wiki/Hurricane_Jose_(1999)

- Joan of 1988 was TS in Windwards Oct 15:

https://en.m.wikipedia.org/wiki/Hurricane_Joan–Miriam

 

- Gonzalo of 2014 was cat 1 H in Leewards Oct 13:

*During El Nino*

https://en.m.wikipedia.org/wiki/Hurricane_Gonzalo

[Windspeed]

Two camps diverge around day three. However, it is important to note that the GFS struggles with developement of 94L despite the potential favorable setup that may be in place. The ECMWF and CMC both like and pick up on development. Clearly, the EPS suites show multiple scenarios of a hurricane traversing the Lesser Antilles. The camps that split do so over differences in modeling of the mid-level steering flow between a stronger versus weaker ridge just north of the MDR. Also, whether the placement of a ULL being in a favorable position to ventilate versus impact on motion of the potential TC.

If you split hairs, you get a strong TS near the NE Antilles. Obviously, a stronger ridge combined with a stronger hurricane gives us all the EPS members screaming major impacts from Barbados to Puerto Rico. It's still quite early, though. The GFS/GEFS camps could quickly swing towards the Euro and Canadian solutions in the coming days, or vice versa.

OHC is plenty high in the western MDR for a strong hurricane. Just need to watch for atmospheric conditions and any potential mid-level shear.

[GaWx]

 I can now add pre-1950 latest Lesser Antilles TS+ hits on record. What’s odd is that while there are none on record for Oct 10+ for the years 1899-1942, there are a whopping 7 just during the 12 year period of 1887-1898, including three during El Niño!

 Starting from latest:

- Dec 7, 1887, TS Windwards *during weak El Nino*
- Nov 27-9, 1896, TS Windwards to Leewards *during strong El Nino*
- Nov 27-8, 1878, TS Leewards
- Nov 1-2, 1888, TS Windwards to Leewards *during superstrong El Nino*
- Oct 29, 1867, 110 knots cat 3 H Leewards
- Oct 27, 1898, TS Leewards
- Oct 15, 1895, TS Windwards
- Oct 12, 1891, TS Windwards 
- Oct 11-12, 1894, H (cat 1?) Windwards to Leewards 
- Oct 11, 1943, TS Windwards

[GaWx]

12Z UKMET for 94L has TS getting to 100 miles N of N Leewards moving NW:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER  96 HOURS
              FORECAST POSITION AT T+ 96 : 12.1N  44.5W

                        LEAD                 CENTRAL     MAXIMUM WIND
      VERIFYING TIME    TIME   POSITION   PRESSURE (MB)  SPEED (KNOTS)
      --------------    ----   --------   -------------  -------------
    1200UTC 17.10.2023   96  12.1N  44.5W     1009            30
    0000UTC 18.10.2023  108  12.3N  47.5W     1007            34
    1200UTC 18.10.2023  120  13.0N  50.6W     1006            42
    0000UTC 19.10.2023  132  13.9N  53.4W     1003            48
    1200UTC 19.10.2023  144  15.3N  55.8W     1000            49
    0000UTC 20.10.2023  156  17.0N  58.9W      997            47
    1200UTC 20.10.2023  168  18.8N  61.6W      995            44