Expert forecasts for 2023 North Atlantic Hurricane Season

[wxman57]

Yes, SAL is close to normal now, very typical of July. I even see some dust over the Gulf of Mexico. There was a brief period in early to mid-June when the trades were at a reduced velocity and SAL was not an issue. That's when Bret and Cindy formed. Both struggled with wind shear. Quite a different environment out there now.

[SFLcane]

Weather channel updated numbers 20/10/5

In my opinion you can't judge a season by July which in most years has 0 named storms

Record Atlantic Ocean Warmth Could Override El Niño Influence

https://twitter.com/weatherchannel/stat ... jITqDzKFmQ

[cycloneye]

UKMET August outlook is out with 19/9/6.

Excerpts:

Issued 01 August 2023

All values given below represent observed activity for the 6-month period from February to July 2023 plus the 6-month GloSea6 forecast activity from August 2023 to January 2024. Note, the official tropical storm season, which usually includes most activity, is from June-November.

The most likely number of named tropical storms (winds of at least 39 mph) predicted to occur in the North Atlantic is 19, with a 70% chance that the number will be in the range 14 to 24. The 1991-2020 long-term average is 14.

The most likely number of hurricanes (winds of at least 74 mph) predicted to occur in the North Atlantic is 9, with a 70% chance that the number will be in the range 6 to 12. The 1991-2020 long-term average is 7.

The most likely number of major hurricanes (winds of at least 111 mph) predicted to occur in the North Atlantic is 6, with a 70% chance that the number will be in the range 3 to 9. The 1991-2020 long-term average is 3. 

An ACE index of 215 is predicted as the most likely value, with a 70% chance that the index will be in the range 120 to 310. The 1991-2020 average is 123.

https://www.metoffice.gov.uk/research/w ... lantic2023

[Category5Kaiju]

UKMET August outlook is out with 19/9/6.

Excerpts:

Issued 01 August 2023

All values given below represent observed activity for the 6-month period from February to July 2023 plus the 6-month GloSea6 forecast activity from August 2023 to January 2024. Note, the official tropical storm season, which usually includes most activity, is from June-November.

The most likely number of named tropical storms (winds of at least 39 mph) predicted to occur in the North Atlantic is 19, with a 70% chance that the number will be in the range 14 to 24. The 1991-2020 long-term average is 14.

The most likely number of hurricanes (winds of at least 74 mph) predicted to occur in the North Atlantic is 9, with a 70% chance that the number will be in the range 6 to 12. The 1991-2020 long-term average is 7.

The most likely number of major hurricanes (winds of at least 111 mph) predicted to occur in the North Atlantic is 6, with a 70% chance that the number will be in the range 3 to 9. The 1991-2020 long-term average is 3. 

An ACE index of 215 is predicted as the most likely value, with a 70% chance that the index will be in the range 120 to 310. The 1991-2020 average is 123.

https://www.metoffice.gov.uk/research/w ... lantic2023

You have to admit, assuming some of these predictions pan out, the University of Arizona may need to be thrown a special celebration.

[SFLcane]

i mean phil k has 9 hurricanes forming so not to far from ukmet as crazy as it might sound.

[cycloneye]

Let's see what CSU does in their outlook next thursday. wxman57, do you have advance word?

[Emmett_Brown]

The Met Office forecast of 215 ACE is bold

[USTropics]

The Met Office forecast of 215 ACE is bold

The ACE forecast is a bit misleading, seems it just takes the lower bound (120) + the upper bound (310) and divides this value by 2. 310 isn't a very realistic ACE value for the upper bound. Main takeaway would be even the lower bounds of this forecast (120) would be an above-average season.

[Woofde]

UKMET August outlook is out with 19/9/6.

Excerpts:

Issued 01 August 2023

All values given below represent observed activity for the 6-month period from February to July 2023 plus the 6-month GloSea6 forecast activity from August 2023 to January 2024. Note, the official tropical storm season, which usually includes most activity, is from June-November.

The most likely number of named tropical storms (winds of at least 39 mph) predicted to occur in the North Atlantic is 19, with a 70% chance that the number will be in the range 14 to 24. The 1991-2020 long-term average is 14.

The most likely number of hurricanes (winds of at least 74 mph) predicted to occur in the North Atlantic is 9, with a 70% chance that the number will be in the range 6 to 12. The 1991-2020 long-term average is 7.

The most likely number of major hurricanes (winds of at least 111 mph) predicted to occur in the North Atlantic is 6, with a 70% chance that the number will be in the range 3 to 9. The 1991-2020 long-term average is 3. 

An ACE index of 215 is predicted as the most likely value, with a 70% chance that the index will be in the range 120 to 310. The 1991-2020 average is 123.

https://www.metoffice.gov.uk/research/w ... lantic2023

6 major hurricanes is a wild prediction for any year, let alone an El nino year. I know there are record breaking ssts, but the Atlantic hurricane season just isnt very long. 2005 and 2020 with seemingly perfect background states still only managed to reach 7 majors total. I just have a hard time imagining an El nino year, even if weakly coupled reaching that same level. It's definitely feels like that part of the season where you can finally see the players on the field clearly, but no one really knows how exactly it'll pan out.

[Blown Away]

If the Ukmet is correct, 2023 will be the most studied hurricane season of all time.

[Category5Kaiju]

If the Ukmet is correct, 2023 will be the most studied hurricane season of all time.

It’ll also become a year like 2004, 2005, or 2017 that is relentlessly tossed around by Storm2k members

[NotSparta]

If the Ukmet is correct, 2023 will be the most studied hurricane season of all time.

It’ll also become a year like 2004, 2005, or 2017 that is relentlessly tossed around by Storm2k members

Could you imagine if it actually somehow met the expectations of some of these ultra-generous forecasts like UKMET? You wouldn't be able to have a seasonal discussion with an El Nino setting in without someone bringing up 2023

[SFLcane]

 https://twitter.com/philklotzbach/status/1686765826647752705

[cycloneye]

 https://twitter.com/philklotzbach/status/1686771668088479744

[cycloneye]

Accuweather is up with 13-17 named storms that is an increase from the March one of 11-15.

Excerpts:

El Niño developed in early June, and while it is related to warm water in the Pacific Ocean, it can have a ripple effect in the atmosphere that results in more disruptive winds across the Atlantic Ocean. Typically, El Niño results in fewer tropical systems in the Atlantic compared to La Niña, but the full effect of the pattern shift can be delayed.

"There's a lag between La Niña and El Niño," Kottlowski explained.

This lag means that the first half of the 2023 Atlantic hurricane season will likely have more named storms and hurricanes than the second half.

"Please get your hurricane plan in place because we could get very active in late August into September," Kottlowski added.

While fewer tropical systems are predicted to spin up in October and November, this part of the season may not be completely quiet.

The other driving factor behind the update to AccuWeather's hurricane forecast is the widespread warmth in the areas where tropical systems typically track.

"Water temperatures across the Atlantic Basin are at record levels," AccuWeather Meteorologist Alex DaSilva said. For instance, a marine heat wave has pushed sea surface temperatures to extreme levels near South Florida.

The warmer water means the tropical systems have a higher chance of development and rapid intensification.

https://www.accuweather.com/en/hurrican ... F3zt2XIXG8

[wxman57]

AccuWeather's numbers of 13-17 NS, 4-8 H, and 1-3 MH, basically 15/6/2, which is below the 30 yr climo of 14/7/3 as far as hurricanes and majors. Considering we're already at 5/1/0, they are forecasting 10/5/2 for the rest of the season. That would be fairly quiet. I' still going with 19/8/3 (14/7/3 remaining after counting storms so far). Hopefully, they are all out to sea.

I was conversing with Klotzbach this morning. He said that wind shear across the MDR is pretty close to what would normally be expected this time of year.

[SFLcane]

AccuWeather's numbers of 13-17 NS, 4-8 H, and 1-3 MH, basically 15/6/2, which is below the 30 yr climo of 14/7/3 as far as hurricanes and majors. Considering we're already at 5/1/0, they are forecasting 10/5/2 for the rest of the season. That would be fairly quiet. I' still going with 19/8/3 (14/7/3 remaining after counting storms so far). Hopefully, they are all out to sea.

I was conversing with Klotzbach this morning. He said that wind shear across the MDR is pretty close to what would normally be expected this time of year.

But, but , el nino lol..Those banking on it to save us all could be for a surprise in a few weeks. we shall see

[Teban54]

https://twitter.com/philklotzbach/status/1686765826647752705?s=20

Wow, that correlation map is almost identical to the current SSTA configuration.

[SFLcane]

We maintain our forecast for an above-average 2023 Atlantic hurricane season. While a
robust El Niño has developed and is likely to persist for the peak of the Atlantic hurricane
season, most of the tropical and subtropical Atlantic has record warm sea surface
temperatures for this time of year. El Niño increases vertical wind shear in the Caribbean
and tropical Atlantic, but the extreme anomalous warmth in the tropical and subtropical
Atlantic is anticipated to counteract some of the typical El Niño-driven increase in
vertical wind shear. The probability of U.S. major hurricane landfall is estimated to be
above the long-period average.



 https://twitter.com/philklotzbach/status/1687116116168978432

[cycloneye]

ABSTRACT
Information obtained through July indicates that the 2023 Atlantic hurricane
season will have activity above the 1991–2020 average. We estimate that 2023 will have
a total of 18 named storms (average is 14.4), 90 named storm days (average is 69.4), 9
hurricanes (average is 7.2), 35 hurricane days (average is 27.0), 4 major (Category 3-4-5)
hurricanes (average is 3.2) and 9 major hurricane days (average is 7.4). These numbers
include the five storms that have formed already this year (January subtropical storm,
Arlene, Bret, Cindy and Don). The probability of U.S. major hurricane landfall is
estimated to be above the long-period average. We predict Atlantic basin Accumulated
Cyclone Energy (ACE) and Net Tropical Cyclone (NTC) activity in 2023 to be
approximately 130 percent of their 1991–2020 average. We are forecasting the same
seasonal numbers with our August forecast that we predicted in early July.
This forecast is based on two early August statistical models that were developed
using ~40 years of past data. Analog predictors are also utilized. We are also including
statistical/dynamical models based on ~25–40 years of past data from the European
Centre for Medium Range Weather Forecasts, the UK Met Office, the Japan
Meteorological Agency and the Centro Euro-Mediterraneo sui Cambiamenti Climatici
model. The statistical/dynamical models unanimously agrees that the 2023 Atlantic
hurricane season should be hyperactive, while statistical model guidance is calling for
an above-average remainder of the Atlantic hurricane season. We stress that there is
considerable uncertainty with this season’s outlook given the large spread in model
guidance, as well as uncertainty with exactly how El Niño will interact with the
extremely warm Atlantic.
The tropical Pacific is currently characterized by El Niño conditions. The
intensity of the El Niño for the remainder of the hurricane season remains unclear,
although a moderate to strong event seems relatively likely. El Niño typically reduces
Atlantic hurricane activity through increases in vertical wind shear.
Sea surface temperatures across most of the tropical and subtropical Atlantic
remain at record levels, so despite the potential for a moderate/strong El Niño, the
impacts on tropical Atlantic/Caribbean vertical wind shear are likely to not be as strong
as is typically experienced given the extremely warm Atlantic.

An analysis of a variety of different atmosphere and ocean measurements
(through July) which are known to have long-period statistical relationships with the
upcoming season's Atlantic tropical cyclone activity, as well as output from dynamical
models, indicate that 2023 will have above-average activity. The big question marks with
this season's predictions revolve around the strength of El Niño and how anomalously
warm the tropical and subtropical Atlantic is for the peak of the hurricane season. We
stress again that there is greater-than-normal uncertainty associated with this outlook.