2024 Atlantic Hurricane Season Forecasts:

[GordMay]

Extended Range Forecast for North Atlantic Hurricane Activity in 2024:

The team at Tropical Storm Risk [TSR]* anticipate 2024 activity to be 30% above the near-term, and 50% above the long-term [1950-2023] norms.

TSR calls for 20 tropical storms to form, 9 of which becoming hurricanes, and 4 developing into intense or major hurricanes, driving an Accumulated Cyclone Energy (ACE) index of 160.

This outlook has large uncertainties.
Extended range forecasts, for seasonal hurricane activity, can be notoriously lacking in accuracy, but they can provide some insight, into how climate conditions are evolving right now, and what they suggest for the next hurricane season.

The National Hurricane Center and Colorado State University also release forecasts for the Atlantic hurricane season.
NOAA’s Climate Prediction Center, a division of the National Weather Service, will issue its 2024 hurricane seasonal outlook in May 2024.
The Atlantic hurricane season officially begins on June 1.

“Extended Range Forecast for North Atlantic Hurricane Activity in 2024" ~ by TSR
Issued 11th December 2023 ➥ https://www.tropicalstormrisk.com/

[GordMay]

Seasonal Hurricane Predictions Skill/Accuracy [NOAA, CSU, TSR]:

The accuracy of a particular prediction will vary, depending on how long before the start of the season, it was generated.
Generally, the closer to the start of the hurricane season a prediction is produced, the higher its accuracy will be. For example, a prediction issued in August will have, in general, higher accuracy than a prediction issued in April.

Below, the real-time skill of seasonal forecast schemes, used by different forecasters, for over one decade is shown.
Forecasts displayed here are issued by the Colorado State University (CSU), the National Oceanic and Atmospheric Administration (NOAA) and Tropical Storm Risk (TSR).
The period compared in this analysis is 2003-2015, which is a time period when all three forecast agencies were utilizing relatively similar techniques for issuing these predictions.

Skill ➥ https://seasonalhurricanepredictions...ormation/skill



FWIW: Any time you read an investment prospectus, you're going to come across a phrase, that is close to this: “Past success does not guarantee future performance”, per SEC Rule 156:
The principles, behind this advice, apply to many other aspects of evaluation & decision making.

17 CFR § 230.156 - Investment company sales literature

”... (2) Representations about past or future investment performance could be misleading because of statements or omissions made involving a material fact, including situations where:
...”

➥ https://www.law.cornell.edu/cfr/text/17/230.156

An interesting perspective on past performance advertising:
“MUTUAL FUND PERFORMANCE ADVERTISING: INHERENTLY AND MATERIALLY MISLEADING?” ~ by Alan R. Palmiter & Ahmed E. Taha
➥ https://digitalcommons.law.uga.edu/c...11&context=glr

[MicHughV]

Predicting how many hurricanes is one thing, but trying to predict where a hurricane will make landfall is pretty much a throw of the dice imo.

And that...to me....is the key. We know that each year brings hurricanes, that is a given, we just don't know where they will hit.

As a Florida resident, I've seen some pretty wild years, near misses, wobble tracks, last minute course change, direct hits, etc...

While predictions can "estimate" whether a hurricane might be a Cat 1 or a Cat 5, this is another throw of the dice imo, and this is also a big ??? as a Cat 1 hurricane is quite survivable, while a Cat 5 is not.

To give the NHC credit, we do have a very long advance warning these days, with reasonable accurate course predictions, to give one ample time to make a decision one way or another.

[GordMay]

Given the [almost] infinite number of possible initial data-point data, and the few, we actually collect, and the chaotic nature of climate/weather; I am amazed at the accuracy achieved, in hurricane prediction.


In all, the National Hurricane Center lists 27 different weather models.
The Hurricane Center breaks some of these models into categories: dynamical models, statistical models, and ensemble and consensus models.
The two we hear about most, are an American model, known as the Global Forecast System [GFS]; and the European model [ECMWF], which is the European Center for Medium-Range Weather Forecasts. The two global models are considered the best in the world, and are often pitted against one another. Experts generally agree the European model, has a slight edge, over the GFS. But, The Euro can forecast 10 days out, while the GFS can model 16 days out.
The Hurricane Center’s forecast generally takes the average of five or six of the world’s most accurate weather models, to create its forecast.

Over the past few decades, the National Hurricane Center's one- to three-day track forecast errors have diminished by 75%, with reductions of about 60% over the past 20 years at four- and five-day lead times.
In 2022, NHC track forecasts set accuracy records at most lead times.

In 1980, the average forecast error, for location, was 125 miles, just 24 hours ahead of time. The two-day forecast was off an average of 275 miles, and the three-day average was 400 miles.

The official National Hurricane Center 2021 forecast bested all individual models, and equaled the best model blends, at all lead times. Crucially, NHC forecasts are also far more consistent, than any individual model, which typically jump around 100 miles, or so, each six hours, for a four-day forecast. NHC four-day forecasts are not only more skillful than individual models, but shift less than 60 miles, on average, between advisories.
More ➥ https://yaleclimateconnections.org/2...1-performance/

NATIONAL HURRICANE CENTER FORECAST VERIFICATION REPORT 2021 HURRICANE SEASON
➥ https://www.nhc.noaa.gov/verificatio...ation_2021.pdf

Hurricane Forecast Model Accuracy
➥ https://hurricanescience.org/science...ill/index.html

How hurricane forecast accuracy has improved over the years
➥ https://www.13newsnow.com/article/we...9-350261a03699

[Montanan]

It is February. Let's discuss this year's hurricane season forecast.

Hurricane season arrives after snowicane season.

[MicHughV]

What gets me is the so-called "spaghetti'" tracks of various weather computing models.
There is certainly a wide disparity among these.
The "euro" model has consistently been one of the more accurate systems.

Nonetheless, the predicted " track" with it's ever widening limits for each day is interesting.

While much is made of the wind speed, the accompanying tidal surge is often the more calamitous (is that a word ?) than wind damage.

I have taken it on myself to visit areas hit by a hurricane to see with my own eyes the damage caused and have seen some spectacular scenes.

Though I've never been impacted by a direct hit, I have had several come relatively close by.....eye being 100 odd miles away. Enuff to give one a taste of what could have been.

Off interest too, are the local weather channels with their respective weatherman/woman giving their take on what might or might not be expected.
Every TV channel have their respective in-the-field reporter hanging on to lamp poles, etc, for dramatic affect.

Interesting topic !!

[Montanan]

The hurricane cone graphic is changing this year.

https://www.cbsnews.com/miami/news/t...hy-its-needed/

[MicHughV]

Back in the day, I was quite intrigued by hurricanes as I was often called upon to design a seawall or other maritime structure strong enough to withstand a hurricane impact in my professional career as a structural marine engineer.

But there is a practical limit to what you can do, and most ships leave port if a hurricane strike is imminent.

Interestingly enough, in my area along the coast, most people carry hurricane insurance on their homes, that is to say, if a hurricane wind blows the roof of your house and floods or destroys everything you own, you'll be covered.
On the other hand, if the roof stays on and a tidal surge comes thru' a window or backdoor and floods or destroys everything you own, you will not be covered, as that requires "flood" insurance, an additional insurance rider needed.
Many people are caught unaware of this difference.

[GordMay]

Originally Posted by MicHughV

What gets me is the so-called "spaghetti'" tracks of various weather computing models.
There is certainly a wide disparity among these...

The term spaghetti models [plots] refers to a visual comparison, of either:
* multiple forecast models [consensus models],
or
* multiple variations of just one model [ensemble plot],
using lines, that
show potential tropical cyclone paths,
given the data available, at the time [a particular set of starting conditions].

Spaghetti plots are often shown in media, as a way of indicating the degree of uncertainty [confidence], in the storm-track predictions. When clustered together, forecast confidence is high.

These models don’t show any representation of intensity, or size of a particular storm, nor do they speak to whether a storm will bring rainfall, hurricane-force winds, surge, or other data; they just contain information about the centre of a storm’s future track, and, perhaps, a loose approximation of timing [of it’s arrival].

Some weather models are built on statistics, some on atmospheric dynamics, others are built on other models, and others yet, called the CLP5 [the CLImatology and PERsistence model and the XTRP (Extrapolated model)] are built entirely on climatology and persistence of the current atmosphere. The CLP5 uses past weather situations [analogs], to diagnose what similar storms have done, in the past. The XTRP simply extends the storm’s recent forward motion, out to five days, and is always a straight line.

The statistical-dynamical weather models are a little more complex. These models combine statistics such as storm location, time of year, and what hurricanes of the past have done with simple dynamics such as steering flow. This suite includes the SHIPS and LGEM models, which are largely intensity models.

The most complex are the dynamical weather models, which take into account the current state of the atmosphere, using observations from the ground, ocean and air, as well as complex physics equations, to forecast the atmosphere. This suite of models includes the AVNO [GFS], ECM [EURO] and the hurricane models [HWRF and HMON], among many others.

Notable Tropical Models [From the NHC]
Model Name, Type & Main Use
American GFS Dynamical Global Model
ECMWF or Euro Dynamical Global Model
CMC Dynamical Global Model
UKMET or EGRR Dynamical Global Model
HWRF Dynamical Hurricanes
HMON Dynamical Hurricanes
GEFS/AEMN GFS Ensemble/Consensus Global Models/Estimate of Model Confidence
EEMN EuroEnsemble/Consensus Global Models/Estimate of Model Confidence
TVC# Track Consensus Estimate of Forecast Confidence
ICON Intensity Consensus Estimate of Forecast Confidence
TABs Trajectory Estimate of Shear
LBAR Basic Dynamical
CLP5 Statistical Climatology

“Why can't we predict weather with 100% accuracy?”
Computer models of the atmosphere are approximations.
The atmosphere is huge, and our supercomputers are relatively small.
Because our computer models are so coarse, we need to make further approximations.
Even if our weather forecasting models were perfect, we don't have enough observations of the atmosphere to know exactly what it is right now.
All observations have errors.
Finally, and perhaps most importantly, the atmosphere is chaotic.
More ➥ https://www.reddit.com/r/askscience/...edict_weather/

NHC Track and Intensity Models
➥ https://www.nhc.noaa.gov/modelsummary.shtml

NWS Model Analyses and Guidance [MAG] User's Guide
➥ https://mag.ncep.noaa.gov/help/index.php

[MicHughV]

Well, Gord, as per usual, you have summed it up quite nicely.

Reminds me off a weather predicting sign I saw somewhere....

It said...
If sign is wet, it's raining.
If sun is dry, sun is shining.
If sign is moving, it's windy.
If sign is gone, a hurricane took it..

[GordMay]

I’m glad to see we’re on the same page[s], MicHughV.
To whit:
I installed a “Weather Rock” at Club Thunderball [now defunct], back in the 1990s, accompanied by a sign indicating how to read it:
•If the rock is wet, it's raining.
•If the rock is swinging, the wind is blowing.
•If the rock casts a shadow, the sun is shining.
•If the rock does not cast a shadow and is not wet, the sky is cloudy.
•If the rock is difficult to see, it is foggy.
•If the rock is white, it is snowing.
•If the rock is coated with ice, there is a frost.
•If the ice is thick, it's a heavy frost.
•If the rock is bouncing, there is an earthquake.
•If the rock is under water, there is a flood.
•If the rock is warm, it is sunny.
•If the rock is missing, there was a tornado.
•If the rock is wet and swinging violently, there is a hurricane.
•If the rock can be felt but not seen, it is night time.
•If the rock has white splats on it, watch out for birds.

And ➥ https://www.cruisersforum.com/forums...html#post13966

[GordMay]

Chaos & Weather:
“Does the flap of a butterfly’s wings in Brazil, set off a tornado in Texas?”

The ability to predict distant [> 24 Hrs away] meteorological events is tied with Edward Lorenz’s “Chaos Theory”, described in “Deterministic Nonperiodic Flow” [1].

Small errors in the initial conditions of a forecast grow rapidly, and affect predictability. Furthermore, predictability is limited by model errors, due to the approximate simulation of atmospheric processes of the numerical models.

Initial condition uncertainties [there are an infinite number of variables] are the dominant source of forecast error.

To determine these initial conditions, a large number of initial, but not identical, states are collected.

To near-perfectly succeed over chaos theory, near-infinitely precise measurements must be done, on near-infinitely accurate computers, running near-infinitely accurate differential equations, that accurately model the behavior of Earth's atmosphere.

Given realistic estimates of initial errors, these simulations led to his conclusion that the limit to useful deterministic predictions, of large-scale (synoptic) atmospheric motion, was about two weeks.

He had concluded that the butterfly effect made it impossible to accurately forecast the weather two weeks ahead. Small errors regarding large-scale weather features, such as recording an imprecise location for a storm, would double in magnitude in about 3.5 days.
Errors in observing small-scale weather features, such as imprecisely recording locations of individual clouds, could turn into errors on a larger scale, within a day.

Experimenting in the 1980s [well after his initial discoveries], Lorenz found small perturbations, introduced into a control simulation, grew with a doubling time of about around 3.5 days.

[somewhat] Reliable forecasts are now possible nine to 10 days out, for daily weather, in the mid-latitudes, where most of Earth's population lives.

New technology could add another four to five days, over the coming decades, according to research [2] published online, in the Journal of the Atmospheric Sciences.

"Edward Lorenz proved that one cannot predict the weather beyond some time horizon, even in principle," said Kerry Emanuel, professor of atmospheric science at MIT and coauthor of the study. "Our research shows that this weather predictability horizon is around two weeks, remarkable close to Lorenz's estimate."

[1] “Deterministic Nonperiodic Flow” ~ by Edward N. Lorenz [Mar 1963]
➥ https://journals.ametsoc.org/view/jo...l?tab_body=pdf



[2] “What Is the Predictability Limit of Midlatitude Weather?” ~ by Fuqing Zhang et al
➥ https://journals.ametsoc.org/view/jo...-18-0269.1.xml

See also, the brief explanation:
“Weather, Climate and Chaos Theory” ~ by the Royal Meteorological Society
➥ https://www.metlink.org/blog/weather...-chaos-theory/

[MicHughV]

I agree with the above.

When I first started sailing in my 20's, I had little of anything.
Besides a vhf, I had little else in the line of electronics. Further than 20 miles off shore, the vhf was not of much use and any weather forecasts I was able to receive was local only.

But I had a variety of "weather" books detailing cloud formations and so on, which I read studiously.
I never really worried about the weather much, for as long as the wind blew I was happy and always managed to get where I wanted to go.

Equally, there were days when there was no wind, and I had little choice but to drift with the current.

But I knew that the weather was not likely to be constant and the weather today was usually not what I had the following day, but it mattered little to me as I would just adjust my sails to suit.
Was I lucky ? Maybe....in all my years of sailing, I only once had weather that was really, really bad. I knew not where it came from off course, so just had to deal with it as best I could at the time.

I tend to have a philosophical view about the weather in that it just is what it is. If it's raining, I wear foulies, if the sun is shining, I wear a hat, etc.

I see many sailors agonize and study weather patterns for eons prior to contemplating to go anywhere, looking for that perfect weather window, which rarely occurs.

[GordMay]

Q: What is a zombie's favourite type of weather?
A: A brainstorm.

Q: What do you get, when you clone a cyborg?
A: A cyclone.

Q: What do you call a weather joke, with a bad punchline?
A: An anti-climactic, climatic joke.

[GordMay]

“Explosive Atlantic hurricane season predicted for 2024" ~ AccuWeather
➥ https://www.accuweather.com/en/hurri...s-warn/1633944

“... AccuWeather meteorologists are forecasting 20-25 named storms across the Atlantic basin in 2024, including 8-12 hurricanes, four to seven major hurricanes and four to six direct U.S. impacts. This is all above the 30-year historical average of 14 named storms, seven hurricanes, three major hurricanes and four direct U.S. impacts...”

See also:
➥ https://www.cruisersforum.com/forums...ml#post3887184
➥ https://www.cruisersforum.com/forums...ml#post3887214