Why the track forecast for hurricane Dorian has been so challenging

From Forbes by Marshall Shepherd

Here is something that you can take to the bank.
We will not see the name "Dorian" used in the Atlantic basin for any future hurricane.
The names of particularly destructive or impactful storms are retired.

Seas warmer than 27.8°C (82°F) are generally considered hurricane fuel.  

HurricaneDorian is now at Category 3 strength.

Although the route of Dorian is uncertain, one thing is for sure: it has plenty of warm water on any path it takes.

According to the National Hurricane Center, Dorian is now tied with the 1935 Labor Day hurricane for the strongest Atlantic hurricane landfall on record. In a 3 pm advisory on September 1st, the National Hurricane Center warned of gusts to 220 mph and 18 to 23 feet storm surges for parts of the Abacos.

I have been in the field of meteorology over 25 years and do not recall seeing warnings about 220 mph gusts for a hurricane.

Hurricane watches have also been issued for Andros Island and from North of Deerfield Beach to the Volusia/Brevard County Line in Florida. At the time of writing, the official forecast from the National Hurricane Center is for a northward curve and no direct Florida landfall.

Hurricane Dorian putting on a lightning show tonight Aug 30th. 
Spectacular imagery.
source Dakota Smith

This is dramatically different from forecasts only a few days ago.

There is still uncertainty with the forecast so coastal Florida, Georgia, and the Carolinas should remain on high alert.

Why has the track forecast been so challenging with Hurricane Dorian?

Hurricane Dorian approaching the Abaco
NOAA/CIMSS

Historically, hurricane track forecasts have outpaced intensity forecasts.

I discuss the reasons why in a previous Forbes article at this link. With Hurricane Dorian, uncertainty about the forecast track and timing of the storm forced officials to move the Florida State - Boise State football game from Jacksonville, slated for a 7 pm kickoff on Saturday, to noon in Tallahassee.

I am certain that many businesses and people are questioning the move given that timing of when impacts are now expected.

Unfortunately, officials and emergency managers often must make decision on the best information at the moment.

Some people may be tempted to use uncertainty with this forecast to spew vitriol or skepticism at meteorologists and our models.

However, challenges with Hurricane Dorian's track forecast do not define the legacy of weather forecasts.

It would be silly to say that the NFL's best field goal kicker is terrible based on a few misses.

 NOAA's GOES-East took this image of Hurricane Dorian the evening of September 1, 2019.
see animation

So what's going on? I asked a panel of tropical meteorology experts.

Speed of motion of Hurricane Dorian has been a significant challenge.

Professor John Knox, a recent recipient of the American Meteorological Society's Edward Lorenz Teaching Award, offers an important lesson.
The University of Georgia atmospheric sciences professor pointed out:

Before you bash the meteorologists for being stupid: one reason the forecasted track has changed is because the forecasts of the forward speed of Dorian have slowed it down more and more.
If it had chugged along as originally forecast, it likely would have hit east-central Florida and then maybe gone into the Gulf, before the high pressure above us in the Southeast would break down.
But, because it's moving more slowly, the high-pressure break down is opening the gate, so to speak, for Dorian to go more northward and eastward.
So, the change in forecast is tied tightly to the arrival timing.

Dr. Phillippe Papin is an Atmospheric Scientist and Associate Postdoctoctor Scientist at the U.S.
Naval Research Laboratory.
Papin also points to the high pressure as being a factor.

He wrote:

the ridge to the north of Dorian has been steering Dorian off to the west the last few days....But there is a weak trough that is swinging into the eastern US that is going to erode the strength to the ridge enough so that a gap forms to the north of Dorian and it begins to move further to the north.

The timing of when that weakness develops and on how far Dorian makes it west in the meantime has been the source of uncertainty in the model guidance for the last 2-3 days according to Papin.

At the time of writing, there is still some spread in the model solutions.

Interaction of high pressure ridging with Hurricane Dorian

Philippe Papin

Dr. Michael Ventrice is a tropical weather expert with IBM and The Weather Company.He has been concerned about the storm environment and how well the models are capturing the rapidly evolving situation.

He told me:

I believe the uncertainty is derived from how the models are resolving Dorian, locally.
The recent intensification of the storm today is not being resolved by the models properly at the time of the 12z initialization.
The interaction with the Bahamas, how that interaction might alter the mesoscale structure of the Hurricane, if that interaction induces a wobble, are all valid questions at this point in time
Michael Ventrice — IBM/The Weather Company

A hurricane of this size and intensity can certainly modify its environment and be modified by that environment.

Sam Lillo, a doctoral candidate at the University of Oklahoma, tweeted an interesting point on the afternoon of September 1st about how worrisome the rapid intensification and track uncertainty of Hurricane Dorian has been:

The track uncertainty in NWP at under 3-day lead-time is very uncomfortable, especially considering proximity to land. This would be uncomfortable for any hurricane. But then make it a category 5.
Sam Lillo, doctoral candidate in meteorology at the University of Oklahoma

 Following hurricane Dorian through wave height
Hurricane Dorian, the most powerful hurricane to hit an Atlantic island on record - projected significant wave height of 11.2 metres by September 5th, from Copernicus Marine Service Waves model.

Our best models have oscillated (and in some cases continue to do so) within the past 24-36 hours on just how close Dorian will get to Florida before curving northward.

Lillo offers some further insight into what Dr. Ventrice was alluding to about the environment:

As Dorian strengthened faster than expected, diabatic outflow developed an upper level anticyclone to the southwest, adding southerly and westerly components to the steering flow.
The westerly component in particular slowed the forward motion of the hurricane, and now its track across the Bahamas coincides with a trough that sweeps across the Mid Atlantic and Northeast on Monday.
This trough cuts into the ridge to the north of Dorian, with multiple steering currents now trying to tug the hurricane in all different directions.
The future track is highly sensitive to each of these currents, with large feedback on every mile the hurricane jogs to the left or right over the next 24 to 48 hours.
Sam Lillo, doctoral candidate in meteorology at the University of Oklahoma

Lillo offers a nice meteorological explanation.

In a nutshell, he is saying that the rapid intensification perturbed the near-storm environment and now there may be other steering influences besides the ridge of high pressure that the models are struggling to resolve.

In a previous Forbes piece last week, I mentioned that forecasts in the 5+ day window and beyond can have errors of 200 miles and that the information should be used as "guidance" not "Gospel." Because there is still uncertainty with the models and Dorian is such a strong storm, residents from coastal Florida to the Carolinas must pay attention and be prepared to act.

I have complete confidence in my colleagues at the National Hurricane Center, and they should always be your definitive source with storms like this.

They still maintain an eventual curve northward before the storm reaches the Florida coast.

However, the issuance of hurricane watches in Florida also indicates that they know the margin of error is razor thin.

Links :

• WSJournal : Why Hurricane Dorian Is So Hard to Track
• NYTimes : Hurricane Dorian forecast map / Those Hurricane Maps Don’t Mean What You Think They Mean
• CTVnews : How forecasters track Hurricane Dorian
• NPR : Historic Hurricane Dorian Bears Down On Northern Bahamas As A Category 5 Storm
• LiveScience : Why Is Hurricane Dorian's Path So Tricky to Predict?
• The Economist : How global warming makes hurricanes more severe
• CNN : Here's what Hurricane Dorian is expected to do as it approaches land / Will Dorian hit Florida? The path is uncertain but officials say to get ready 

The Balmain bug: historic six foot skiff

'Too much sail and not enough boat' is the unwritten axiom that has underpinned the development of the famous Sydney Harbour skiffs for more than 130 years.
And never was that maxim more true than for the smallest of the historic skiffs, the tiny 6 footer sometimes known as The Balmain Bug.
Look out for the full story in Yachting World's 'Extraordinary Boat' series in the July 2017 issue.

Posidonia en las cartas nauticas de Formentera

A turquoise blue sea, white sand banks and the dark green of Posidonia Meadows are the colors with which Formentera receives the visitor.

Purity and Clarity of its waters, filtered by the largest and oldest living being in the world, The Oceanic Posidonia, with its 8 km of extension and 100,000 years of age, was declared a World Heritage Site by UNESCO, offers visitors unique beaches in the Mediterranean.

Posidonia seagrass symbols in rasterized ENC from IHM for the Formentera island

with the GeoGarage platform

IHM paper maps
St. Wd. info for Stones & Weed 

 

Carta nautica de IHM (scale 1:175000)

Campaign “to support” Posidonia
Help with anchorage in the Balearic islands

U.S. cyberattack hurt Iran’s ability to target oil tankers, officials say

The June 20 cyber attack on Iran took out a key database on tanker traffic and curbed,

at least for a time, Iran's ability to launch covert attacks.

From NYTimes by Julian E. Barnes

A secret cyberattack against Iran in June wiped out a critical database used by Iran’s paramilitary arm to plot attacks against oil tankers and degraded Tehran’s ability to covertly target shipping traffic in the Persian Gulf, at least temporarily, according to senior American officials.

Iran is still trying to recover information destroyed in the June 20 attack and restart some of the computer systems — including military communications networks — taken offline, the officials said.

Senior officials discussed the results of the strike in part to quell doubts within the Trump administration about whether the benefits of the operation outweighed the cost — lost intelligence and lost access to a critical network used by the Islamic Revolutionary Guards Corps, Iran’s paramilitary forces.

The United States and Iran have long been involved in an undeclared cyberconflict, one carefully calibrated to remain in the gray zone between war and peace.
The June 20 strike was a critical attack in that ongoing battle, officials said, and it went forward even after President Trump called off a retaliatory airstrike that day after Iran shot down an American drone.

Defying U.S. Sanctions, China and Others Take Oil From 12 Iranian Tankers
The U.S. has been unable to halt Iranian oil exports

Iran has not escalated its attacks in response, continuing its cyberoperations against the United States government and American corporations at a steady rate, according to American government officials.

American cyberoperations are designed to change Iran’s behavior without initiating a broader conflict or prompting retaliation, said Norman Roule, a former senior intelligence official.
Because they are rarely acknowledged publicly, cyberstrikes are much like covert operations, he said.

“You need to ensure your adversary understands one message: The United States has enormous capabilities which they can never hope to match, and it would be best for all concerned if they simply stopped their offending actions,” Mr. Roule said.

Islamic Revolutionary Guards Corps patrolling around a seized British tanker in Bandar Abbas, Iran, last month.

An American cyberattack in June took out a critical database used by the Revolutionary Guards.

Credit : CreditHasan Shirvani/Agence France-Presse 

Cyberoperations do not work exactly like other conventional warfare.
A cyberattack does not necessarily deter future aggression in the same way a traditional military strike would, current and former officials say.
That is in part because cyberoperations are hard to attribute and not always publicly acknowledged by either side, the senior defense official said.

Yet cyberoperations can demonstrate strength and show that the United States will respond to attacks or other hostile acts and impose costs, the official said.

Cyber Command has taken a more aggressive stance toward potential operations under the Trump administration, thanks to new congressional authorities and an executive order giving the Defense Department more leeway to plan and execute strikes.

The head of United States Cyber Command, Army Gen. Paul M. Nakasone, describes his strategy as “persistent engagement” against adversaries.
Operatives for the United States and for various adversaries are carrying out constant low-level digital attacks, said the senior defense official.
The American operations are calibrated to stay well below the threshold of war, the official added.

The strike on the Revolutionary Guards’ intelligence group diminished Iran’s ability to conduct covert attacks, said a senior official.

The United States government obtained intelligence that officials said showed that the Revolutionary Guards were behind the limpet mine attacks that disabled oil tankers in the Gulf in attacks in May and June, although other governments did not directly blame Iran.
The military’s Central Command showed some of its evidence against Iran one day before the cyberstrike.

The White House judged the strike as a proportional response to the downing of the drone — and a way to penalize Tehran for destroying crewless aircraft.

The database targeted in the cyberattacks, according to the senior official, helped Tehran choose which tankers to target and where.
No tankers have been targeted in significant covert attacks since the June 20 cyberoperation, although Tehran did seize a British tanker in retaliation for the detention of one of its own vessels.

The US and Iran are engaged for a long time in an undeclared cyber-conflict, which is carefully remains within the gray zone between war and peace.

Though the effects of the June 20 cyberoperation were always designed to be temporary, they have lasted longer than expected and Iran is still trying to repair critical communications systems and has not recovered the data lost in the attack, officials said.

Officials have not publicly outlined details of the operation.
Air defense and missile systems were not targeted, the senior defense official said, calling media reports citing those targets inaccurate.

In the aftermath of the strike, some American officials have privately questioned its impact, saying they did not believe it was worth the cost.
Iran probably learned critical information about the United States Cyber Command’s capabilities from it, one midlevel official said.

Cyberweapons, unlike a conventional weapon, can be used only a few times, or sometimes even once.
Targets can find the vulnerability used to get access to their networks, then engineer a patch to block that opening.

“Iran is a sophisticated actor.
They will look at what happened,” said Mark Quantock, a retired major general who served as the director of intelligence for the United States Central Command, which oversees operations related to Iran.
“Russia, China, Iran and even North Korea would all be able to see how they were penetrated.”

Cyberstrikes also inevitably cut off access to intelligence that American operatives gained from exploiting that vulnerability, once the adversary discovers and fixes it.
Losing even some access to the Islamic Revolutionary Guards Corps, Tehran’s paramilitary force that is deeply involved with proxy forces around the Middle East, is a high price to pay, according to some officials.

Military and intelligence agencies always weigh the costs of a cyberoperation and the risks of lost information ahead of a strike, according to former officials.
Intelligence officials have long been skeptical of some cyberoperations, worried that the benefits are not worth the costs.

“It can take a long time to obtain access, and that access is burned when you go into the system and delete something,” said Gary Brown, a professor at the National Defense University and former legal counsel for Cyber Command.
“But on the same token, you cannot just use that as an excuse not to act.
You can’t just stockpile access and never use it.”

Links :

• CNET : US cyberattack damaged Iran's ability to target oil tankers, report says
• Business Insider : The US hit Iran with a secret cyberattack to disrupt oil tanker attacks ..
• BankInfoSecurity :  Sizing Up Impact of US Cyberattack Against Iran 
• Forbes : State-Sponsored​ Cyberattacks 'Challenge The Very Concept Of War'
• EurAsiareview : Battle Of Wits: US-Iran Cyber Escalation – OpEd
• technology review :The Middle East is already a cyberwar hotbed. Things just got worse. 
• Safety4Sea : Cyber criminals target the shipping industry, Norway warns
• TechHQ : The great seaborne cybersecurity threat

Belgium (Vlaamse) layer update in the GeoGarage platform

5 nautical raster charts updated

see GeoGarage news