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Why The Track Forecast For Hurricane Dorian Has Been So Challenging

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. 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. 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?

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.

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

Today In: Innovation

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.

Professor John Knox, University of Georgia

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.

Dr. Phillippe Papin, U.S. Naval Research Laboratory

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.

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

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.

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Dr. J. Marshall Shepherd, a leading international expert in weather and climate, was the 2013 President of American Meteorological Society (AMS) and is Director of the University of Georgia’s (UGA) Atmospheric Sciences Program. Dr. Shepherd is the Georgia Athletic Association Distinguished Professor and hosts The Weather Channel’s Weather Geeks Podcast, which can be found at all podcast outlets. Prior to UGA, Dr. Shepherd spent 12 years as a Research Meteorologist at NASA-Goddard Space Flight Center and was Deputy Project Scientist for the Global Precipitation Measurement (GPM) mission. In 2004, he was honored at the White House with a prestigious PECASE award. He also has received major honors from the American Meteorological Society, American Association of Geographers, and the Captain Planet Foundation. Shepherd is frequently sought as an expert on weather and climate by major media outlets, the White House, and Congress. He has over 80 peer-reviewed scholarly publications and numerous editorials. Dr. Shepherd received his B.S., M.S. and PhD in physical meteorology from Florida State University.

Source: Why The Track Forecast For Hurricane Dorian Has Been So Challenging

National Hurricane Center director Ken Graham provides an update on Hurricane Dorian. RELATED: https://bit.ly/2NFZCak Dorian’s slow crawl, estimated at about 7 mph on Sunday afternoon, placed it within 185 miles of West Palm Beach, Florida. But forecasters remained unsure of whether, or where, it might make landfall in the U.S. after it makes an expected turn to the north.

That left millions of people from South Florida to North Carolina on alert and preparing for the worst. » Subscribe to USA TODAY: http://bit.ly/1xa3XAh » Watch more on this and other topics from USA TODAY: https://bit.ly/2JYptss » USA TODAY delivers current local and national news, sports, entertainment, finance, technology, and more through award-winning journalism, photos, videos and VR. #hurricanedorian #dorian #hurricanes

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A Tale of Two Communities – People & Fish – Recovering from Harvey By Larry McKinney

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One year after Hurricane Harvey hammered the Texas coast, divergent pictures of recovery and resilience have emerged. The coastal marine communities of fish, shrimp and crabs that thrive along our Gulf coast, are dynamic, resilient and on the mend. The coastal human communities are also dynamic but their resilience is being challenged.

The coastal marine community has an important advantage over coastal human communities — millions of years of evolution driven by hurricanes. Hundreds of hurricanes have entered the Gulf of Mexico since we started keeping track of them, and the Coastal Bend has seen its share. The plants, animals and even the physical landscape of the coast are shaped by hurricanes. It’s survival of the fittest, as the animals so fundamental to ecosystem health — the shrimps, crabs and fish such as red drum and spotted seatrout — all have life cycles that respond well to hurricane-induced stress.

Hurricanes are the giant cement mixer: nutrients and sediments are resuspended, mixed up and flushed from inland reaches into bays and estuaries. Freshwater mingles with saltwater and vice versa. The physical environment also changes; some habitats, like oyster reefs and seagrass meadows, can be buried. Deep pockets scattered across otherwise shallow coastal flats fill in, new ones form, and as the hurricane passes, barrier island passes open and close.

Harvey was different from most hurricanes in that it hit the Texas coast twice. It stalled after landfall, hung around Victoria, then went back into the Gulf over San Antonio Bay, where it sucked up more water, heat and power, moved northeast and slammed into Houston, dumping unforeseen amounts of water over the metropolitan and neighboring areas. The result was really two storms: South Texas had to deal with wind, waves and storm surge, especially from the bayside, but northeast Texas had to deal with massive floods.

The combination of winds, storm surge, low salinity, and low dissolved oxygen had devastating effects on coastal habitats up and down the Texas coast. Floods dumped unprecedented freshwater carrying huge quantities of organics into bays, causing extensive hypoxia. Despite the stress, coastal habitats showed signs of recovery by spring 2018, followed by a genuine bloom through summer.

We saw a burst of new life, particularly in South Texas, as the bays filled with huge schools of juvenile fish. Spotted seatrout grew fat and lazy with so much bounty. Over the next several years the marine ecosystem, as well as anglers and seafood lovers, will reap that bounty. The renewal is reminiscent of a forest fire, which is initially devastating, but recovery brings back a boom of new life.

Our coastal communities also respond with immediacy to hurricanes. While we have not been around so long as the fish and shrimp, we have learned how to survive on the edge of the sea. Our abilities to predict a hurricane’s course and energy has increased impressively, and the emergency responses of coastal leaders and communities are nothing short of heroic. The rush to aid by all after Harvey was inspiring, renewing faith in our neighbors both near and far.

However, as Texas communities continue to recover, our human systems for social support, economic recovery and governance of public resources have faltered. This is particularly evident in South Texas, where we lack the capacity of large cities like Houston. Even there, some neighborhoods are failing to recover from this unprecedented natural disaster.

Our political leadership can muster funding, both short term and for the long haul, but when they leave the coast for their various seats of government and bureaucracy takes over, recovery efforts can break down. Judges, mayors, county commissioners and local leaders have their hands full meeting the immediate needs of their citizens. Adding another “job” to a long list simply does not work.

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The sheer complexity of recovery is mind-boggling. There are dozens of federal, state, philanthropic and private programs offering assistance. However, there is no one-stop shop spanning very different recovery issues. Tough issues persist, such as renters who lost housing; individuals struggling with mental health through recovery; communities trying to rebuild schools and bring back families that have moved away; small businesses that need a jumpstart to rebuild local economies on a shrinking tax base; and what to do when critical infrastructure is privately owned and does not qualify for federal assistance.

Acquiring the planning capacity needed to navigate this complexity while making sure communities are building back in a safer, more resilient way adds further burden. Even in a community like Rockport, which has invested in dedicated staff to address these issues, recovery will be hard-fought for years to come. For those communities that could not make such an investment, the road is hard indeed.

To build long-term resilience, we must better understand the complexities of recovery programs and resources; link them with coastal communities through careful planning that addresses future risks; and integrate these efforts with the environment of which we are a part.

Hurricanes are a reality of coastal life, and people are now part of that coastal ecosystem. If we are to live and thrive on our coastal margins we have understand and adapt to that reality and secure the capital needed to plan for our resilient future. We have a lot to learn from the fishes.

 

 

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