Florida and Georgia: Hurricane Matthew Is Aiming At You Now [Greg Laden's Blog]

Hurricane Matthew has been one of the most interesting hurricanes to ever form in the Atlantic. This storm has exhibited a number of features that are either rare or never before observed.

There are two things you need to know about this storm.

Hurricane Matthew Is Global Warming Enhanced.

Hurricane Matthew is so bad — so strong, formed so quickly, has done so much damaged, and killed so many, and will do so much more damage, and put so many more people’s lives at risk — because of three things that the human release of greenhouse gasses from the burning of fossil fuels have caused.

Matthew formed very quickly. Hurricanes don’t normally form this quickly, but when sea surface temperatures are this high, they do, and over the last few years, we have seen this more and more often, because of anthropogenic global warming caused high sea surface temperatures.

Matthew shrugged off a fair amount of wind shear. Wind shear was supposed to attenuate hurricane and tropical storm formation in the Atlantic, and it does. But the above mentioned effects, probably all three of them, left hurricane experts scratching their heads this time around, as wind shear had less of an effect than expected on this monster storm.

Matthew has grown very strong and did so in a region known as the Hurricane Graveyard. In this region, dry air form the continent and unfavorable winds tend to mess up incipient tropical systems or attenuate hurricanes. The southern Caribbean is kryptonite for hurricanes. But Matthew grew stronger in the so called hurricane graveyard, not weaker, probably owing to all three human caused effects listed above.

Matthew, the storm, may have happened anyway. But Matthew the Major Hurricane happened because of human burning of fossil fuels. This means that when you go to the voting booth less than one month after this storm has finished with us, you should consider voting for candidates, at all levels, who have made a commitment to address global warming.

I do not like the fact that I have to use an impending disaster to make this point. But that is how the system works. I didn’t break the system, and I can’t fix that aspect of it. But I can remind you that Matthew, the Major Hurricane, is an effect of human greenhouse gas pollution, and that you can help solve this problem by the way you vote.

Hurricane Matthew Will Affect Florida, Maybe Georgia, in a Unique And Dangerous Way

Most of the projections for this storm have it affecting the Florida and Georgia coast, then either wandering off into the Atlantic or looping back to about where it is now. Which of these two scenarios is the most likely has changed back and forth a couple of times over the last several hours, as far as I can tell. We won’t know for a few days. In the mean time, the storm is heading for Florida RIGHT NOW and will be there by some time Thursday night. Graphic from Weather Underground:

Different experts are saying different things about the potential strength of the storm. Jeff Masters notes:

Powerful Category 3 Hurricane Matthew has steadily intensified over the warm waters of The Bahamas, and is poised to become a Category 4 hurricane this afternoon…. There is hope, though, that the current intensification cycle may be leveling off. Satellite loops at 8 am EDT Thursday morning showed a solid but not spectacular major hurricane, with plenty of heavy thunderstorms with cold cloud tops in the eyewall. However, the eye had gotten less prominent since the early morning hours. There was no obvious cooling of the tops of the eyewall thunderstorm clouds going on, or large-scale expansion of the hurricane’s size. The 8:17 am EDT eye report from the Hurricane Hunters noted that the eyewall was open on its west side, which may halt intensification.

Meanwhile, Paul Douglas, of AerisWeather, told me last night, “I suspect Matthew will hit Florida as a Category 4 storm, 1 in 4 chance it could strengthen into a 5.” He also suggested that much of Cape Canaveral will be underwater by Friday AM, but that Miami will avoid a worst case scenario.

I want to highlight the key messages from the National Weather Service. I’ve never seen some of these concerns expressed about an Atlantic hurricane before. If you are in the affected region, pay attention:

1. Matthew is likely to produce devastating impacts from storm surge, extreme winds, and heavy rains in the northwestern Bahamas today, and along extensive portions of the east coast of Florida tonight.

2. Evacuations are not just a coastal event. Strong winds will occur well inland from the coast, and residents of mobile homes under evacuation orders are urged to heed those orders.

3. Hurricane winds increase very rapidly with height, and residents of high-rise buildings are at particular risk of strong winds. Winds at the top of a 30-story building will average one Saffir-Simpson category higher than the winds near the surface.

4. When a hurricane is forecast to take a track roughly parallel to a coastline, as Matthew is forecast to do from Florida through South Carolina, it becomes very difficult to specify impacts at any one location. Only a small deviation of the track to the left of the NHC forecast could bring the core of a major hurricane onshore within the hurricane warning area in Florida and Georgia. Modest deviations to the right could keep much of the hurricane-force winds offshore. Similarly large variations in impacts are possible in the hurricane watch and warning areas in northeast Georgia and South Carolina.

5. The National Hurricane Center is issuing Potential Storm Surge Flooding Maps, and Prototype Storm Surge Watch/Warning Graphics for Matthew. It is important to remember that the Potential Storm Surge Flooding Map does not represent a forecast of expected inundation, but rather depicts a reasonable worst-case scenario – the amount of inundation that has a 10 percent chance of being exceeded. In addition, because the Flooding Map is based on inputs that extend out only to about 72 hours, it best represents the flooding potential in those locations within the watch and warning areas in Florida and Georgia.

If I said that humans are stupid, you, being a human, might bridle at the thought. But then after a few moments you would agree, because you know it is true. The way in which Matthew is likely to affect the US east coast is the worst possible way it could do so in order to enhance the negative effect of human dumbosity.

We tend to think of hurricanes as a big giant storm that slams into the land and then turns into a big wet mess that later causes flooding. The part where the hurricane slammed into the land gets pretty messed up from wind, rain, and coastal flooding. Everybody gets this.

Meteorologists define the formation of a hurricane as when observations indicate that certain features of the storm’s morphology are in place (like, it has an eye, and other features) and when wind speeds are up to a certain level. Similarly, meteorologists define the moment that a hurricane does not exist any more as the moment when observations indicate that those features go away. Meteorologists are also required to define when a hurricane strikes land, because land striking hurricanes are very special and important and we all pay great attention to them.

A long time ago, meteorologists decided to define a thing called “land fall” which is the moment that the leading edge of the eye of the hurricane passes over the shoreline. The location of landfall is, thus, the place where that happens.

This has caused a great deal of confusion. When Hurricane Katrina made landfall, climate science deniers in the Bush Administration and elsewhere had reason to deny that New Orleans was devastated by a hurricane. The eye of Katrina made land fall a ways to the east of NOLA. So, they said, “Look, ma, no hurricane! The hurricane landed over THERE. This here devastation, in New Orleans, well, that there was a flood that happened, not a hurricane.” Similarly, science denying Republicans and the like needed to pretend that Major Hurricane Superstorm Sandy didn’t exist. They got rid of Sandy the Hurricane pretty easily, because Sandy, before affecting land, ate a Nor’Easter. This is like a cougar eating a wolf and turning into a grizzly bear. Since Sandy had just eaten a Nor’Easter, it lost some of its structure and didn’t look like a classic hurricane on land fall, so it was not called one. Therefore, one of the most devastating storms to strike the US, which was so large and damaging because of global warming enhanced energy, was taken off the books as a thing that happens by the lie that the definition of landfall allows.

This idea is so utterly idiotic that you probably don’t believe that it happened in either case, that people tried to say Katrina never hit New Orleans, or that Sandy was not a hurricane affecting New Jersey and New York. But your argument from incredulity does not impress. Thewse things happened.

These were embarrassing political gaffs caused by misunderstanding the concept of landfall, willfully, but a much more significant gaff, that is a matter of life and death, may happen with Matthew.

It is absolutely possible that Matthew will not make landfall in Florida or Georgia. It might not make landfall, and then, later, blow out to sea. If so, does that mean that hurricane Matthew did not affect Florida or Georgia?

No, of course not. The idea here is that the eye of the hurricane may remain off shore, while the storm moves along out at sea and parallel, but close to, the land, for up to hundreds of miles. Hurricane force winds could plow across every beach and coastal community, perhaps at 5-10 miles an hour or so, arriving, blowing hard on everything, moving off, for a day and a half, from southern Florida to northern Georgia.

And in the end, people can say, “nope, we haven’t had a major hurricane make landfall in the US in many years!” Even though a major hurricane directly affected hundreds of communities across two or three states. I’m telling you now that if people say that later they will be lying for political reasons. But of more immediate importance is this: People in the area to be affected have to understand that the simple and incorrect landfall concept is not what we need to be watching right now. This is not a good time to be stupid about landfall.

Alternatively, the hurricane’s core, with its strong winds, could actually come ashore. If the eye stays off shore, then the storm surges may occur over hundreds of miles of coast line, but they won’t be as bad, because the worst surges are really near the eye, to it’s right, as it comes on shore. But, at any moment, this storm could turn left and do that at any point along its route. Large scale steering weather systems that will put the hurricane off the Florida or Georgia coast will be ignored by this storm at the scale of moving this way or that way a few miles.

If the storm parallels the shore, it will weaken along the way. Interaction with the land mass and wind shear in the area will weaken it a lot.

But if the storm parallels the shore far out, that weakening will be much less and it even grow in strength because of warm waters. But it will be farther form the shore while that happens.

But a strong or even strengthened storm off shore could then turn to the shore, or run into, say, the Carolinas (which stick out into the ocean).

So, close to the shore means a long swath of damage. Far from the shore means less damage, but a stronger storm that can then move towards the shore or make landfall and have super heavy damage.

You can see why people have to be smart and thoughtful about this storm. Or else.

Paul Douglas provided me with this assessment (I paraphrase slightly):

The worst storm surge flooding will likely occur along the east coast of Florida north of Palm Beach, from Port St. Lucie and Vero Beach to Melbourne, Cape Canaveral, Daytona Beach and Jacksonville. Expect extended transportation outages (land, sea and air). Power outages may extend to well over 1 week in these communities with a potential for a 6’+ storm surge at high tide, capable of considerable damage to homes and businesses on barrier islands.

If Hurricane Matthew takes a course that hugs the coast, Category 3+ damage is possible as far north as Savannah, Hilton Head and Charleston by Friday and Saturday. Facilities on or near the coast should prepare for a worst-case hurricane scenario – Matthew is the first major (Category 3+) hurricane to strike the USA since 2005.

Paul also indicated that over 150 years of recording US Atlantic hurricanes, only two had a similar to what Matthew’s likely course, but none were as strong at Matthew. So we are in uncharted waters. Flood waters.

This is not a point-danger situation. This is not a thing you can spot, identify, locate, and walk away from, to avoid. Even in evacuation, you can’t just move up the coast and be safe. People of Florida, Georgia, and maybe the Carolinas, you are going to be walking down the street with a very large and dangerous dog paralleling your path off to the side. For two days.

Do. Not. Take. Your. Eyes. Off. This. Storm.

It is absolutely possible, about a 2 in ten chance, I’d say, that Hurricane Matthew will stay far enough away from Florida, Georgia, and South Carolina that it will only cause a bunch of rain (which can still be a local nuisance) and that’s about it. But, if that happens, there will be a very large hurricane off North Carolina. Guess what that hurricane is expected to do?

Current models suggest this storm, regardless of how close it stayed to the shoreline, may make a second pass. It may make a huge clockwise turn and go back to the Bahamas. Cooler water and wind shear may result in the storm being downgraded to below hurricane status by the end of that loop, but then, Matthew (or ex-Matthew?) will be back in the zone where tropical storms turn into hurricanes. And, it will take a second pass at Florida. Or, even, go into the Gulf of Mexico. Or, who knows what.

Previous discussions and updates are here.