EIIP Virtual Forum Presentation — June 16, 2010
Hurricane Season 2010
Understanding National Hurricane Center Product Changes
Bill Proenza
Director, Southern Region
National Weather Service, NOAA
Amy Sebring
EIIP Moderator
The following has been prepared from a transcription of the recording. The complete slide set (Adobe PDF) may be downloaded from http://www.emforum.org/vforum/NWS/2010HurricaneBrief.pdf for ease of printing.
[Welcome / Introduction]
Amy Sebring: Good morning/afternoon everyone. Welcome to EMforum.org. I am Amy Sebring and will serve as Moderator today. We are very glad you could join us.
As you know, hurricane season began June first. The National Hurricane Center has made some changes to its procedures and products this year, and we wanted to learn more about them. Please note: there are links to a summary of these changes, as well as a full user’s guide from our home page or on today’s Background Page. Our guest will also talk a bit about hurricane climatology and the outlook for this season.
Now it is my pleasure to introduce today’s guest:
[Slide 1]
Bill Proenza is Director of the National Weather Service's (NWS) Southern Region, which encompasses one of the most severe weather active areas in the world. You may recall that he served for a time as Director of the National Hurricane Center during 2007.
He previously served as chairman of the World Meteorological Organization's Hurricane Sub-Committee and now serves as a senior member of the U.S. delegation to the WMO's Region IV which encompasses over 30 nations in the Americas.
Please see today’s Background Page for further biographical details. Welcome Bill, and thank you very much for being with us today. I now turn the floor over to you to start us off please.
[Presentation]
Bill Proenza: Good day, folks, and thank you very much for the opportunity to chat with you here today, and also to handle some of your questions as we look at what should be an active season this year. We are in an area of the world, as Amy mentioned, that is certainly viewed as some of the most active severe weather you will find anywhere, and certainly from that standpoint, we have the mission among us all to be engaged in the world around us and make sure that we understand to the best of our ability what the threats are that we face in this very active severe weather region.
From that standpoint, we have some changes that are coming up this year and this season that we wanted to share with you to make sure we have a better understanding how those changes may impact us all. As we look at our mission—if I can just share with you— the National Weather Service encompasses the entire nation, of course, and it is looked at as the nation that has some of the world’s most active severe weather.
If you look at the coastal areas, you can see the enormity of the threat that we face in this part of the world. The one thing we share among us, is the fact that there is no higher calling anywhere than the protection of life. The partnership we have with emergency managers, the media, and people who are interested, is indeed a vital one in making sure that we have the best team possible to enable us to be in the best position to protect ourselves, our families and our communities.
From that standpoint, let’s proceed into the program.
[Slide 2]
Just a little bit of background, so you’ll understand a little more about the National Weather Service and its National Hurricane Center that is centered in Miami. The National Weather Service encompasses 122 forecast offices and about 13 river forecast centers, plus such centers as the National Hurricane Center, the Storm Prediction Center, the Aviation Weather Center, and so forth.
Those centers are very, very key because they bring the best expertise that we have in a particular arena that challenges us when it comes to those particular kinds of storms. In the case of the National Hurricane Center, they are the ones that are monitoring all the activities across the tropical ocean to make sure there are no surprises out there.
They monitor them, and they issue accordingly advisories. They do issue the storm advisories and warnings as they are necessary when any land areas are threatened as well as shipping out at sea. The National Weather Service is divided into 4 major regions, plus two other big sized regions in the Pacific and Alaska. As you can see, obviously the Southern region and the Eastern region, because of the normal tracks of hurricanes, are the most susceptible areas when it comes to tropical storms and hurricanes.
[Slide 3]
There you have the nation’s breakdown of the National Weather Service’s forecast offices and river forecast centers. Keep in mind that your National Hurricane Center is located in Miami.
[Slide 4]
For example, we’re going to be giving you some information about some other events that may be of interest to you because they potentially could be impacted by this upcoming hurricane season. For the latest on the satellite pictures involving the Deepwater Horizon oil spill, I wanted to give you this website for your information.
http://rapidfire.sci.gsfc.nasa.gov
[Slide 5]
This is just an example of the type of activity that we have that makes this nation so active when it comes to severe weather. We’re essentially a confrontational battleground between the continental air and the tropical air. The tropical air becomes more dominant across the southern states now as we head into the hurricane season.
We see the nation’s toll in 6 years of activity when it comes to tornados. We had over 8,000 tornados—an enormous number, when it is viewed against the other numbers of tornados that exist around the world.
[Slide 6]
Geographically, we are placed in that tropical arena where we are certainly hurricane vulnerable. You see the hurricane tracks, if we go back to 1851 that have shown us that indeed the east coast and the southern coast of the U.S. and the Caribbean are the areas most susceptible to the hurricanes and tropical storms.
When we say hurricanes and tropical storms, we can encompass both types of storms by saying tropical cyclones. You see we have had over 1,400 such events since 1851.
[Slide 7]
Back to the issue in the Gulf of Mexico, this is one of the pictures from NASA. If you look carefully, you can see in this particular picture that was taken a few days back where the oil spill is occurring to the greatest extent, where it shows up as a plume, and we’ve also superimposed on here the currents as you can see the eddies and the loop current, and so forth. That’s interesting to note because, again, a hurricane into the Gulf would be a complication to this particular event as well.
[Slide 8]
Again, this is another site where you can get the very latest information from NASA as far as the activities in the Gulf.
http://rapidfire.sci.gsfc.nasa.gov/subsets/?project=gulfofmexico
[Slide 9]
What we’re going to cover today are some of the changes that Amy spoke about that we look for in the upcoming tropical season. These are some of the design changes that have been collaborated with all of our partners. It involves, for example, the Saffir-Simpson scale—the adjustments and changes we have made there—to clarify, that particular scale or category is going to be wind based only—not surge or pressure related.
The storm surges beginning this year are going to be depicted as the height above ground, and I’ll explain more about that later.
The watch and warning lead times are all being increased by 12 hours and that is basically due to the improvements we’ve been able to show for quite a few years now in the track forecasting from your National Hurricane Center.
The Tropical Cyclone Public Advisory format is changed, and we’ll cover that as well. Then, we’ll go into some of the tropical cyclone genesis, their characteristics and what are their normal movements in this part of the world.
[Slide 10]
Going back now to the Saffir-Simpson scale changes. Originally, the Saffir-Simpson scale was designed to be independent of storm surge as well as atmospheric pressure and so forth. Yet, later, for the convenience of communicating the threat to the coastal areas, the definition was allowed to slip into becoming a tool by which we could convey, to some extent, the strength of the expected storm surge.
But we realized, especially with some of the recent storms, that storm surge forecasts are really dependent on many other factors besides just wind. Included in that of course is the size of the maximum wind field, the motion of the storm itself, the barometric pressure, the bathymetry, or the sea bottom as it approaches the land fall of a particular storm, and the local topographical features as well.
Storm surge is now being viewed and is going to be forecast as a separate storm component. If I can just recall the history associated with Katrina, Ike, and Charley—in Katrina and Ike, even though the storms had been stronger at one time, when they did make land fall they were weaker as far as their wind field. Yet, they had some very significant storm surges associated with them.
That’s why it’s important that we look at both of those factors of impacts when it comes to tropical storms and hurricanes separately in our forecast.
[Slide 11]
We had the Saffir-Simpson wind scale defined a certain way, and most of you will recognize those definitions, especially for the type of damage associated with the Categories One, Two and Three. You’ll see the damages illustrated here as far as described in words.
[Slide 12]
What we did this year, in order to add emphasis to the potential danger from these particular categories, we added some clarifications that indeed we feel would carry more emphasis in making sure our public would understand that indeed, because it may be a category one that there is still danger to life from these particular category storms.
The category one hurricane—and I’m going to summarize some of the more significant changes that you’re going to see—in this definition people, livestock and pets struck by flying or falling debris could be injured or killed. We show that there is more extensive damage, and we’re a little more emphatic about the potential for that damage in the category one, as we are in the category two.
The language we use in category two is, of course, a little more emphatic. Extremely dangerous winds will cause what we call extensive damage and substantial risk or injury and potential death to people, livestock and pets due to flying and falling debris. Mobile homes have a very high chance of being destroyed. Again, the idea is to better communicate the potential for this particular category, and the lower categories that had been in the past maybe not as emphasized as much as we should have had them emphasized.
[Slide 13]
In category three, what we define and have always defined as a major storm, we’re talking about devastating damage will occur with high risk of injury or death to people, livestock, and pets, etcetera.
[Slide 14]
Storm surge is another area that we are now not only going to forecast it more separately and independent of the wind field of the hurricane, but the way we’re going to depict it is going to change. If I can for just a moment—let me recap a little bit about storm surge and the way it has been done in the past and the way it is going to be done now.
First of all, the storm surge in the past was forecast to be the amount of water from the storm above sea level plus the tide. For example, if we had a storm surge forecast of 15 feet, and the normal high tide at that particular time of land fall was supposed to be 2 or 3 feet, we would actually add the 2 together and that would give us the storm tide that we would expect with the storm. In other words, the storm surge, plus the tide, would give us the storm tide. Then, keep in mind, that above that the wind generated waves are even higher yet.
What we’re doing this year is when we forecast storm surges we’re actually going to take into account the elevation of where that storm surge forecast applies. As you go inland, the storm surge would be depicted in a manner that gives you the amount of water over that particular elevation.
To be more specific, too, when it comes to a local impact in lower areas, the local forecast offices will take that information and the storm surge information that comes from the advisories of your hurricane center, and your local forecast from local forecast offices, and apply the tidal influence to it. Your hurricane local statement will be more specific as to your actual storm surge forecast in your area.
[Slide 15]
A traditional display, the old storm surge height display that you see there, is what we were expecting above normal sea level. Regardless of how far inland we would be looking at that, we would simply say that is what we would expect above normal sea level. Then, you had to apply the particular height above sea level that you may be at—2 feet, 3 feet, 5 feet, whatever the case may be.
[Slide 16]
The new way this is being done will depict it a little more accurately, and it will be a new surge height display that is going to come from your hurricane center and your local forecast offices. This particular display will tell you the height above ground level at your location.
[Slide 17]
As I mentioned earlier, there have been improvements in hurricane forecasting as far as track is concerned. Track forecasting has gradually improved in the past 15 years to the extent that if we go back to 1990 and we look at, for example, the 24-hour forecast of track, it was usually about 100 miles off as far as the center of the land fall of the storm was concerned.
Now we’ve gotten that down, in the last 5 years, to around 50 nautical miles. Likewise, on the 48-hour forecast, from 200 miles nautical miles, it’s down to 100 miles. Because of that, we wanted to provide, as far as the watches and warnings are concerned, more lead time, especially considering that the coastal populations are increasing—more lead time for emergency management, the local government officials, the first responders, and to the public at large.
Too, if there is going to be an evacuation area, to actually make plans accordingly and to leave the area. In addition to that, and most important in the fact that this applies to the entire impact of the storm, we want to give as much time as possible to all of our partners and the public. That we are able to give you based on the improvements we’ve made in track, we wanted to pass those benefits on to you.
What is happening this year is we are increasing by 12 hours the tropical storm and hurricane watches from 36 to 48 hours. In addition, your tropical storm and hurricane warnings are increasing from 24 to 36 hours. That is largely based on the track forecast improvements from your National Hurricane Center.
[Slide 18]
The format of your Tropical Cyclone Public Advisory is also changing. To make the text a little bit clearer, it’s going to be more carefully aligned into and organized into sections. Within these sections, key words will be used to assist the human and computer software to find the specific information that they need more readily.
The summary section of the advisory will move to the top of the product immediately following the headline. For obvious reasons, we wanted to summarize indeed the major message of that particular advisory. Watch and warning information will be organized differently and will be presented in a list, or bullet, format. You will grow accustomed to that, and we believe it will be an easier communication to make sure that we are clear in what that advisory is telling us.
[Slide 19]
I wanted to discuss a little bit of tropical cyclone climatology. As we have, and some of you have been monitoring the tropical weather outlook, there has been one area of disturbance east of the islands, out in the birthing areas of the Atlantic. It is important to understand the typical movements that you can expect from the storms based on where they are in a particular month.
There is a certain climatology that can aid us in planning for the potential impact of these land falling tropical storms and hurricane. In June, you see there are storms are more typically forming in the Western Caribbean Sea, and they tend to move west and north, as you will see there. If there is a prevailing track that is most likely, you will see those particular tracks highlighted by the appropriate color on these particular charts. All of these will be available to you.
[Slide 20]
In July, we pick up a little bit on the season, of course, and the activity, but nowhere near the most active months which I will share with you shortly. But nevertheless, the storms tend to have a longer life and they tend to form a little further out into the birthing areas of the Atlantic and into the Eastern Caribbean.
As you see there, the tracks begin to have a more westward movement before they finally do curve northward. These more westward movement tracks are an indication of the Easterlies being more prevailing across the tropical oceans. As the tropical season gets more and more defined and established, the easterly becomes more established as well and moves further to the north.
[Slide 21]
With August, and into September and October, we enter the most active part of our hurricane season. Again, the prevailing track and the stronger prevailing Easterlies show that the tracks are more defined to move westerly, especially when they are in the birthing areas of the Atlantic and the Caribbean Sea and into the Gulf before they have a slight movement to the northwest and eventually, if they go up the east coast, they move as the Westerlies catch them further to the north and northeast.
But again, August is a month that increases the activity across the birthing areas of our tropical oceans quite a bit.
[Slide 22]
Our season peaks in September, and again you will see the activity in the prevailing directions. Sometimes we will have storms that form in August in the far reaches of the eastern Atlantic, and they will prevail and move quite a bit to the west and have a long track that will eventually bring them into a threatening position in the Caribbean and then eventually the southern and eastern portions of our nation.
[Slide 23]
Into October, we’re beginning to have the seasonal changes. As you know, fall begins in the latter part of September and the Westerlies begin to prevail a little further south. The storms that form in the warm waters of the Caribbean and the Atlantic tend to be moving in response to the prevailing steering current, with a slight westward movement, but actually more to the north and eventually curving on to the northeast, as you see there.
[Slide 24]
Finally, in November we have a significant drop-off in the amount of storms. As you know, the Westerlies become much more pronounced and the storms move off to the northeast. The end of the normal hurricane season is November 30.
[Slide 25]
I mentioned how active the coastal areas are around the country. As you can see there, this is a chart that will give you the number of significant hurricanes and some tropical storms that have hit across the coastal areas. Mostly, in this case it’s the hurricanes from 1950-2009, and you will see some very significant, infamous storms listed there.
[Slide 26]
What we’ve done here, by pictorial chart, we’ve indicated the number of storms that have struck the various coastal areas across the U.S. southern coastal areas, around the peninsula of Florida and up the east coast. The number of strikes from 1900-2009 are listed.
[Slide 27, 28]
Here’s a greater clarification of those numbers.
[Slide 29]
This particular site I wanted to share with you. It’s an important one. You can use it operationally day to day, but it also has a lot of clarification for you of some of the changes that are taking place.
http://www.srh.weather.gov/ridge/
The first listing you see there is a listing for all of the weather radars across the country. In this particular case, you would certainly be looking at the radars that we call "ridge"—that are GIS based radars that have looping capability. In this particular site, you’ll be able to select the radar that is most appropriate, especially with a land falling tropical storm or hurricane. That is an active website that the radar pictures are being updated every 5-6 minutes.
http://www.nhc.noaa.gov/gtwo_atl.shtml
The latest tropical weather outlook, which I’m sure a lot of you are using already— that, is indicated there on the second line.
http://www.srh.noaa.gov/srh/tropicalwx/tropical.php
The tropical weather updates—that is another site that gives you a little bit more varied information, access to a lot of information that concerns the upcoming season.
http://www.srh.noaa.gov/srh/tropicalwx/satellite.php
The tropical weather satellite imagery—this is an excellent site where you can actually go into and select the particular satellite imagery that best suits your needs. In each case, it shows you sort of a format of the particular area that is being covered.
http://www.nhc.noaa.gov/aboutsshs.shtml
The next one is the Saffir-Simpson hurricane wind scale fully defined for you by the National Hurricane Center website. That one is listed there.
http://www.nhc.noaa.gov/aboutcone.shtml
Next, we have the definition of the NWS track forecast, the Cone, and that is also there for you and for your use.
[Slide 30]
Obviously, the outlook for the upcoming season is an important one. As you know, we released the very latest outlook just recently on May 27. I also added here the Colorado State University’s outlook as well. As you can see, they are very, very close in the number of named storms that are expected this season.
In both cases, they are looking in the range of the mid-teens on up. The normal number that has been averaged out is about 9 to 10. We are looking at a more active season as far as named storms. Named storms are tropical storms and hurricanes. As far as hurricanes, it is normally about 6, and they are outlooking from 8 to as many as 14 in the latest National Weather Service/NOAA outlook. Major hurricanes—that is a category 3—111 MPH sustained one-minute winds, or higher—in that case, we normally have about 2 a season. As you see there, they are forecasting anywhere from 3 to 7.
[Slide 31]
I’d like to open it at this time for questions or comments—anything we might be able to address for you.
Amy Sebring: Thanks very much, Bill. Now, to proceed to our Q&A.
[Audience Questions & Answers]
Question:
Erin Meyer: FABULOUS presentation, thank you. Can you recommend some good sources for these new storm surge layers (e.g., to be used in conjunction with Google Earth or other GIS systems)?
Bill Proenza: That is an excellent question indeed. We want to be able to make sure that feature is utilized to the fullest and that capability is brought to bear in making sure that when it comes into the storm surge that a particular point, it can be determined what the actual storm surge’s forecast is for that particular point, based on latitude and longitude—essentially based on a particular GIS format.
With that, I would suggest, if I may here, that they work with their local forecast office, their nearby forecast office. If they’re not near a coastal area, then they can certainly address me or the National Hurricane Center and we will certainly work with them to make sure they have access to that information in that format.
Question:
Karen Scott-Martinet: Great talk! Are tornadoes normally associated with hurricanes? If so, is there guidance on the size of them relative to the hurricane size?
Bill Proenza: Excellent question. Thank you, Karen. I would like to say that tornados can occur with land falling hurricanes. They are more likely to occur as we go further north in their land fall locations. Some of the most active hurricanes that have made land fall in the North Gulf coastal area have caused a significant number of tornados.
We usually will put that type of information, if there is a significant tornado threat associated with these land falling storms, into the advisories and of course the local forecast offices will also have that in their hurricane local statements. Beyond that, they will also be issuing tornado warnings.
The warnings themselves are issued by the local nearby National Weather Service forecast office and they will try to pinpoint the particular location and the impact areas of a particular tornado, if it is showing up and existing in radar that we have for that particular land falling storm.
Keep in mind that with the amount of heavy rain usually associated with these storms, sometimes tornados are embedded in the storm and are not always picked up by weather radar. They tend to be on the weaker side—not as large a tornado as we would find in the Midwest—the more significant Fujita scale categories, but nevertheless, when it comes to F1’s and F0’s, those storms at times can be picked up by weather radar and the very latest information will be provided and warned for by the local forecast office.
Question:
Paul John: Is there a forecast/prediction for the number and severity of hurricanes in the New York City Metro area?
Bill Proenza: It is a good timely question from Paul, and I appreciate hearing that. What really happens when we are doing the outlook, we are really not able to have any signs that are conclusive at all at letting us know—when we have, for example, an outlook of an active season, like we have this season this year, if that means there is going to be a particular land fall area that is going to experience a greater number of storms.
Obviously, if we have a forecast of more storms for a season, the threat of land falling storms has got to increase. But we really can’t tell where they are going to occur. Obviously, also, the upper east coast has been overdue as far as hurricanes and tropical storms are concerned. That concerns us, too because they have occurred in history, and they will occur.
I appreciate Paul’s interest and I think the best advice we can give is to always be prepared regardless of the type of season that is outlooked and regardless of the frequency of hurricanes or tropical storm land strikes that may exist—even in areas of the upper east coast—they are still vulnerable to them.
Question:
Joe Sukaskas: Much of NWS's weather radio information is now becoming increasingly automated, and often difficult to understand if abbreviated information is being disseminated. You mentioned increased use of lists and bullet items to provide detailed information. Will the automated vocal delivery systems be improved to communicate lists and bullet items?
Bill Proenza: It’s a very good question, Joe. We are always working on the quality of that voice. It is automated—you are exactly correct. The automated system enables us to be able to provide the very latest information and put it into the system, and immediately the computer picks it up and translates it into the recording so we can get that information out there in the shortest amount of time.
At the same time, when we do that, and you’re correct, there’s a certain amount of lost eloquence that we could normally have in the clarity of the voice. We are working on improving that all the time. In addition, I wanted to also add that the local forecast offices as well as the Hurricane Center are trying as much as possible to have multiple device types of alerts for folks out there.
If you go into the internet and look at your local, nearby NWS forecast office website, they will have instructions for you on how you can get some of the latest information on your PDA or your cell phone text. Perhaps that is another way we can communicate effectively with our public and with our partners, and users, in a way that they can be sure to get the very latest information.
Comment:
Amy Sebring: They have added some additional RSS feeds.
Question:
Ken Carter: Are current LiDAR data used to develop the storm surge predictions?
Bill Proenza: LiDAR is, and indeed, we are using LiDAR as much as possible for topographic and in some cases for bathymetry studies, and so forth, but in reality, when it comes to the storm surge forecast, we are providing that, and trying to relay that on a GIS basis, and in real time, we are sending that information out, and we’re trying to forecast the actual storm surge in advance, so LiDAR could possibly give us that when it is occurring, but it may not be able to do it in advance. That, of course, is what we’re trying to do—we’re forecasting this in advance.
Question:
Chris Hosman: Will the surge forecast be given in a graphic format or just in text?
Bill Proenza: Both. That is a good question because what we’re trying to do—of course, it will be given in text, and it will also be given under hurricane local statements from the local forecast office. It will be coming out in advisories from the hurricane center, and in addition to that, on the website, because we know the value of graphical depiction, they will put these in graphical form as you saw in the presentation we had.
Plus, in addition, some of the local forecast offices are doing that already so they can convey with the greatest clarity possible what the potential impact is of the storm surge above ground level in their areas.
Question:
Amy Sebring: If that surge happens to be carrying oil this year, that will be even more significant, right?
Bill Proenza: It will. That is a very important issue, because the wind is always impacting the surface of the ocean, and at the same time, we all know that oil is lighter than water. The oil that is being spilled in the Deep Water Horizon spill in the Gulf is obviously showing up at the top of the ocean. Unfortunately, if we have very strong winds, the ocean currents are going to be overwhelmed, as far as being the major steering factor in how the oil moves.
The storms are really going to complicate the issue in the Gulf as far as the movement of the oil. Certainly, the wind will become a big factor in how that oil moves, depending on the course of the wind fields associated with these storms.
Question:
Amy Sebring: You mentioned the improvement in the forecast track predictions over the last several years and that has been quite amazing. I find them at 48hrs in particular to be close on. Is there any research going on in the area of trying to improve the intensity forecast?
Bill Proenza: That is such a timely point. Indeed, track forecasting has been getting better, and significantly so. In the past 15 years, we have been able to improve it to where we have cut the error in track forecasting in half. Unfortunately, that has not been the case when it comes to intensity forecasting.
If I can give you an illustration of the difficulty we’re facing—first of all, if we go back to 1990, and that’s a significant amount of time, we have been essentially at about the same location as far as the graph would show, when it comes to the error that is associated with the forecast of intensity changes.
Take for example a 24-hour forecast. If we are forecasting a particular storm, and we are forecasting the intensity that storm is supposed to be at in 24 hours, we are ending up on the Saffir-Simpson categories—we are about 1 Saffir-Simpson category off, as far as the average error is concerned. That is about 10 knots or so that we have been off.
I share that with you because it’s a much more difficult problem, because to understand what is happening thoroughly in a storm, such as, for example, a hurricane that may be 120 miles across, and we are looking at a particular storm cell that is so large, and we are trying to understand the inner workings of it, the dynamics of that particular storm.
We just don’t have the data in the density that we need to have to enable us to really have a good handle on all the intricacies that are working into how that storm is going to change in its intensity. We have done a good job in holding to the 10 knots, because we have had a lot of storms that have been very significant and intensifying very rapidly. But at the same time, we have not improved beyond the 10 knots or so.
If I look at the last several years, it’s been about a 10 knot variation on our forecast average error in the first 24 hours, and it’s been approaching the upper teens to near 20 knots off in a 48-hour forecast.
Amy Sebring: Is there any promising research on the horizon in that area Bill?
Bill Proenza: We have a lot of things working for us. The aircraft is gathering more data than ever before with their scatterometry data, and they are also able to also scan to the sides and pick up more data as they are flying through the storm and analyzing the storm, and those flights are very important for us. They are not important only to determine where the storm is, and the intensity of it—of course, all of those are important, but not only for that reason are they important.
They are also important for the reason that we’re addressing right now—for understanding better the intricacies of these hurricanes so that we can better forecast the changes that may be occurring in the storm well out into the 24, 48, and 72 hour timeframes, so we can be more accurate in the intensity changes we sometimes see.
Amy Sebring: Have there been any changes to the various computer models that are being used to generate those forecasts this year?
Bill Proenza: That’s another very timely question because, indeed, we are always working on the computer models. We have a mix in the models now that allows us to bring in more of your dynamic models into the equation. For example, the Hurricane WRF model is very promising—the GFDL model. All of these models, instead of being more purely statistical, these models get involved in the dynamics.
That is indeed the arena in which we have to have the best models working, for us to be able to achieve an improvement in the part that has to do with the intensity changes of a hurricane. The other models have been very good to us. The track models have helped us a lot in maintaining our improvement in track.
In fact, the improvement has been so good that we sometimes cringe at the thought that they are going to get to the point where we’re not going to see the same amount of improvement anymore, but rather the real challenge is what you brought up, Amy—when it comes to forecasting intensity. Indeed, the higher resolution, and although they are limited area dynamic models, those are the ones that hold the most promise for us right now—the Hurricane WRF and the GFDL.
Question:
Erin Meyer: Are there any predictions as far as other impacts the oil spill might have, e.g., health impacts of oil-laden water deposited in coastal areas? Increased warming in Gulf waters accelerating storm strengthening?
Bill Proenza: Very good points, and as we all know with the outlooks and the basis for the outlooks that we have had for this season, we know that the birthing areas of hurricanes and tropical storms are running above normally warm in the Atlantic and the Caribbean Sea. It’s not so at this time in the Gulf. The Gulf warms up fairly quickly, so we’re not seeing anything too out of the ordinary yet in the Gulf.
But, as far as the impact, and there are so many impacts that are potential out there when it comes to the Gulf oil spill that we have and the whole nation is contending with. Our parent agency, NOAA, has got tremendous expertise in the National Ocean Service people, Marine Fisheries people—and they’re looking at it from the ecological standpoint, the impact on life and fishing, and all types of life in that area.
The Ocean Service people are looking at it from the standpoint of contributing what they can as far as ocean currents. We have quite a team of experts working on that. You can go to NOAA.gov, and there is a site out there that can give you the very very latest expertise in that particular area as far as what are the potential impacts, and so many other areas from this Gulf oil spill.
As far as the hurricanes, obviously, when we apply the storm winds of a hurricane and even a tropical storm across the sea, in the Gulf of Mexico, for example, that is certainly going to complicate things for us. We are hoping that the oil spill will be capped to some extent before the full-fledged hurricane season is upon us. Only time will tell.
I would advise you, if you can, all of you go to your NOAA.gov website and again, there is some very timely information on the Gulf oil spill on that site.
Question:
Lew Fincher: Just curious why more cities and counties aren't posting elevation of streets, especially in areas that have the potential of being impacted by not only storm surge, storm tides, but even rainfall flood and flash flooding? This could assist local EMC's in educating citizens to that type of threat and help citizens understand that they need to respond as asked by the EMC, Mayors and County Judges. Great presentation.
Bill Proenza: A good question from Lew—I know Lew well. He is on top of things, and he makes a very good point there. Indeed, we are using the heights above sea level as far as topography is concerned, and so forth, in analyzing and doing our flash flood forecast, and so forth.
Some of that will not be as fine a resolution as you can have, but at the same time, it will be conveyed in the forecast for the storm surge as well as, of course, when we’re dealing with flash flooding, which has been a very recent active season for us, as far as flash floods across the southern U.S. especially.
They use the topography of the area to determine the watersheds and the potential areas that will be impacted as far as streets are concerned and communities are concerned with the flash flood warning. Going back to the coastal areas, the storm surge depiction from your local forecast offices will get finer and finer as to the areas in which a certain storm surge and height above the ground level will be for those areas, the depiction of which limits us to how fine a resolution we can portray.
We are working on it to get better at what we’re doing. So is the Hurricane Center. Jamie Rhome and his staff, they are doing everything they can to bring the very latest and the highest resolution to this storm surge forecast. We are looking very optimistic to the future of getting better at a very important part of the impact, and really, a very deadly part of the impact when it comes to land falling hurricanes.
Amy Sebring: Perhaps that needs to be part of the outreach preparedness message--know your elevation-- especially since now it will be meaningful to people in context of the new format for the surge.
Question:
Amy Sebring: It seems to be commonly accepted these days in the media that global warming is going to cause more and more intense catastrophic hurricanes. Could you comment on that issue?
Bill Proenza: Certainly. That is a very interesting issue, because it’s like so many of these issues with the global warming or climate variability that we are facing, and in so many ways, there are so many factors that are playing a part in that, sometimes what may be obviously pushing us in one direction may not be manifested so simply in just saying, "Because there are warmer waters, there are going to be more storms." There may be. We’re still studying that.
There are two schools of thought in that particular arena. I will mention both. One is that indeed, the warmer sea surface temperatures will cause us to have either more storms or actually also more intense storms.
Another one is, still recognizing that the ocean is getting warmer, and therefore there is more energy for storms in the ocean, that may lead to larger storms, but not necessarily a type of regime that would favor the display of that extra energy and that sea surface temperature being warmer into the hurricane development arena. It may not be so simple that we will have stronger storms and more storms.
It really is an argument that is, I think, interesting and academic, in certain ways, though. In reality, we are such a susceptible area to tropical storms and hurricanes, that there can’t be a year that we can let down our guard. Our people love to live near the ocean. We love to recreate near the ocean. If we’re going to do that, and have the opportunity to enjoy what nature offers us being close to the ocean, we have to be as prepared as we can. We have to be vigilant and we have to be aware.
I guess it is being prepared and aware that makes us resilient as a people. If we are working together, and not only the emergency management community that is so vital to the National Weather Service, and the media, and of course, all the interested organizations and first responders and local government, but it is also going to take the public—the public engaging in being aware that they have a responsibility to themselves, and to their loved ones, and their communities to do everything they can to stay prepared and aware. And we will do everything we can to make sure the latest information is there for them.
[Closing]
Amy Sebring: On that note we will wrap it up for today. Thank you very much Bill, I think this has been very helpful. We appreciate your taking the time to share this with us. I think you wanted to mention working with your local weather forecast offices?
[Slide 32]
Bill Proenza: Indeed, and I appreciate that point, Amy. That is the fact that I feel that local government closest to the people that we’re working with and closest to our partners, works best. From that standpoint, they take the very latest information, the most valuable information, from your National Hurricane Center, part of the National Weather Service, and we blend that information with the local expertise, and we try to get that information out as accurately as we can for the local impacted areas. So, working with your local office—they are there for you.
Amy Sebring: Thanks Bill. Again, the recording should be available later this afternoon. If you are not on our mailing list and would like to get notices of future sessions and availability of transcripts, just go to our home page to Subscribe.
Thanks to everyone for participating today. We will have a program next Wednesday, June 23 at this same time and our announcement will come out tomorrow.
Our topic will be "Critical Infrastructure Protection and Resilience," and our guest will be Darrell Darnell, formerly the emergency manager for Washington D.C. and more recently with the White House National Security Staff. Please join us then. Until next time have a great day everyone!