Does an ominous hurricane season refer to lots of named storms making landfall, or simply to lots of named storms?

~sg: That's a key question. You can have a lot of storms but if they don't make landfall, who cares? However, from a statistical standpoint, the more storms you have, the greater the probability you get landfalls.

Yes, exactly! Is there compiled statistical evidence correlating a higher number of named storms with a higher number of landfalls made by named storms? Or, one I've always wondered about: A statistical correlation among tracks of named storms in any given year, and from year to year? In other words, can the tracks of named storms be shown to be statistically repetitive within a season as opposed to across seasons?

I believe one thing to think about is that storms forming in the same area over the course of a season sometimes "remember" the earlier tracks... think 2005 with all the Caribbean born and eventual Gulf Coast storms. It's possible that the conditions across the Atlantic remain somewhat similar for the majority of the season, and we see many recurves out to sea prior to them being a threat to the U.S. Then again, Cape Verde systems are often difficult to get all the way across without something pulling them away.. and it only takes one big hit to make a season a bad one (see Hugo in 1989). This idea can maybe not yet be expanded to storms which may form in or near the Gulf/Caribbean, as steering flows are somewhat different in those areas, and we've not seen a storm so far to show what the "preferred" paths in that region might be. It's also July and Bertha is rare, so maybe nothing in this post really matters. ;-)

This sounds ominous!!! Here's some hurricane history from those years.

1954 was the year of Carol and Hazel. 1961 was marked by Carla, Esther and Hattie. As I recall, Esther passed out to sea but menaced the Eastern Shore with at least a Category 4 threat. Carla was very bad in the Gulf States. Hattie devastated Belize, killing over 2,000. Carol struck New England bad. HAZEL struck D.C. with hurricane force Oct. 15, 1954. I'm still not sure if the Feds closed that day but they should have done so. Winds gusted as high as 98 mph at DCA.

1969 was a hurricane year this region and the Gulf will never forget! The reason, in one name: CAMILLE!!! Prior to Katrina, Category 5 Camille was the worst hurricane ever to hit the Mississippi Gulf Coast and the decaying storm caused a 25+ inch DELUGE in one night over the VA Appalachians before reviving to tropical storm force over the Atlantic. I'm not sure how many deaths occurred during the floods from Camille, but I believe the number was 250 or more.

This does not guarantee that 2008 will be a notable hurricane year but definitely points us in that direction. We may take some comfort in the fact that Bertha's track indicates that the Cape Verde storms may tend to recurve before hitting the Southeast coast. However we may need to monitor closely those named storms which tend to form in the vicinity of the Windward Islands, the Caribbean and over the Gulf Stream. These storms could pose us on the mainland a bigger threat than the long-path Cape Verde storms this year.

One tidbit I forgot to post. Hurricane Hazel was one of the few tropical cyclones to maintain its strength far inland. This was why it hit DC so bad!

Apparently this circumstance was due to the hurricane's fortuitous interaction with an eastward-moving cold frontal trough coming in over the Appalachians. At any rate the hurricane retained Category 1 strength far inland and caused wind damage as far north as Lake Erie and into Ontario before dissipating.

Today a storm similar to Hazel would exceed Katrina in monetary damage and could put the entire East Coast "out of commission" for a minimum of six weeks. If it were to happen THIS YEAR it would only add to the economic dislocation already caused by our high oil and gas prices and the Midwest floods.

Ian, thanks for your mention of 'steering flows' - I think that's exactly what I'm getting at: The study of the stability of steering flows and attendant conditions, and their impact on named storm tracks/landfall likelihood in a given season. Or is that is a slippery slope, akin to attempts to predict how active a season will be? Seems no one remembers the range of predictions or the confidence levels of the studies.

El Bombo, you're SO right about the economic damage a Hazel-like storm on the right coast could cause this year. That's part of what fuels my interest - along with personal concerns, of course!

El Bombo refers to Hurricane Hazel maintaining its strength far inland. Strictly speaking this is not true.

As El Bombo indicates, Hazel(1954) interacted with an approaching mid-latitude trough. In doing so, as true of about 1/4 of all hurricanes moving northward of 30-40N, Hazel redeveloped in a process known as extra-tropical transition. In effect, Hazel became an extra-tropical cyclone (think "nor'easter")- one with very different (relative to tropical storms) structure and physical processes governing its intensity.
In some cases, like Hazel, the transformed system is larger and more asymmetrical and with high winds as strong, if not stronger, extending over broader expanse than the parent hurricane. The rainfall can be as heavy and spread over a much larger area than the purely tropical system.

I remember vividly (as a 9 year old in Brockton, MA) being more scared of Hazel's continuous heavy rain - lasting for at least 3 days - than the fury of Hurricane Carol earlier in the year. Although on relatively high ground, I recall the torrential rain producing what seemed to be shallow river flowing rapidly around our house with no recourse other than to wait it out.

Steve, thanks for the extended explanation of Hazel's behavior. I recall a pre-wapo.com CWG post last year discussing the term 'extra-tropical' and its resultant confusion potential.

A recent peer-reviewed study (Landsea, EOS, 2007; subscription required) found that the average percentage of named storms making landfall was 75% from 1900 to 1965 and 59% from 1966 to 2006. There was also a large variation between individual years.

CapitalClimate

"Steering flows, of course, are critical in determining the forecast track of a hurricane - when they exist (and predicted correctly). When the basic flow is weak, the internal dynamics of the hurricane largely govern the storm's motion - generally slow and erratic. We (science community) do not yet have a sufficient grasp of reality to deal reliably with this.

Stay tuned for a series of posts I plan on issues such as this in the near future.

The issue of tropical cyclone frequency and variability was also discussed last July.

You guys are geeks, but thanks for caring so much. I feel safer, and somewhat globally warmer.

I am surprised that no one mentioned the significance of La Nina vs El Nino weather patterns in Hurricane/Tropical Storm frequency/intensity and path.

Also, our ability to image hurricanes is very recent and truthfully we can't say with any confidence that Bertha is the furthest east to date with out indicating the date we started using satellites/airplanes to track hurricane formation.

Think the surprise from the Hurricane of 1938 hitting Long Island and New England without any prior warning.

As least you didn't blame it on Global Warming and lose all credibility but you came close. Landsea left the IPCC over their claims of increased hurricanes due to global warming. As he and many other have pointed out, hurricanes are fueled by the difference in temperature between the ocean surface and the lower troposphere. The famous South American hurricane used by Al Gore to promote himself, er, promote Man-Made Global is an example of VERY cold ocean water and cool air. However, your statement that the water temperature during Bertha's formation was higher was misleading to the average reader who is not aware that global lower tropospheric temperatures (as measured by satellite) are at a near 30-year low for June/July. In Bertha's case, we have a residual warmth from the ocean interacting with the much cooler air. This can also account for the surge in strength. This is the first major PDO shift since the development of satellite tracking and modern modeling. Bottom line, we really don't know what is going to happen yet.

Bertha now down to Category 1, 85 mph.

CapitalClimate

While it is somewhat disconcerting that Bertha formed from an African Wave so early, looking at other factors (ENSO, Madden Julian Oscilation) it doesn't look as ominous as 2005.

Yet.

Having studied meteorology in grad school, and living in Florida for over a decade, one quickly learns there are weather forecasts, and then there is the actual weather. Certainly the forecasting skill has improved in the 20 years since I was in grad school, but forecasting intensity changes for tropical systems remains difficult. Track forecasts have gotten much better in that time.

Still, there are track forecast errors. In 2004 Hurricane Charley was "supposed" to Tampa's storm. Until about 2 hours away, when it took a hard right turn into the Port Charlotte area. I wasn't happy to see that part of my state devestated, but I was pretty relieved that I wasn't going to be starting down the barrel of what seemed to be a coming category 2...

And Charley had one more surprise - a rapid intensification into a category 4 just before landfall.

CapitalClimate,

thanks for summarizing the Landsea report. The landfall frequencies you cite are pretty interesting. Since I don't have a subscription to access the study, does it mention whether the 16% landfall discrepancy for pre-1965 storms v. post-1965 storms could be attributed in part to lack of reliable radar during the first half of the century? It seems logical to me that a higher percentage of storms would appear to make landfall in the absence of this technology because it would be easier to miss storms that did not track close to land or across shipping lanes. If the only/majority of storms being identified were those close to land in the first place, it makes sense that they stand a better chance of hitting land. I know this wasn't the point of your post, but the differences in storm landfalls caught my eye so I was just wondering if the study addressed how technological advances might have skewed the results. Thanks for any insight.

Could Capital Climate be a start-up like Capital Weather was back in the good old days??? I like the site Capital Climate!

I find nothing ominous about hurricanes. It is the continued population growth in the path of potential storms that worries me.

I'll tell you who cares -- everybody. Hurricanes cost literally millions of dollars in additional fuel costs for shipping and air travel...

Wow, you guys can do so much with 60 years of data! Amazing and so impressive!

Parker,
Good question. Landsea says:

This difference in the longterm percentage of tropical cyclones that struck land (75% from 1900-1965 versus 59% from 1966-2006) indicates a large bias toward underreporting of tropical cyclones that remained over the open Atlantic Ocean. Even though aircraft reconnaissance began in 1944, this covered only about one half of the Atlantic basin, as systems east of 55°W were generally not monitored or observed with this type of observational platform. Thus aircraft reconnaissance should not have been expected to provide complete monitoring of all tropical cyclone activity in the Atlantic.

I would tend to agree with that assessment personally, but there is an interesting counter-argument: In the years before good reporting, ships would be more likely to encounter tropical cyclones by accident, so they wouldn't necessarily go unreported even if there were no satellite or aircraft reconnaissance. (On the other hand, if the previously unknown storm was strong enough, there might not be any survivors to do the reporting!)

Capital Climate

"Today a storm similar to Hazel would exceed Katrina in monetary damage and could put the entire East Coast "out of commission" for a minimum of six weeks."

I think you're right, going on the widespread power outages after Isabel in 2003.

Does a westward shift of a "Bermuda High" help create an earlier shift northward as in the case of Bertha? Or does it have any impact in terms of storm track?

Nate Freeman
Vermont

Perfect! Just what I was looking for - The Subtropical Ridge.

Nate: Yes-- a westward shift in the Bermuda high increases the odds of landfalling U.S. storm.

Some great comments and info. Thanks all. I work as a US property insurance broker, mainly placing risks into Lloyds of London. The data is very interesting. Right now we are in one of the 'softest' property insurance markets we haev ever had experienced, which means premiums are very low due to the huge serge in insurance comapanies and insurance capacity. With Katrina the large hit to isnurers and subsequent premium prices which spiked, were fairly short lived with a rush of Bermuda based and US based carriers. However, a similar insurance loss from a hurricane, with todays finanical climate (inflation due to oil prices, struggling house prices, wobbling economies) will lead to a pro longed hard market with prices staying high for years. Again the impact of high insurance prices with the economy is going to hit hard and fuel a recession further. Historically we are in a very unique year with no parallels (insurance speaking)
Cheers

Yeah. The experts say it should've moved NNW Thursday Morning. It's now Thursday evening and it's moving from WNW to NW. There are no signs of NW.