Questions for Professional Mets

[EDR1222]

Just thought I would pose a question as many of us reflect back on this year. Earlier in the year, I think it was back in May, meteorologists and hurricane researchers were indicating there was evidence of a greater threat to the east coast due to a stronger bermuda high, extending further west than in previous years. I guess there are many things that go on in the atmosphere that influence this. Such things as PDO and North Atlantic Oscillation are terms that were mentioned as I am sure all of you know. Interestingly, to me, is that with Charley, there was a very strong trough that steered the hurricane Northeast on a more October like path. But after that, the ridge that was discussed back in May seemed to establish itself for the rest of the summer. Obviously seasonal forecasts are getting much better thanks to the hurricane center and also many of meterologists who do such an outstanding job including many of you who are on this forum. Do you feel there is significant progress being made in forecasting where these storms are likely to strike? Is the time coming where we will be able to say that maybe this year, NC is at great risk, or Florida the next and Texas after that? Just thought I would see what everyone thinks.

[weatherwindow]

although a lot is made of the numbers game ala Gray et al, this subject far outweighs it in importance. the reversal of the thermohaline cycle occurred almost 10 years ago(1995) with the widely publicized(and continuing) spike in storm formation. however, it had relatively little effect on the US. exluding the el nino years of 1997 and 2002, the average number of storms per year was 14. hence this year was somewhat average that regard. the caveat was, obviouslly, where they went! a one year reversal of the long wave pattern created all of this havoc. trough-ridge replacing the eight year run of ridge-trough opened the door to the US mainland and kept it open. with the resultant anamalously strong and westerly bermudal high, that pattern change made the difference between another busy season and catastrophe. we would be better off focussing on next year's tracking setup than on the numbers game....with regard to charley, that strong bermuda high was already in place. remember charley traverssed the entire caribbean on a wnwly course south of that high and reached well west of the east coast of the US before recurvving ahead of that trough. in previous years since 1995, many storms on charleys early track simply recurved over or east of the islands. obviously a different ball game this year. let us hope it is not to be repeated soon. i am also anxious to see everyone's thoughts in this area.....

[cycloneye]

I am not a pro met but an amateur person that has followed the tropics for more than 35 years.Only what I have to say is that the Atlantic Basin has since 1995 turned into an active cycle of seasons with a few exceptions being the strong el nino year of 1997 when a not active season occured.I fear in the next two decades of the active cycle that we will witnesss more landfalling hurricanes some of them powerful ones in the US coastline but changing areas in the different seasons.For example in 2004 Florida saw 5 tropical systems of which four were powerful hurricanes.But in 2005 may see a shift in landfalling areas as the patterns are in a constant change however still it is early to say with a concrete thinking where will in 2005 the landfalls may occur in the US.However as the active cycle in the atlantic will continue for the next decade or two in 2005 we will see another active season but without many major canes due to an east QBO factor that tends to inhibit systems to grow very strong.Also in 2005 we will have to watch the pacific because if the weak el nino now present grows more to a moderate/strong way (That I dont expect) then it will be like the 1997 season when the strong el nino capped most of that season.In summary my take is that the atlantic basin in the next 10-20 years will see more active seasons.

[wxman57]

If you look at my signature below, you'll see that I was one of the mets thinking that Florida was under-the-gun in 2004. While it's very difficult to take current conditions and use some sort of computer model to project where storms might go in a given season, one can analyze general climatological patterns and compare those patterns to what has happened in the past. That's more what Dr. Gray does.

What we could identify was that the Atlantic SSTs began an upward spike in 1995. History tells us that such spikes, caused by an increasing Atlantic Thermohaline Circulation, typically last 2-4 decades. It has been found that warmer SSTs are a major contributing factor toward hurricane intensification and development..

But as has been mentioned, it wasn't until recently that the tremendous number of major hurricanes since 1995 (38, I believe) began threatening the U.S. Atlantic & Pacific SSTs play a large part in determining the relative positions of highs/lows in the Northern Hemisphere. A warm Atlantic SST regime is good for development/intensification, but when combined with a cool east Pacific PDO (Pacific Decadal Oscillation), the mean position of the U.S./Atlantic ridge/trof axes tends to shift westward. from 1995 to 2003, there was a trof along the east U.S. coast for most of each season, helping to steer many hurricanes northward and out to sea before they reached the U.S. (or even the Caribbean).

Just so happens that very recently, the Pacific Decadal Oscillation switched phases to a pattern similar to back in the 1940s-1960s, when the U.S. was hit by a large number of powerful hurricanes. The PDO tends to last a couple of decades as well. So with a cool PDO in the eastern Pacific and above-normal Atlantic SSTs for decades to come, look for the mean trof to be displaced westward over the U.S. rather than along the east U.S. coast. This means hurricanes will recurve later, more likely threatening the U.S. for the next decade or two.

I think that the one thing that saved the western Gulf of Mexico this year (from Charley, for example), was the "funky" early season flow pattern that happened to develop in July. We actually had several moderate cold fronts move through Houston in late July/early August. That's something we typically see in October. There's no guarantee the same will happen in 2005. I think that once again, the U.S. will be at high risk of a major hurricane landfall in 2005. Florida and the southeat U.S. are right up there atop the list of most-likely landfall areas. And I think it'll be Texas's turn in 2005 as well.