… a controversy is brewing over decisions of the National Hurricane Center to designate several borderline systems as tropical storms.

Some meteorologists, including former hurricane center director Neil Frank, say as many as six of this year’s 14 named tropical systems might have failed in earlier decades to earn “named storm” status.
…such information is vital to scientists trying to determine whether global warming has had a measurable impact on hurricane activity.

Likewise, no one should be surprised if we have Tropical Storm Humberto and/or Ingrid by later today or tomorrow.

Any bets on whether TD 9 will be Ingrid or Humberto?

Our best guess is the TD 9 will be Humberto and TD 8 will be Ingrid. [Turned out to be the way it happend. ]While TD 8 looks more impressive on the satellite, an Air Force aircraft will be investigating TD 9 sooner than TD 8 and given its proximity to Texas, it will likely be named first. [As time showed, Humberto’s overall organization improved very quickly after this post.]

Maximum winds were 165 mpg with gusts reaching 200 mph with a centeral pressure of 906 mb.

The 1935 Labor Day hurricane (892 mb) which hit the Florida Keys.
Hurricane Gilbert (900 mb estimated) hit Cancun, Mexico in 1988.

Only 8 other Category 5 Hurricanes have hit land in recorded history: Hurricane Andrew in 1992 (165 mph winds at landfall) and Hurricane Camille in 1969 were two others.

Hurricane Wilma (2005) remains the strongest Atlantic hurricane with 882 millibars while the strongest Pacific storm was Typhoon Tip (1979) with 870 mb and 190 mph winds.

Currently the model consensus has Dean passing directly over Jamaica. Several things should be noted. If the eye of Hurricane Dean does pass directly over Jamaica, the high elevations of Jamaica should disrupt the storm significantly. Simiarly, if the eye passes near enough to Jamaica the mountainous terrain will likewise disrupt Dean, the question is how much of an impact the mountains will have.

All that said, it will be interesting to see how accurate the models are. Given that we are still around 40 hours away from a potential Jamaica impact, much can changed based on the speed that Dean continues to move westward. Dean’s westward speed will determine how much various features (e.g. the high over the SE US right now) move Hurricane Dean around. A slowing Dean (now 18 mph speed) will probably lead to a more southerly track whereas a faster moving Dean would lead to a more northerly track the farther out you go.

Up to 72 hours models are generally pretty accurate (some exceptions such as Hurricane Erin in 1995 when bad data was entered) so take precautions now. For more than 48 hours, everyone from Florida, through the Gulf Coast down to Central America should watch this storm and be prepared to take action as directed by local authorities. As you can see (as of 11pm, August 17, 2007), the NHC has a large area still in the 5% Tropical Storm Force Wind Speed Probabilities.

Preparation is key.

To see where we stand, let’s recall some other record breaking years, starting with 2005 which as we all know was a record-breaking season. If you had to guess, how many storms had formed by the end of June 2005? Well? 5? 7? By June 30, 2005, there had been a total of 2 storms - Arlene and Bret. It wasn’t until July 5 that we had both Tropical Storm Cindy and Dennis. We had Emily on July 11th and then Franklin on July 22. Gert arrived on July 23. So, we had 2 storms through the end of June in 2005 and 7 storms by the end of July 2005.

The second busiest season was 1933 had one storm form in May and one storm form in June. Just like 2007. July ended with five storms and the season ended with 21 storms. 1934 also had one May storm and one June storm, and three storms by the end of July, again just like 2007. It ended with 11 storms. So a record breaking season, and a below average season both had the same number of storms by the end of June.

Now, looking at 2004, another season that was memorable. By the end of June 2004 we already had 0 storms. Zero? Seriously? Yes. Alex didn’t arrive until July 31st. But by the end of August 2004 though, we had already had Hermine. 2004 was memorable not for the shear number of storms, but for the places they hit.

Some other seasons:
2002: 1 by the end of July, season ended with Lili.
2003: By June 30th, we had had Ana (April 20-24) and Bill (June 29-July 02) and we ended up the season with Peter.
2004: Zero storms by the end of June and 1 on July 31st. Ended with Otto.
2005: 2 storms by the end of June and ended with Zeta.
2006: 1 storm by the end of June, 3 by the end of July, ended with Isaac.

(Interesting note, in 1981, Arlene formed on May 6-May 9 and Bret from June 29-July 1, so the season was similar to 2007 so far and 1981 ended with 12 storms including a subtropical storm in November).

So what does it mean that there have “only” been two storms by the end of June, 2007? Absolutely nothing in our view. Busy seasons like 2005 and 1933 have had a June like this, while more quiet seasons like 1981 and 1934 have had similar Junes.

In fact, there are only 13 known seasons (as of 2007) since 1851 that have had 2 tropical storms form in June. June 2007 has only had one storm form during the month, but one in May.

The Chicken Littles would have you think that the Junes of 2005, 2006, and 2007 should be significantly worse than the Junes of 1933 and 1934 given we’ve had nearly 75 years of carbon emissions. Perhaps the link isn’t quite as strong as some people want to believe? Remember that it only takes one storm - see Andrew, the first storm of the season in 1992 hitting Miami - to have a devastating and memorable season. Preparation is key whether we have one storm or ten storms.

Will 2007 be a busy season? We’ll let you know in November 2007, but it is difficult to predict the rest of the season based on the season up through June.

The article includes this quotation:

Climate stability has never been a feature of planet Earth. The only constant about climate is change; it changes continually and, at times, quite rapidly. Many times in the past, temperatures were far higher than today, and occasionally, temperatures were colder. As recently as 6,000 years ago, it was about 3C warmer than now. Ten thousand years ago, while the world was coming out of the thou-sand-year-long “Younger Dryas” cold episode, temperatures rose as much as 6C in a decade — 100 times faster than the past century’s 0.6C warming that has so upset environmentalists.

(more…)

Hurricane Hunters did find flight level winds around 60 miles per hour around 2-3pm EDT today while at 500 feet, so there are some good winds in the area but no organization - which is obvious from the satellite views. Lots of rain and some convection. Likewise the hurricane hunters found a pretty low pressure for a system with such poor organization - around 1000 MB (which is around 29.53 inches of mercury).

The primary impact so far for those of us in Florida is rain in the southern 3/4 of the state which is certainly welcome.

We’ll keep you informed as more information is known.

• NHC/NOAA Hurricane forecast summary:
13 to 17 tropical storms
7 to 10 of them becoming hurricanes.
75% chance of above normal hurricane activity according to the NOAA’s NHC.

Other people are predicting:
• William Gray from Colorado State predicts 17 named storms with 9 hurricanes.
• AccuWeather calls for 13-14 tropical storms with 9 becoming hurricanes.
• Tropical Storm Risk (back in March) expected to bring 17 tropical storms, of which nine will strengthen into hurricanes.

Essentially all within the same ball-park.

What does this MEAN? It means that the experts think that we’ll have a busy season - we may or we may not, see below. So what should you do now? You have two choices: prepare now and be ready if a hurricane hits your area or don’t prepare and have no options. Preparation is a pretty simple matter when you have time to prepare, so the smart choice is to be ready.

In our view, these forecasts are an educated guess based on statistical analysis of previous seasons as applied to current seasons’ weather patterns. There is currently no magic box (or even sophisticated computer program) that can provide an accurate forecast for the number of storms. That said, the annual predictions are a worthwhile exercise in order to advance our knowledge. Studying current weather patterns, comparing these patterns with previous years, and then attempting to forecast based on the intersection between the two advances our knowledge incrementally and advancing knowledge is very worthwhile.

When the actual number of storms falls near the long term average, the forecasts are general correct since the forecasters generally end up predicting trends near the average while adjusting for various well known factors. The way forecasting works (usually) is you start with a long term average as your prediction and then you adjust it up or down based on various factors. For example, El Nino or La Nina’s presence or lack thereof will cause forecasters to adjust their predictions up or down. Patterns over the Atlantic, dust or lack of dust from Africa work similarly. Sea surface temperatures impact the forecasts also. It is merely a matter of how much each factor will impact storm formation and whether the impact will be up or down.

Let’s recall previous year predictions compared with the actually events. Please remember, the forecasters do their best with the knowledge they have.

****2006****
2006 ended with 10 named storms (one between Alberto and Beryl that was unnamed during the season and only identified in the post-season analysis).
CSU had predicted 17 storms
AccuWeather: 6 tropical cyclones (3 major) will strike US coast (none did), with a total number “above average”
NHC/NOAA predicted:
* 13-16 named storms (hurricanes and tropical storms)
* 8-10 of which will become hurricanes
* 4-6 of which will be major hurricanes (category 3 or higher)

In summary, the number of storms was well below predictions.

****2005*****
Actual: 28 tropical storms, 15 hurricanes, 7 major
CSU’s May forecast, predicted 13 named storms for 2005, which was obviously well off.
NOAA: 12-15 Storms, 7-9 hurricanes, 3-5 of them major

In short, the number of storms greatly exceeded pre-season predictions.

****2004****
Actual: 15 storms, 9 hurricanes, 6 major
NOAA: 12-15 Storms, 6-8 hurricanes, 2-4 major
CSU: 14 storms, 8 hurricanes, 3 major (May 2004 forecast)

The number of storms in 2004 fell in the average range and consequently pre-season predictions were quite accurate, only fall well below actual numbers in the “major storms” category.