You can't predict the weather, concludes Carvill's ReAdvisory

In terms of the number of storms and their generic category, 2007 was an average to above-average year when compared to the average number of storms experienced since 1900.

However, 2007 was a significantly below average year in the current period of increased hurricane activity. Indeed, 2007 is very similar in this regard to both 2002 and 2006.

This is according to ReAdvisory’s 2007 hurricane season wrap-up.

Four named storms made landfall along the US coast in 2007 – Barry, Erin, Gabrielle and Humberto.

The problem is compounded by the fact that several storms in 2007 conspired to break a number of records. For example:

  • 2007 was the first year in the record where two Category 5 storms have made landfall as Category 5’s (Dean and Felix).
  • Hurricane Felix set an Atlantic record for the fastest time to reach Category 5 status from the time of first report – 51 hours (NHC Advisory 1 at 1600 CDT on 8/31 to Advisory 10 at 1900 CDT on 9/2).
  • Hurricane Humberto set the record for the fastest time from first report to Category 1 status – 14 hours and 15 minutes (NHC Advisory 1 at 1000 CDT on 9/12 to Advisory 4 at 0015 CDT on 9/13).
  • Hurricane Lorenzo set the record for fastest intensification from tropical depression to Category 1 status – 9 hours (NHC Advisory 8 at 1000 CDT on 9/27 to Advisory 10A at 1900 CDT on 9/27).

While Humberto and Lorenzo were, in the grand scheme of Atlantic hurricanes, unimpressive Category 1 storms at their peak, they did both exhibit rather interesting behavior.

Both storms put on their record-setting intensifications while very close to land. Typically storms weaken before landfall but both Humberto and Lorenzo strengthened into landfall.

According to ReAdvisory, 2007 presents a conflicting set of data.

At the beginning of the season, the factors influencing hurricane activity pointed to an above average season.

The results of the 2007 season, depending on how one examines the data, show a below average season.

Several predictions were borne out (namely intense storms in the Caribbean and Gulf of Mexico) but, in general, the seasonal forecasts over-predicted the seasonal activity.

While the season was impacted by an unforeseen influence (increased dust over the Atlantic) recent work has shown that the ability of seasonal forecasts to predict the actual activity is limited and we should not be entirely surprised that the forecasts were not correct.