Well, do ya miss them?

This past Friday marked the Autumnal equinox and is denoted by the sun being directly over the equator. It is also typically a very busy time for hurricanes in the Northern Hemisphere but despite dire predictions that this year would roughly match or be slightly lower than the events of last season it has been a rather benign year for land falling hurricanes in the Atlantic Basin.

Here is last years map chart-


We are only up to tropical systems beginning with the letter "H" so far as compared to already reaching the letter R this time last year. That is quite a difference! Sea Surface Temperatures are a key ingredient to fueling these storms and they are above normal in the Atlantic and the Caribbean this year. There have been a number of disturbances coming off of Africa that have formed into depressions, Tropical Storms and Hurricanes but none of them of any consequence have landed here in the US. Why?

Steering currents in the North Atlantic have re-curved many of the systems well East of where they would normally travel. The western edge of the Bermuda High just has not built in this year and this has allowed an early turn to the north for many of the developing systems.

Sputtering…For whatever reason (and there of lots of thoughts on this) the storms have been slow to go from depressions to full blown hurricanes. Saharan desert dust has been in greater abundance this year over the Atlantic. Could it be that this is somehow hindering the evaporation? Or are the tiny particles of dust slowing the development of the storms once they are entrained into the system? Studies will have to be performed but right now it is simply an observation that the developmental cycle of the cyclones seems slower than normal this year given the atmospherics and warm SSTs that would normally kick storms into gear faster than they are.

The gauntlet of upper level lows….Upper level lows and their associated winds that operate at higher levels in the atmosphere have been wandering around the Atlantic in greater abundance than they were last year. Few things hurt the development of a tropical cyclone more than shear and when there is an upper level system in the area, it puts the brakes on existing or developing cyclones.

El Nino on the way back…It is clear that the beginnings of an el Nino are returning to the waters off Peru and there is now a huge pool of warmer than normal water in the Western Pacific. This means several things but among them- Diminished Atlantic Hurricane development (In terms of the number of storms NOT their intensity) and a wetter than normal winter for those of us here in California.

No matter what the reason, this year's hurricane season has produced little in the way of TERROR the way last season did to the United states coast lines. This does NOT mean that we are out of the woods. In fact in some el Nino cycles massive and very intense Hurricanes like Mitch develop and ravage coast lines. Just ask the people in Belize who received 20+ inches of rain in less than 24 hours killing more than 11,000 people. It formed toward the end of the 1997-8 el Nino cycle but is proof positive that the most destructive of storms on earth can form during one of these cycles.

If the upper level lows and weakness in the Bermuda High continue then I believe that we are in for a safer than normal year for those on the East and Gulf coasts than normal but this does not mean that you should let your guard down. In fact, just the opposite. With no major storms developing in these normally tepid waters and assisting in rebalancing the sea surface temperatures the possibility of a Category four or five storm grows even more likely. Keep your guard up as September and October are the busiest months and the lack of big storms so far does not in any way indicate that it won't end up being a massively destructive year again. (Knock wood right now if you live in Hurricane prone areas)

If and when they do form though, we'll be watching and forecasting their progress. Comments?

Mark Michaelsen


09/27/06