Continued quiet in the Atlantic
August 2, 2009
It was five years ago yesterday afternoon that Tropical Storm Alex formed and 29 years ago yesterday evening that Allen formed. With that, the 2009 season moves up the list of seasons late to have a tropical storm (year links point to the season’s Unisys page, hurricane links point to the storm’s Wikipedia page):
of first tropical storm (Zulu/UTC)
|1949||21 August||Hurricane #
In compiling this list, I went back to 1944, the first year of airborne storm reconaissance and one of the starting points for a reliable storm climatology. Out of season sub-tropical storms were not considered, but in-season ones were. This put 1992 on the list and keeps 1974 off (and affects the first storm date for 1984). Any list extending back more than a few years is going to have its limitations due to the increased amount of remote sensing data available.
A key thing to note when reviewing these seasons, is that while a few of the overall quietest seasons on record are on the list, these were not seasons without noteworthy storms. In fact, 7 of the 15 seasons (47%) featured a category five storm, which is a bit higher than climatology for the period (32%).
As we look at the Atlantic this morning, we see the basin as about quiet as can be. Some stray showers near Bermuda and that’s it. In the southeast, we see dry air pushing down to the ITCZ.
Looking further east, we see the latest thunderstorms to roll off the African coast along with the dry air just north of it. The GFS model has intermittently suggested a surface low forming from this over the next few days. A somewhat dubious propsect, but it is the only prospect of tropical cyclone formation out there at the moment. Regardless of what happens with this, we should see this season advance past 2000 on the list. If nothing materializes, 1988 and 1987 are likely to be surpassed as well before anything else threatens to form.