JACKSONVILLE, Fla – So much for Tropical Depression Kirk. It ran out of steam just like a runner with bad pacing.
Kirk clipped along at 25 mph which is double the average speed for a tropical cyclone just 10 degrees north of the equator.
At that rate, Kirk constantly struggled to organize and no longer exists.
Faster moving storms often suffer the consequences of weakening due to the influence of stronger winds aloft.
So what is a normal pace after all in the Atlantic? The answer depends on the latitude of the storm.
Hurricanes east of Jacksonville typically average 17 mph, but often slow down as they recurve or turn more northerly from their westward track.
Storms move slower around 12 mph between 10°-15° North.
When hurricanes track west in the Atlantic, they typically are driven along by the subtropical high-pressure ridge in the western Atlantic.
This feature results in fairly constant movement because of the ridge’s unwavering presence in sending a large fetch of easterly trade winds.
But around the mid-latitudes, upper-level troughs pick up and speed storms over 50 mph around 45°-50° North.
The fastest hurricane in the record was Emily in 1987, whose maximum speed reached 68.65 mph as it raced over the North Atlantic.
Hurricanes that generate major tornado outbreaks typically have forward speeds from about 8-18 mph.
Hurricane Ivan was an example of a large hurricane in 2004 that caused a multi-day outbreak of 127 tornadoes, with the bulk of the tornadoes on Sept. 17 in the mid-Atlantic region.