Lots of excitement in the weather world about Invest 90L. Even though the hurricane center tracks and monitors these storms this in not a tropical storm or hurricane. Far from it…. it will more likely just be a sub-tropical storm. What’s that you ask? NHC(National Hurricane Center) defines them like this.
“A non-frontal low-pressure system that has characteristics of both tropical and extratropical cyclones. Like tropical cyclones, they are non-frontal, synoptic-scale cyclones that originate over tropical or subtropical waters, and have a closed surface wind circulation about a well-defined center. In addition, they have organized moderate to deep convection, but lack a central dense overcast. Unlike tropical cyclones, subtropical cyclones derive a significant proportion of their energy from baroclinic sources, and are generally cold-core in the upper troposphere, often being associated with an upper-level low or trough. In comparison to tropical cyclones, these systems generally have a radius of maximum winds occurring relatively far from the center (usually greater than 60 n mi), and generally have a less symmetric wind field and distribution of convection.”
The hurricane center didn’t even start giving these storms names until 2002. Before then they just received numbers. There has been at least one “real” tropical storm to form in February that was in 1952 called the Groundhog Day Storm. Here’s what Wikipedia says about that storm.
The 1952 Groundhog Day Storm was the only Atlantic tropical cyclone on record in the month of February. First observed in the western Caribbean Sea on February 2, it moved rapidly throughout its duration and struck southwestern Florida within 24 hours of forming. In the state, the winds damaged some crops and power lines, but no serious damage was reported.
Invest 90L will likely be just a big rain maker for Florida and bring some gusty winds to the north and east of the track. The water temperatures and satellite presentation make this more of a glorified Nor’easter than a tropical system. Some fun to watch as the tropical models plot it’s course and it will bring some much needed rain to Florida. If it does become a full fledge subtropical storm it will receive the name Alberto which comes from the 2012 Atlantic Hurricane name list thanks to the change in naming that started in 2002.
More info on Subtropical versus Tropical may be found on the Weather Underground.
Also on the National Hurricane Center Page.