Special tropical weather analysis - February 5, 2012
I never thought I'd be doing this in February. Oh well, it could be quite interesting.
For the last several days, a preexisting, quasi-stationary area of cloudiness and showers has overtaken much of the western Caribbean Sea, as well portions of the western Atlantic and eastern Gulf of Mexico. This activity appears to have been primarily related to a surface trough interacting with an upper-level trough/cold front. Meandering over the still warm waters of the western Caribbean (approximately 26°C to 27°C), the system eventually began to acquire a somewhat organized, albeit highly sheared, appearance in satellite imagery.
Today, finally, the system piqued the curiosity of the National Hurricane Center (NHC), and was officially designated an investigative area ("90L"). The low pressure center appears to be situated in the Yucatan Channel, between Yucatan and western Cuba. Objective analysis of available data suggests that the surface circulation associated with this low has become better-defined today.
Strong upper-level southwesterly vertical wind shear is keeping the shower activity confined well downstream of the low-level center.
Figure 1. Latest infrared satellite image of Invest 90L, courtesy of RAMMB imagery, Colorado State University (CSU).
It is important to note that this is only a reflection of the upper-tropospheric shear; mid-level shear is much lower. With mid-level shear values forecast to remain generally in the 15 to 30 kt range, there may be just enough potential for this low to acquire subtropical characteristics over the next day or so before it merges with a frontal zone in about 36 hours.
As a cold front over the Gulf of Mexico approaches the storm from the west, the low should accelerate north-northeastward relatively soon. This heading will take it in the direction of south Florida by early Monday evening.
Regardless of development, locally heavy rainfall and strong gusty winds are likely over portions of western Cuba, the Florida Keys, and south Florida through Monday.
It should be noted that if this system becomes a subtropical or tropical cyclone, it would be the first such occurrence since a tropical storm formed on Groundhog Day in 1952. This storm took a similar path across extreme south Florida and into the western Atlantic. The 1952 storm is the only recorded incidence of a February tropical or subtropical cyclone in the historical record, which dates back to 1851. So if this system forms, it will be truly remarkable.
Before closing, I want to emphasize that early season activity has literally no correlation to the rest of the season. So even if this storm becomes Alberto, one would be hard-pressed to claim any sort of correlation between this event and the rest of the season. Remember, conjecture and speculation do not mesh well with science, where actual evidence matters, not hunches.
Genesis probability (through 48 hours): 30%