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A late look at Invest93L

By: Dr. Jeff Masters, 6:52 AM GMT on June 27, 2009

Hi everybody, this is Rob Carver, R&D Scientist for Wunderground, filling in for Jeff Masters.

Summary of the situation

In the Tropical Weather Outlook NHC has tagged a tropical wave in the NW Caribbean Sea as Invest93L and believes that it has a 30-50% chance of developing into a tropical cyclone in the next 48 hours. As of now (11 PM PDT, June 26), the Hurricane Hunters are scheduled to investigate this area on June 28. The track models have Invest93L moving through the Yucatan Straits into the Gulf of Mexico. After that, most of the models take the cyclone north and east making landfall along a wide swath of Florida's Gulf Coast on Wednesday of next week. The intensity models predict that at landfall, the system will be a weak Category 1 hurricane or strong tropical storm.

Figure 1. Plot of upper-level wind shear from CIMSS

Wind Shear Aloft

The wind shear patterns are favorable for intensification of Invest93L if it can make it through the Yucatan Straits. Figure 1 shows that currently, Invest93L is an unfavorable environment, with shear > 20 knots. However, north of the Yucatan Straits and SW of Florida, the shear drops to a favorable 5 knots. Both the GFS and NAM predict that that this shear pattern will be fairly constant over the next several days. Also, the water temperatures in the Gulf of Mexico are either normal or slightly above normal, so that will be favorable for storm development.

What happens next?
If Invest93L can survive long enough to get in the Gulf of Mexico, then I believe it can develop into TS Ana, the first named storm of the year. However, survival is not guaranteed, the convection around Invest93L is not that persistent. That said, people with interests along the coast of the Gulf of Mexico should keep an eye on this storm this weekend and into the early part of the next week.

Rob Carver


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.