Eta made landfall across the FL Keys overnight and has now moved west into the SE Gulf of Mexico.
Eta is the 12 landfalling tropical system on the US coast this season…the previous record was 9 in 1916.
Discussion:
Eta’s large center made landfall on the middle FL Keys late yesterday evening and has continued westward across FL Bay and is now over the SE Gulf of Mexico. Eta has maintained a fairly well defined circulation, but there has been a general lack of deep convection near the center. Numerous curved bands continue to rotate into southern FL where over 13 inches of rainfall has been recorded. The wind field of Eta has also expanded with tropical storm force winds extending well away from the center and well north along the FL coast.
Track:
Eta will move west to WSW for the next 24 hours steered by high pressure along the US east coast and the upper level trough over the NW Caribbean Sea. After 24 hours, Eta will begin to slow as steering currents collapse and the storm will begin to meander over the SE/E Gulf of Mexico into the middle of the week. It is possible that Eta stalls over the warm waters of the Gulf loop current. By later this week a strong upper level trough is expected to approach the southern plains and the northwest Gulf of Mexico and this feature should begin to turn Eta north and then northeast back toward FL. The ECMWF is the most consistent with this solution, while the GFS is completely different and shows a much weaker trough and drifts Eta west into the southern Gulf of Mexico. The NHC is indicating a slow northward and then NNE motion bringing Eta, toward the west coast of FL by late this week. Given the complex steering pattern toward the end of the week confidence is low regarding the track forecast and large changes remain possible.
Intensity:
Eta is entangled in the upper level trough over the NW Caribbean Sea and this is resulting in limited convection near the center, even though the storm is passing over warm waters. Wind shear and dry air is lurking around the system and limited convective bursts are likely a function of dry air intrusion into the center. As Eta moves into the SE Gulf of Mexico, there may be a window where shear relaxes allowing slightly more intensification, especially since Eta will be over the very warm and deep loop current waters. However, there is a massive amount of dry air surrounding Eta, and this dry air will likely intrude into the center at times keeping intensification in balance. The official forecast brings Eta to a minimal hurricane over the SE Gulf of Mexico before weaken as shear increases by late week.
Tropics:
Two other areas of interest have developed in the Atlantic basin and 97L over the eastern Atlantic has a high chance of developing into a tropical system while the tropical wave approaching the Caribbean has a medium chance of developing later this week. The next tropical storm will break the previous record for the most tropical storms in an Atlantic hurricane season.
Jeff Lindner
Director Hydrologic Operations Division/Meteorologist
Harris County Flood Control District