Loc: Orlando, FL
Tropical Storm Erika Forms East of the Leeward Islands
Sun Aug 30 2009 07:54 AM
4:50 PM EDT 1 Sep 2009 Update
More to Come soon, but the wave known as 94L has become Tropical Storm Erika.
It is moving West Northwest at 9MPH, and has 50mph winds.
The forecast track has it east of the Bahamas in 120 hours, and after that depends on how strong or weak the system gets. If it gets stronger, it will likely move more north and out to sea, while a weaker system will likely stay more westward.
6:20 AM EDT 1 Sep 2009 Update
The wave east of the Caribbean is looking good on satellite, but is missing the low level circulation it needs to become a tropical cyclone. This morning there are actually signs of that happening, but all the convection and storm energy seems to be the east of it. This is due to persistent shearing in the area keeping it a bit disorganized, which has been common this year. Ie, the low level is doing one thing, while the mid level is doing another.
It still has a greater than 50% chance of becoming a depression in the next 48 hours. By 11AM is likely today.
With the weaker system, the more west it goes. Those in the Leeward islands, Virgin Islands, and Puerto Rico will want to continue to watch this system. Models still have not been handling the initialization of the system well. However, the GFDL model, now no longer dissipates the system. Until this gets organized it is impossible to say if it will have any impact on the US or not, again odds are slightly in favor of it staying out to sea. The forecast for this system will likely be more difficult than most.
The other wave east of the Bahamas is mostly an upper level feature, but it has been persistent. But there are currently no signs of a low level move that would allow for development.
In the Pacific, Hurricane Jimena has become a strong Category 4 Hurricane nearing a Category 5, and is expected to landfall in Mexico along the Baja California Peninsula as a Category 3 hurricane .
9:40 AM EDT 31 Aug 2009 Update
There is a better chance this morning that a depression will form from 94L. The overall structure is there, but the convection around the center still lacks (see dvorak estimates). It looks fairly well this morning so it may become a depression at 11AM. There is some shear ahead of it, which may keep it from organizing, and also the circulation center is not under most of the convection, this may keep it from being upgraded.
The Windward islands of the Caribbean still need to watch 94L closely, and longer range models have bent back further west, which will keep the Bahamas and the southeast US in a monitor mode until it gets closer. Recon aircraft will start to head out there tomorrow.
Odds this year favor systems out to sea, but 94L has a better than usual chance of breaking it and heading more west. We will have to monitor it..
The wave east of the Bahamas (has no invest number) has little low level activity and is not likely to develop soon, it too is worth watching to see if anything changes with it.
The wave east of the Caribbean, 94L, has survived the last few days weak, and moved more west. It is now poised to develop today or tomorrow, it has greater than a 50% chance to develop within the next 48 hours.
Most forecast models have had a terrible time with this system, trending it north incorrectly over and over again. It remaining weak and mostly low level has kept it more on a westerly track. If and until this develops, the models will not be of much worth with it. That said, those in the Leeward and Windward Caribbean islands need to watch this system. It may strengthen some then weaken again. There is some shear north of the system, so the further south and west it stays the more chance it has for survival.
If it does develop movement to the northwest and north is more likely, and the odds are that it will not affect the US if it does.
The best course of action is to continue to wait and see what occurs with the system.
Other things to watch include a smaller wave north of the Lesser Antilles, and energy in the Southwestern Caribbean for any persistence.