This mornings discussion from Rob of Crown Weather:
http://www.crownweather.com/?page_id=4557Invest 97L Located 400 Miles East Of The Lesser Antilles:
Satellite imagery this morning indicated that Invest 97L has become better organized overnight with deeper convection developing over or very near a developing center. The developing center appears to be located about 400 miles east of the island of St. Lucia. Movement based on satellite loops appears to be tracking west-northwestward. Further organization is likely this weekend and it would not surprise me to see it upgraded to a Tropical Depression or even a Tropical Storm late this afternoon or this evening once reconnaissance aircraft investigate it.
I urge all of our friends in the Leeward Islands, Virgin Islands and Puerto Rico to closely monitor this developing system. As it looks right now, heavy rainfall with strong gusty winds of up to 40 to 50 mph can be expected across the Leeward Islands from this afternoon through Sunday. As for the Virgin Islands, it appears that heavy rainfall with tropical storm force winds and rough seas can be expected starting Sunday afternoon and continuing through Sunday night and into much of Monday. For Puerto Rico, heavy rainfall with tropical storm force winds and very rough seas, especially on the south coast, can be expected starting late Sunday night and continuing through Monday and Monday night and into part of Tuesday. It should be pointed out that hurricane conditions are possible on the south coast of Puerto Rico should this system strengthen more than what is forecast now.
As it stands right now, 97L will reach the eastern Caribbean during Sunday afternoon where it will slow down some in forward speed and potentially start to strengthen significantly as it bundles energy and takes advantage of a favorable environment and very warm ocean waters.
Now, let’s look into next week and how this system could impact the rest of the Caribbean and then potentially the eastern US Gulf Coast and Florida. The latest global model guidance have shifted a little bit to the east.
The Canadian and UKMET models are on the furthest west side of the guidance envelope with the Canadian model showing a track through the Yucatan Channel & then landfall in New Orleans next Sunday morning.
The latest GFS operational model forecasts a track that takes 97L just south of Hispaniola and then tracks it across central and western Cuba and into southwestern Florida on Friday.
The latest European operational model forecasts a track that takes this system just south of Hispaniola and then across central Cuba on Thursday before tracking across southern and western Florida on Friday into Saturday. This type of track would significantly impact all of the major cities in Florida, including Miami, Orlando, Tampa and Jacksonville.
The GFS ensemble guidance forecasts a track that takes 97L south of Hispaniola and then skirts the south coast of Cuba before crossing central/western Cuba on Thursday. The GFS ensemble guidance then forecasts a track that takes this system just off of the west coast of Florida before making landfall about halfway between Tampa and Cedar Key next Saturday night.
The European ensemble guidance forecasts a track that takes this system across western Cuba on Thursday night and has it in the eastern Gulf of Mexico due west of Tampa near 86 West Longitude next Saturday evening. The mean of all of the ensemble members of the European model forecasts landfall near Mobile, Alabama next Sunday night, however, there is a huge amount of spread in the ensemble members at that time with some members as far east as the eastern North Carolina with others as far west as Galveston, Texas.
The consensus track guidance, like the TVCN & TVCC models forecast a track that is further north than the global operational and ensemble guidance. They forecast a track that takes this system just a hair south of Puerto Rico on Sunday night and then right across Hispaniola on Monday night into Tuesday before skirting the northeastern coast of Cuba on Tuesday night into Wednesday. The consensus track guidance then forecasts a turn to the north and ultimately takes this system into the east of Florida very near Vero Beach.
Even though the model guidance as a whole has shifted a little to the east in their overall forecasts, I think given the overall upper air pattern this summer of the southern US high pressure system holding strong and the tendency for the model guidance to erroneously weaken it, I would say the consensus track guidance (TVCC/TVCN models) is too far north and that I think this system’s track will be like the GFS ensemble and European ensemble model means.
What does this mean? Basically I think it will track to the south of Hispaniola from Monday evening to Tuesday evening and then track about halfway between the north coast of Jamaica and the south coast of Cuba later Wednesday. A track across western Cuba on Friday seems reasonable at this time. After that, I think this system will track into the eastern Gulf of Mexico next Saturday with a potential landfall anywhere between Mobile, Alabama and Naples, Florida between next Saturday night and next Sunday night. Based on the entire upper air pattern over the next week to ten days, I think the Florida Peninsula has the highest chance of feeling the full impact of this system, however, whether it comes ashore over southwest Florida or up near the Big Bend of Florida cannot be resolved at this time.
I want to strongly caution that there is a high amount of uncertainty with this forecast as a center has not fully developed. Once we get a fully developed center of circulation, then the track forecasts for this system will become more resolved and better defined. I do think that the ridge of high pressure is being modeled too weak and that the ridge of high pressure will be stronger in the end leading to a further south and west track.
I strongly urge all of our Crown Weather friends across the Caribbean, the central and eastern Gulf coast, the entire Florida Peninsula and the US Southeast coast north to Cape Hatteras to closely monitor this system and go over your hurricane preparedness kits and think about what you would do in case of Hurricane Watches & Warnings. I will be monitoring this developing system extremely closely and I will keep you all updated.
I will write up an update to this discussion should 97L be upgraded to a Tropical Depression or a Tropical Storm this afternoon or this evening; otherwise the next full tropical weather discussion will be issued by 11 am EDT/10 am CDT Sunday morning.
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