"Isaac" Remnants in the Gulf of Mexico But Would Get New Name IF it Develops; Twin Hurricanes: "Leslie" & "Michael" (Not Buresh)...........
***** A high rip current risk at First Coast beaches due to easterly swells from "Leslie" through at least Fri. & probably into the weekend - use caution at area beaches *****
The mid & upper level disturbance that was "Isaac" has made it back into the Gulf of Mexico & is still accompanied by a persistent cluster of showers & t'storms, especially in the south quadrant of the circulation though is otherwise disorganized. There remains a good deal of shear -- 25+ mph -- over the E. Gulf on the backside of an upper low sitting over/near the Bahamas. Forecast models still show a weak surface low over developing over the Gulf of Mexico but that's about it. Shear will increase even more this weekend as an upper level trough digs into the Eastern U.S. which could be the primary limiting factor. The "window of opportunity for this disturbance is probably no more than through early Sat. Models do not develop a strong low, but this is something to watch as the eventual interaction with the strong upper level trough that moves into the Eastern U.S. this weekend could give the disturbance a bit of a boost (upper level divergence) despite increasing mid & upper level shear. The upper level storm system should eventually pull the surface system east/northeast although if it continues to drop steadily south/southwest, it's possible the trough could miss the low . The combination of the tropical disturbance + the strong upper trough should lead to the potential for heavy rain for the First Coast (& much of the Southeast U.S. & Gulf Coast) by the weekend. Here is the Nat. Hurricane Center's reasoning on labeling this disturbance a new name ("Nadine"):
"Our analysis of the satellite, surface, and lower-tropospheric radiosonde data suggested that the disturbance we're currently following originated within Isaac's broad circulation, but that it had its own surface pressure minimum distinct from Isaac's. This was perhaps most apparent late in the day on Monday, when the residual surface center of Isaac was located over western Kentucky while a second weak low was located over northern Mississippi and Alabama. Isaac's circulation continued to weaken after that and became difficult to track, while the new disturbance moved slowly toward the Gulf coast. So what basically happened here is that a little piece of Isaac broke away and moved south.
OK, now everybody get your lawyer and grammar hats on. The National Weather Service rule that applies here reads: "if the remnant of a tropical cyclone redevelops into a tropical cyclone, it is assigned its original number or name".
Notice the rule says "the" remnant, and not "a" remnant. This means that the storm's primary remnant (and not just any old part of it) has to re-develop in order for the name to be retained. Since the primary remnant of Isaac was still in Kentucky when the new low formed and broke away, the rule dictates that the new low is not entitled to the name Isaac.
This rule actually makes a lot of sense. If a storm died and each of two parts re-developed, we couldn't give the same name to both parts. Only the primary remnant would retain the name, while a lesser remnant or part would get a new name."
IMAGE FROM LAST THU., AUG. 30TH:
is still battling some shear & dry mid & upper level air but remains a broad hurricane. The upper level trough in the NW Atlantic will not entirely pick up the cyclone leaving "Leslie" in a weak steering flow which will cause the storm to stall at or just north of Jacksonville's latitude in the Central Atlantic. There could be a momentary jog west but indications are that "Leslie" will still get steered north then northeast in time. If we look at the W. Pacific last week, the 2nd typhoon moved to the China coast west & southwest of Japan, so we'll have to beware of a farther west track in the long run than forecast models are currently indicating but still no threat to the First Coast other than rough seas/surf. All will hinge on the timing & intensity of the strong upper level trough that will dig into the Eastern U.S. late this weekend. "Leslie" should start to increase its forward speed to the north or north/northwest as the trough approaches moving near Bermuda Sunday. Very rough & dangerous surf will likely affect New England this weekend & parts of Nova Scotia &/or Newfoundland could be directly impacted late in the weekend into early next week.
In any case... "Leslie" will be strong enough & large enough to continue to send an easterly swell to First Coast beaches through at least Fri. increasing the rip current risk....with at least an elevated risk continuing into the weekend.
"Michael" (not Buresh!) became the 7th hurricane this season in the Atlantic Basin Wed. undergoing rapid intensification & is now the first "major" (Cat. 3+) of the Atlantic season. The hurricane is likely to only move very slowly to the north then turn northwest & is no immediate threat to any land areas. There may be some eventual interaction with much bigger "Leslie" in the N. Atlantic next week.
A wave in the far E. Atlantic well south of "Michael" & southeast of "Leslie" at a much lower latitude has been stretched by shear. This wave will move just about due west the next few days. Another strong wave is just coming off the coast of Africa. A new named storm seems likely in the Atlantic Basin next week.