Saturday, September 01, 2012

Updating The Tropics At Start Of September

The tropics are active still -- with two storms spinning around in the middle of the Atlantic, one won't impact the East Coast, the other is likely to avoid impacting the US East Coast.

The smaller storm that's in the center of the below graphic is Kirk, sporting 75 mph max winds as of this morning.  Kirk was stronger yesterday and has had some shear impact its eastern side, weakening it a bit from yesterday's 105 mph max.  It is about to be beamed up into the westerlies out ahead of a trough that's pushing off of the East Coast and will scoot into the North Atlantic, likely to transition into a nontropical entity by Monday.

The southern system, Leslie, is a much larger storm but is a bit weaker, with 70 mph max winds as of this morning.  Leslie is working west-northwest through the Atlantic and will continue to nudge more northwest and then northerly over the coming days. It will also be pushing into some wind shear from an upper trough just to the northeast of the Bahamas.  While it may briefly reach hurricane status today or tomorrow, the potential for wind shear increasing over the next several days may cause it to weaken a fair bit.

Modeling with Leslie keeps the storm safely to our east and most models keep Leslie to the east of Bermuda as it rounds the subtropical ridge.  Leslie will slow markedly over the coming days, however, as the trough that picked up Kirk misses out on taking Leslie as well.  However, a second trough will eventually help nudge Leslie along late next week.  We'll keep a slight eye on it but all computer modeling at this point keeps it away from the East Coast.

For now, the tropics look like they will settle down a fair bit after Leslie moves through as the main upper level pattern for tropical development because more unfavorable.  The next signs of possible development in the Atlantic reside in about two weeks if the GFS is right.