Irene is gone, focus turns to 92L
It has been a long time since I have done a blog entry, so I thought I would give it a shot!
Atlantic Wide View Infrared:
What's left of Irene is now moving through Southeast Canada and should continue to transition into an extra-tropical cyclone. In the Gulf of Mexico, northwest flow aloft prevails due to the 4-Corners States' ridge (i.e. Texas Death Ridge) and the presence of a large trough over the Eastern United States induced by Irene's circulation. The Caribbean is disturbed because of weak tropical wave in the Western Caribbean and an upper level low in the Eastern Caribbean. The Eastern Caribbean upper low is the one that helped ventilate Hurricane Irene. Tropical Storm Jose is moving harmlessly out to sea northwest of Bermuda and should dissipate within 36 hours. An African waved, tagged 92L, is entering the picture south of the Cape Verde Islands and will be the next big story in the Tropical Atlantic.
92L is set to become the next big story in the tropics. The NHC is giving 92L a near 100% chance of development as of the 8/28/2011 8:00pm TWO. I would have to agree with the percentage and believe that 92L will become a tropical depression by the 5AM advisory, or the 11AM advisory at the latest. 92L is embedded within slower easterlies than we have seen so far this season, so the movement to the west will be slower than normal. The 00z SHIPS intensity forecast brings 92L up to 100kts in 120 hours. We have seen time and time again this season that the models tend to over-do development in the Eastern Atlantic, so I'm more inclined to believe in gradual strengthening. However, we must remember that the Eastern Atlantic is reaching its prime-time for development and it is much easier for a wave to quickly develop there now than earlier in the season when we were loaded with SAL. I would expect a quicker jump in intensity closer to 50W since at that point 92L will have a lot more heat to help with intensification.
As we can see, SAL is almost non-existent across the Atlantic Basin.
Current steering for 92L is pretty basic and shouldn't change much over the next 2-3 days. It should be steered basically due west tomorrow, with possibly a more northward component in 3 days. At that time, a lot is going to depend on how quickly 92L strengthens. As most of us know already, a deeper (stronger) storm is much more likely to feel any weakness to its north and will be tugged towards the weakness. However, a weaker system is more likely to continue west.
After 50W, I don't see much to limit 92L from strengthening quickly as TCHP and SSTs will be prime. SAL is at a season low and should not be an issue. The only impediment could be any sort of TUTT or cut-off upper low that could be meandering around just north of the Antilles.
At this time, I believe a track north of the island chain and Puerto Rico is most likely. A trough is being forecast to stall and split near or just east of Bermuda in the coming 4-5 day period. A tropical cyclone or hybrid low is forecast by the models to form out of this trough and it leads to the first weakness which would pull possible Katia north of the islands. However, this is far out and forecasting cut-off lows/trough-splits that far out is very difficult for the models. At this time, I believe Puerto Rico and the northern-most islands should keep a close eye on 92L. Steering and intensity will become more clear in the next few days.
Elsewhere in the tropics, the Gulf of Mexico states, particularly Texas and Louisiana, should keep an eye out for a possible tropical disturbance in the middle part of the week. The 00z NAM brings a tropical wave into the Central Gulf and develops it into a tropical storm. The NAM is not the most reliable model at forecasting tropical cyclone genesis, but the GFS and European models have both shown a disturbed area of weather moving through the same location at the same time frame. I believe it will still be difficult for anything to develop in the Gulf since the Texas Ridge will be moving towards the Ozarks region and should cause a great deal of subsidence across the Gulf. We will keep a look out in the next couple of days to see what happens.
Thanks for reading!