Thursday, July 9, 2009

Atlantic Tropical Outlook

The tropical Atlantic basin continues to remain very quiet with only a few areas worth mentioning. A small tropical wave centered near 11 N 56 W will approach the southern Lesser Antilles tonight and tomorrow. A few showers and thunderstorms along with breezy winds will accompany this wave and impact Grenada, The Grenadines, St. Vincent, St. Lucia, and Barbados. Development of this system does not appear likely even though it is surrounded by light wind shear and water temperatures in the lower 80s. The main negative factor for short-term development will be its low latitude and possible impact with South America. Once it moves into the Caribbean, wind shear dramatically increases and will contribute to the wave's dissipation by the end of the weekend.


A second tropical wave emerged off the coast of Africa yesterday and is currently centered near 7 N and 24 W. Development of this wave seems highly unlikely given an unfavorable climatological period, strong wind shear, and a significant amount of Saharan dust in its path. The low latitude nature of these tropical waves can be attributed to the fact that the subtropical high in the Atlantic is suppressed further south than normal.

The main area of concern is an area of showers and thunderstorms off the coast of the Carolinas in association within a stalled frontal boundary. An upper air trough remains in proximity to the old frontal boundary and is contributing to very strong wind shear. Until this trough lifts out, which is not forecast to happen until this weekend, development is highly unlikely given the hostile environment. Even if development does occur with this system this weekend, it will not pose any threat to the U.S. mainland. The rain will be welcomed relief for many parched areas in North and South Carolina.

2 comments:

LDCT said...

Hey buddy, great post like usual... I wanted to see if you got a chance to check out Joe Bastardi's column today on why El Nino is just a symptom on why the hurricane season will be down, NOT the cause!!! I know I'm guilty of this all the time but just saying El Nino is going to kill the hurricane season is just bad science... Each El Nino setup is different and it's too dependent on global water temperatures, not just the warmer water off South America... Also El Nino is often the effect of many different causes coming together in tandem... He points out years like 69, 02, and 04 where we were in a similar weak to moderate El Nino setups... Of course in 69 you had Camille, 02 you had Isidore/Lili, and in 04 you had Charley and his Florida friends...

We're still hovering around -1 for the 90 day average which honestly I think will trend near neutral (slightly negative) for awhile longer... Hardy a hardcore El Nino setup at this point! I wish everyone could watch his long ranger because I thought it was one of his better ones I have ever seen... Good stuff on the other symptoms and the AMO in general.... Also ties back into global warming stuff and the NATURAL global cycles we are finally starting to understand as meteorologist (last 30-40 years)... According to Joe were entering the 50's now and have about 10 years left until we start entering a cooling cycle... Of course there will be spikes here and there like 1969, but I couldn't agree more with his assessment! Also really interesting how in the 50's we starting seeing many more east coast hurricanes strikes which I think we'll start to see as well in the next 10 years... GREAT STUFF!!!

Ps... It's funny to me when the AMO was in a cooling cycle you had a warm spike in 1969 also in tandem with an El Nino setup... So did the AMO spike cause the El Nino or did the El Nino cause the AMO spike? HMMM???

Justyn Jackson said...

Thanks man. You should start writing again too. I did see his videos yesterday, and the Long Ranger was excellent. It's a good slap in the face to show you that El Nino is just a small player in controlling the hurricane season. It looks like numbers will be below average this year, but I'm just worried about the one the slips through. Waters close to home are above normal, and that always has to be a little worrisome.

Yeah, I think there is an ongoing struggle between the ocean and atmosphere. The ocean argues for El Nino and several other global patterns suggest it's in control. However, angular momentum remains negative and argues for La Nina. I don't think the monsoon arrival in India is helping the El Nino either. Also, the pressure in Tahiti has remained much higher than you would normally see with an El Nino. I think when the monsoon in India begins to end by early September, the pressure in Darwin will rise and then we'll start to see a prolonged negative SOI and positive AAM. When any westerly wind burst hits the Eastern Pacific, it will bring some really warm water up to the surface (http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/wkxzteq.shtml).

All this should be fun to watch for the next several months and years.