Aletta is weakening, Bud may be on the way, and the Western Caribbean is bubbling

What once was Tropical Storm Aletta is now Tropical Depression Aletta. Although Aletta is now a tropical depression she has recently experienced a flare-up in convection primarily due to the assistance of the diurnal maximum. However, increasing shear and dry air will cause Aletta to meet her demise over the next few days. The dry air is clearly seen in water vapor imagery:


To the east of Aletta, we have invest 92E. As of 18Z today, the NHC is giving invest 92E a 30% chance of becoming a tropical cyclone over the next 48 hours. Recent satellite imagery shows some broad cyclonic turning on the low-levels, which is a sign that 92E is trying to become our next named storm in the Eastern Pacific. The next name on the list is Bud. The latest RGB imagery shows scattered convection without too much organization:


Wind shear over 92E is about 20 knots out of the SW, which is low enough to allow slow organization. Another sign that 92E is organizing is CIMSS analysis showing a decent amount of vorticity at 850mb. The 12Z GFS run shows 92E becoming a very powerful hurricane that may threaten the Mexican Coast. As a result, this is definitely a system worth monitoring.

Over on the Atlantic.

Although Hurricane Season in the Atlantic doesn’t officially begin until June 1, we are already seeing some signs that hurricane season is here. Climatologically, early season activity is very common in the Western Caribbean, so it is not surprising that we are seeing flare ups of convection in this area today.


In the infrared image above, we can see 92E on the far left side of the image as well as the new area of interest in the Western Caribbean. Latest analysis from the Hydrometeorological Prediction Center (HPC for short), shows that there is a broad surface trough over this area, extending from the Yucatan Peninsula NE to Florida. In fact, visible imagery this morning and afternoon shows some broad cyclonic turning in the lower levels in the Western Caribbean. The GFS has been very persistant in hinting that we may see cyclogenesis in this region. Although wind shear is currently at unfavorable levels over this area, it may decrease enough over the next few days to allow some development. Any development would be slow to occur.

It is also worth noting that many other computer models have been trying to develop a possibly subtropical feature off the coast of the Carolinas over the next couple of days as a upper-level low gets cut-off and meanders around over the Gulfstream. If something does develop here, chances are it will slowly accelerate off to the NE, possibly brushing the Mid-Atlantic and New England areas before getting swept out to sea.

Needless to say, things are starting to get interesting in the tropics over on this side of the world. I’ll post again as things change.



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