Invest 96L: Future Cristobal?
If you haven’t heard by now, you probably will within the next couple of days: another tropical wave is making its way across the Atlantic and causing quite a stir in the weather community.
Up until this morning, nothing besides the GFS ensembles had really shown much potential with this wave, however the overnight and daytime runs of both the operational GFS and GEM (Canadian) have jumped on board with sending this wave traveling through the Caribbean and into the Gulf of Mexico by next week. That said, we are talking about next week and there are several important factors to look at.
First off, current satellite shows an incredibly disorganized mess out off the NE coast of South America.
It has a pretty good moisture envelope going for it at the moment, however glancing out ahead of 96L towards the Caribbean is a much different story, with quite a lot of dry air entrenched across and west of the Lesser Antilles.
This dry air is primarily associated with the Saharan Air Layer (SAL), or dust from the Sahara spreading out across the Atlantic hindering development. A quick comparison of the SAL yesterday compared to today shows significant eroding in front of 96L, with 96L’s moisture envelope expanding. This should allow 96L to continue slow development over the next few days without ingesting a significant amount of dust, especially compared to previous waves.
The other big killer and important factor is shear. Shear has killed off several waves trying to enter the Caribbean so far this season, There are two large areas of high shear ahead of 96L, however the most immediate threat is associated with a lingering trough has been scooting west ahead of 96L and modeling shows that continuing to happen, with the shear eventually dissipating. The other area located over the southern Caribbean isn’t moving, but the GFS/CMC both show it dissipating as well over the next several days, and well before 96L arrives on the scene.
An expanding area of high pressure will fill the gap and force 96L over into the Caribbean vs turning out to sea.
How strong this high pressure becomes will play a significant role on the eventual track of 96L, as well as possibly the strength of the system approaches the United States. If the high pressure turns out a bit weaker, a CMC-like track directly over the islands of Hispaniola/Cuba will be possible, which would have significant impacts on the strength of the system through that area. The tall mountains are known for doing a number on tropical systems. However, if the wave can somehow stay south of the islands, it will have incredible potential to grow in a low-shear environment with LOTS of warm water to work with. Below is the TCHP (tropical cyclone heat potential) which shows incredible amounts of heat for any storms to work with.
Speculating anything much past it’s trip through the Caribbean is rather pointless, especially given how many storms have failed to survive the trip in the past few years, however IF, and I strongly stress this, IF 96L is able to make it into the Gulf of Mexico intact as a tropical depression/storm or even hurricane, it will have incredibly warm water and a very conductive atmosphere for strengthening. But I’ll save that for another blog post.
If you have interests along the Gulf Coast or in the Caribbean, definitely keep an eye on 96L, but let’s try to keep the social media melee toned down for now, because a lot can and will happen in the next 10 days. ~TW