Allison
(Weather Guru)
Wed Aug 22 2007 08:36 PM
Re: ULL for a novice.

Quote:

How do I regognize a ULL? ie. I am looking at water vapor images of what was/us invest92L, I see a clear area to the east, which the images seem to be wrapping around, yet I believe it was mentioned that the ULL that would affect this system had moved into the GOM. Is there another map I should be watching? How do I know what I am looking at is the ULL? Do the low pressure systems push or pull a wave? I can recognize the high pressure ridge to the north in the Atlantic. More importantly, is there a site where I can begin to understand this information. Thanks




As a fellow amateur, I can tell you that I've learned to recognize many types of features, including ULL's, by taking the NHC Tropical Weather Discussion (example here) and comparing it with the relevant satellite loops, etc. It is also very helpful to follow along with the lengthy discussions provided by the mets on the forums.

As for what you're seeing on the WV loops, my understanding is that it's no longer a ULL, but an open tropical wave. You are correct that there was previously a ULL over the Bahamas while Dean was still in the Caribbean, but that has since moved through the GOM and into Texas.



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