cpdaman wrote:any pro's watching hanna right now care to comment on her structure right now
loops are difficult to discern things right now because you have two circulations at different levels in the atmosphere i would assume. a ULL and Hanna and they are partially overlayed which is making things appear "strange". Assuming hanna has not done anything crazy (any south movement) it is relatively safe to say she is in the process of getting away from the ULL (which is diving SSW) and that hanna will be creating more distance from this feature in at least the short term although she will be hampered by some dry air that she entrained, how long this hampers her is anyone guess
Obviously, Hanna is still tangled up with the ULL. Like I said this morning...it still has a period of tough times to get through first before conditions become less hostile for a while. However, more difficult times are waiting in the wings in a few days as it comes under increasing northerly shear.
The first thing Hanna will need to do is get itself away from the ULL , which I alluded to this morning was going to be a slow process, before any possibility of intensification begins. I would expect Hanna to turn more to the WNW and eventually westward as what is being forecast by the NHC, with no strenghtening until is draws farther away from the ULL and the outflow pattern improves.
Keep an eye on WV over the next couple days to monitor the evolution of the eastern CONUS ridge and the cutoff low that's forecast to develop to it's east and dig southward. Also, it'll give you a good idea to what extent the outflow form Gustav will impinge on Hanna.
Exactly where this cutoff forms will have huge implifcations for the track and intensity of Hanna: the farther west this takes place, the more erosion of the DLM ridge north of Hanna will occur, which will slow/stop it's forward motion, and the stronger the northerly flow impinging on the cyclone will be. Farther east would mean that the ridge would be jutting out a bit farther into the ATLC...this Hanna would be more likely to continue a motion with a slow westward component. In the latter scenario, I don't know that the upper tropospheric shear would be appreciably weaker - a lot depends on how quickly the outflow associated with Gustav wanes after landfall. I still think we're looking at ~40kt of UL flow impinging on Hanna, which would induce weakening. YOMV.
Although I am curious as to what the NHC will officialy do with the track tonight. I have a feeling they will have to move the 120hr position slightly north... unless they state the the guidance is so divergent they want to wait?
