Post by simeon9benjamin on Sept 13, 2008 22:12:23 GMT -6
One thing that did happen. Remember a few weeks ago how we were model watching and all the models were showing the train coming off of Africa. Well we felt the train live and first hand. It was so amazing how fast Gustav developed in the Caribbean. And it all got started with Fay.
Post by futuremet on Sept 13, 2008 23:22:43 GMT -6
This isn't really about 91L more of just what I see in the coming weeks for us... Okay, I’m not going to say hurricane season is over for us because that would be foolish and premature. However, our risk in Louisiana is substantially decreasing each day from this point on. There are several reasons why I say this. First, climatology supports this as only 5 storms have made landfall in Louisiana following the 16th of September since 1950. Typically around this point in the year cold fronts begin nearing the Gulf Coast and the westerlies (jet stream) approach the Gulf of Mexico. This will also be the case in the coming days as a cold front approaches from the North/West. As seen in this graphic, westerly winds can be seen across the majority of the Gulf of Mexico.
This can do 2 things to help the decline of our risk for hurricanes: 1. Westerly wind shear and drier continental/mid latitude air mass makes for a less favorable environment for storms. 2. Westerly flow across the Gulf of Mexico highly favors a Florida landfall/recurve away from Louisiana scenario.
This shows the continued pattern in the coming weeks of westerlies across the Gulf of Mexico.
Also, the TCHP in the Gulf and SST's have been significantly reduced by Gustav and particularly Ike. At this point the Gulf doesn't have much time to recover as peak summer temps have passed and temps will decline from here on out. Ultimately water takes longer to heat and cool than land. The Gulf will still likely recover some but time is ticking. Also, the W Gulf and Bay of Campeche are still very conducive.
Now taking a look further out into the Atlantic nothing appears imminent for development. The Cape Verde Season will be drawing towards a close in the next couple weeks. At this point it would be very hard to get a storm to track all the way across the Atlantic from Africa to us. It wouldn’t be reaching us until the end of September. Very few storms have ever done this with one of the few exceptions being Hurricane Georges. However, I don’t see any storms forming in the next week or more in the eastern Atlantic because of unfavorable Upper Level Conditions. Upper Level winds have been Easterly across the Atlantic which is conducive for tropical cyclone formation. However, an ULL and troughing will cause upper level winds to become more westerly. This induces even more shear because a westward moving storm will enhance the shear. Because of these unfavorable conditions, there should be no significant development for the next week and if something formed beyond that it wouldn’t even reach the Gulf until October. At this point the Subtropical ridge is much weaker and unless we get an anomalous high pressure to the north, which doesn’t appear likely, the threat of Cape Verde systems for the U.S. should be drawing to a close.
At this point the main thing I believe we have to look out for is home brewed storms. The highest threat for us would be a storm that developed in the Bay of Campeche. A storm forming in the W Carib could still pose a threat to our area and the Northern Gulfcoast as climatology has shown is possible; however, the majority of these storms recurve towards the Florida peninsula. Even a Bay of Campeche storm will have trouble affecting our area with strong enough westerlies. The bottom line is don’t let your guard down yet; but I believe our highest risks (Gustav and Ike) for a landfalling tropical cyclone have passed.
Last Edit: Sept 13, 2008 23:25:13 GMT -6 by futuremet
U of U Atmospheric Science - Focus in Rapid Intensification of Tropical Cyclones
Great write up FM. The next couple of weeks IMO, in the pattern we are in may still pose a threat to the north central gulfcoast, this is only mid September. I don't like the fact that the Bahamas/western Atlantic ridge might still be present through the next couple of weeks for anything that would form in the western Caribbean and southern GOM to recurve to FL. But you are right, by looking at models UL shear might be present in the northern gulfcoast for anything to stay or get too strong.