Good evening and Good morning...I'm going to keep this brief given it's early morning at my house and the GFS and ECMWF ensembles are split this evening as many of you are well aware of. Looking at the 26/00Z upper charts it is quite evident what the GFS ensemble is looking at; the narrow ridge axis that was depicted at 25/12Z from off the coast of central LA to Orlando, FL then ENE into the AO to the Bermuda upper ridge has built and strengthened by 20 meters everywhere and the longwave trough over the east has lifted out quite nicely and everything south of Charleston is inverted now and winds are from the NE aloft at 500 millibars. I went hunting for this low/mid level low NHC mentioned in their 11 pm discussion; darn if I could find it though I did pick up a surface trough...possible positive tilt shortwave along generally a west to east then northeast then north and northwest into Issac where thunderstorms are firing. I can find no definitive data to indicate what Issac is to do once in the Gulf of Mexico nor am I going to speculate where and when. Right now, the westward shift is viable if this ridge axis and multiple upper centers remains in place; however, the model have been insistent about retrograding the upper ridge west and progressing the shortwave in the middle of the country and deepening once again the long wave trough along the eastern US and what remains is all timing as to what will be where and when and the ensembles are simply split; the irony is it is now the ECMWF and its ensemble implying recurvature and sending the cyclone into northern FL coast and the GFS advertising a date with New Orleans and the Mississippi Gulf Coast; opposite from a couple of days ago. I see no evidence on satellite imagery this evening that Issac will undergo rapid intensification soon; the southern half of the cyclone is void of convection and over land, over Cuba. The long wave trough at 200/300 millibars extends south through the peninsula of FL then exiting SW FL into the GOM...wind shear analysis continues to show 30 knots from the SW aloft over convection over FL, Florida Straits near the Keys decreasing to 10 knots to near the center of Issac; overall shear is decreasing in velocity. One note, I do not input data from previous or similar tropical storms and/or hurricanes; while there may be similarities the bottom line is the data in the here and now and the data inputted into the models and their respective ensembles is unique to that storm. Only in regards to climatology what a storm's track and strength are relevant; tropical cyclones present themselves in an incredible number of personalities, flavors, hybrids and structures just to name a few; we have much to learn as why one storm does this and another with the same "ingredients" does another. Issac thus far has been a bit like the family black sheep; different!
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