Isaac still looks pathetic on IR satellite with very little strengthening during the 11 PM advisory. The first half of the forecast has shifted slightly to the east. With a long passage over land, Isaac is expected to remain a tropical storm until he emerges in the Florida straights. Although the center of the forecast track takes the storm over the Alabama/Mississippi border on Tuesday, there is still a lot of disagreement among the models. The GFS computer model is very similar to the NHC track. The European model is forecasting a landfall near the Louisiana/Texas border. BIG DIFFERENCE!!
The differences are caused by confusion over the strength of the subtropical ridge located north of the storm. The ridge is steering the storm west. But a weaker ridge means an earlier turn to the northwest. Luck for us, hurricane hunters flew into the ridge tonight taking much needed upper air data! That data will then go back into the computer models and hopefully help iron out some of the differences.
By the way, tropical storm Joyce is now a depression. She might impact Bermuda Tuesday of next week as a tropical storm. But there's no chance of an east coast landfall with that one.
See you tomorrow! Geoff Fox is still off and I'm filling in. At least in this locally boring weather pattern I have something to talk about.