Lane spares Mexico the worst; Helene strengthens

Hurricane Lane made landfall at 12:15pm PDT Saturday as a destructive Category 3 hurricane with 125 mph winds. Lane struck a sparsely populated region of the Mexican coast about 50 miles northwest of Mazatlan. The storm surge of approximately six feet affected only an uninhabited barrier island and some adjacent farmland, and did very little damage. The extreme Category 3 winds of the eyewall affected an area of coast about 20 miles wide and stretching 20 miles inland. Only a few hundred people lived in this region, and wind damage from Lane was mostly felt in the city of Culiacan about 30 miles inland. Lane had weakened to a Category 1 hurricane when it passed 30 miles east of that city of 750,000, and brought sustained winds of approximately 65 mph to the city.

Lane has been downgraded to a tropical storm, and is rapidly breaking up over the high mountains of Mainland Mexico. Flooding remains a concern today, and Lane could trigger flash floods in the mountains thanks to its expected 5-10 inches of rain. Lane has been responsible for two deaths so far--a man killed in the village of Pueblos Unidos when he was knocked over by fierce winds, and a 7-year-old boy in a rockfall in Acapulco. Overall, Mexico was very lucky with Lane. Had the storm made a direct hit on Mazatlan, it would have been one of the most destructive Pacific hurricanes of all time for Mexico, and Lane would have become just the 4th Pacific Mexican hurricane to have its name retired.


Figure 1. Hurricane Lane at landfall. Image credit: Servicio Meteorologico Nacional of Mexico.

Helene strengthens
Hurricane Helene is now a large and impressive hurricane, with a huge 50 mile diameter eye. Helene continues to strengthen, but it appears that the storm will be no threat to land, with the possible exception of Bermuda. The computer models are in two camps this morning--the GFS and BAMM models, which take the storm on a westerly track starting Monday, and the rest of the models, which show recurvature to the north. The models differ in how they handle a weak trough of low pressure that is expected to pass to the north of Helene early this week. If the GFS and BAMM are right, the trough will be too weak to pick up Helene, and high pressure will build in, forcing the storm to the west for several more days. The rest of the models think that the trough will be deep enough to turn Helene to the north. These model solutions are more likely to be correct the stronger and larger Helene grows, since a larger storm will extend further north and higher in the atmosphere, making it more likely to feel the effects of the trough of low pressure.

If this trough does miss picking up Helene, the storm has to avoid being pulled north by one or two more troughs in order to make it all the way to the U.S. East Coast. This is a pretty tall order this time of year, as the troughs coming off the East Coast are expected to get stronger and dive further south. The GFS model is predicting a trough late this week will turn Helene northwards, bringing the hurricane very close to Bermuda on Sunday or Monday of next week.

The rest of the tropical Atlantic
Hurricane Gordon is still out there, but is no threat to land. There are no other threat areas to discuss.

Remainder of hurricane season outlook
I posted my outlook for the remainder of hurricane season Friday, in case you missed it.

I'll have an update Monday morning.
Jeff Masters