Tropical Storm Nate
Tropical Storm Nate formed in the southern Gulf of Mexico yesterday afternoon after the Hurricane Hunters found a well-defined surface circulation and 45 mph surface winds. Nate is the 14th named storm this year, and comes three days before the climatological half-way point of the Atlantic hurricane season, September 10. A typical hurricane season has just 10 - 11 named storms, so we've already had 35% more than a whole season's worth of storms before reaching the season's half-way point. At this rate, 2011 will see 28 named storms, equaling the all-time record set in 2005. Nate's formation date of September 7 puts 2011 in 2nd place for earliest date of arrival of the season's 14th storm. Only 2005 had an earlier formation date of the season's 14th named storm (September 6, when Hurricane Nate got named.) Third place is now held jointly by 1936 and 1933, which got their 14th storm of the season on September 10.
Latest visible satellite loops show that Nate's low-level center is exposed to view, due to northeasterly upper-level winds that are creating a moderate 10 knots of wind shear. This shear is keeping all of Nate's heavy thunderstorms pushed to the south side of the center. Sustained winds at Buoy 42055, about 100 miles to the northwest of the suspected center of Nate, were north at 31 mph at 6:50 am CDT this morning. We haven't had a hurricane hunter aircraft in the storm since yesterday afternoon, and the next plane is due to arrive near 2 pm this afternoon. Water vapor satellite loops show that here is a large area of very dry air from Texas to the north of Nate, and this dry air is probably interfering with the storm's development.
Up until last night's 8 pm EDT runs of the computer models, the models were in general agreement that Nate would meander in the Bay of Campeche for several days, until a ridge of high pressure built in to the north of the storm, forcing it westwards to a landfall in Mexico. However, the latest 2 am EDT run by the GFS model predicts that Nate may gain enough latitude to escape being forced westwards by the ridge, and instead move northwards to make a landfall along the U.S. Gulf Coast. The GFDL, which uses the GFS for its initial conditions, is also on board with this idea, as is the HWRF model, to a lesser degree. The 2 am EDT run of the NOGAPS model did not go along with this idea, though. We will have to wait until the NOAA jet makes its first mission to sample the steering currents in the Gulf of Mexico to get a better idea on how probable this northern path might be; their first flight will be tonight, and the data will make it into the 8 pm models runs that will be available first thing Friday morning. As far as intensity goes, the very dry air to Nate's north should begin being less of a problem for it by Friday, when the upper level winds shift more to blow from the southeast, and the shear drops to the low range, 5 - 10 knots. Since the storm is moving very slowly, it will upwell cooler waters from the depths that will slow intensification, though. The earliest Nate would become a hurricane is probably on Saturday.
Wunderground
[ Bericht 0% gewijzigd door #ANONIEM op 08-09-2011 20:18:38 ]