11 October 2017

09 October 2017

Tropical Storm Ophelia forms west of the Azores

The season's 15th named storm, Ophelia, formed about 860 miles west-southwest of the Azores on Monday.  This has been a feature of interest for several days, and it finally consolidated and took on tropical characteristics.  It is forecast to remain over the open ocean and is absolutely no threat to land.  Right now it is embedded in strong vertical wind shear and is disorganized.

The environment should become more favorable later in the week, and Ophelia could easily become the season's 10th hurricane. Not too many seasons ever get that many hurricanes: 2012 had 10, 2010 had 12, 2005 had 15, 1998 had 10, 1995 had 11, etc.  If it does become a hurricane, it would incredibly be the 10th *consecutive* storm this season to reach hurricane status! The steering currents are weak in the region, so we could still be taking about Ophelia next Monday and beyond... and still near the Azores.

After Nate and now the beginning of Ophelia, the season's total Accumulated Cycle Energy (ACE) is up to 254% of average for the date.  And we are just at the beginning of October, a month that historically has proven that it cannot be dismissed; some of the strongest hurricanes on record have occurred during October.

Deeper in the tropics, an easterly wave that we've been watching since it left Africa on Oct 2nd continues to track quietly across the tropics, and is still expected to reach south Florida this weekend (the model consistency on this is remarkable, going back to the middle of last week).  Models bring the disorganized wave north of the Leeward Islands, across the Bahamas on Thursday-Friday, then across the Florida peninsula on Friday-Sunday.  As of now, there is no indication that it is anything of concern, but it's worth keeping an eye on it and at least expect a breezy and wet weekend in south Florida.

07 October 2017

Hurricane Nate racing toward landfall, bringing big storm surge concerns

Nate strengthened as it passed through the Yucatan Channel and was upgraded to the ninth hurricane of the season late Friday night.  As of Saturday's 5am EDT advisory, maximum sustained winds are 80mph and tropical storm force winds extend 115 miles from the center on the east side. Those TS-force winds will arrive on the coastline by mid-late afternoon, so all preparations and evacuations must be carefully rushed to completion.

Landfall is expected to occur late Saturday night near Biloxi, putting Gulfport, Mobile, New Orleans, and Pensacola also at risk for significant impacts.  It is moving rapidly to the north at 22mph so impacts such as storm surge will be much greater to the right/east of where it makes landfall... such as Mobile Bay which could see up to a 9-foot storm surge. Unfortunately, locations from Grand Isle LA to Panama City FL will have high tide around midnight, coinciding with landfall and peak storm surge... maximizing coastal inundation anywhere east of the landfall point.

Hurricane Nate could reach Category 2 intensity today, but if it takes full advantage of the hot Gulf water and low wind shear, it could even reach Category 3 intensity (115mph+). Long, updating radar loops from the Gulf coast are available at http://andrew.rsmas.miami.edu/bmcnoldy/tropics/radar/

Nate's incredible similarity to the infamous 1916 Gulf Coast Hurricane so far is haunting:

This is also now the first season to have 9+ hurricanes since 2012 (which had 10), and then before that there were 12 in 2010, 15 in 2005, etc.

Elsewhere, an area way out over the northeastern Atlantic, west of the Azores, could become a subtropical cyclone in the coming days, but is no threat to land.  The next name on the list is Ophelia.

Water vapor image of Invest 91L, a developing low pressure system southwest of the Azores.

04 October 2017

Tropical Storm Nate expected to form Wednesday and may strike U.S. Gulf Coast as a hurricane Sunday

The system in the southwestern Caribbean that we've been watching for a WEEK has finally developed and is now Tropical Depression 16... could become Tropical Storm Nate later today.  My full update is available on the Capital Weather Gang blog:

Tropical Storm Nate expected to form Wednesday and may strike U.S. Gulf Coast as a hurricane Sunday