Epsilon becomes season's 4th major hurricane

Since my previous update on Monday, Tropical Depression 27 quickly strengthened into Tropical Storm Epsilon, the 26th named storm of the 2020 season.  Then it reached Category 1 hurricane intensity on Tuesday night (the 10th hurricane), and Category 3 hurricane intensity on Wednesday night (the 4th major hurricane). 

In this spectacular satellite image showing mid-level water vapor, Epsilon is the green thing in the middle in its envelope of moisture (blues) but is embedded within a huge trough flanked by dry air.  Not something you see every day, or year. Bermuda is the tiny red dot just west of Epsilon.

Fortunately for Bermuda, it is staying further east than originally predicted, so impacts will only be long-distance such as possibly getting periods of tropical storm force winds and large surf as the large and powerful hurricane passes by. Tropical storm force winds extend as much as 310 miles from the center.

Elsewhere in the basin, the pesky area of disturbed weather in the western Caribbean is still festering. 

NHC is giving it a 20% probability of development during the weekend as it drifts by south Florida and the Bahamas.  Regardless of development, it will bring elevated chances of heavy rain with it. Should it happen to reach tropical storm status, the next name on the list is Zeta. 

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New Depression could threaten Bermuda as Hurricane Epsilon

After a 1.5-week lull in activity, Tropical Depression 27 has just formed southeast of Bermuda. This area of interest first appeared on the National Hurricane Center's five-day outlook for potential formation five days ago... spot on!  Although not yet a named storm, it is fully expected to become a tropical storm later today and take the next name in the Greek alphabet: Epsilon. This would be the season's 26th named storm.

The current forecast from NHC brings the storm to a Category 1 hurricane by Thursday, and then maintaining that intensity into the weekend as it approaches Bermuda.

Looking at the model guidance, there is not much to suggest that it will be much stronger than that, but the models should improve once it matures a little more. This plot has forecasts from regional and global dynamical models (deterministic and ensemble means), statistical-dynamical models, and consensus. 

This has already been a rough year for the tiny island of Bermuda: Tropical Storm Edouard passed by on July 5, Hurricane Paulette passed directly over on September 14, and then Hurricane Teddy passed to the east on September 21.

Through October 19, this year's ACE (Accumulated Cyclone Energy) is at 142% of average for the date. That amount of ACE is half of what the 1933 season had accrued by this date and 54% of the 2005 season by this date.

Elsewhere across the basin, there is a slowly-evolving large-scale circulation in the western Caribbean -- this is rather typical for this time of year. If something should eventually form from it, it would head generally north toward Cuba and the Yucatan.  If and when the time comes, the name after Epsilon will be Zeta.

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Hurricane Delta following in Hurricane Laura's footsteps

In the 2+ weeks since my previous post (the first half of that was due to the Atlantic taking a break, and the second half was due to me taking a break), there was Tropical Storm Gamma and Hurricane Delta. Tropical Storm Gamma lasted for just under three days and was located near the Yucatan peninsula.  Then right behind it was Delta, the season's 25th named storm and 9th hurricane. Delta experienced a period of remarkable rapid intensification on October 6th, jumping from a tropical storm to a Category 4 hurricane in one day as it approached the northern Yucatan peninsula... reminiscent of Wilma in 2005.

As of Thursday afternoon, Delta is a powerful Category 3 hurricane and is headed north toward Louisiana. A clear eye is becoming evident, signaling some additional strengthening. As the title of the post mentions, Delta's landfall location will be almost identical to Laura's back in late August.  Much of that area has still not cleaned up or started to recover before Delta's arrival. The last time two hurricanes impacted western Louisiana in the same year was 1886.

As it tracks north, it will encounter slightly cooler water temperatures, lower ocean heat content, and somewhat drier air; these factors should limit significant intensification prior to landfall (meaning a Category 4 or 5 is very unlikely).

Landfall is expected in western Louisiana on Friday evening, though conditions are already going downhill with rising water levels and outer rainbands scraping the coast. Tropical storm force winds should begin in coastal areas of eastern Texas and Louisiana by Friday morning.

No major changes in intensity are expected, so it should make landfall as a Category 2-3 hurricane, and produce a 7-11-foot storm surge to the right of its center. Rainfall totals could reach one foot in parts of western Louisiana.

The Accumulated Cyclone Energy (ACE) for the season is about 138% of the average value through October 8. Other years that had higher values by this date were 2019, 2017, 2010, 2008, etc -- in other words, this season is not that notable by this metric. Sure, we have cruised through named storms at a record pace, but 14 of the 25 named storms were around for three days or less!

Elsewhere across the basin, no new activity is expected in the coming week. But if and when the time comes, the next couple of names on the list are Epsilon and Zeta.

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