Tropical Storm Epsilon formed in the central Atlantic 735 miles southeast of Bermuda at 11 a.m. Monday, October 19, 2020, becoming the 26th named storm of this record-busy 2020 Atlantic hurricane season. Epsilon is expected to threaten Bermuda as a category 1 hurricane on Friday, but it is not a landfall threat for the U.S.

Epsilon’s October 19 arrival marks the earliest date that any Atlantic season has produced its 26th named storm, surpassing the record held by Delta from November 22, 2005. In total, 23 of the 26 2020 named storms have set records for being the earliest-arriving for their respective letter; only Arthur, Bertha, and Dolly fell short.

The Atlantic typically has over 85% of its activity by this date. So far, there have been 26 named storms, nine hurricanes, three intense hurricanes, and an accumulated cyclone energy (ACE) index of 123 (34% above average for the date). Only one Atlantic hurricane season since 1851 has had more named storms during an entire season: 2005, with 28 named storms. According to Colorado State University hurricane scientist Phil Klotzbach, the averages for this point in the season are 10.6 named storms, 5.5 hurricanes, 2.5 intense hurricanes, and an ACE index of 92.

Forecast for Epsilon

Moderate wind shear of 10 – 20 knots and warm ocean temperatures near 27.5 Celsius (82°F) will favor development of Epsilon through Tuesday. However, the system is embedded in a dry atmosphere with a mid-level relative humidity of 45%, which will slow its development. By Wednesday, Epsilon will move into a region with light wind shear of less than 5 knots, which will favor more rapid strengthening.

Epsilon will meander slowly through Tuesday, but a ridge of high pressure is predicted to build over the Atlantic by mid-week, forcing the storm on a west-northwest to northwest track that will put it near or to the east of Bermuda on Friday. As Epsilon progresses to the northwest, cooler ocean temperatures will limit the amount of intensification that can occur. By the time Epsilon makes its closest approach to Bermuda on Friday, ocean temperatures will be near 26.5 degrees Celsius (80°F), which is marginally warm enough to support a category 3 hurricane. The 12Z Monday run of the SHIPS model gave Epsilon a 19% chance of becoming a category 3 hurricane with 115 mph winds by Thursday.

Keep an eye on the western Caribbean this week

A broad area of low pressure has formed over the western Caribbean. Over the past weekend, the GFS model and its ensembles were suggesting that this low could produce a hurricane during the last week of October, but they have backed off considerably from that idea in recent runs. In the 6Z Monday run of the GFS ensemble model, about 20% of the 31 forecasts predicted that a hurricane would be spawned by the western Caribbean low by next week; just one of the 51 members of the 0Z Monday European model ensemble predicted a hurricane. Any storm that does form in the region would likely move slowly west or west-northwest, potentially bringing heavy rains to Cuba and/or Mexico’s Yucatan Peninsula. In a 2 p.m. EDT Monday Tropical Weather Outlook, NHC gave two-day and five-day odds of development of 10% to this system.

King tides causing significant flooding on U.S. East Coast

Significant coastal flooding has been affecting much of the Southeast and mid-Atlantic U.S. coast since October 15, during the high “king tide” period associated with the October 16 new moon. The October king tides are some of the highest of the year, as the moon is near perigee (its closest approach to the Earth). Tidal levels were particularly high on Sunday over the southeastern U.S., because of powerful northeast onshore winds associated with the clockwise flow of air around a strong area of high pressure over the North Atlantic near Newfoundland. At least four tide gauges with a long period of record experienced a top-20 coastal flood event on Sunday:

Charleston, South Carolina (records since 1921) experienced a major coastal flooding event on Sunday morning, with water levels reaching its 14th highest level on record. The city has had 52 days in 2020 with at least minor coastal flooding, mostly from “sunny day” high tide floods. The city is predicted to see at least minor coastal flooding during every high tide through Wednesday, with major flooding expected on Monday afternoon.

Fort Pulaski, Georgia (records since 1935) experienced a moderate coastal flooding event on Sunday morning, with water levels reaching their 15th highest level on record.

Jacksonville, Florida, at Mayport on the St. Johns River (records since 1928), experienced a minor coastal flooding event on Sunday morning, with water levels reaching their 19th highest level on record.

Also see: Swells from Hurricane Teddy drive major king tide coastal flooding

Myrtle Beach, South Carolina, (records since 1957) experienced a minor coastal flooding event on Sunday morning, with water levels reaching their 20th highest level on record.

King tide flooding will gradually diminish during the coming week.

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Posted on October 19, 2020(1:16 p.m.EDT).