Hurricane warnings are up for portions of Louisiana, Mississippi, and Alabama as Tropical Storm Zeta reorganizes over the Gulf of Mexico after a Monday night landfall as a category 1 hurricane in Mexico’s Yucatan Peninsula. Zeta is expected to re-intensify into a category 1 hurricane and make landfall on the U.S. Gulf Coast on Wednesday afternoon or evening.
Hurricane Zeta made landfall near Tulum, Mexico at 11 p.m. CDT Monday night, October 26, 2020, as a category 1 storm with 80 mph winds and a 978 mb central pressure. Near the time of landfall, a Weatherflow station just south of Playa del Carmen reported sustained winds of 74 mph with a gust to 87 mph. Another Weatherflow station in Cancun reported sustained winds of 60 mph with gusts up to 79 mph. A storm surge of over one meter (3.28 feet) was observed at Puerto Morelos. A personal weather station in Chemex, located about 50 miles inland from the landfall location, recorded 5.15 inches of rain in the 12 hours ending at 11 a.m. CDT Tuesday.
Zeta is the third Greek-named storm to make landfall in Mexico’s Yucatan Peninsula this month. Tropical Storm Gamma made landfall within 10 miles of Zeta’s landfall location on October 3 with 70 mph winds; Hurricane Delta hit Cancun on October 7 as a category 2 storm with 110 mph winds.
Zeta re-organizing over the Gulf of Mexico
After spending approximately nine hours over land, Zeta emerged over the southern Gulf of Mexico late Tuesday morning. At 10 a.m. CDT Tuesday, Zeta had sustained winds of 65 mph and a central pressure of 985 mb, and was headed northwest at 14 mph. The storm was spreading heavy rains over western Cuba and Mexico’s Yucatan Peninsula. Zeta was a medium-sized storm, with tropical storm-force winds that extended out 140 miles from the center.
Satellite images early Tuesday afternoon showed that Zeta remained well-organized, with an area of intense thunderstorms near its core, and a large spiral band wrapping into the north side of the center.
Track forecast for Zeta
A ridge of high pressure to the northeast will keep Zeta on a northwesterly track at a speed near 15 mph through Tuesday afternoon, carrying Zeta into the central Gulf of Mexico. By Tuesday night, an approaching trough of low pressure over the central U.S. is expected to turn Zeta more to the north and then north-northeast, with a landfall expected along the U.S. Gulf Coast on Wednesday afternoon or evening.
The models are in excellent agreement on the track of Zeta. As Zeta will be curving to the northeast at the time of landfall, the center may emerge over water for a few hours after its initial landfall in southeastern Louisiana, and make a second landfall on the coast of Mississippi or Alabama.
If Zeta makes landfall in hurricane-beleaguered Louisiana, it will be the record-breaking fifth landfall in a single season by a named storm in the state: Earlier this year, category 2 Hurricane Delta, Tropical Storm Cristobal, Tropical Storm Marco, and category 4 Hurricane Laura all hit the state. The current record for most landfalls in a single season in Louisiana is four, which 2020 shares with 2002, when Tropical Storm Bertha, Tropical Storm Hanna, Tropical Storm Isidore, and Hurricane Lili all hit the state.
Intensity forecast for Zeta
Zeta will have favorable conditions for intensification up until Wednesday morning, with light wind shear of 5-10 knots, ocean temperatures of 28-29 degrees Celsius (82-84°F), and a moist atmosphere with a mid-level relative humidity of 60-65%. Zeta will be passing over Gulf of Mexico waters with a modest heat content capable of supporting rapid intensification, but not highly so. However, for it to develop in these conditions, Zeta needs to fully reorganize after being disrupted by passage over the Yucatan Peninsula.
The 12Z Tuesday run of the SHIPS model gave modest odds that Zeta would undergo rapid intensification by Wednesday morning: a 20% chance of becoming a category 2 hurricane with 100 mph winds (two times higher than the climatological odds), and a 12% chance of becoming a category 3 hurricane with 115 mph winds (five times higher than the climatological odds). In the Tuesday morning run of the European model ensemble forecast, about 10% of members predicted that Zeta would intensify into a category 3 hurricane.
On Wednesday, when Zeta will be approaching the U.S. Gulf Coast, the storm will encounter more hostile conditions for intensification. Waters beneath the storm will be significantly cooler, wind shear will rise, and dry air over the Gulf could wrap into its core. However, a strong band of upper-level winds to the north of Zeta will provide a more efficient upper-level outflow channel as the storm approaches the coast, helping to counteract the increased shear. The official National Hurricane Center forecast calls for Zeta to make landfall as a category 1 hurricane with 80 mph winds, and a reasonable uncertainty range for Delta’s winds at landfall is 60-110 mph (strong tropical storm to category 2 hurricane strength).
Zeta will be moving rapidly at landfall in the U.S., with a forward speed over 25 mph. This will limit the amount of rainfall. The current NHC forecast calls for two to four inches of rain in the U.S., with isolated amounts of up to six inches – an unusually low amount of rainfall for a landfalling category 1 hurricane.
The rapid forward speed will also mean that there will be a much larger disparity than usual between the wind impacts on the storm’s right side versus the left side; the HWRF and GFS models are predicting that at landfall, Zeta’s winds will be 15 – 20 mph stronger to the east of the center, compared to the west of the center. Since Zeta will be curving to the northeast at the time of landfall, the storm’s strongest winds will affect a wide swath of coast, from southeastern Louisiana to Alabama. Wind damage is likely to be the greatest threat from Zeta.
Zeta was the 11th Atlantic hurricane of 2020
Zeta is the 11th Atlantic hurricane so far in 2020. According to Phil Klotzbach of Colorado State University, only two other Atlantic seasons on record (since 1851) have had 11 or more hurricanes by October 27: 1950 and 2005. Seven full Atlantic hurricane seasons have had 11 or more hurricanes: 1887, 1933, 1950, 1969, 1995, 2005 and 2010. The record is 15 hurricanes, set in 2005.
With five weeks still to go in the 2020 Atlantic hurricane season, there have been 27 named storms, 11 hurricanes, four intense hurricanes, and an accumulated cyclone energy (ACE) index of 140 (45% above average for the date). The averages for this point in the season are 10.9 named storms, 5.6 hurricanes, 2.5 intense hurricanes, and an ACE index of 96.
Zeta intensified by 30 mph in a 24-hour period ending at 4 pm CDT October 26, from 50 mph winds to 80 mph. That intensification falls short of the official NHC criteria for rapid intensification – a 35 mph increase in winds in 24 hours. (However, it is quite possible that in post-season analysis, Zeta will meet the definition of rapid intensification, because of the timing of the Hurricane Hunter report that triggered Zeta’s upgrade to hurricane status.)
Ex-Hurricane Epsilon bringing huge waves to Europe
Hurricane Epsilon brushed Newfoundland, Canada, on Sunday morning as a category 1 storm with 75 mph winds, before merging with a trough of low pressure and transforming to a powerful extratropical storm on Sunday afternoon.
On Tuesday morning, Ex-Epsilon was a near hurricane-force storm with sustained winds of 65-70 mph and a 940 mb central pressure south of Iceland. The storm was producing a large area of massive waves exceeding 48 feet, as analyzed by NOAA’s WaveWatch 3 model. These waves were affecting much of the far northern Atlantic Ocean, and rank among the biggest in recent memory, according to the surfing website magicseaweed.com.
Vietnam braces for category 3 Typhoon Molave
Louisiana and Mexico’s Yucatan Peninsula have competition for the 2020 honors for worst tropical cyclone season: Vietnam. Vietnam has ordered massive evacuations in advance of the arrival of Typhoon Molave, a category 3 storm with 120 mph winds at 10 a.m. CDT Tuesday, according to the Joint Typhoon Warning Center. Molave is expected to make landfall near 8 p.m. CDT Tuesday on the central Vietnam coast as a category 2 typhoon. According to NOAA’s typhoon database, only eight category 3 or stronger typhoons have hit Vietnam in recorded history.
Earlier this month, torrential rains from Tropical Storm Linfa killed 90 people and left 34 missing in Vietnam, causing at least $518 million in damage, according to Steve Bowen of Aon. Tropical Depression Saudel caused additional flooding and damage in Vietnam on October 25, as did Tropical Storm Nangka on October 16, Tropical Storm Sinlaku on August 2, and Tropical Storm Noul on September 18.
Vietnam may yet experience another tropical cyclone next week. The GFS and European models are predicting that Tropical Storm Goni will form over the Philippine Sea late this week, and make landfalls in the Philippines on Saturday and in Vietnam on Monday.
Posted on October 27, 2020 (2:16pm EDT).