Kate Strengthens in Atlantic; Megh Dissipates in Yemen

Tropical Storm Kate is nearing hurricane status well east of Florida and Georgia as it begins sweeping into the open Atlantic. As of 10:00 am EST Tuesday, the National Hurricane Center pegged Kate’s top sustained winds at 60 knots (70 mph), based on peak surface winds of 61 kt from Hurricane Hunter data collected via the SFMR radiometer. Kate is a compact storm, with tropical storm force winds extending only 80 miles from its center, but its structure is considerably better than on Monday, with a symmetric core of strong convection (showers and thunderstorms) and some banding on its east side. The effects of increasing southwesterly wind shear (15 – 20 knots) are becoming evident, as Kate takes on the comma shape common to tropical cyclones undergoing subtropical/extratropical transition.


Figure 1. Latest satellite image of Tropical Storm Kate.

Even as Kate moves northeast at an increasingly rapid clip--more than 20 mph--the storm is passing over waters that are near record-warm levels for the time of year, at 1°C to 2°C above the seasonal average. Later on Tuesday, Kate’s track will take the storm over waters cooler than the threshold for tropical development of 26°C (79°F), hastening its extratropical transition. Phase space diagrams from Robert Hart and Jenni Evans (Florida State University) show Kate morphing into an asymmetric warm-core cyclone over the next couple of days. At the same time, Kate’s peak winds should continue to increase and expand, powered by the strong upper-level jet stream that will soon envelop the storm. Kate is likely to become a hurricane later on Tuesday or early Wednesday before going post-tropical by later in the week.

Kate is the Atlantic’s most intense tropical cyclone on record for November during the five years since 1950 with strong El Niño conditions present in October-December: 2015, 1997, 1982, 1972, and 1965. Only one other named system was observed during those Novembers: 1972’s Subtropical Storm Delta. See our Monday post for more on Kate’s significance as the 11th named system of the year.

Other Kates in Atlantic hurricane history
Kate shares the name of 1985’s Hurricane Kate, which produced the latest US landfall of any hurricane on record. Kate brushed by Key West and moved into the eastern Gulf, where it peaked as a major hurricane, with top sustained winds of 120 mph. On the afternoon of November 21, Kate made landfall near Mexico Beach, FL, bearing sustained winds of 100 mph. Kate was a destructive storm, causing an estimated 15 fatalities and $700 million of damage in 1985 US dollars. Another Hurricane Kate also became a Category 3, this time in early October 2003, but it spun harmlessly over the central Atlantic, finally taking a swipe at Newfoundland near the end of its life.

Tropical Cyclone Megh makes a second landfall in Yemen and dissipates
Tropical Cyclone Megh penetrated deep into the Arabian Sea's narrow Gulf of Aden to make an improbable landfall in western Yemen near Aden at approximately 6 pm EDT Monday evening. At landfall, Megh was a rapidly weakening tropical storm with top winds of 40 mph. Megh rapidly dissipated after landfall, spreading only a few heavy rain showers over western Yemen. Satellite data suggests that Megh dumped very little rain over western Yemen, and only minor flooding and damage likely resulted. That's not the case on Yemen's Socotra Island, where Megh made a direct hit as a major Category 3 storm with 125 mph winds on Sunday, bringing a second round of devastation to an island hard-hit the previous week by the passage of Tropical Cyclone Chapala.

According to Dr. Phil Klotzbach, Magh has pushed the Accumulated Cyclone Energy (ACE) in the North Indian Ocean in 2015 to 39.3 ACE units. Since 1990, only 1999 (44 ACE) and 2007 (46 ACE) have had more. An average season has just 18 ACE units.


Figure 2. MODIS image of Tropical Cyclone Megh over western Yemen at 07:25 UTC November 10, 2015. Megh made landfall near Aden, Yemen about 7 hours previous to this image, with top winds near 40 mph. Image credit: NASA.

Forty years ago today: the wreck of the Edmund Fitzgerald
The “gales of November” immortalized in a hit record struck 40 years ago this week, on November 10, 1975, when a fierce midlatitude storm hammered Lake Superior and sank the US freighter SS Edmund Fitzgerald, killing all 29 crew members. Fans of the Canadian balladeer Gordon Lightfoot already know many particulars of the story, although “The Wreck of the Edmund Fitzgerald”--which hit #2 on the U.S. Billboard chart in 1976--was not a precisely accurate retelling of the disaster. The ship was heading east across Lake Superior with a load of iron ore pellets when the unexpectedly intense storm struck early on the 10th, packing northeast winds of 52 knots (60 mph). As the Edmund Fitzgerald headed toward the east end of Lake Superior through the day, the surface low passed close by, throwing the ship into a “hurricane westwind,” as Lightfoot put it. By late afternoon, the ship’s systems were failing, and the last transmission from the Fitzgerald reached a nearby ship at 7:10 pm. The ship’s wreckage was found over the next several days, although none of the victims were ever recovered.


Figure 3. A 1971 photo of the SS Edmund Fitzgerald. It remains the largest ship known to have sunk in the Great Lakes. Image credit: Greemars/Wikimedia Commons.

A CIMSS Satellite Blog post on Tuesday included satellite imagery from 1975 depicting the storm that sank the Edmund Fitzgerald. WU weather historian Christopher Burt included this storm in a roundup of Upper Midwest weather events that all happened on November 10. In a fascinating Weatherwise article, Steve Ackerman and John Knox related the Edmund Fitgerald storm’s particulars in the context of Gordon Lightfoot’s lyrics. The website Songfacts has a variety of interesting tidbits about the song itself. Apparently Lightfoot was motivated to write “The Wreck of the Edmund Fitzgerald” in part because the ship’s name was repeatedly misspelled in a magazine article.

Wunderblogger Steve Gregory has a new Monday afternoon post, Stronger Storm Systems and Wild Model Forecasts.

Bob Henson and Jeff Masters


Figure 4. Surface weather map valid at 12Z (6:00 am CDT) on Monday, November 10, 1975. The Great Lakes storm that sank the Edmund Fitzgerald later in the day was then located over the Upper Peninsula of Michigan. The storm’s central pressure later fell to 975 millibars. Image credit: CIMSS Weather Blog.