WunderBlog Archive » Category 6™

Category 6 has moved! See the latest from Dr. Jeff Masters and Bob Henson here.

Isis, Odile Removed from Northeast Pacific Tropical Cyclone List

By: Jeff Masters and Bob Henson 1:18 PM GMT on April 20, 2015

The Northeast Pacific list of hurricane names got a shake-up on Friday, when the U.N.'s World Meteorological Organization (WMO) voted to remove the name "Isis" because of its potential confusion with the Islamic militant group, the Islamic State of Iraq and ash-Sham (ISIS). Isis is the name of an ancient goddess of Egypt, and was scheduled to be used in the Northeast Pacific (also called the Eastern North Pacific by WMO) in 2016. The ISIS militant group has been accused by U.N. war crimes investigators of committing brutal atrocities against civilians during a bloody conquest of large portions of Syria and Iraq over the past two years. The WMO Hurricane Committee for Region IV (North America/Central America/Caribbean), composed of experts from 27 member states and territories, met in in Costa Rica last week and elected to replace the name "Isis" with "Ivette". It is rare but not unprecedented for a name to be removed from the list of hurricane for reasons other than retirement due to death and destruction. Both "Adolph" and "Israel" were removed from the Northeast Pacific hurricane list for reasons of sensitivity in 2001.

Figure 1. MODIS satellite image of Hurricane Odile approaching the tip of Mexico's Baja Peninsula, taken at approximately 4:30 pm EDT Sunday September 14, 2014. At the time, Odile was a Category 3 storm with 125 mph winds. Image credit: NASA.

Hurricane Odile's name retired
One other Northeast Pacific name was removed from the list of hurricanes for that basin during last week's meeting: Odile. Hurricane Odile roared ashore near Cabo San Lucas as a Category 3 storm with 125 mph winds on September 25, 2014, and was the strongest storm on record to hit Baja. The storm killed eleven and did $1.22 billion in damage, making it the 6th most expensive Northeast Pacific hurricane ever. "Odile" will be replaced by "Odalys", which will appear on the list of names for the 2020 season. Odile is one of only thirteen hurricanes in the Northeast Pacific to get its name retired since naming began in 1960.

For the first year since 2009, no Atlantic names were retired in 2014. If we manage to go without retiring a hurricane name in 2015, it will be the first time since 1993 - 1994 that the Atlantic will have gone back-to-back years without a retired hurricane (thanks to wunderground member Mark Cole for pointing out that Ingrid was retired in 2013, which I overlooked originally.) Overall, hurricanes in the North Atlantic have a much better chance than those in the Northeast Pacific of reaching shore and inflicting enough damage to prompt a name’s retirement. Since the Atlantic’s current naming system began in 1954, a total of 79 names have been retired. Some intriguing randomness shows up in the alphabetic arrangement of the Atlantic’s retired names. As you might expect, there’s a greater concentration toward the first part of the alphabet, but the pattern is far from linear. Seven “A” and “D” storms, eight “F” storms, nine “C” storms, and ten "I" storms have been put on the shelf--but only three “B” and three “E” storms. The name “Janet” was retired in 1955, but it took until 1990 for a “K” name (Klaus) to be put on the shelf. Once the North Atlantic entered its current era of intensified activity in 1995, retirements began to surge through the alphabet, reaching all the way to “Wilma” in 2005.

Tornado activity remains at a near-record slow pace
Severe weather dotted the southern Plains from Thursday through Saturday before spreading across the South on Sunday. Hail and high winds made up the bulk of the action, although a few short-lived tornadoes were reported. Two twisters with preliminary EF1 ratings brought down numerous trees and caused some structural damage in east central Alabama on Sunday, and another EF1 was reported in southwest Louisiana on Saturday. Several highly visible tornadoes spun across the eastern Texas Panhandle and far western Oklahoma on Thursday, causing little damage.

Figure 2. Cumulative tornado activity through April 18 is running at close to a record-slow slow pace, as tracked by the NOAA Storm Prediction Center’s “inflation-adjusted” database. Image credit: NOAA/SPC.

Despite the high-profile EF4 tornado in Illinois on April 9, the nation continues to be experiencing one of its quietest tornado seasons on record. The preliminary total for January 1 through April 18 is 112, just barely above the record low of 109 for the “inflation-adjusted” database kept by NOAA’s Storm Prediction Center. (These data are adjusted to correct for the rise in tornado reports over recent decades produced by greater observing.) The slow-moving upper low that triggered severe weather this past weekend should generate a parting round of intense storms across the mid-Atlantic on Monday. Attention will then shift back to the south-central states by midweek, as an upper low rides in on a strong subtropical jet stream.

Jeff Masters and Bob Henson

Figure 3. A thunderstorm-generated shelf cloud near Mounds, OK, on Sunday, April 19. Image credit: wunderphotographer mrwing.


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.