Tropical Storm Carlos Forms South of Acapulco, Mexico

Tropical Storm Carlos spun into life Thursday morning in the Pacific Ocean, about 230 miles south of Acapulco, Mexico. Satellite loops show that Carlos is a small storm in the early stages of organization. But with very warm waters of 30°C (86°F) beneath it and wind shear a moderate 10 - 20 knots, Carlos appears destined to intensify into a hurricane by the weekend. Radar out of Acaupulco shows that the outer spiral bands of Carlos lie just offshore from the Mexican coast, and the storm's west-northwest motion, parallel to the coast, should keep the heaviest rains just offshore. However, if Carlos takes a path slightly closer to the coast than expected, dangerous flooding rains will occur along the coast.


Figure 1. Tropical Depression Three-E south of Acapulco, Mexico as seen at 1:15 pm EDT June 10, 2015, before becoming Tropical Storm Carlos. Image credit: NASA.


Figure 2. Predicted total precipitation for Tropical Storm Carlos from the 06Z Thursday June 11, 2015 run of the HWRF model. Widespread areas of 4 - 8" were forecast just offshore from Mexico. Image credit: NOAA/NCEP/EMC.

An unusually early and severe Eastern Pacific hurricane season
Carlos' formation on June 11 continues a remarkable run of early-season activity for the Eastern Pacific. The third named storm usually does not appear until July 5, and Carlos' formation on June 11 comes just two days later than the record for the earliest appearance of the season's third named storm: June 9 in 1956 and 1990. Some other notable items from this year's Eastern Pacific hurricane season:

We've already had two major hurricanes this year (Andres and Blanca), and the second major hurricane of the season typically doesn't form until August 19. An entire season typically has only four major hurricanes (using stats from 1981-2010.) The record is eight major hurricanes in a season, accomplished most recently in 2014. Only six Northeast Pacific major hurricanes have occurred prior to June 5 since accurate satellite records began in 1971, and two of them were this year:

1) Hurricane Amanda, 2014: 155 mph winds on May 25
2) Hurricane Andres, 2015: 145 mph winds on June 1
2) Hurricane Adolph, 2001: 145 mph winds on May 29
4) Hurricane Blanca, 2015: 140 mph winds on June 3
5) Hurricane Alma, 2002: 115 mph winds on May 30
6) Hurricane Bud, 2012: 115 mph winds on May 25

- Hurricane Andres topped out as a Category 4 storm with 145 mph winds on June 1, becoming the second strongest Northeast Pacific hurricane for so early in the year.

- Blanca became a hurricane on June 2, setting a record for the earliest appearance of the season's second hurricane (previous record: Hurricane Boris of 1990 on June 5.) Blanca also set a record for the earliest appearance of the season's second major hurricane (June 3), and was the fourth strongest Northeast Pacific hurricane for so early in the year.

- Blanca made landfall on the west side of Mexico's Baja Peninsula on June 8, 2015, with top winds near 45 mph. Blanca's landfall came a month earlier than the previous earliest landfall on record for Baja (Tropical Storm Calvin on July 8, 1993.)

Wunderblogging hurricane expert Steve Gregory put up a Wednesday afternoon post looking at the tropics and long-range summer outlook for the U.S.; he plans to issue regular Atlantic hurricane updates twice per week.

Bob Henson will have an update on El Niño this afternoon.

Jeff Masters