Category 3 Raymond Drenching Acapulco; TD 13 Forms; Extreme Air Pollution in China

Hurricane Raymond roared into life on Sunday just offshore from Acapulco, Mexico, rapidly intensifying from a minimal-strength tropical storm with 40 mph winds to a major Category 3 hurricane in just 24 hours. Raymond is the first major hurricane in the Eastern Pacific in 2013, making it the first year since 1968 that both the Eastern Pacific and Atlantic had made it into October without a major hurricane. Raymond has brought more than 3" of rain so far to Acapulco, where a Hurricane Watch is posted. As of 8 am EDT, Raymond was drifting slowly northwards at 2 mph toward Mexico, and was centered about 165 miles west-southwest of Acapulco. Raymond is expected to bring heavy rains of up to 8" to the coast, and this is an area where heavy rains are definitely most unwelcome. Hurricane Manuel hit this region of Mexico with extreme torrential rains when it made landfall on September 15, triggering deadly mudslides and flooding that left 169 people dead or missing and caused $4.2 billion in damage. According to EM-DAT, the International Disaster Database, this was the second most expensive weather-related disaster in Mexican history, behind the $6 billion in damage (2013 dollars) wrought by Hurricane Wilma in October 2005.

Raymond is in an area with weak steering currents, and is likely to show some erratic movement until Wednesday, when a ridge of high pressure is forecast to build in and force the storm westwards, away form the coast. Given Raymond's very slow movement, the storm may weaken later today and on Tuesday, as it stirs up colder water from below. However, there is no evidence of weakening on the latest satellite loops, which show a well-organized hurricane with a prominent eye and impressive-looking eyewall clouds with cold tops that reach high into the atmosphere.

Wunderblogger Lee Grenci has a detailed look at the ocean temperatures and steering flow affecting Raymond.


Figure 1. Aerial view of the landslide triggered by Hurricane Manuel's rains, which killed 43 people in La Pintada, México, on September 19, 2013. (Pedro Pardo/AFP/Getty)

TD 13 forms in the Middle Atlantic
Tropical Depression Thirteen has formed from an area of disturbed weather located about 650 miles east-southeast of Bermuda. Satellite loops show TD 13 has a moderate area of heavy thunderstorms and solid low-level spin. An ASCAT pass from 1:22 UTC Monday morning showed a closed surface circulation, and top winds of 30 - 40 mph on the storm's east side. Wind shear is moderate, 10 - 15 knots, but is expected to increase to the high range by Tuesday night, giving TD 13 a short window in which to develop. If it does intensify, it will become Tropical Storm Lorenzo. TD 13 will not be a threat to any land areas.


Figure 2. MODIS satellite image of Tropical Depression 13, taken at approximately 12:30 pm EDT October 21, 2013. At the time, TD 13 had top winds of 35 mph. Image credit: NASA.

Typhoon Francisco headed towards Japan
Category 2 Typhoon Francisco has steadily weakened on Sunday and Monday, after spending just over a day as Earth's third Category 5 storm of 2013 on Saturday. Satellite loops show a large, cloud-filled eye and a decaying eyewall. Since wind shear remains low, the weakening is likely in response to cooler ocean temperatures, since Francisco is now traversing a large cool patch of ocean up to 2°C colder than the surrounding waters, left behind by the churning action of Typhoon Wipha last week. By the time Francisco makes its closest approach to Japan on Thursday and Friday, it will be undergoing transition to an extratropical storm. Francisco's interaction with a cold front over Japan during this process will bring very heavy rains to Japan, and these rains will pose a serious flooding threat, as the soils have not had a chance to dry out much from the record rains that Typhoon Wipha brought last week. The 00Z Monday run of the HWRF model predicted a large swath of 4 - 8 inches of rain for Japan from Francisco. The University of Wisconsin CIMSS Satellite Blog has some impressive images of Francisco from when it was a Super Typhoon.


Figure 3. Infrared satellite image of Super Typhoon Francisco, taken at 15:48 UTC on October 18, 2013. At the time, Francisco was a high-end Category 4 storm with top winds of 155 mph. Image credit: University of Wisconsin CIMSS Satellite Blog.

China's 10th-largest city shuts down because of extreme air pollution
Harbin, China, the nation's 10th most populous city with a population of 11 million, has virtually shut down today because of extreme levels of air pollution reaching up to 1,000 micrograms per cubic meter. The safe level recommended by the World Heath Organization (WHO) is just 25 micrograms per cubic meter. The dense pollution was created by stagnant air on a day when the city's heating systems kicked in for the first time this fall. With visibility less than 50 yards, the airport was forced to close, as well as most schools and some roads. Cir.ca has some remarkable images of the event, and here is zoomable map of real-time Chinese air quality.


Figure 4. A woman walks along a road as extreme air pollution engulfs the city on October 21, 2013 in Harbin, China. ChinaFotoPress/Getty Images


Video 1. Extreme air pollution in Harbin, China on October 21, 2013. Thanks go to wunderground member Patrap for alerting me to this video.

Jeff Masters