Tropical Storm Newton Makes a 2nd Mexican Landfall, Spreads Heavy Rains to SW U.S.

Heavy rains have moved into Southeast Arizona as Tropical Storm Newton plows northwards at 18 mph. As of the 11 am EDT Wednesday advisory, Newton had top sustained winds of 50 mph and was located just 135 miles south of Tucson, Arizona. Newton made two landfalls in Mexico during the previous 36 hours. The first came early Tuesday morning, when Newton hit the southern tip of the Baja Peninsula with sustained winds of 90 mph, with the eye of the storm passing directly over the resort town of Cabo San Lucas. After crossing the spine of the Baja Peninsula on Tuesday, Newton weakened to a tropical storm with 70 mph winds and made landfall in southwest Mexico near Bahia Kino early Wednesday morning. Here are some peak wind gusts measured during and after this final landfall, according to NHC:

• 66 mph: Guaymas, Mexico
• 64 mph: East of Bahia Kino
• 50 mph: Hermosillo International Airport

The storm is being blamed for two deaths, with three others missing, from a capsized fishing boat near the town of La Paz on the Baja Peninsula. Newton is expected to cross into southern Arizona as a tropical depression or weak tropical storm on Wednesday afternoon, and dissipate over the dry, rugged terrain of Arizona by Wednesday night.


Figure 1. A woman wades through a street flooded by the heavy rains brought on by Hurricane Newton in Cabo San Lucas, Mexico, Tuesday, Sept. 6, 2016. (AP Photo/Eduardo Verdugo)


Figure 2. MODIS visible satellite image of Hurricane Newton on Tuesday morning, September 6, 2016. At the time, Newton was a Category 1 storm with 80 mph winds, located over the center of Mexico’s Baja Peninsula. Image credit: NASA.

High moisture available to Newton
By late Wednesday morning, Newton was bringing heavy rains to southeastern Arizona, southern New Mexico and southwest Texas. Widespread heavy rains of 1 - 3” and the risk of flash floods are expected in the region, and a Flash Flood Watch is posted. Ocean temperatures in the waters off the southwest Mexico coast, including the Gulf of California, are about 1°C (1.8°F) above average, which is allowing high amounts of water vapor to evaporate into the atmosphere and feed Newton’s heavy rains. This rich moisture was streaming into the Southwest U.S., where on Wednesday morning, four upper-air observing stations—Amarillo, TX, El Paso, TX, Phoenix, AZ, and Tucson AZ—recorded top-ten amounts of moisture on record for the month of September (1st, 2nd, 3rd, and 7th highest, respectively.) The upper-air soundings measured total precipitable water (TPW)—the amount of water that would result if one condensed all the water vapor in a column above and precipitated it out. Upper-air balloon soundings began in the U.S. in 1948.

New African tropical wave may develop late this week
A tropical wave that emerged from the coast of Africa on Tuesday was bringing a modest area of disorganized heavy thunderstorms near the Cabo Verde Islands on Wednesday morning, as seen on Meteosat satellite images. This tropical wave could develop into a tropical depression by the weekend, a few hundred miles west-southwest of the Cabo Verde Islands, predicted the 00Z Wednesday run of the UKMET model. Our other two reliable models for predicting tropical cyclone genesis, the GFS and European models, were less impressed with this tropical wave than in their previous runs, and showed only weak development of the system late this week, due to dry air coming off the coast of Africa. In their 8 am EDT Wednesday Tropical Weather Outlook, NHC gave this system 2-day and 5-day development odds of 20% and 70%, respectively. The long-range models are showing a west-northwesterly track for this storm into the Central Atlantic to a location where few storms ever become a threat to the Lesser Antilles Islands or North America.

Satellite images on Wednesday morning showed that the tropical wave (Invest 92L) that was over the central Caribbean near Hispaniola on Tuesday had grown very weak and disorganized. NHC no longer considers 92L an area of interest, and stopped issuing model forecasts for it.


Figure 3. MODIS visible satellite image of Post Tropical Cyclone Hermine on Tuesday morning, September 6, 2016. At the time, NHC was about to issue its final advisory on the storm. Image credit: NASA.

Hermine still spinning off the coast of Long Island
Post-Tropical Cyclone Hermine is still gradually spinning down as it meanders over the cool waters just over 100 miles southeast of Long Island, New York. Hermine was bringing extensive cloud cover to the Northeast, but little in the way of strong winds or precipitation. On Tuesday afternoon at 2 pm EDT, the National Hurricane Center (NHC) judged that Hermine no longer represented a danger, and issued its last advisory on the storm. This ended a marathon 19-day period where they tracked the storm first as Invest 99L, then as TD 9, Tropical Storm Hermine, Hurricane Hermine, and finally, Post-Tropical Cyclone Hermine. What’s left of Hermine is expected to get absorbed by a low pressure system passing to its north on Thursday, and Hermine should no longer be identifiable as a separate entity by Friday.

Record September heat in Europe and the Mideast
All-time September heat records for Spain and Portugal fell this week, thanks to a massive dome of high pressure that settled over the region that sent temperatures soaring as high as 46.4°C (115.5°F) in Sanlucar La Mayor, Spain—a new September European heat record, if verified. Perhaps more extraordinary was the record September heat in the Middle East this week; Mitribah, Kuwait recorded 51.2°C (124.2°F) on September 4—the hottest reliably measured temperature on record so late in the year, world-wide. Wunderground’s weather historian, Christopher C. Burt, has the details in his Wednesday post, Hottest Temperature Ever Measured in September for Europe.

Jeff Masters