TD 4-E Little Threat to Hawaii; Switzerland has its 2nd Warmest Temperature on Record

Tropical Depression Four-E spun into life Tuesday night in the waters about 1000 miles east-southeast of Hawaii, and is headed northwest at 16 mph on a path that should keep the center of the storm about 200 miles to the northeast of the islands at the time of closest approach on Saturday. Satellite loops show an unimpressive storm, with heavy thunderstorm activity not is not particularly intense or well-organized. Wind shear is moderately high, near 20 knots, and ocean temperatures are marginal, near 26°C. The 8 am EDT Wednesday run of the SHIPS model predicted that wind shear would steadily rise over the next few days, and ocean temperatures would stay cool, near 26°C. These conditions should prevent much intensification of TD 4-E. Given its current state of organization, it is questionable whether or not this system can become a tropical storm. One of our two most reliable track models, the GFS model, shows TD 4-E dissipating by Friday before the storm reaches Hawaii, and I give a 70% chance that TD 4-E will be dead by Saturday.


Figure 1. Typhoon Chan-hom as seen by the MODIS instrument on NASA'a Aqua satellite at 8:25 pm EDT Tuesday, July 7, 2015. At time time, Chan-hom was a Category 1 storm with 90 mph winds. Image credit: NASA.

Typhoon Chan-hom a dangerous storm for China
Category 2 Typhoon Chan-hom is headed west-northwest at 12 mph towards China, and promises to be a dangerous and very expensive typhoon for a portion of the country unused to strong typhoons. Chan-hom will be steered by a strong ridge of high pressure towards the west-northwest through Thursday night (U.S. EDT), when the typhoon will pass between Japan's Miyakojima and Okinawa islands. Wind shear will be moderate and ocean heat content will be high until just after the storm passes these islands, so intensification into a Category 4 storm by Thursday night is expected. On Friday, as Chan-hom approaches China, ocean heat content will fall and wind shear is expected to rise, which should cause weakening. Chan-hom is likely to make landfall in Mainland China north of Taiwan on Saturday morning (U.S. EDT.) However, the landfall location in China is quite uncertain, as a strong trough of low pressure is expected to turn the typhoon northwards as the center nears the coast on Friday. As Chan-hom curves to the north and weakens, due to interaction with land, the storm is expected to pass very close to Shanghai as a very large and very wet tropical storm. Significant coastal flooding and flooding due to heavy rain is possible in Shanghai, which is China's most populous city (14 million people.)

Elsewhere in the tropics
Category 4 Typhoon Nangka is expected to pass through a sparsely populated portion of the Northern Mariana Islands on Thursday. Nangka could threaten Japan 8 - 10 days from now as a weaker storm. Tropical Storm Linfa hit the Philippines' northern island of Luzon over the weekend, and is expected to make landfall in China on Thursday as a tropical storm. The Atlantic remains quiet, and is dominated by high wind shear and stable dry air. None of our reliable genesis models are showing tropical storm formation in the Atlantic over the next five days.


Figure 2. People re-fill bottles of water at a fountain in front of Rome's Pantheon, Wednesday, July 8, 2015, during Europe's record heat wave. (AP Photo/Andrew Medichini)

Switzerland has its highest reliably measured temperature on record
It was another day for the record books on Tuesday as Europe's intense heat wave broke scores of all-time heat records at cities in Spain, Switzerland, France, and Italy. Geneva, Switzerland hit 103.5°F (39.7°C), smashing its old historical record of 102.0°F (38.9°C) set almost a century ago, in July 1921. The only higher temperature ever measured in the country was a 106.7°F (41.5°C) reading on August 11, 2003 at Grono. As reported at the Swiss news site swissinfo.ch, this was recorded "using an old measurement technique of weather huts, which generally recorded temperatures a few degrees higher than modern instruments." Weather records researcher Maximiliano Herrera agrees that yesterday's 39.7°C reading in Geneva is the highest reliably measured temperature ever in Switzerland, though the August 11, 2003 temperature at Grono was probably warmer (near 40°C), after correcting for the known problems with the site. Although Tuesday does not hold the official record for hottest day in Swiss history, it was their hottest July day, and they have joined five other nations that have set all-time July national heat records this month: Germany, the Netherlands, the U.K., Thailand, and Colombia. The European heat wave continues, with more all-time heat records at risk across Southeast Europe on Wednesday, and possibly on Thursday. The heat wave will finally die down by Friday, ending a remarkable 9-day span.

Jeff Masters