It’s tropics, tropics, and more tropics this week, with a hint of fall and a report on the hottest month the earth has hosted in over ten thousand years.
Let’s go Around The World.
First Atlantic Hurricane Of The 2015 Season
As Decoded Science reported last week, the first serious easterly wave with any chance of development came off the African coast about ten days ago.
The waters near the Cape Verde Islands are now warm enough to support at least minimal tropical development, and the wave held together into the middle of the ocean, where the water was warmer.
Atmospheric conditions over the central Atlantic were favorable for cyclone development: Light winds at all levels of the atmosphere to go with the warm water. Tropical Storm Danny was born more than a thousand miles from the Lesser Antilles, and quickly spun up to a category three storm, with winds of 120 miles per hour. A casual observer would say Danny was a threat to the Caribbean islands, and then possibly Puerto Rico, Hispaniola, and eventually the United States.
The meteorologists at the National Hurricane Center knew better. Winds closer to the Antilles were hostile, changing direction and speed with height, and they literally blew Danny apart. The former menace was barely a tropical storm when it reached Antigua. The remnants of Danny are now just an area of rain over Puerto Rico — not a bad thing as we shall see.
Danny was the fourth named storm in the Atlantic Basin this year. Another vigorous wave came off the African coast last week and is now in the favorable zone, half way across the ocean.
Tropical Storm Erika
Last night, the wave became Tropical Storm Erika. Erika is forecast to skirt the most hostile area of winds and become a hurricane in the Bahamas in five days. Tropical storm watches have already been issued for the northern Leeward Islands, as Erika is moving fairly rapidly.
More waves will follow Erika, and it is possible that conditions will become more favorable for cyclones all across the Atlantic during the next few weeks. The statistical peak of the Atlantic tropical cyclone season is September 10.
El Niño is correlated with unfavorable conditions for cyclones in the Atlantic, and the current El Niño is becoming one of the strongest in the last few decades. As a result, most forecasters have predicted lower than normal hurricane activity in the Atlantic this season.
Decoded Science is the outlier, predicting an average season due to the positive effect of water temperature, particularly in the western Caribbean and Gulf of Mexico, where late-season storms are common. We reiterate our hurricane forecast.
Remnants Of Danny Help Alleviate Severe Drought In Puerto Rico
The northern Caribbean islands, particularly Puerto Rico, have suffered through one of their worst droughts during the last two years. July didn’t help. In Puerto Rico, July, 2015 was the driest July on record, and the fourth driest month ever.
Danny’s remnants are now dumping two to four inches of rain on Puerto Rico — not enough to completely erase the drought, but with improved measures in place to conserve water, a big help.
Typhoon Goni Bashes The Philippines, Lashes Japan
Last week we talked about the difference it makes to Japan which direction a typhoon comes from. The dangerous typhoons approach from the south, and this week’s Typhoon Goni is a case in point.
Goni skirted the Philippines, keeping the center 60 miles from the northern island, then bypassed Taiwan at a similar distance. This left the storm intact over extremely warm water, and it blossomed to category four.
In the wake of Goni’s close approach to the Philippines, nineteen people are confirmed killed and sixteen are still missing.
As Goni moved north, it encountered somewhat cooler water. Nevertheless, the typhoon maintained category two strength across Kyushu, brushed the western tip of Honshu, then lost some intensity over the cold waters of the Sea of Japan. With rapid movement, Goni will still be a tropical storm as it makes landfall in extreme southeast Russia near the borders of North Korea and China.
26 people have been reported injured on Kyushu, but there have been no fatalities.
Hawaii Gets Drenched But Avoids A Wind-Whipping
Tropical Storm Kilo was expected to move towards the northern Hawaiian island of Kauai, but veered far off to the west. Nevertheless, moisture from Kilo was carried on southwest winds aloft into all of Hawaii, causing some flash flooding.
Jet Stream Reflects The Changing Season
Decoded Science has noted the qualitative change in the northern hemisphere’s jet stream pattern in the last few years: The jet stream appears to be displaced southward by higher pressures at the pole, consistent with a rapidly warming Arctic. The result is an occasional southward push of colder than normal air.
Last Thursday, a cold front brought relief from the summer heat to much of the midwest and the plains, and Thursday morning the mercury bottomed out at 50 degrees in Oklahoma City — fully six degrees below the previous record.
The last two winters — colder than normal over southeastern Canada and the north central and northeastern US — are also consistent with this pattern.
Now we have a powerful El Niño, which normally forces the jet stream northward over the eastern two-thirds of the US. Skirmishes have already begun between the two circulation patterns, with undulations in the jet stream causing heat waves to wax and wane, while cold fronts dip southward on occasion.
NOAA’s July Global Land And Sea Temperature Analysis
As Decoded Science reported yesterday, July, 2015 was the hottest month for combined land and sea temperatures on a worldwide basis in thousands of years. Temperatures have been rising since the industrial revolution, but the recent spike is worrisome for its intensity. The year-to-year increase from 2014 to 2015 extrapolates to a rise of twenty degrees per century. This is probably not a realistic expectation, but a rise of just a quarter of that would cause massive problems.
Climate Change; Season Change
Climate change will have different results in different places. As the season changes, attention will shift from the tropics to the middle latitudes.
What’s changing where you are?