Tropical activity shifted its aim with a vengeance this week.
After Severe Cyclone Hudhud hit India and Typhoon Vongfong whacked Japan, the Indian and eastern Pacific Oceans quieted down, while the Atlantic and central Pacific heated up and now threaten to boil over.
The Quiet Atlantic Hurricane Season Gets Noisy
Last week Hurricane Fay blossomed as it approached Bermuda. Now Major Hurricane Gonzalo is bearing down on the island. These one-two punches have occurred several times this season, affecting Hawaii in early August and Japan last week.
For Bermuda, Fay was a wake-up call and Gonzalo is the Real Deal.
Conditions In The Atlantic Are Favorable For Hurricanes — At Last
This summer’s tropical Atlantic weather has been dominated by dry Saharan air and high vertical wind shear (change of wind with height). Neither of these conditions is conducive to tropical storm formation. Recently the dry air dissipated and the vertical wind structure became less hostile. With very warm water covering the western Atlantic, Fay and then Gonzalo underwent explosive intensification.
Gonzalo brushed the Virgin Islands and Puerto Rico with minimal tropical-storm-force winds, then rapidly strengthened into a category three storm with winds over 125 miles per hour. As of Thursday morning, Gonzalo had reached category four status with top winds of 140 miles per hour. The forecast calls for a direct hit on Bermuda, with winds still in the category three range.
A Record Tropical Storm Year For Hawaii
Hawaii has already experienced glancing blows this summer from back-to-back tropical storms Iselle and Julio. Both weakened as they approached the islands from the east-southeast, traversing colder water.
Tropical Storm Ana will take a slightly more southern route, and so will stay over warmer water. Forecasts, which a day ago had Ana striking the Big Island directly, have now shifted south, so that Hilo will be spared the strongest winds. Honolulu is expected to be within 50 miles of the center as Ana passes, and winds could gust to hurricane force.
Times Of Hurricane Conditions On Bermuda And Hawaii
Gonzalo is expected to pass just west of Bermuda around midday Friday. Winds will still be around 125 miles per hour. After that, Gonzalo will accelerate northeastward, clipping the southeast coast of Newfoundland as it transitions to an extra-tropical low pressure system. By Tuesday, the remnants of Gonzalo will be approaching Ireland.
The predicted path of Ana has shifted slightly to the south over the last day. The center is expected to pass south of the Big island on Saturday and maintain strong tropical storm strength as it passes within 50 miles of Honolulu Saturday night. The weakening storm will then continue through the northernmost islands and on into the open Pacific, losing strength over the colder water.
Next Week’s Tropical Threat
The waters south of Mexico have been an incredible breeding ground for hurricanes this season. The water has been warm and the vertical wind structure has been favorable for development. No fewer than 20 systems have been named, of which 14 became hurricanes — Ana, if it reaches the hurricane threshold of 75 mile-per-hour winds, will be the 15th.
And now another tropical system is in its infancy south of Mexico. An area of disturbed weather is given a 70% chance to become a named storm. This one could come perilously close to the Mexican mainland, or it could parallel the coast like so many others. At this time of year the jet stream is dipping south, and could nudge the storm to a landfall.
Is It Global Warming?
Fifteen hurricanes do not a proof of global warming make. As Decoded Science takes pains to point out: Recent extreme weather events are consistent with, but don’t prove, climate change. Nevertheless, after enough drops in the bucket, the bucket overflows.