A series of training thunderstorms that moved over and near Valencia state in eastern Spain led to catastrophic flooding on Tuesday afternoon and evening, making for one of the nation’s worst natural disasters in years. At least 72 fatalities had been reported by midday Wednesday EDT, according to Reuters.
Some of the worst flooding was in outlying parts of the Valencia metro area. As noted by climate scientist Erich Fischer, the community of Chiva – about 20 miles (32 km) inland and close to 1,000 feet (305 m) above downtown Valencia – reported 160 millimeters (6.3 inches) of rain in just one hour, 343 millimeters (13.5 inches) in four hours, and 491 millimeters (19.33 inches) in eight hours. Fischer pointed out that the large-scale weather situation during the current flood was similar to that of the Valencia flood of mid-October 1957, which killed 81 people and prompted a rerouting of the area’s main river: “Remarkably similar but now happening in a warmer and moister atmosphere.”
On Tuesday night, floodwaters cascaded toward the sea through the narrow streets of many towns and neighborhoods in the Valencia area, piling up cars and trapping people.
The floods drew on warm, humid conditions that have prevailed across the Mediterranean Sea this autumn. The Climate Shift Index from Climate Central showed that the unusually mild air temperatures across much of northeastern Spain on Wednesday were made two to three times more likely by human-caused climate change, while the unusual sea surface warmth over the western Mediterranean was made four to eight times more likely (Fig. 1).
While the factors above helped intensity the rainfall, the storms themselves were triggered by a “high-over-low” blocking pattern, featuring an upper low stalled over Spain – detached from the polar jet stream – and a summerlike upper high, one even more anomalous than the upper low, arcing from the northeast Atlantic across the British Isles and pushing toward northern Europe. Temperatures throughout Europe are running 5 to 20 degrees Fahrenheit (3-11°C) above average this week, ahead of the high-over-low block. The stuck pattern could bring up to two inches (50 mm) of additional rain to coastal and near-coastal areas of eastern Spain through the coming weekend.
The blocking pattern led to a deep corridor of moist easterly winds blowing from the Mediterranean into eastern Spain, feeding a group of intense thunderstorms that were moving west but continually regenerating near Valencia (see embedded post below).
The type of “stuck” upper-level features and extreme weather events unfolding over western Europe, though occurring in this case in autumn, are similar to summertime patterns that have been linked to climate change and that are predicted to occur increasingly often later this century through a phenomenon called quasi-resonant amplification.
The record- and near-record-warm oceans prevailing across the Northern Hemisphere this year have sent mammoth amounts of moisture into the atmosphere and have helped generate a train wreck of disastrous floods. These include several in Africa, Asia, and Europe that we spotlighted in a September 18 post as well as the catastrophic flood disaster caused by Hurricane Helene across the southern U.S. Appalachians. According to a recent New York Times analysis, horrific flooding in mid-September in Maiduguri, Nigeria – the result of unusually heavy rains over the semiarid Sahel region, together with a long-neglected dam that collapsed – may have produced as many as 1,000 deaths. And in the Philippines, Tropical Storm Trami spawned major flooding last week, with at least 81 people killed and dozens more missing.
Enormous Typhoon Kong-Rey to bring widespread torrential rain and fierce winds across Taiwan
Typhoon Kong-Rey – formerly a super typhoon with 150 mph winds, but still a formidable Cat 4 storm with 140 mph winds just hours before landfall – is predicted to plow into southeastern Taiwan and cross the island on Thursday afternoon and evening local time, a major change from forecasts several days in advance that had kept Kong-Rey well east of Taiwan.
As of 8 a.m. EDT Wednesday, Kong-Rey’s top sustained winds (one-minute average) were 140 mph (220 km/h), making it the equivalent of a Category 4 hurricane. Kong-Rey’s top winds are expected to drop to the Cat 3 range by landfall as the storm goes through early stages of an eyewall replacement cycle, but the winds will spread out to cover an unusually broad area – along with colossal rains, flash floods, and mudslides.
Kong-Rey’s size is near the top end of the typhoon spectrum. Its swath of hurricane-force sustained winds spanned more than 230 miles (370 km), and gale-force winds spanned more than 450 miles (725 km). Kong-Rey had an inner eyewall about 35 miles (56 km) wide, an outer eyewall about 170 miles (275 km) wide, and a “moat” of somewhat drier air in between.
Taiwan is no stranger to intense typhoons and is well prepared for them, but Kong-Rey is large and strong enough to produce significant impacts regardless. Workplaces and schools are closing throughout much of the island on Thursday. Rainfall totals well above 500 mm (20 inches) can be expected across much of the higher terrain of interior Taiwan and coastal locations where Kong-Rey’s winds will be pushing onshore, especially toward the east-central and northeast coast.
Watching the Western Caribbean for Patty
A broad area of low pressure will be developing over the southwestern Caribbean over the next few days, and it could spawn a named storm in the Atlantic by next week. Conditions are generally favorable for development over the region, with moderate wind shear of 10-20 knots, a moist atmosphere, and sea surface temperatures near 29 degrees Celsius (84°F), which is about 0.5-1.0 degree Celsius above average.
The GFS and European models have had varying degrees of enthusiasm about the potential for the season’s next named storm to develop here, with the most recent runs fairly lukewarm about the prospects. Any storm that does develop will likely drift north and then northwest, potentially bringing heavy rains to much of the western Caribbean and adjacent land areas next week. In their 8 a.m. EDT Wednesday Tropical Weather Outlook, the National Hurricane Center gave the disturbance two-day and seven-day odds of development of 0% and 40%, respectively. The next name on the Atlantic list of storms is Patty.
A hostile environment in the Gulf of Mexico
If wanna-be-Patty does eventually make it into the Gulf of Mexico, it will have an environment much less favorable for development than encountered by the two recent catastrophic Gulf of Mexico hurricanes, Helene and Milton. Recurring fall cold fronts have spread cool air over the Gulf in recent weeks, causing significant cooling of the waters. More importantly, the jet stream has shifted more to the south and will bring high wind shear accompanied by dry air, making it difficult for a tropical cyclone in the Gulf to intensify.
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