July 27

Weather Quirks, Oddities and Discoveries – July 27, 2020

Another “Mega-Rain” Event For Minnesota

“Without data, you are just another person with an opinion” said engineer and quality control guru W. Edwards Deming. When does a fluke become a trend? How much data is required to accurately discern the difference? According to the Minnesota DNR, the storm complex that dumped over 8 inches of rain on Mankato qualifies as a “mega-rain“; the first since 2016. They estimate over 1,000 square miles of land picked up 6 inches or more of rain. By the DNR’s calculations there have been 21 of these extreme flood events since Minnesota became a state in 1858. 14 of the 21 mega-rains have been observed since 1983. A warmer atmosphere holds more water vapor, increasing the potential for downpours and biblical floods.

Saturday night rainfall estimates courtesy of the Twin Cities National Weather Service.

Mega-Rain Details. The Minnesota DNR has more perspective on Saturday night’s monsoon just south of MSP: “…This storm produced six inches of rain or more over an area of roughly 1000 square miles, making this event the first “mega-rain” since 2016. Apart from water covering roads and filling many ditches, however, this event produced little in the way of major damages. Most rains of this magnitude produce landslides, wash out roads, and damage public and private property, but fortunately, this one came when river levels had been relatively low, and when area soils had been in good condition after a mostly “normal” summer...”

Photo credit: “Flooded campground in Fort Ridgely State Park.” Courtesy: A. Boddy, DNR Staff.

Southern Sizzle – Some Relief Seattle to Boston. Northern tier states will avoid the worst of the heat and humidity by the second week of August. But the southern USA will continue to experience a streak of debilitatingly hot days.

Hurricane Douglas Moved Over Territory Where No Hurricane Has Been Observed in Decades of Satellite Monitoring. Bob Henson provides perspective at Yale Climate Connections: “...Already, Douglas is traveling over oceanic territory just north of the Big Island and east of Maui where no hurricane has been observed in decades of satellite monitoring. The closest analog for strength among west-northwest tracking hurricanes, Lester (2016), passed about 130 miles northeast of Hawaii as a Category 1 storm. Douglas’s forecast track is most similar to that of Flossie (2013), which weakened to tropical depression status before passing just north of Kauai and Oahu. A number of other systems have passed north of Hawaii as tropical storms or tropical depressions, as shown above. By far the strongest hurricanes to affect Hawaii are those approaching from warmer waters to the south. Category 5 Lane (2018) passed within about 150 miles of the Big Island while still a Category 3...”
Monday evening visible image: NOAA and AerisWeather.

Briefing: Issued Monday, July 27th, 2020:
  • Over the past day the center of Hurricane Douglas has been passing north of Hawaii. Douglas will continue to quickly move away from Kauai today.
  • We are also tracking an area of low pressure moving west across the Atlantic. This system has a HIGH chance of becoming a tropical depression or storm in the next two days and could start to impact the Lesser Antilles Wednesday.

Hurricane Douglas

Latest On Douglas. The center of Hurricane Douglas has been moving north of Hawaii over the past day and will continue to move away from Kauai today. As of the 2 AM HST update, Douglas had winds of 90 mph. The center of Douglas was about 60 miles north-northwest of Lihue and was moving west-northwest at 16 mph. The Hurricane Warning has been cancelled for Kauai County but a Tropical Storm Warning remains in place for portions of the Papahanaumokuakea Marine National Monument from Nihoa to French Frigate Shoals to Maro Reef. Douglas will continue to move west-northwest over the next few days with weakening expected.

Potential Tropical Formation

Potential Formation In The Atlantic. Out in the Atlantic an area of low pressure is working westward over the next few days. While the showers and thunderstorms associated with this system are less organized this morning vs. yesterday, conditions are favorable for development in the next couple of days. There is a HIGH chance (80% in the next two days, 90% in the next five days) that a tropical depression or storm could form out of this area of low pressure. This system – whether it forms or not – will start to impact the Lesser Antilles Wednesday.

Potential Track. We are monitoring potential trends of this system as we head through the next several days – and it must be noted that nothing is set in stone, as a lot of it depends on how quickly this system can strengthen. A system that strengthens quicker will get pulled on a more northern track, while a weaker system will move farther south. A lot of model guidance, like what is shown above, show this system strengthening quicker, which could bring a storm threat to portions of the Leeward Islands, the Greater Antilles, and potentially the Bahamas. Meanwhile, the European model keeps the storm weaker, crossing the Leeward Islands and fizzling out in the Caribbean. We will continue to monitor these trends over the next few days and provide updates.

D.J. Kayser, Meteorologist

It’s Not Just Siberia as Record Heat Spreads Across the Arctic. If only we had been warned, huh? Oh yeah, this was predicted 30-40 years ago. Gizmodo has the details: “Siberia has been hot and on fire. Perhaps you’ve heard? The relentless heat that’s buffeted the region has decided to expand to other parts of the Arctic, from Norway to Canada, with high-temperature records breaking over the weekend. A nearly all-encompassing heat wave has spread across the highest reaches of the globe. Weekend temperatures reached 71.4 degrees Fahrenheit (21.9 degrees Celsius) in Eureka, Canada, one of the northernmost settlements on Earth located on Ellesmere Island. Meanwhile, in Longyearbyen, a small town on the northern Norwegian island of Svalbard, it hit 71.1 degrees Fahrenheit (21.7 degrees Celsius) on Saturday. Both are all-time records for the two locations…”

Sultry Nights and Magnolia Trees: New York City is now Subtropical. In case you missed this at The New York Times (paywall): “…New species are thriving in the Metropolitan area, while those more associated with New England are slowly vanishing. This is because of rising temperatures, which are largely the result of human activity, including emissions from fossil fuels, according to the National Climate Assessment. New York City, after years of being considered a humid continental climate, now sits within the humid subtropical climate zone. The classification requires that summers average above 72 degrees Fahrenheit — which New York’s have had since 1927 — and for winter months to stay above 27 degrees Fahrenheit, on average. The city has met that requirement for the last five years, despite the occasional cold snap. And the winters are only getting warmer…”

Inside Venice’s 50-Year Fight Against Deadly Floods. Here’s an excerpt from a harrowing (and apparently true) story explained by CNET: “…On July 10, all 78 gates were raised for the first time during a public demonstration, but the government is still anxious to reassure Venice’s citizens that the plan, which won’t be fully functional until the close of 2021, will work. Beset by corruption and delays, MOSE itself has become a problem. Critics say that the gates won’t be as effective as the government envisions and that they’ll have to be raised so frequently that Venice’s sewage will be trapped in the Lagoon, killing off its ecosystem.  “This is the death of Venice,” said Fabrizio Antonioli, a geologist at ENEA, a public sustainable development firm…”

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