Tuesday, June 25, 2013

Storms with Names (derecho explanation; peek at 4th of July Outlook)


Storms with Names

What happened to late afternoon, garden-variety popcorn showers and T-showers? We still see them, of course, but now (increasingly) we have to be on the lookout for their mutant relatives: supercells, tornadoes, meso-convective swarms of T-storms that pop up at night, and derechos.

Last Friday's wind damage was triggered by a particularly aggressive bow echo, a powerful T-storm downdraft of rain and hail-cooled air that reached the ground and spread out, fanning straight-line wind damage.

Monday evening a much larger "derecho" swept into Chicago, a much larger boomerang-shaped swirl of thunderstorms. To be called a derecho a vast arc of storms has to travel at least 240 miles. June 29, 2012 one such derecho traveled 800 miles, from Iowa to Norfolk, leaving millions without power.
The threat of heavy storms diminishes today as a cool front turns on a drier northwest breeze. We salvage a dry sky Thursday and Friday; a few pop-up instability T-showers Saturday afternoon. 

Sunday looks sunnier & drier. Keep your holiday weather expectations low & you'll never be disappointed. It's that kind of summer.

Right now models hint at 80s & isolated T-showers for the 4th. It may even feel like summer out there.

* image above courtesy of the Twin Cities National Weather Service, which has a good explanation of Friday evening's severe storm here.

What Is A Derecho? Friday evening's severe wind storm was triggered by a bow echo, powerful thunderstorm downdrafts spreading out into violent straight-line winds at ground-level. A derecho is an even larger phenomenon, a swirl of severe storms traveling hundreds of miles over multiple states. Details in today's edition of Climate Matters: "After historic derechoes rolled through Chicago and Minneapolis/ St. Paul, we turn our attention to an increasing threat that is usually downplayed because "it's just a garden variety thunderstorm." WeatherNationTV Chief Meteorologist Paul Douglas explains that these are different than normal thunderstorms, exactly what a derecho is, as well as what causes them."

Wednesday Severe Threat. The best chance of strong/severe storms this morning comes east of the Twin Cities, a greater risk of hail and damaging winds from Chicago and St. Louis across the Ohio Valley and much of the Northeast. Map: SPC.

Trending Slightly Drier. No cold fronts or stalled storms/fronts in sight, just a drier day on Thursday and Friday, a risk of more clouds and a few passing showers Saturday, then dry weather Sunday into the 4th of July; heavy showers and T-storms just south and west of Minnesota. I hope the ECMWF (European) model is right.

4th of July Outlook. Here is the ECMWF model outlook for midday on the 4th of July (next Thursday), showing a few showers and T-storms over the central and northern Plains, with a risk of a shower or T-shower over southern Minnesota. It's way too early to get specific, but showers and storms seem likely east of the Appalachians, with a better chance of puddles south/west of Minnesota. We'll see. Model map: WSI.

Not All Of The Corn Belt Is Wet. Check out the rainfall amounts over southeastern Minnesota in this post from The Illinois Climatologist: "Here is the latest map of 90-day precipitation departures from average across the Midwest. The greens, blues, and purple show areas that were 2 to 12 inches above average. That is the dominate feature of much of the western and central Corn Belt. Meanwhile, the areas in light tan and yellow in southeastern Indiana, southern and eastern Ohio, and small patches in Kentucky and southern Illinois show areas that are 1 to 4 inches below average. The dry areas are nowhere near as severe as 2012. However, it is worth watching as we move through the growing season." (map: Midwestern Regional Climate Center).
 
Fishing Tops List Of Lightning Death Activities. Another good reason to have a few radar apps on your smart phone in the boat, or a portable NOAA Weather Radio with you. Here's more from Yahoo News: "Most lightning deaths in the United States occur while people are enjoying outdoor activities, with fishing the most deadly, government weather officials say. From 2006 to 2012, 238 people died after being struck by lightning in the country — 82 percent of them male. Of the total number of victims, 152 were taking part in leisure activities, according to new findings from the National Weather Service . Fishing topped the list with 26 lightning deaths, followed by camping with 15 deaths, boating with 14, soccer with 12 and golf with eight, NWS officials said. Other lightning victims died while at the beach, swimming, walking, running or picnicking. [Electric Earth: Stunning Images of Lightning] Activities like fishing and camping may be most hazardous during a storm because they often require extra time to take shelter in a safe place, explained John Jensenius, a lightning safety specialist with the NWS..." (photo image: discovery.com).

Cleaner Air Linked To More Hurricanes. Here's a snippet of an interesting story at The Telegraph: "Researchers from the Met Office established a direct link between levels of industrial pollution and the frequency of hurricanes in the North Atlantic. For much of the 20th century, sooty pollution in the atmosphere has made conditions unfavourable for the storms, causing their numbers to drop. But since the 1980s, cleaner air over the Atlantic has created better conditions for hurricane formation, with more tropical storms developing and battering American and Caribbean coasts as a result..."

Lessons Learned From The June 21 Mega-Storm. Last Friday evening's bow echo, severe winds and flooding rains were a subtle (yet blunt) reminder that damage from severe thunderstorms can be even more extensive than a tornado touch-down. The latest edition of Climate Matters is here: "It wasn't a tornado, but hurricane force winds combined with a saturated ground that led to widespread damage and the largest power outage in Minnesota's history. Friday night's storm was the equivalent of a 15-mile-wide EF-0 tornado, and WeatherNation Chief Meteorologist Paul Douglas says it serves as a reminder that you need to take severe thunderstorms seriously."

Extra Severe. A radar loop from Friday evening's bow echo (courtesy of NOAA) shows a severe gust front as rain and hail-cooled air rushed east at 50 mph. A few thoughts from Friday's severe gust front:
 
* Sirens are not sounded for Severe Storm Warnings (with the exception of Dakota County).
 
* Tornadoes get more attention, but severe storms can be just as destructive. Damage is often more extensive, but not as severe as in a major tornado. To put things into perspective, the damage left behind from Friday's 70-80 mph gust front was roughly equivalent to an EF-0 tornado, one that was 15-20 miles wide. At some point it becomes a matter of semantics: did a tornado or a severe storm gust front bring down that big tree in your yard?
 
* The supercell thunderstorm that morphed into a bow echo raced east at 50 mph, moving faster than high-res models were predicting. Winds gusted over 60-70 mph over portions of Hennepin County for 10-15 minutes. The persistence of the high winds, coupled with wet, saturated ground from early morning storms, helped to bring down even more trees.
 
* This rotating supercell was able to sustain itself, keeping the rain and hail-cooled gust front intact for several hours, prolonging the damage. A typical thunderstorm self-destructs after 30-45 minutes, but spinning supercells can protect the warm updraft, sustaining a storm for a long period of time.

How Big Can A Tornado Actually Get On Earth? Good question: the (new) record is 2.6 miles wide, wind speeds around 300 mph. Here's an excerpt from DVICE: ..."We don’t really know," tornado researcher Joshua Wurman of the Center for Severe Weather Research told DVICE. "There are certainly extreme limits; it’s unlikely you would get wind speeds greater than the speed of sound, for instance. Whether they can even get close to that, probably not. Nature is always trying to get rid of strong, anomalous things. If there is an extremely strong wind, there are extremely string dissipative forces seeking to get rid of that anomaly." By mapping damage on either side of the storm’s path, weather spotters determined the El Reno twister spanned 2.6 miles across as it raged over 16.2 miles of ground west of Oklahoma City May 31. With surface winds greater than 200 miles per hour, it was hardly the most powerful tornado ever recorded, however. The record-holder, on May 3, 1999, reached wind speeds of 301 mph. That storm, incidentally, hit Moore, Okla., recently devastated in a powerful tornado a week before the El Reno storm. It’s possible that about 300 mph is just about as powerful as tornadoes get, Wurman said. The 1999 storm caused $1 billion in damage..."

Photo creditNational Severe Storms Laboratory

For Weather Satellites, Forecast Is Cloudy. Here's an update on the tenuous situation with America's weather satellites, courtesy of news.gnom.es: "As hurricane season gathered force, the main U.S. weather satellite watching the eastern seaboard failed last month for the second time in a year. The difficulties with the seven-year-old weather satellite are a symptom of a broader problem: Scientists are losing their orbital eyes on Earth. Lee Hotz reports. Photo: AP. The main U.S. weather satellite watching the eastern seaboard malfunctioned last month for the second time in a year, underscoring the hazards of aging satellites that monitor the planet as a threatening hurricane season gets under way..."

Lightning Safety. After concern was raised about recent Little League baseball games played during questionable weather (lightning observed nearby) I wrote this note to an ump who asked me about criteria for calling off a game, and when it's safe to resume play. Here is my reponse:

"With the recent spate of severe and damaging thunderstorms impacting the metro area, I wanted to drop you a quick note and remind you and your colleagues that lightning-related fatalities are most likely at the very beginning and tail-end of an outdoor event. This is where we see the most lightning-related injuries and fatalities, not during the height of the storm, when heavy rain/hail is falling.
Here’s the problem: lightning can travel 8-10 miles in a horizontal direction. In fact every year people are struck with blue sky overhead, a thunderstorm on the distant horizon. The National Weather Service’s “30-30 Rule” has become a defacto standard in the weather business. When you can count 30 seconds between lightning and thunder it’s time to head for shelter; and wait 30 minutes after the last thunderclap before resuming safe play on the field.

From a National Weather Service link focused on Lightning Safety and Outdoor Sports Activities:
“Because electrical charges can linger in clouds after a thunderstorm has passed, experts agree that people should wait at least 30 minutes after the storm before resuming activities”.

I realize the wet spring has compressed the season, and players (and their parents) are anxious to get these games in and complete the season. However the overriding goal should be safe play and lowering weather risk. Any temptation to “push the weather” and get coaches, players (and spectators) out onto a ball field within 30 minutes of the last report of thunder is not only unsafe, but a potential disaster in the making. From a litigation standpoint, there’s a large and growing body of evidence that waiting 30 minutes significantly increases safety margins and helps to avoid lightning-related disasters. Taking a chance and resuming play within that 30 minute window is a recipe for fatalities, life-long, chronic, lightning-related injuries, and litigation.

As an interested parent who spent many long weekends at the local ballpark with my two son (checking Doppler on my smart phone more often than I would have liked) I have an interest in safe play and taking any and all steps to reduce the potential for weather-related tragedy."

- Paul Douglas, CBM Meteorologist. Founder of Media Logic Group.

Alberta Flood Volunteers: "People Have Really Come Together". Portions of Calgary are still underwater; this is reportedly the worst flooding Alberta, Canada has experienced in recorded history. CTV News has a story of the aftermath and clean-up operations underway: "As southern Alberta deals with the worst flooding in its history, volunteers and staff with the Canadian Red Cross say they are working around the clock to help those affected get through the crisis and begin the cleanup. Matt Baden, a Red Cross emergency response team lead, has been working at an emergency shelter in Blackie, just a few kilometres east of High River, the community that was hardest hit by the flooding. He says currently, the Red Cross is working to supply the evacuees at the shelter with the basic necessities, such as cots, blankets and hygiene kits, and to make people as comfortable as possible..."

Photo credit above: "A flooded downtown Calgary, Alberta is seen from a aerial view of the city Saturday, June 22, 2013. The two rivers that converge on the western Canadian city of Calgary are receding Saturday after floods devastated much of southern Alberta province, causing at least three deaths and forcing thousands to evacuate." (AP Photo/The Canadian Press, Jonathan Hayward)

Tsunami-Like Wave In New Jersey Being Investigated. It must have been a fairly small "tidal wave". I don't remember the cable networks covering this (breathlessly) from sunrise to sunset. Here's an excerpt from nj.com: "A six-foot wave that crashed through Barnegat Inlet and swept three people off a jetty and into the water earlier this month is being investigated as a possible tsunami by federal officials, according to the National Oceanic and Atmospheric Administration. The June 13 wave was observed at over 30 tide gauges and a buoy throughout the northwestern Atlantic Ocean, according to a report on NOAA’s website. The cause of the incident is "complex and still under review," the report said, but it is believed to have been connected to a strong weather system known as a "derecho," which had passed through the area shortly before the wave was reported..."

Google Maps image credit: "A six-foot-wave that crashed through Barnegat Inlet in mid-June is being investigated as a possible tsunami, federal officials said."

* The Wall Street Journal has more on the alleged tsunami here (subscription may be required).

Map Shows The Most Famous Brand From Each State Of The U.S. Details from DesignTAXI.com: "Charts and infographics website Maps on the Web has created a map that shows the most famous brand to come from each state in the US. While the origins of some popular brands, like Apple and Starbucks, are common knowledge, others are less well-known—for instance, do you know that Dr. Pepper is from Texas or that Hooters is a native of Florida?  Do you agree that the “most famous” brand from your state is as depicted on this map?"

U.S. Pet Poll: Most Prefer Dogs; 18% Want Dinosaur. This story gets the honor for most unusual (and terrifying) headline of the week. Dinosaur? 20% of people polled would rather spend time with their pets than people. National Geographic has the story; here's the intro: "Americans love their pets—and a new poll shows just how much we dote on our critters, while revealing some curious attitudes toward animals (and people). Six out of ten voters interviewed have a pet, with a third reporting that their critters sleep in the bed with them. (No word on whether that includes reptiles.) Perhaps not surprisingly, one in five people said they'd prefer to spend time with their animals than with other people. (See pictures of pampered pets.) Fifty-two percent prefer dogs, 21 percent prefer cats, and 27 percent aren't sure which species they like better..."

85 F. high in St. Cloud Tuesday.
80 F. average high on June 25.
79 F. high on June 25, 2012.

17.76" precipitation since January 1 in St. Cloud.
11.8" average precipitation since January 1, to date.
 

TODAY: Passing shower or T-storm. Partial clearing later in the day. Winds: W/NW 10-15. Dew point: 71. High: 82

WEDNESDAY NIGHT: Partly cloudy, turning less humid. Low: 64

THURSDAY: Plenty of warm sun, more comfortable. Dew point: 65. High: 85

FRIDAY: Mix of clouds & sun. Dew point: 56. Wake-up: 59. High: 80

SATURDAY: Sunny start, then increasing clouds. Brief passing shower or T-shower. Wake-up: 57. High: 77

SUNDAY: More sun, more pleasant. Dew point: 55. Wake-up: 58. High: near 80

MONDAY: AM sun, PM clouds increase. Wake-up: 59. High; 81

TUESDAY: Some sun, thunder far western MN. Wake-up: 61. High: 82

Climate Stories...
 
Obama Moves To Limit Greenhouse Gas Emissions Through Executive Order. Here's an excerpt from the PBS NewsHour Tuesday evening:

GWEN IFILL: The president today renewed a pledge he has been making since 2008 to reduce greenhouse gas emissions and slow global warming. This time, he plans to exert executive authority to force action. With today's announcement, the president zeroed in on the new and existing power plants that burn coal and turn out 40 percent of the nation's carbon dioxide emissions.

PRESIDENT BARACK OBAMA: As a president, as a father, and as an American, I'm here to say, we need to act...Right now, there are no federal limits to the amount of carbon pollution that those plants can pump into our air. None. Zero. We limit the amount of toxic chemicals like mercury and sulfur and arsenic in our air or our water, but power plants can still dump unlimited amounts of carbon pollution into the air for free. That's not right, that's not safe, and it needs to stop..."

"We Need To Act". Obama's Climate Fight Draws A Green Line On Keystone. Here's an excerpt from a story at The Atlantic Wire: "...Eventually he turned to politics, and the need for action, not denial. "We don't have time for a meeting of the Flat Earth Society!" he exclaimed. "Sticking your head in the sand may make you feel safer, but it won't keep you safe from the coming storm." He demanded that the Senate approve Gina McCarthy, his nominee for administrator of the EPA, and asked Americans to "broaden the circle of those willing to stand up for the future" by championing his plan in their communities. By cutting away early, the networks missed what was perhaps the most unexpected bit of news Obama laid out: that he would insist that the Keystone XL pipeline not result in an increase in greenhouse gas emissions. Even last night, during a call the administration held with members of the media, it was suggested that Keystone wouldn't be a topic of conversation. That the president would draw a red — or, rather, green — line on the controversial proposal was only revealed shortly before the speech..." (photo: AP).

Goodbye Miami. From Rolling Stone: "...Sea-level rise is not a hypothetical disaster. It is a physical fact of life on a warming planet, the basic dynamics of which even a child can understand: Heat melts ice. Since the 1920s, the global average sea level has risen about nine inches, mostly from the thermal expansion of the ocean water. But thanks to our 200-year-long fossil-fuel binge, the great ice sheets in Greenland and Antarctica are starting to melt rapidly now, causing the rate of sea-level rise to grow exponentially. The latest research, including an assessment by the National Oceanic and Atmospheric Administration, suggests that sea level could rise more than six feet by the end of the century. James Hansen, the godfather of global-warming science, has argued that it could increase as high as 16 feet by then – and Wanless believes that it could continue rising a foot each decade after that. "With six feet of sea-level rise, South Florida is toast," says Tom Gustafson, a former Florida speaker of the House and a climate-change-policy advocate. Even if we cut carbon pollution overnight, it won't save us. Ohio State glaciologist Jason Box has said he believes we already have 70 feet of sea-level rise baked into the system..." (image: Phillip's Natural World).

 
Introducing The New Profession Of Extreme Weather Architect. Yes, the upward spike in T-storm winds, hail and flash flooding is already impacting the way some architects design homes to better withstand weather extremes. Here's an excerpt from Quartz: "Daniel Horn, a fresh New York architecture graduate, has launched a global competition around a tricky design question—what is the most aesthetic way to raise the elevation of an entire neighborhood block by eight to 10 feet? Call it extreme weather architecture. Horn, a 23-year-old graduate of the New York Institute of Technology (more on him below), is part of a boom in design competitions and urban reconstruction initiatives built around climate change. A rash of storms, drought and fires in recent years has ignited this contemplation of a new school of design cutting across cities and shorelines, homes and commercial buildings. The emerging class of architecture suggests the onset of a global design-and-construction industry worth tens of billions of dollars in the coming years..."

Photo credit above: "Mantoloking, New Jersey on March 22, 2013." Reuters/Lucas Jackson.

We Haven't Hit The Global Warming Pause Button. The Guardian has the story - here's an excerpt: "...In the 1980s and 1990s when air temperatures were warming in step with the overall warming of the planet, that was fine. However, over the past decade, the warming of surface air temperatures has slowed. At the same time, the overall warming of the planet has continued, and if anything it has accelerated. This has been difficult to reconcile for those who previously focused on surface air temperatures – what do we say about "global warming" now? The result is a spate of articles from the New York Times, Washington Post, The New Republic, and Der Spiegel, all of which get most of the facts right (including noting the warming of the oceans), but that all begin from the premise that "global warming" has slowed. It would be more accurate to say that global surface air warming has slowed, but the overall warming of the Earth's climate has sped up..."

Graphic credit: "Global heat accumulation from Nuccitelli et al. (2012)".

Climate Change And The Alberta Flood. Is there a connection? Here's an excerpt of a story at Maclean's: "...Meanwhile, there is the matter of the flooding in Alberta and to what extent that flooding might be said to have been caused by climate change. Jason Kenney says there’s no connection. Alberta hydrologist John Pomeroy says climate change was a factor. And Andrew Nikiforuk thinks this will prove a moment of realization for Albertans.
Albertans have also learned that climate change delivers two extremes: more water when you don’t need it, and not enough water when you do. The geographically challenged have also become learned, once again, that water travels down hill and even inundates flood plains.
So climate change is not a mirage. Nor is it weird science or tomorrow’s news. It is now part of the flow of daily life."
Photo credit: "This undated photo provided by the Calgary Flames shows the inside of the Calgary Saddledome in Calgary, Alberta. The Saddledome, home to the National Hockey League's Calgary Flames, was flooded up to the 10th row, leaving the dressing rooms submerged. The two rivers that converge on the western Canadian city of Calgary are receding Saturday, June 22, 2013 after floods devastated much of southern Alberta province, causing at least three deaths and forcing thousands to evacuate." (AP Photo/Calgary Flames).

No comments:

Post a Comment