At Least 78 Deaths in China Tornado; Midwest Dodges Major Damage

By: Bob Henson , 4:29PM,GMT on June 23,2016 





 

A tornado reportedly struck the outskirts of the east-central Chinese city of Yancheng during a powerful thunderstorm on Thursday afternoon, killing at least 78 people and causing widespread destruction. Yancheng is an urban area of more than 8 million people with a city-center population of about 1.6 million, located in the coastal plain of China’s Jiangsu Province about 200 miles north of Shanghai. Chinese state media are reporting nearly 500 injuries, with 200 critical. The storm also produced hail and heavy rain.


Figure 1. Residents pass houses destroyed in the aftermath of a tornado that hit Funing county, in Yancheng city in eastern China's Jiangsu Province on Thursday,June 23,2016. A powerful tornado killed dozens and destroyed large numbers of buildings Thursday in the eastern Chinese province of Jiangsu, state media reported. Image credit: Color China Photo via AP.


Figure 2. A villager stands near houses destroyed in the aftermath of a tornado that hit Funing county in Yancheng city in eastern China's Jiangsu Province on Thursday, June 23, 2016. Image credit: Color China Photo via AP.


Figure 3. Himiwari-8 satellite image from 0600Z on June 23, 2016 (2:00 am Thursday EDT, or 2:00 pm Thursday local time in Yancheng, China). A band of intense thunderstorms stretched more than 600 miles across central and northeastern China. The apparent tornado struck the Yancheng area around 2:30 pm local time Thursday. Image credit: CSU/CIRA/RAMMB, courtesy Japanese Meteorological Agency.

Another deadly result of the Mei-yu front
Intense storms are common along the Mei-yu (or baiu) front, which typically persists for a few weeks in late spring and early summer. This semi-permanent feature extends from eastern China across Taiwan into the Pacific south of Japan, associated with the southwest monsoon that pushes northward each spring and summer. The AMS Glossary notes: ““The mei-yu/baiu front is very significant in the weather and climate of southeast Asia as it serves as the focus for persistent heavy convective rainfall associated with mesoscale convective complexes (MCCs) or mesoscale convective systems (MCSs) that propagate eastward.” A number of studies have found that the Mei-yu rainfall tend to be particularly heavy in the summer following an El Niño event.

On June 1, 2015, China experienced its worst peacetime maritime disaster on record, as 442 people died when a cruise ship capsized on the Yangtze River during an intense Mei-yu thunderstorm. Although a tornado struck about five miles away, an official report found that a strong microburst was most likely responsible for the capsizing. Similarly, it may take time to determine how much of the damage in Yancheng was related to tornadic activity as opposed to any downbursts that may have occurred. As shown in the map below, eastern China is one of the more tornado-prone parts of Eurasia.


Figure 4. The relative likelihood that the atmosphere would support tornado production within grid boxes of 2° latitude and longitude, as estimated from model-generated atmospheric profiles. A value of 0.01 corresponds to 15 six-hour periods per year that are tornado-favorable. Image credit: Courtesy Harold Brooks, NOAA National Severe Storms Laboratory. An earlier version of this graphic appears in Brooks et al., “The spatial distribution of severe thunderstorm and tornado environments from global reanalysis data,” Atmospheric Research 67-68 (2003).

Widespread wind damage from Wednesday night’s storms
NOAA’s Storm Prediction Center has logged more than 130 preliminary reports of high wind stretching from Illinois to North Carolina in the wake of a fast-moving thunderstorm complex that swept along a surface front parallel to a strong upper-level jet stream late Wednesday. Although far-flung, the high-wind episode does not appear to have been exceptionally destructive. In order to place an event as a derecho in the NWS Storm Data archive, wind damage and/or wind gusts of at least 50 knots (57 mph) must extend along a band at least 250 miles long, with at least three reports of gusts reaching 65 knots (74 mph) separated by at least 40 miles. Most of the reports on the SPC log do not yet indicate wind speeds, so we don’t yet know if this event’s winds will be strong enough to qualify. The number of wind reports is also on the low side for a derecho, according to Jon Erdman (weather.com). As of late Thursday morning, SPC logged 19 preliminary tornado reports, all from a string of supercell storms that intensified just before nightfall across north-central Illinois. No major damage or injuries were reported from the twisters, although one storm chaser drove directly into a tornado.


Figure 5. Reports of severe weather logged by the NOAA/NWS Storm Prediction Center as of 11:44 AM CDT Thursday, June 21, 2016, for the period from 8:00 AM CDT Wednesday through 8:00 AM CDT Thursday.

The most intense storms on Wednesday were suppressed until late afternoon by a cap of very warm air several miles above the surface. Once they formed, they congealed fairly quickly into a broken area of severe storms (see embedded tweet at bottom) that produced lots of wind and heavy rain but not much large hail. There were just 14 reports of severe hail on Wednesday, with only three reports of hail of at least 2” diameter (and those were from storms in Minnesota separate from the fast-moving complex later that night).

More severe weather is on the agenda for Thursday, although the odds of significant severe storms appear a bit lower than on Wednesday. NOAA/SPC has placed parts of the central Appalachians and upper Ohio Valley under an enhanced risk of severe weather for Thursday afternoon and evening, with a slight risk extending from most of Kentucky to the Virginia/North Carolina coast. A few severe storms may also pop up in eastern Colorado. On Friday and Saturday, a strong upper-level low moving across southern Canada may generate intense storms along a cold front as it moves from Montana to Minnesota.

Bob Henson