UPDATE, 6 p.m.: Looks like good news for U2 fans. The risk of storms this evening has dropped to 20 percent - "slight." And there is nothing on radar ATM. Enjoy.
UPDATE, 4 p.m.: Now it's a tossup. NWS forecasters have eased back slightly - from 60 percent to 50 percent - on the chances downtown Baltimore will see showers and thunderstorms this evening. That slips to 30 percent overnight.
Nevertheless, they said: "THUNDERSTORMS ARE STILL EXPECTED TO DEVELOP LATE THIS AFTERNOON AND EVENING. SOME OF THE STORMS MAY BECOME SEVERE...CAPABLE OF PRODUCING LARGE HAIL AND DAMAGING WIND GUSTS."
Earlier post below:
Tens of thousands of U2 fans headed for the M&T Bank Stadium this evening should come prepared for the possibility of showers and thunderstorms. And some of those storms could Lightning Ravens Stadiumbecome severe, with up to a half-inch of rain, hail and damaging winds
Sound like fun? Maybe not. The concert and the storms come in the middle of Lightning Safety Awareness Week. If you can hear thunder, you are at risk of being struck by lighting. And the safest place to be is inside. Or, as the National Weather Service puts it: "When thunder roars, go indoors!"
Heat near 90 degrees and tropical humidity are expected this afternoon as the 7 p.m. concert time nears. Forecasters out at the regional forecast office in Sterling, Va. are calling for a 60 percent chance of showers and thunderstorms, mostly after 4 p.m. A quarter- to a half-inch of rain is possible.
The storm risk continues until about 8 p.m., with another quarter- to a half-inch of rain possible into the evening. But some showers and storms could linger into the overnight hours.
"Some of the storms may become severe, capable of producing large hail and damaging wind gusts," forecasters said in a Hazardous Weather Outlook posted early this morning.
John Jensenius, a NWS lightning expert based in Gray, Maine, said concert-goers should not depend on lightning arrestors at the stadium to protect them, should a thunderstorm strike. "When you look at events that have happened in other parts of the world, there have been soccer teams that have been struck in the field. People attending the event have to consider whether or not it is a good idea to be there" in an electrical storm.
In June 1998, several concert-goers were struck by lightning on the first day of the Tibetan Freedom Concert at RFK Stadium outside Washington. And in August 2005, a Miami Dolphins video director survived a strike on a practice field that was surrounded by lightning arrestors.
"If there is something coming down close to the field, it could very well strike the field or the stands without hitting the arrestors," he said. "Do they help? Yes. If you're asking whether they eliminate the threat, then the answer is no."
"Obviously, if you want to be safe, you have to get inside," Jensenius said. Or, if the stadium's inner reaches are full, "if you can get to your car, that's probably even better."
Here's more from Chris Strong, the warning coordination meteorologist at NWS Sterling, who plans to attend the concert, though not in an official capacity:
"Staying in your seats or on the field is a bad idea. In this case, 'When thunder roars, at least get to the ground level concourse or any enclosed area.' While it's not the best situation, it is making the best of a bad situation. That's what I'll be doing if a thunderstorm comes tonight.
"Staying informed also helps tremendously. For those who have smart phones, stay in touch with a local radar internet page to see what is around and what is approaching! Many media outlets and the NWS all have such pages and phone apps to monitor (such as our page ... http://radar.weather.gov/radar.php?rid=lwx&product=N0R&overlay=11101111&loop=no )
"Lastly, people should certainly follow instructions from the stadium authorities (stadium screens, announcements) if they are given."