Warm weekend; strong storms later Sunday

Seasonable temperatures today and Friday will give way to highs mainly in the 80s statewide on Saturday and Sunday. Dew points will do a slow climb on our way to Sunday, as well.

Enjoy the lovely just-past-full moon that will rise after sunset this evening, at 9:21 p.m. in the Twin Cities. For lunar geeks, it will be a 99 percent waning gibbous moon.

Scattered thunderstorms will pop up Friday afternoon in northern and then central Minnesota. The hit-and-miss nature should be brief.

Independence Day Saturday will provide fine weather for parades and picnics all across the state with just the slight chance of an isolated shower at any one location as a result of the heating of the day.

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July 2 - Saturday fcst
Nearly all of Minnesota will be storm-free on Independence Day. NOAA Storm Prediction Center

By Sunday we will have to keep our weather eye on the sky. A cold front will plow into Minnesota from the northwest. Early indications are that this front will be strong enough to scoop up the moisture reflected in our increasing dew points and kick of a significant band of thunderstorms that will build and become widespread during the afternoon and evening as they advance southeastward across the state. In the metro area, these storms are likely to hold off until late Sunday evening or overnight. Some storms could be strong and heavy rain is a distinct possibility. Severe weather is not in the forecast yet but certainly is possible later that day.

July 2 - Sunday rain fcst
The NAM forecast predicts a large area of thunderstorms across Minnesota by 7 p.m. Sunday. College of DuPage/NOAA

Lightning: dangerous flashes

July 2 - lightning photo
All lightning is dangerous and potentially deadly. NOAA

Recent serious lightning injuries in Minnesota have put this danger of nature in the news again. Even non-severe, garden variety storms pack a lethal electrical punch and tend to be an underrated summertime hazard.

The United States receives approximately 25 million cloud-to-ground lightning strikes every year. Many, but not all, strike a local high point.

Lightning data show that men, especially young men, are the most likely to be injured or killed by lightning. Historically, many men worked outdoors, often far from shelter and medical treatment, so that might have been a major factor. Farming has become safer, however, as most field equipment has a metal cab that can safely conduct the strike around the driver and to the ground.

The National Weather Service studied lightning deaths in the United States during 2006-2013. Of the 261 people killed by lightning during that period, a remarkable 81 percent were men and just 19 percent were women. The reasons could be many. Among them are that men are still more likely to work outdoors than are women, and they might do more outdoor recreation. The data suggest that men might be more reluctant than women to seek shelter when storms approach.

The most lightning-dangerous activities

Contrary to popular belief, golf is not the most dangerous recreational activity when it comes to lightning. Golfers have been told repeatedly how dangerous lightning is, and some golf courses even have lightning alert systems to call golfers to shelter. In fact, golf accounted for just three percent of the deaths, the same as yard work and walking to/from or waiting for vehicles.

Perhaps because of its increased popularity, soccer led the list as the sport with the most lightning deaths (5 percent).

By far the leader for most deaths during a recreational activity is fishing (11 percent of all). Fishermen/women often are in an open boat where they are the highest point around, and they are far from shelter. Fishing is followed by boating and camping with about half as many deaths.

There are some patterns as to what turn normal human activities into risky behaviors. One common theme is waiting too long to take shelter. In particular, people tend to delay getting off lakes and are struck as they head for shore. Other people are struck as they head for shelter in buildings or vehicles. Waiting out the storm by standing beneath or near a tall tree is a classic mistake.

Lightning - ground current
Dangerous ground current spreads out after lightning strikes a tree or similar object. NOAA

Another risky behavior is not having access to shelter when thunderstorms are active. Examples would be going out for a run, hike or bicycle ride when thunderstorms are in the vicinity.

A more subtle risk is thinking you are sheltered and protected when you are not. Examples of unsafe structures would be tents, garages and bus shelters that are unable to absorb the charge or conduct it safely to the ground.

A large area of significant lightning risk this afternoon has been in Georgia along with adjoining South Carolina and Florida.

July 2 - ltng
Cloud-to-ground lightning strikes were focused on the Southeast and the West today. Vaisala

When lightning flashes or thunder rumbles, it is time to be indoors.