Heat alert and bad air; August exits ugly

The week is already looking a lot like July. The Maryland Department of the Environment has issued a Code Orange air quality alert for Monday as high temperatures and combustion exhaust combine to raise ground-level ozone and particulate levels to levels considered unhealthy for people in "sensitive groups." These include the very young, the very old and those with heart or respiratory problems. Those folks should avoid outdoor exercise and strenuous activity today.

The Code Orange alert covers the entire state west of the Chesapeake, Cecil County, and adjacent counties in Northern Virginia.

In Baltimore, the Health Department has declared Monday a Code Red Heat Alert day, opening cooling centers across the city. Residents should call 311 for cooling center locations and hours. So far this summer heat has been a factor in 26 deaths across the state. Seventeen of those dead were found in dwellings without air-conditioning.

Please check on vulnerable friends, family and neighbors, especially those who don't have, or refuse to use air conditioning.

The hot, sunny weather is the work of the large high-pressure area sitting over the Eastern U.S. As it drifts to our south this week, we will get more westerly winds, bringing already-warm air over the Appalachians and down the eastern slope. That will compress and heat the air, making it even hotter - at least 10 degrees above the averages for this time of year.

Relief, if any, would come from somewhat lower humidities than we saw in July, and any bay breeze that may kick up in the afternoons. And the clear skies should allow some radiational cooling, dropping overnight lows into the 60s outside the cities.

By the weekend we may be paying more attention to Hurricane Earl. More on that shortly.