Area temperatures are expected to hover in the upper 90s Wednesday and Thursday as a heat wave envelops the mid-Atlantic region, prompting the National Weather Service to issue a heat advisory for part of Maryland.
A heat advisory will be in effect for Frederick County from noon to 8 p.m. today, but a similar advisory had not been issued for Washington County as of Tuesday afternoon, said Heather Sheffield, a weather service meteorologist in Sterling, Va.
The expected heat wave prompted the Maryland Department of Health and Mental Hygiene to activate its state heat plan for Central Maryland today and statewide for Thursday, the agency said in a news release.
The plan is activated when the heat index is expected to meet or exceed 105 degrees, the release said.
A large area of high pressure will move over the mid-Atlantic region, with temperatures expected to reach the mid- to upper-90s, Sheffield said.
The heat index — a measure of how hot it feels after combining air temperature and relative humidity — is expected to be 100 to 105 degrees in Frederick today and in the neighborhood of 100 degrees in Washington County, Sheffield said.
“Heat can kill, so now is the time to take precautions,” state Health Secretary Joshua M. Sharfstein said in the release. “It is especially important to look in on vulnerable family, friends and neighbors.”
Extreme heat can cause life-threatening conditions such as heatstroke and heat exhaustion, especially in high-risk groups, including children, youth athletes, the elderly and those with other medical risk factors, such as heart disease and high blood pressure, the release said.
There were 34 confirmed heat-related deaths in Maryland between May and August 2011, the release said.
Heat advisories are not rare for this time of year; the National Weather Service issued one over the Memorial Day weekend, Sheffield said.
“(But) This is definitely above normal,” Sheffield said.
Daytime temperatures are normally in the 80s this time of year, she said.
The state health department’s extreme heat website is dhmh.maryland.gov/extremeheat/SitePages/Home.aspx.