High temperatures

Warm conditions are forecast across the eastern part of the country this week, into the 90s across the mid-Atlantic. (National Weather Service / June 16, 2014)

The hottest stretch of the young summer (or late spring, technically) is expected to bring the heat index to near 100 degrees by Wednesday, with temperatures in the 90s and high humidity.

Monday was the second day to hit 90 degrees this year, and it could be followed by two more days above that mark. Temperatures reached 90 degrees at BWI Marshall Airport by 3:30 p.m. and 88 in the Inner Harbor by 3 p.m.

Highs are forecast in the lower 90s Tuesday and the mid-90s Wednesday, and with dew points in the upper 60s, that could make it feel like the triple digits, or close to it.

"Code orange" air quality, an unhealthy level for children, the elderly and those with respiratory conditions, is forecast Tuesday and Wednesday, according to Clean Air Partners.

Maryland is expected to be on the edge of a ridge of high pressure bringing warm and humid conditions across much of the southeastern quadrant of the country.

While it isn't technically even summer yet -- the solstice arrives Saturday at 6:51 a.m. -- the region is typically more used to this sort of heat by this time of year. Baltimore had surpassed 90 degrees four times at this point last year, five times at this point in 2012 and eight times by this point in 2011, according to the National Weather Service.

Local jurisdictions typically don't declare heat emergencies until the heat index is at least 105 degrees.