Map of record highs tied or exceeded (circles with x’s) on Wednesday across the central and Eastern U.S. (National Climatic Data Center)

Live online video chat at 1 p.m. on heat

After more than 300 record highs were broken or matched Wednesday from the Midwest to the Northeast, the core of the latest U.S. heat wave focuses on the mid-Atlantic and Northeast. North and west of the Ohio Valley, the worst of the heat is over as a cold front is pushing southeastward.

Wednesday’s record highs included Baltimore (99), Washington D.C. (99), Wilmington (DE, 96), Fort Wayne (IN, 97), Detroit (96), Syracuse (97), New York City (97, LaGuardia), Toledo (OH, 97), Philadelphia (97), Allentown (PA, 96), Pittsburgh (91), and Milwaukee (93).

Forecast high temperatures along I-95 from Richmond to Boston are in the upper 90s to near 100. (

It’s these same areas where air quality is compromised. Code orange air quality alerts cover much of this region, signifying unhealthy air for sensitive groups like older adults, young children and those with respiratory problems such as asthma. recommends taking the following actions on days when ozone pollution is expected to be high:

*Conserve electricity and set your air conditioner at a higher temperature.
*Choose a cleaner commute—share a ride to work or use public transportation. Bicycle or walk to errands when possible.
*Refuel cars and trucks after dusk.
*Combine errands and reduce trips.
*Limit engine idling.
*Use household, workshop,and garden chemicals in ways that keep evaporation to a minimum, or try to delay using them when poor air quality is forecast.

Somewhat cooler arrives in the mid-Atlantic and Northeast Friday as a cold front sinks south, triggering thunderstorms along the way. The relief will be least noticeable in the mid-Atlantic as the front stalls in the region. Although clouds will reduce temperatures by about five degrees, humidity levels will remain high.

Check this video on the heat: