An air quality alert has been issued for all 21 counties in New Jersey, and an excessive heat warning is in effect for several counties.
A combination of "dangerous heat" and bad air quality expected on Wednesday has prompted a series of advisories and alerts from the National Weather Service and the state Department of Environmental Protection.
An excessive heat warning is in effect for Camden, Gloucester and Mercer counties, as well as northwestern Burlington County, from 11 a.m. on Wednesday to 6 p.m. Friday.
The National Weather Service has also issued a heat advisory for Essex County and New York City, from 1 p.m. through 8 p.m. Thursday.
The heat and air quality alerts were issued in advance of the wave of hot and humid weather that will arrive Wednesday morning and linger into Saturday. In most parts of the Garden State, temperatures are expected to climb into the mid 90s, and the combination of heat and humidity - known as the heat index -- will make it feel like it's about 100 degrees or higher at times this week.
"Dangerous heat is expected, primarily in the late morning through the late afternoon hours," the heat alert reads. "Hot and humid conditions may lead to strain on those outdoors in the heat along with sensitive groups, such as the elderly, children and pets."
Forecasters are calling for a sunny afternoon, with highs around 94 across the state and a slight breeze.
In addition to the NWS advisories, the state DEP has issued a code orange air-quality alert for all 21 counties in New Jersey, effective early Wednesday morning through 6 p.m. Wednesday. The alert means "air pollution concentrations within the region may become unhealthy for sensitive groups," such as children, the elderly and people suffering from asthma, heart disease and other lung ailments.
"The effects of air pollution can be minimized by avoiding strenuous activity or exercise outdoors," the alert says.
Overnight, temperatures will dip to around 70 degrees. Patchy fog is expected in parts of the state around 3 a.m.
It could feel like 100 for several days this week
More of the same hot and humid weather is on tap for Thursday, with a threat of showers and thunderstorms after 2 p.m. Highs will be in the mid 90s and lows around 70 degrees at night again. Rain is also possible in the evening into Friday.
Despite the intense heat that's expected Wednesday, the mercury will be far from record territory, meteorologists said.
To match their all-time high temperature for July 6, Freehold and Marlboro would have to hit 100 degrees, Atlantic City would have to hit 102 degrees, and Newark, New Brunswick and Plainfield would have to hit 103 degrees.
Those daily records were all set in 1999 or 2010, according to climate data from the National Weather Service.
For more information on ground-level ozone and fine particles in the air, check www.airnow.gov. Tips on how to avoid heat-related strokes and other heat-induced ailments can be found on this page of the New Jersey Office of Emergency Management: www.ready.gov/heat.
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Craig McCarthy may be reached at CMcCarthy@njadvancemedia.com. Follow him on Twitter @createcraig. Len Melisurgo may be reached at LMelisurgo@njadvancemedia.com. Follow him on Twitter @LensReality. Find NJ.com on Facebook.