Philly has its first ‘heat emergency’ of the season and it might feel like 106 degrees

Philadelphia has declared a “heat emergency” for Thursday and Friday, when it might feel like it’s 106 degrees in the shade.

This would be a bigger deal if this were, say, January, but this one is notable for the fact that nearly two-thirds through the meteorological summer, it would be the city’s first heat emergency of the season. So far, the city’s heat-related death toll stands at zero, said Health Department spokesman Jim Garrow.

While the Southwest has broiled under record heat, in terms of temperature, this has been quite a temperate summer around here, with only one negligible four-day heat wave so far.

And it appears this one will be short-lived, said Mike Lee, a meteorologist at the National Weather Service Office in Mount Holly, paralleling a counterintuitive trend, given that summers in Philly this century generally have been quite warm.

Highs were forecast to reach the mid-90s, with the heat index peaking near 104, the weather service says.

» READ MORE: Despite those forecasts, so far Philly's summer has been quite temperate

Friday’s forecast high, 98, would be the heat apex of the summer so far. The record for the date, set in 1941, is 100, something we haven’t seen around here in awhile.

It has been 10 years since Philly has reached 100 — something that has happened 63 times in records dating to 1872.

That lag may be related to an increase in water vapor in the atmosphere as the planet’s temperature has increased, meteorologists say. When the sun has to spend energy evaporating water, it has less to bake the ground. Dry air heats up faster. (Check out those Southwest temperatures.)

Increased moisture also may help explain why the city has avoided long-lasting heat waves in recent years. Philadelphia hasn’t had 10 consecutive days of 90 degrees or higher since 2012. By comparison, the city endured prolonged deadly heat waves in 1993, 1995, and 1999.

» READ MORE: Summers are hotter, but heat wave deaths are down

But that moisture also contributes significantly to discomfort. Sweat cools the skin by evaporating; moist air inhibits evaporation. Plus, a succession of steamy nights won’t provide much relief at night and will accelerate the warm-ups during the day.

The steamy combination of temperature and humidity prompted the city to declare the emergency, during which the Philadelphia Corporation for Aging will operate its Heatline — 215-765-9040 — and the city will open several “cooling centers.” Residential utility shutoffs will be stopped temporarily.

This heat wave should be toast by Sunday, the weather service says, when the outlook is almost too good to be real for a July 31 — sunny, with the high in the low to mid-80s, followed by a refreshingly cool night.

A variant of the persistent upper-level pattern that had shielded the region from extensive periods of heat this summer shows signs of returning next week, said Dave Dombek, a senior meteorologist with AccuWeather Inc.

“It’s like the atmosphere wants to keep going back,” he said. “You can’t build any kind of heat in that pattern.”

Can those pumpkin spice lattes be far behind?

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As the body remains overheated, it will continue to sweat and further lose liquids. If an individual’s skin becomes cold and pale, they complain of dizziness and headaches, and seem tired or weak, these are all signs they might be suffering from heat exhaustion. Consider calling 911 if a person is vomiting, the symptoms get worse, or last longer than one hour.

» READ MORE: How to avoid heatstroke and heat exhaustion

Heatstroke is when the body can no longer regulate its temperature. People may stop sweating and spike a fever. The cold, pale skin could turn hot and red. In addition to the fever, people may be confused, pass out, and vomit.

If someone is vomiting, unable to drink, or losing consciousness, medical attention is likely needed in an emergency department. Medical staff there can cool the person down and provide intravenous fluids. If you suspect that someone is suffering heatstroke, call 911.

Staff writer Abraham Gutman contributed to this article.