It may feel like 100 degrees in Philly on Thursday and Friday. The early heat could pay off.
Early hot spells help prepare the body — and mind — for summer, a health expert says.
With the summer solstice still two weekends away, already the temperature has reached 90 degrees or higher in Philly nine times.
And while the sequence of 90s has been extraordinarily premature, the early experience may come in handy this week as the region could experience triple-digit heat indexes.
“It will definitely feel different,” said Ray Martin, lead meteorologist with the National Weather Service office in Mount Holly, as the humidity and dew point, the measure of absolute moisture in the air, reach their highest levels of the year to date.
Any 100-plus heat indexes may present challenges to some older residents, and those with heart and other health issues.
But the heat the region has experienced, starting in mid-April, could be viewed as a sort of spring training for the discomforts to come, said Samuel Eldrich, director of the Temple Health-Chestnut Hill Hospital Emergency Department.
“It’s all about adaptability,” he said. And it’s not just physiological, he said.
In addition, a juicier atmosphere may squeeze out some much-needed rain.
The regional forecast for the next several days
Showers are possible Wednesday morning and late in the day, Martin said, with highs in the mid-80s. However, it might not get cooler than 70 degrees early Thursday, a sign that mugginess is on the increase.
A moist air mass inhibits daytime heating from escaping into space, and the heat and humidity build for real on Thursday.
“It’s not going to feel nice out there,” said Tom Kines, senior meteorologist with AccuWeather Inc.
The weather service said it likely would be issuing heat advisories for Thursday and Friday for heat indexes of 100 or higher.
Shower chances are in the forecast Wednesday through Friday, and at times the atmosphere will be highly energized, Martin said. The Storm Prediction Center in Norman, Okla., has outside chances for severe thunderstorms for the entire region Thursday and Friday. Isolated flooding downpours are not out of the question, Martin said.
The heat and storm threats should back down some by the weekend, when Philadelphia hosts the World Cup match between Ecuador and the Ivory Coast, with a high about 90, the air less muggy, and rain looking unlikely.
How hot has it been in Philly so far?
Philly has logged four daily highs of 90 degrees or more so far this month, and nine since April — including four record highs — almost a third of the average for an entire year.
Whether that is a harbinger of a punitive summer is beyond the realm of reliable forecasting, but the early heat is likely to have some positive effects, Eldrich said.
Far more dangerous are hot spells that come abruptly after the weather has been relatively cool and comfortable for a period, he said.
Early heat, which typically is short-lived, can make a difference in terms of how we respond to subsequent hot spells. “You’re more accustomed” to the heat, Eldrich said. “You’ve adapted to the lifestyle. You sweat more quickly, more easily.”
People are more likely to stay inside, and stay hydrated.
“It’s both the physiological and the cultural factors,” he said. “In the South, you don’t hear about heat exhaustion or heat emergencies. It’s something they deal with three-quarters of the year rather than a quarter of the year.”
Drought conditions persist, but more rain may be coming
The longer-range outlooks favor above-normal temperatures for the rest of the month, but they also see the odds tilted toward above-normal rainfall.
That would be a switch. Philadelphia’s precipitation has been below normal for 10 consecutive months.
“We could certainly use the rain,” Martin said. The interagency U.S. Drought Monitor has most of the region under “severe drought” conditions. State-declared drought emergencies remain in effect in New Jersey and Chester County.
Any showers would mean temporary breaks in the heat Wednesday and Thursday, and the heat wave is not expected to survive the weekend, in keeping with a trend.
Even though average summer temperatures have been rising, the hot spells this century have not lasted as long as some of those of the 1990s.
“Let’s hope that streak continues,” Martin said.
Whether it is related to heat-wave durations or the city’s responses to hot-weather emergencies, heat mortality is way down in Philadelphia.
From 1991 through 2000, 227 heat-related deaths were recorded in the city. In the last 10 years, there were 37.
