Philly declares an ‘emergency’ as heat wave intensifies, with 100 degrees possible Sunday

With temperatures forecast to head deep into the 90s for the next several days and with a heat advisory in effect through Sunday — when it might hit 100 — Philadelphia has declared its first “heat health emergency” of the season.

The Public Health Department announced the emergency declaration would be in effect from noon to 8 p.m. Thursday but could be extended if conditions warrant during what might become the region’s longest heat wave in nine years.

By 9 a.m. Thursday the heat index already had crept up to 95 on what the National Weather Service says is going to be the most-oppressive day of the heat wave so far. And it might be one- or two-upped during the weekend.

With an official high of 96 degrees, heat-index levels reached triple digits Wednesday. Temperatures are due to be in the same range Thursday and Friday — this, even though a reputed “cold front” is due to cross the region late Thursday.

Then, it’s expected to get hotter.

Along with the third consecutive day of 90-plus temperatures — the informal benchmark for a “heat wave” — Wednesday marked the ninth straight morning in which the temperature failed to get below 70 degrees in the city, with overnight cooling impeded by heat-retaining buildings and atmospheric moisture.

Health officials say hot nights are especially dangerous for the elderly who live alone in rowhouses without air-conditioning, a hazard that is a primary target in the city’s heat-response plan. The lack of overnight cooling allows the houses to warm quickly after the sun comes up.

It includes setting up cooling centers and encouraging residents to look in on elderly neighbors. It also steps up outreach to those experiencing homelessness, something it began doing Tuesday. Plus the Philadelphia Corporation for the Aging operates a “heatline” (215-765-9040), which will be available from noon to 8 p.m. Thursday, the city said. The city Water Department has suspended any water shutoffs.

On Thursday morning Philadelphia’s low was a sultry 79 degrees, near the record for the date for the highest minimum temperature.

On Sunday, Philly could make a run at a daily high-temperature record when it might hit 100 degrees for the first time since 2012, said John Feerick, senior meteorologist with AccuWeather Inc. The July 24 record is 98 degrees, set in 2011.

» READ MORE: Nights could be especially dangerous as heat wave gains steam in Philly

But in the short term the weather service hasn’t issued an “excessive heat warning” for Thursday because “heat index values should be slightly below warning criteria,” said Sarah Johnson, the warning-coordination meteorologist in the Mount Holly office.

The weather service consults with city officials, but the decision on declaring an emergency is City Hall’s call, Johnson said.

City officials obviously decided it was plenty hot enough.

The CDC and the National Oceanic and Atmospheric Administration have held up Philadelphia’s aggressive, low-tech, low-cost heat-response plan — launched in 1995 — as a national model. It is unclear how much the program has been responsible for a decline in fatalities, but in the last 10 years only 33 heat-related deaths have been reported in the city, compared with as many as 400 in the 10-year period ending in 2002.

That drop also could be related to the fact that although summers have trended hotter, the city in recent years has avoided the prolonged heat waves that characterized the 1990s. In 1995, temperatures reached 90 or better on 17 consecutive days.

» READ MORE: Philly’s getting a heat wave. Here’s what to know about symptoms and treatment for dehydration and heat exhaustion.

In this case, the forecast calls for 90-plus temperatures to persist through Monday, which would make this an eight-day heat wave, the longest since the eight-day one that ended on July 21, 2013.

Showers, which have been evading much of the region in the last month, are possible Sunday night and Monday.

And for those of you who have had enough already, “it definitely looks more comfortable Tuesday, Wednesday, and Thursday,” Feerick said.

» READ MORE: Where to cool off in a Philadelphia heat wave

Here is the list of cooling centers that will be operating Thursday. All will be open until 7 p.m., except the Cobbs Creek and Fox Chase sites, which will close at 8 p.m.:

The city also is urging residents to visit the Parks and Recreation Department’s spraygrounds and pools.