Ida’s remnants to bring severe storm risk, heavy rainfall to Philly region

Updated 5:34 p.m.

Ida, once a Category 4 hurricane, is currently barreling toward the Delaware Valley. With sustained winds of 150 m.p.h., it is the fifth strongest storm to ever hit the U.S. mainland.

Though the storm is now a shell of itself, it is still likely to leave its stamp on the region, which has been pummeled with heavy rains and tornadoes lately.

Meteorologist David Murphy says downpours from Ida’s remnants could cause flash flooding into Wednesday night.

A Tornado Watch has been issued for the entire area, including Philadelphia, suburban Pennsylvania counties, central and southern New Jersey, and Delaware, until 10 p.m. Wednesday.

Jonathan O’Brien, a meteorologist with the National Weather Service in Mount Holly, said the tornado threat is “due to the really strong wind shear and level of instability that we’re going to have as the remnants of Ida move through.”

Flood watches and warnings have also been posted for large parts of the area.

Preparation

Philadelphia was opening a couple of overnight shelters, at West Philadelphia High School at 4901 Chestnut St., and at Roxborough High School’s reception center for shelter on Ridge Avenue.

“If you are concerned about being in your home, and you’re concerned about flooding, we have made this shelter available to you overnight,” Carolyn Caton, deputy director for planning at the Philadelphia Office of Emergency Management, said at a 4 p.m. briefing.

PECO has opened its emergency operations center. The energy company, which provides electricity in the region and natural gas service in the suburbs, said that support staff will be ready to address issues as they come along.

“At this point … we’re going by the direction of the municipalities to give us any sort of feedback that they’re getting from the general public,” PECO government affairs manager Jose Aguirre said.

Fire Commissioner Adam Thiel, Philadelphia OEM director, stressed the preparations being made but said the possibility of tornadoes in the city was troubling.

“I guess there used to be a time when we thought tornadoes didn’t happen in Philadelphia. We’ve had one this year already, and we had one last year associated with that hurricane, so please take this seriously,” Thiel said.

Tornado Watch vs. Tornado Warning

A Tornado Watch is issued when conditions are favorable for a tornado. It doesn’t mean severe weather is imminent.

A Tornado Warning is issued when a tornado has either been spotted or radar has picked one up. If you are in an area with a Tornado Warning, act immediately. Get to a safe space such as a storm shelter. If you don’t have one, the best option is usually in the basement or the middle of a building, away from windows, preferably in an area with reinforced walls.

O’Brien said getting into a car in these situations is not a good idea. Though the wind is definitely giving him pause, he said another force of nature will be the thing most people in the area should worry about: rain.

“It’s really that rainfall and flooding component. That’s our greatest concern with this system,” O’Brien said.

Rainfall totals

According to O’Brien, the precipitation shield is “migrating” eastward and will remain on that path well into Wednesday evening.

“It still looks like we’re on track for some very heavy rain as we head through, say the evening commute and beyond,” O’Brien said.

The heaviest rain will fall in the western and far northern counties — those areas can expect 4 to 6 inches of rainfall. Meanwhile, the communities hugging the I-95 corridor can expect 2 to 4 inches of rain.

South Jersey and Delaware will be spared the most and should expect “only” 1 to 2 inches of rain, with a high of 76.

“We will have really high rainfall rates over the area,” O’Brien said. “And with that, we do expect a pretty significant risk for flash flooding.”

Flash Flood Watch

The Flash Flood Watch is in effect Wednesday and continues through Thursday morning across every local county.

“We think that the rates are going to be high enough that it’ll be pretty widespread flash flooding, as well as the potential for significant rises, and eventually some flooding on a number of our area’s rivers,” O’Brien said.

In fact, some forecasters are worried that the Delaware River could flood for the first time in 10 years.

The threat of flooding already has Lower Providence Township in Montgomery County encouraging residents near the Perkiomen Creek to evacuate. The creek is currently at 1.3 feet but is expected to rise to upward of 17.8 feet.

While things appear bleak now, there is some light at the end of the tunnel — the storm could be gone for sunrise tomorrow.

“After the heavy rainfall that will be coming, temperatures will be on the cooler side than they have been. We’ll have a nice breeze. It should be a really nice day overall,” O’Brien said.

7-Day Forecast

• WEDNESDAY: It’s cloudy and humid with some rain arriving during the morning and afternoon. Heavy downpours and thunderstorms eventually develop.
• THURSDAY: Rain ends very early although flooding near some waterways may still be an issue through the day. Look for partly sunny skies with lower humidity. It’s breezy and cooler with a high of 77.
• FRIDAY: It’s mostly sunny and pleasant. High 75.
• SATURDAY: This is another mostly sunny and comfortable day. High 78.
• SUNDAY: Sun mixes with a few clouds. It’s a tad warmer during the afternoon with a high of 82. A very spotty storm is possible late in the day or at night, but most areas remain dry.
• MONDAY (LABOR DAY): Look for a partly sunny, nice holiday with only a slight chance for a scattered shower or thunderstorm. The high is 82.
• TUESDAY: Partly sunny skies appear likely. A spotty thunderstorm can’t be ruled out. The high is 82.
• WEDNESDAY: It’s a partly sunny, nice day with another high around 82.