BETHLEHEM, Pa. — A line of storms that spared the Lehigh Valley on Saturday raked the Philadelphia region and surrounding areas, with eight tornadoes confirmed by the National Weather Service, including one rated an EF-3 with estimated winds of 140 mph.
Several damage surveys were done Monday, with one additional area still under investigation in Mays Landing, New Jersey.
Monday night, survey teams confirmed two additional tornadoes in New Jersey. One was in Crosswicks and another from Allentown to Cream Ridge, with additional details expected to be available on Tuesday.
- Saturday's storms spared the Lehigh Valley but hit the surrounding Philadelphia-New Jersey area
- It ended a week that saw deadly tornadoes in the South and Midwest
- Experts say that in conversations about tornadoes increased presence in the area, climate change can't be left out of the equation
It came at the tail end of a week of devastation in the South and Midwest, where dozens were killed, and was related to the same system that spawned reports of 80 tornadoes on Friday.
Regionally, the system began with a posted tornado watch from the government’s Storm Prediction Center that covered the entire Philadelphia region and most of New Jersey on Saturday.
As the storm system — a squall line with embedded thunderstorms — trekked eastward, severe thunderstorm warnings also spread to include the Lehigh Valley.
But the Philly region and points south and eastward were hardest hit, with confirmed tornadoes in areas including:
- Cinnaminson-Delran-Moorestown, New Jersey, area — EF-1 tornado with winds estimated at 100 mph, a path length of 6 miles and a maximum width of 600 yards
- Wrightstown Twp-Newtown, Bucks Township, area — EF-1 tornado with winds estimated at 105 mph, a path length of 3.9 miles and a maximum width of 200 yards
- Bridgeville-Ellendale, Delaware, area - EF-3 tornado with winds estimated at 140 mph, a path length of 14.3 miles and a maximum width of 700 yards and one fatality
- Jackson Township, New Jersey, area - EF-2 tornado with winds estimated at 130 mph, a path length of 2.1 miles and a maximum width of 200 yards
- Jackson-Howell Township, New Jersey, area - EF-2 tornado with winds estimated at 120 mph, a path length of 1.4 miles and a maximum width of 150 yards
- Sea Girt, New Jersey, area - EF-2 tornado with winds estimated at 120 mph, a path length of 0.14 miles and a maximum width of 50 yards.
- Crosswicks, New Jersey, area - EF-1 with estimated winds at 90 mph
- Allentown to Cream Ridge, New Jersey, area - EF-1 with estimated winds at 90 mph
Damaged areas in Mays Landing, NJ, were still being investigated.
The ratings are based on the Enhanced Fujita scale, which rates tornado intensity based on the severity of the damage they cause.
An EF-3 tornado is considered severe, with 136-165 mph winds. One fatality occurred from this tornado, the weather service said, but no other known serious injuries occurred.
The only other recorded fatality in a tornado in Delaware occurred with an F2 tornado on July 21, 1983 near Hartley in Kent County.
Creating a volatile atmosphere
Meteorologist Bobby Martrich of EPAWA Weather Consulting said there were higher dew points in parts of the region, into which the storms were able to tap, fueling them and leading to greater instability in the atmosphere.
“The tornado part of it was always there,” Martrich said, citing storm relative helicity values — or the measure of updraft rotation in supercells moving left to right — being one reason why the squall line was so dangerous.
“Storm relative helicity values are measured in two different altitude levels — at 0-1 kilometers [a half mile] above the surface and 0-3 kilometers [1 ½ miles] above the surface,” Martrich said.
“The most important is the former, as tornadoes obviously make contact with a ground-up-to-the cloud-base, which is typically in that lowest level.”
The higher the SRH values, the more spin, Martrich said. He said Saturday’s values were “pretty significant for potential tornado development.”
Alex Staarmann, a NWS meteorologist, said Monday the closest tornado confirmed near the Lehigh Valley was in Wrightstown, Bucks County. As the storm moved, it collected energy, sparing the Valley but causing tornadoes to the south and east of the region.
“It really came down to the fact that the surface-based instability and moisture was much greater closer to the I-95 corridor and points southeast, closer to the coast,” Staarmann said.
“So as the system moved through the Lehigh Valley, it was mainly just rain, and some lightning.
“But as the system got closer to the I-95 corridor into the coast, it strengthened due to the increasing instability and moisture and kind of continued to strengthen as it moved offshore.”
In addition to those already confirmed, forecasters were investigating three other possible tornadoes in New Jersey across Burlington, Monmouth and Atlantic counties.
While Staarmann said having that many confirmed tornadoes is “pretty unusual,” he noted there were significant outbreaks in January 2021 and, less than a year after that, September 2021’s Hurricane Ida.
The former caused three strong tornadoes over eastern Pennsylvania and New Jersey, while the latter is credited with particularly strong and damaging tornadoes over Gloucester County, N.J. and Montgomery County.
“Those were quite a bit more prolific, a lot more longer-lived, long-tracked, stronger tornadoes than we saw a couple of days ago, but certainly an unusual severe weather outbreak for the area,” Staarmann said.
One reason why the instability was lower over the Valley could be attributed to dry air over the Appalachian region, he said.
“It's hard to say," Starrmann said. "If there was a few more hours before the storms moved in, maybe it would have been a little bit farther north, but, there certainly could be — I'm not saying it's gonna happen — but there certainly could be another setup where there is more instability farther north and then there's more tornadoes farther north as well."
‘Climate change can’t be out of the conversation’
“Tornadoes can happen in the Lehigh Valley,” Staarmann said.
But while they can happen, Martrich said he thinks the focus needs to fall on why tornado outbreaks are happening more frequently in the region.
“It’s still an unknown, but certainly climate change can’t be out of the conversation, especially as it relates to the urban heat island effect near the I-95 corridor and points southeast,” Martrich said.
I do think there is something "there" in terms of the heat island effect he refers to playing a role in severe storms/tornadic activity in the I-95 corridor and points SE across NJ/MD/DE. Yesterday was a case of storms tapping into higher dewpoints (there) than the rest of the… https://t.co/WU8vJjYMMH
— Bobby Martrich | EPAWA (@epawawx) April 2, 2023
An urban heat island occurs when cities experience much warmer temperatures than other nearby areas and has to do with how well the surfaces in each environment absorb and hold heat.
“Is this the new norm? It may very well be,” Martrich said in a tweet Sunday, expressing interest in peer-reviewed research and case studies looking at the uptick in extreme severe weather events in the Mid-Atlantic.
"Is this the new norm? It may very well be."Meteorologist Bobby Martrich
“I am well aware of the difference between weather and climate, but at some point, we as scientists have to ask the tough questions and acknowledge all possibilities,” Martrich said.
“Climate change is inherently part of that conversation.”
Urban heat islands are significantly warmer than surrounding areas, normally due to human activities, and the temperature difference is usually larger at night than during the day.
“Theories cannot be dismissed until proven otherwise,” Martrich said. “That’s literally how science works, and how any scientist in any science field should approach it.”
Being prepared
Allentown has a high-speed public notification system called CodeRED that sends weather specific warnings to residents, and it was used Saturday when a thunderstorm watch was issued, and later when the watch was upgraded to a warning.
The system offers city officials the ability to quickly deliver messages to targeted areas or to the entire city, automatically alerting affected citizens in the path of severe weather or for other reasons (such as road closures or shelter-in-place alerts).
The weather alerts tap into the National Weather Service’s storm-based warnings and are deployed to recipients through location-based targeted alerts.
It means anyone in the path of the storm Saturday who signed up should have received an alert, with messages on Caller ID reading “OnSolve” or the number 800-566-9780.
“It depends on who deploys the message" whether it’s a text, email or phone call, said Lee Laubach Jr., the city’s emergency management coordinator.
“If it’s a tornado warning, they might send all three. Usually it’s when it’s the highest priority that’s what you’ll see.”
Laubach said it’s his strategy not to deploy warnings through a text message or phone call if the information is not actionable.
“As long as you have your location services on it will ping that and it will tell you what’s going on,” he said. “It’s a great system and we were lucky enough to get it and we have it in six different languages.
"I don’t think there’s another place in Pennsylvania that has it in multiple languages.”
In Lehigh County, there’s also a push through education, training and volunteer service to make communities safer, stronger and better prepared to respond to emergencies.
Community Emergency Response Training, or CERT, that was slated for this month has been pushed to September. The session will address some weather-associated hazards.
“We get people prepared to be their own first responders,” said John Semonich, the community outreach manager.
“Let’s say you have strong winds and it knocks over something onto a gas line, or you had to put out a small fire or conduct a limited search and rescue," Semonich said.
"A lot of what CERT is about is preparing for those scenarios and preparing to have a go-bag, so if you’re without utilities for 72 hours and you have to [leave your house] you have what you need to keep you, your family and your pets safe and healthy."
CERT trainers also talk about emergency shelters, including information for residents with special needs who might need to stay in a shelter during an emergency.
Semonich encouraged residents interested to attend the upcoming CERT training in the fall and learn more about taking action in an emergency situation.
“There’s value to you and there’s value to the people you know,” he said.
