Extreme heat moving into Bucks County. How hot will it get in heat wave?
The heat is moving in and it will be hear to stay once it does.
While temperatures on Monday fell just shy of 90 degrees in the Delaware Valley, the forecast is still calling for above 90-degree days for the rest of the week, according to the National Weather Service's latest outlook.
The heat wave could start Tuesday with sunny skies and a high of 92 in the forecast as a high-pressure system from the Carolinas comes to settle over the mid-Atlantic, according to meteorologist Sarah Johnson at NOAA's Mount Holly/Philadelphia forecasting center.
By Friday and Saturday, temperatures are forecast to tie or break all-time records. Bucks County could see n forecast as of Monday morning calls for a record-tying 99 degrees on Friday, and 94 degrees on Saturday. Saturday's record in Philadelphia is 100 degrees.
High humidity means the heat index could be above 100 starting Wednesday, which is what triggered an excessive heat watch by the weather service. By Friday and Saturday, the heat index may get as high as 106, before a cold front is expected to slide in from the west on Sunday.
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The heat wave will be especially notable because the weather will stay hot for a number of days, Johnson said, and because it's occurring so early in the season before Bucks County and the region has had time to acclimate to higher temperatures, exposing people to the potential risk of heat illnesses.
With the heat in the 90s and the index topping 100 degrees, and high humidity, heat-related illnesses increase significantly. Bucks County residents need to find places to cool off, stay out of the direct sun and hydrate, officials say.
The excessive heat watch was issued as the National Weather Service expects "dangerously hot conditions with heat index values up to 106 possible."
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Where will it be the hottest?
The heat wave will likely follow what meteorologist Johnson calls a "typical pattern": It'll be hotter in the city, not just during the day but overnight. The highest temps will be seen along the I-95 corridor from Wilmington to Philadelphia to Trenton, Johnson said.
Why? Pavement and buildings heat up fast, stay hot and create their its weather patterns, a phenomenon known as the urban heat island effect.
"You've got a lot of concrete, which tends to tend to absorb heat and then re-radiate it, especially at night," Johnson said.
Cooler temps will be found where there's greenery and shade, or by the coast — especially with lower water temperatures early in the season. That said, "by the beaches" really means by the beaches. Temperature relief only really extends a mile or two inward from the water. Beyond that? Just as hot again.
We will also be dealing with the heat dome effect, officials said.
Cooling centers in Bucks County
Bensalem Senior Citizens Association, 1850 Byberry Road, Bensalem
Bristol Borough Senior Center, 301 Wood St., Bristol
Bristol Township Senior Center, 2501 Bath Road, Bristol Township
Morrisville Senior Service Center, 31 E. Cleveland Ave., Morrisville
Riegelsville Borough Hall, 615 Easton Road, Riegelsville
YMCA of Bucks County–Warminster Branch, 624 York Road, Warminster
What is a heat wave?
The term "heat wave" means different things to different people, and depends on geography, Joe DiSilva, a meteorologist with the National Weather Service said.
"The 'heat wave' definition varies on where you are," DeSilva said. "But across the mid-Atlantic region, a heat wave is any three-day stretch of 90-degree weather or hotter.
"This will certainly be the first heat wave of the year."
This article originally appeared on Bucks County Courier Times: Bucks County weather calls for heat wave as temperatures rise
