- High humidity and light winds are adding to the heat misery across the Northeast.
- Some severe thunderstorms are possible Wednesday afternoon and evening in portions of the Northeast.
- A farmworker in Oregon died at a workplace on Saturday as temperatures that day hit 104 degrees.
Although not as extreme as the one in the Pacific Northwest, the Northeast is enduring its own heat wave this week.
After hitting at least 90 degrees Monday, temperatures are forecast to remain in the 90s in the big cities of the Northeast through Wednesday. Three days of highs in the 90s officially constitutes a heat wave in the region, according to AccuWeather.
High humidity and light winds add to the heat misery.
An excessive heat warning is in effect in Philadelphia through Wednesday evening, the National Weather Service said, expecting “dangerously hot conditions with heat index values up to 105 degrees.”
The heat index is what the temperature feels like to the human body when humidity is combined with the air temperature.Most temperatures in the Northeast will feel above 100 because of humidity, said the weather service.
“Extreme heat and humidity will significantly increase the potential for heat-related illnesses, particularly for those working or participating in outdoor activities,” the weather service said.
Fortunately, the stagnant weather pattern of sunny, hot and humid conditions is forecast to break down during the second half of the week, AccuWeather said.
“A southward dip in the jet stream and a cool front are likely to shift into the northeastern U.S. beginning on Wednesday,” AccuWeather meteorologist Matt Benz said.
Some severe thunderstorms are possible Wednesday afternoon and evening in portions of the Northeast from Pennsylvania to Maine, the Storm Prediction Center said.
The effect of clouds, showers and thunderstorms will tend to keep a lid on temperatures in the Northeast on Thursday and Friday and potentially into the holiday weekend. After a forecast high of 98 degrees Tuesday in Boston, the high on Saturday is expected to be around 69 degrees, the weather service said.
On Monday the Vermont Electric Cooperative asked its members to conserve electricity Tuesday and Wednesday evening because demand for electricity across the region is expected to increase in response to the hot weather.
Historic Northwest heat wave easing in some areas
A historic heat wave smashed all-time records in the Northwest over the past few days, and though some relief is arriving for areas closer to the coast, interior locations will continue to bake in record heat into the July Fourth holiday weekend, Weather.com said.
The weather service said Tuesday that “the unprecedented heat will continue through the rest of this week for the northern Great Basin and northern Rockies, while areas east of the Cascade Mountains enjoy temperatures closer to normal starting today.”
“The core of the extreme heat will be found across interior Washington and Oregon through midweek, as well as northern Idaho and northwest Montana,” the weather service said. “High temperatures are expected to soar into the 100s and 110s across this region.”
The weather service in Portland said people will see some relief Tuesday, and weather models predict a high in the mid- to high 90s.
Seattle and Portland will see high temperatures in the 80s by Wednesday, still above average but far from the incredible heat from recent days, forecasters said.
Seattle set a record of 104 degrees Sunday and broke that Monday with 107 degrees, the World Meteorological Organization said. Portland broke the record twice: 108 on Saturday and 112 on Sunday. Many other records tumbled Monday.
In Dallasport, Washington, the mercury rose to a staggering 118 degrees Monday afternoon, which tied the state’s record high, AccuWeather said.
In the Willamette Valley south of Portland, a farmworker died Saturday at a workplace in St. Paul as temperatures that day hit 104 degrees.
The heat is caused by an atmospheric blocking pattern that led to a heat dome and low pressure on either side, which is not being moved along by the jet stream, the WMO said.
This heat wave comes on the heels of another historic heat wave less than two weeks ago that baked the desert Southwest and California with hundreds of record highs.
Kristie Ebi, a professor at the University of Washington who studies global warming and its effects on public health, said heat waves are becoming more common as the world warms.
“We know from evidence around the world that climate change is increasing the frequency, intensity and duration of heat waves,” she said. “We’re going to have to get used to this going forward.”
Contributing: Lindsay Schnell, USA TODAY; The Associated Press.