GREENVILLE, N.C. (WNCT) — A historic heatwave shattered record after record in the northwestern US and Canada. This is not only possible because of global weather patterns, but also what is known as a heat dome.
The early spring forecast by NOAA actually hinted at a high chance for heat dome development this summer. This is thanks to La Nina going into the neutral phase.
Simply put, Pacific Ocean waters are cooler in the eastern Basin and warmer in the west, with the temperature difference creating winds that blow tropical air from west to east. This warm, tropical air can get caught in the jet stream and pushed into the western portions of North America.
When this airmass gets caught under a high-pressure system, it pushes the hot air down to the ground. As it sinks, it continues to warm by compression. The hot air expands vertically and gets pushed right back down to the ground, trapping it all in a bubble at the surface. This is known as a heat dome, which is currently affecting the northwestern portions of the US and into Canada.
Millions of people were under excessive heat warnings, with temperatures around 30-40 F above average for this time of year. The airport in Portland broke its 80-year record high three days in a row, with temperatures up to 116 degrees.
According to the National Weather Service, Salem, Oregon, may have set the highest temperature on record west of the Cascades in the Pacific Northwest when it soared to 117 degrees on June 28. The Canadian national record was broken three days in a row, with the town of Lytton reaching115 Monday and then Tuesday peaking at 121 F, smashing the record of 113 back in 1937.
In addition to the all-time national record, 37 other locations in Canada with records at least since the 1960s in Alberta, British Columbia and the Northwest Territories tied or set new all-time records, so far.
Luckily, no triple digits temperatures quite yet for us here in Eastern North Carolina.