Updated

Updated · The New York Times · Aug 7

Heat Dome Pushes Triple-Digit Temperatures Across North America as Wildfire Smoke Traps Haze

Updated

Updated · The New York Times · Aug 7

Heat Dome Pushes Triple-Digit Temperatures Across North America as Wildfire Smoke Traps Haze

Q: While the West bakes, what surprising atmospheric shift is preparing to unleash destructive floods and tornadoes across the Midwest?

The shift is the development of a new jet-stream-driven pattern along the northern edge of the heat dome, where a creeping cold front and repeated upper-level disturbances tap deep Gulf moisture over the Midwest. That setup is important because the same ridge baking the West helps steer storm systems around its perimeter. Forecast outlets and meteorologists describe moisture-rich air riding the northern flank of the ridge “like boxcars on a train track,” allowing thunderstorms to repeatedly form and move over the same areas. That raises the risk of training storms, flash flooding and excessive rainfall, especially where soils are already saturated. At the same time, the stronger jet-stream energy and frontal boundary create enough wind shear and lift for severe storms, including damaging winds, large hail and isolated tornadoes. Recent Midwest forecasts have specifically highlighted corridors from Missouri and Illinois into Indiana, Wisconsin and Michigan for both flood threats and tornado potential. So while the West remains under a stagnant heat dome, the Midwest is being primed by a more active atmospheric transition: the jet stream dipping eastward around the ridge, a slow-moving front, and abundant warm moisture combining into a classic late-summer severe-weather and flood pattern.

3 articles · Updated · The New York Times · Aug 7

Triple-digit heat is building across the West this weekend, with parts of the Southwest at risk of daily records and even new monthly highs as a heat dome strengthens.
That heat is expected to drift into the Plains early next week, while New York City, the coastal Northeast and eastern Canada endure sultry heat and humidity with only brief shower relief.
Thunderstorms could flare in many of those hot, humid areas, bringing a slight risk of damaging winds and excessive rain; in the Southwest, monsoon moisture is also keeping overnight lows unusually high, with some spots staying above 80 degrees.
Wildfire smoke is worsening conditions in eastern Washington and Oregon, where air-quality alerts were issued Friday and the heat dome may keep haze trapped over parts of the Pacific Northwest and Intermountain West for days.
Next week, forecasters see the main hazards shifting toward excessive rain in the Midwest and persistent heat from Texas to Florida, while the Northeast could cool to near or below average in a little over a week.