Northwestern US heat wave to trend less extreme this weekend
The northwestern United States heat wave will ease slightly this weekend but linger well into next week.
Temperatures in some locations have been rivaling the highest mark on record for any date.
"A northward bulge in the jet stream, an area of high pressure at the surface, intense sunshine and dry soil conditions are responsible for the extreme heat," according to AccuWeather Senior Meteorologist Brett Anderson.
The jet stream is a fast river of air at the level which aircraft cruises. The jet stream separates heat to the south from cool air to the north.
High pressure is a large area of sinking, dry air that spins in a slow clockwise direction. The sinking air heats up as it descends through the atmosphere. The stronger the area of high pressure, the greater the amount of heat is produced.
It will still be hot this weekend but not as extreme.
"This weekend, the jet stream will straighten out a bit, and the area of high pressure will weaken slightly," Anderson said.
"Temperatures this weekend will throttle back between 5 and 15 degrees Fahrenheit, when compared to most days this past week across much of Washington, Oregon and Idaho," Anderson said.
Highs in the 110s will be replaced with highs near 100 across the interior hot spots. Highs near or above 100 over the rest of the interior will be replaced with highs in the 90s.
Farther south, in Northern California and Nevada, it may take until next week before temperatures lower. That trend may only represent temperatures a few degrees lower.
A true end to the heat wave may not come until late next week or next weekend for much of the Northwest.
For example, by next Friday, high temperatures will be in the lower to middle 80s in Portland, Oregon, and will replace highs in the 90s this weekend and the first part of next week.
In the meantime, the heat wave will continue and people should limit strenuous activity during the midday and afternoon hours. Be sure to drink plenty of fluids.
Smoke from wildfires in British Columbia further reduced already poor air quality in portions of Washington and Oregon from Wednesday afternoon into Thursday. The smoke was thick enough to hold temperatures back by a few degrees in some locations.
Air quality may improve in some locations with a change in the wind direction this weekend.
The risk of wildfire ignition and spread will remain elevated due to limited rainfall and dry landscape.
As of Friday morning, Aug. 4, approximately 30 wildfires were burning across the three-state area of Idaho, Oregon and Washington, according to the Wildfire Incident Information System.
Officials urge residents and visitors to observe all restrictions on the use of open flames.
People using power equipment and cooking outdoors to reduce the buildup of heat in their homes should use caution. Never park over high brush as the heat from the exhaust system can start a fire. Be sure to extinguish campfires prior to leaving the vicinity.
In terms of rainfall, enough moisture may return to the region to produce very spotty thunderstorms next week. However, some of the storms may bring little or no rainfall and may raise the risk of lightning-induced wildfires.
Report a Typo
