4 days ago
National Weather Service issues extreme heat watch for Oregon's Willamette Valley
The National Weather Service has issued an extreme heat watch for the Willamette Valley from July 15-16.
Dangerously hot conditions with temperatures between 95 and 105 degrees are possible across much of northwest Oregon, including the northern and central Willamette Valley.
The highest chances are in the Portland/Vancouver metro area and Columbia River Gorge.
Low temperatures between 65 to 70 degrees may occur in the evening of July 15, which would limit overnight relief.
Both daily high and nightly low temperatures are considered when determining an extreme heat watch should be issued, according to Lee Picard, lead meteorologist at the National Weather Service in Portland.
"(A low of) 65 is an important threshold for us," he said. "If it doesn't go below that, it's difficult for people to cool down overnight."
An extreme heat watch doesn't mean extreme heat will definitely occur, Picard said. It is issued ahead of time, in this case six days in advance, to allow people to prepare for a potentially dangerous event.
High and low temperatures factor into an index known as HeatRisk, which provides a forecast of heat-related impacts in a 24-hour period. The formula accounts for climatic factors as well, like how unusual extreme heat is during a particular time of years. If the HeatRisk in an area falls into the two highest categories, major or extreme, it meets the criteria for a hazardous event.
"A watch is when a hazardous event is possible. We usually say about 50% likely that it will occur," Picard said.
Heat related illnesses increase significantly during extreme heat events, the National Weather Service said.
The agency advised people to drink plenty of fluids and to stay out of the sun in a cool place during the heat of the day and check up on relatives and neighbors.
For those without air conditioning, people should use fans to keep air moving and keep windows closed during the day and open at night, unless air quality is degraded due to wildfire smoke.
"Do not leave young children and pets in unattended vehicles," the alert from NWS said. "Car interiors will reach lethal temperatures in a matter of minutes."
Rose Shimberg is an outdoors journalism intern at the Statesman Journal. Reach her at rshimberg@
This article originally appeared on Salem Statesman Journal: NWS issues extreme heat watch for Oregon's Willamette Valley
