Better late than never.
After waiting a little longer than usual for the arrival of summer weather this year, Vancouver can expect a relatively rare September heat wave this week, according to the National Weather Service in Portland.
The temperature at Vancouver’s Pearson Field reached 91 on Tuesday — the first of what could be five consecutive days above the 90-degree mark, according to the weather service. A run like that hasn’t happened in September since 2003, said meteorologist Liana Ramirez.
“It’s not unusual for us to see warm temperatures, but it is unusual to see them for a long stretch,” Ramirez said.
This week’s forecast from the weather service calls for a high temperature of 92 degrees Wednesday. Thursday’s high is expected to dip to 90, then bump back up to 91 and 93 on Friday and Saturday.
The reason? A strong high-pressure system will build over the Northwest in the next few days, Ramirez said. Combined with stagnant winds, that will allow temperatures to climb well above the average of about 78 for this time of year.
Vancouver waited until Aug. 20 — almost two months after the official start of summer — to see its first 90-degree day of 2011. Three more followed by the end of the month.
On average, September sees only one day above 90, Ramirez said. In September 2010, Vancouver didn’t have any such days.
For Vancouver or Portland, this week’s temperatures aren’t likely to shatter any records. The longest September run of 90-plus highs recorded at the Portland International Airport is six consecutive days, set in 1974, according to Columbian weather blogger Steve Pierce, also president of the Oregon chapter of the American Meteorological Society. That year, a total of eight September days registered above 90.
This year could have five by week’s end. But temperatures should drop back into the 80s by early next week.