Seattle or Phoenix? This is why it's so hot in the Northwest right now

Western Washington faces a third day in triple digit heat Monday. A first since weather records have been kept.

The record temperatures in the region are being driven by conditions more commonly found in the Southwest, in cities like Phoenix, Arizona.

Justin Pullin, a meteorologist with the National Weather Service said that warm winds coming from the Cascades are getting trapped under high atmospheric pressure, creating a heat-dome effect. This sort of high pressure system leads to the infamously high temperatures in areas like Phoenix.

"Plenty of days in the 100s and the 110s, and it's normal down there for them this time of year," Pullin said. "We're basically translating that weather pattern and bringing it over the Northwest, an area that is not used to that."

Depending on where you are, you may feel that heat pass 110 degrees. Seattle set a record high at 104 degrees on Sunday, (beating the 103 degree record set in 2009, and then matched the day before, on Saturday). Also a record — Seattle hit above 100 degrees two days in a row. It's looking like that record won't stand long as a third triple digit day is expected Monday.

An excessive heat warning is in place for the region until 11 p.m. Tuesday night. Fire danger is also high in the Northwest. The National Weather Service has also issued a red flag warning on the western slopes of the central Cascades.

Phoenix is also slated to hit 110 degrees on Monday. Las Vegas is expected to be at about 108.

Though places like Phoenix will stay in the triple digits the rest of the week, the Northwest is likely to cool down by Wednesday.

"Even by our normal standards we're still going to be almost 10 degrees above normal come Wednesday. Temperatures (Tuesday) will cool down — and I use that term very loosely," Pullin said.

Pullin says that a "cool-down" will still be in the upper 80s and 90s Tuesday, followed by much cooler weather in the evening.

The other good news is that, for now, such abnormal heat is not expected to be a new normal for the Seattle area.

"You know, while our climatological normals show that we are, you know, warming by a little bit each year, this is not necessarily a precursor to what a new normal is going to be."