Temperatures in Seattle are expected to push 90 degrees this week, with most of the heat coming in the first half of the week.

The warm weather is being caused by a large ridge of high pressure off the coast. This should push us well into the 80s on Tuesday with a high of 90 on Wednesday.

We could set a new heat record on Wednesday. The current high for June 20 is 88 degrees, set back in 2004.

Highs along the coast are staying in the upper 60s to low 70s.

By Thursday, the ridge will shift into northern British Columbia, and this will signal another shift in our weather pattern. This will allow a weak weather system to approach the coast later in the week.

It should cool us back to the mid to upper 70s Thursday for the official start of summer. As the onshore winds increase, more clouds will roll in on Friday and Saturday for cloudy starts to the days before turning sunny in the afternoons. Highs should drop back into the mid 70s.

The first in a series of weak weather systems may brush us on Sunday for a couple of showers, and it looks like we will stay in a much cooler and cloudier pattern next week.

RELATED: Latest weather forecast

The warm weather is in line with NOAA's Climate Prediction Center that calls for a June with above normal temperatures and below normal rainfall for Washington state. In the Pacific Northwest, average summer temperatures trend around 70 degrees for June, 75 degrees for July, and 76 degrees for August. Average rainfall for June is 1.57 inches, July is 0.77 inches, and August is 0.88 inches.

The record for most 90-degree days in a summer is 12 days, which was set in 2015. Ten of those days happened in July.

NOAA's one-month outlook for rain and temperature in June 2018.