Sunday, June 28, 2015
A large and stable ridge of high pressure over the Great Basin responsible for the record warmth in the northwest will stay just west of our area through most of the next week. Some moisture moving around the periphery of the ridge will continue the threat of afternoon storms through Tuesday as temperatures stay seasonably warm to hot.
By Tuesday night or early Wednesday, models forecast some cool air from the Canadian plains flattening the Great Basin ridge and allowing for the possibility of nocturnal activity late Tuesday and then afternoon storms Wednesday. Another weak wave passes Thursday and is forecast to be followed by some drier air for the rest of the workweek and into the first part of the Fourth of July weekend, reducing the threat of afternoon storms for then.
By Saturday, models have a much stronger Pacific northwest storm crossing the coast and threatening our weather later in the long Fourth of July weekend as it incorporates another surge of cool Canadian plains air. At this time, it looks noticeably cooler and more showery certainly by Monday, and perhaps as early as Sunday, with unsettled weather extending into the first half of that week.