July 10, 2018 – Hot temperatures continue through the week. Monsoonal moisture will bring chances for showers and thunderstorms to the higher elevations late week into the weekend.
Discussion (Today through Friday)
Upper level trough continues moving through the PacNW through overnight through the morning with an upper level ridge located over the Great Basin. Winds have begun shifting to the north due to the trough passage and will be locally breezy throughout Tuesday. Smoke from the Klamathon Fire could push south into Shasta county again, though it is expected to remain mainly aloft. Ridging builds Wednesday with the ridge over the Great Basin beginning to retrograde Thursday and Friday. This will allow monsoonal moisture to push northwest into the area beginning late Wednesday. As of now, mountain storm chances remain limited to the far southeast portion of our forecast area. Temperatures remain hot with temperatures ranging from the mid 90s over most of the valley to 106 in the northern Sacramento valley. Foothills will remain in the 90s and the mountains 70s to 80s.
Extended discussion (Saturday through Tuesday)
Latest model runs of the GFS and ECMWF are in better agreement with a upper level ridge of high pressure dominating the forecast for this weekend into early next week. Current temperature trends will have afternoon high temperatures right around normal for mid July.
Monsoon moisture will be in the vicinity of the region under the high pressure system centered over the Great Basin, and general afternoon convection is possible each afternoon for the Sierra. Although conditions are not that great for thunderstorm development, scattered showers and thunderstorms cannot be ruled out for the afternoon and evening hours.