Cooler weather pattern next week

September 9, 2018 – Warm and dry weather persists this weekend. Cooler and locally breezy next week. Areas of smoke and haze from wildfires will continue.

Discussion

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Short-wave trough is shifting east through the Great Basin while short-wave ridging over the eastern Pacific moves into NorCal. Some high clouds are moving in from the west, otherwise skies are clear. Current temperatures are mostly a little cooler compared to 24 hours ago and generally range from the mid 30s in the colder mountain valleys to the upper 50s to upper 60s across the Central Valley. Persistence will continue today and Monday with warm and dry conditions. Cooler and breezier conditions develop Tuesday and Wednesday as the closed low presently off the BC coast is forecast to shift southward to off the mouth of the Columbia River lowering heights and thickness across the region.

Extended Discussion (Thursday through Sunday)

Upper level troughing and continued onshore flow will bring continued well below normal daytime temperatures Thursday. Shortwave disturbances pivoting out of this trough may bring some cloud cover to the northern CWA but at this time all models keeping any precipitation north of the Forecast area. Temperatures warm up a bit on Friday as the upper trough shifts into the Pacific Northwest and high pressure pushes back over the west. Even with the warming…daytime highs Friday will remain a little below normal. Warming and drying continue on Saturday as upper ridge amplifies over the west coast with highs reaching up to right around normal. If current long term model projections are on track, warming trend will be brief with next Pacific trough approaching the coast by the end of the weekend. Still no precipitation in sight, however so extended forecast remains dry.