Air temperatures warming up to normal levels, water temps remain cold

June 29, 2019 – Temperatures gradually warm the next several days, returning to around average by early next week. Dry weather is expected throughout the period.

Discussion

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Much of the high-level cloudiness which filled the region is long gone and has exited toward Nevada. The synoptic pattern does not change appreciably over the weekend as a broad trough extends from the eastern Pacific to the coast. A weak shortwave analyzed around 130W longitude will cross northern California. Little to no moisture is associated with this disturbance so only some scattered high clouds are expected this afternoon. Otherwise, below average temperatures (3 to 7 degree departures) will continue. Mid-level heights rise a bit more on Sunday affording an increase in temperatures to conclude the weekend, albeit a couple degrees below climatology.

For the first half of next week, another upper low looms off the coast but will remain near the Pacific Northwest. Little to no impacts are expected outside brief periods of enhanced west- southwesterly flow. This would diurnally increase Delta surface winds, particularly early in the week. While a positively-tilted longwave trough remains over the West Coast through mid-week, not expecting much in terms of sensible weather impacts outside of some high clouds. Temperatures continue to slowly rise reaching climatology by Tuesday as Valley highs reach the low to mid 90s while 70s and 80s will be more commonplace toward the foothills and mountains.

Extended Discussion (Wednesday through Saturday)

The extended period starts off with a weak upper trough remaining along the coast with southwest to west upper flow over the north state. Still looks like any precipitation will remain well north of the forecast area and daytime highs should come in near or just a little above normal. Wednesday will start a very slow warming trend with extended models showing the upper trough starting to lift out as high pressure aloft slowly shifts back west. Main change through the dry extended period Thursday through Saturday will be the continued slow warming trend with daytime highs reaching about 6 to 10 degrees above normal by next weekend.