Above normal temperatures during the day, decent cooling off overnight

July 2, 2017 – Warm and mostly dry this week across interior northern CA.

Discussion

Temperatures are running several degrees warmer this morning for most locations. Onshore gradient is weaker this morning at 1.7 mb between SFO-SAC with decent morning flow through the Delta continuing that will increase late in the day and this evening. Temperatures will be a little warmer today, generally 1 to 3 degrees warmer over yesterday’s highs.

Previous Discussion

Yesterday’s weak upper trough has pushed east into the Great Basin, with high pressure over the eastern Pacific building into the region and bringing clear skies. The onshore gradient is a bit weaker than it was yesterday, though the marine layer remains quite extensive along the coast. Temperatures across the region are generally running a couple of degrees warmer than 24 hours ago.

Dry weather is expected today across the region and should continue through at least midweek under the influence of high pressure. Today will likely be the warmest day of the next few, with temperatures reaching the mid 90s to around 103 degrees across the Valley, and 70s to 90s over the mountains.

The overall pattern will see some amplification over the next few days, as high pressure strengthens over the Great Basin, and an upper trough deepens over the northeast Pacific. NorCal will be caught in between the two features, which will likely bring seasonal temperatures. We should see enough of an onshore breeze and coastal stratus with this pattern to respectably cool off during the overnight hours through midweek, particularly in those locations near the Delta.

Extended discussion (Thursday through Sunday)

Warm and dry weather continues in interior NorCal as upper level high pressure centered over the southwest US builds through the weekend. Temperatures warm to slightly above average.