Dry, hazy and very mild – emphasis on hazy

September 5, 2018 – Warm and dry weather continues this week. Areas of smoke and haze from wildfires will persist.

Discussion

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Clear skies cover interior NorCal early this morning. The marine layer remains between 1500-2000 ft and onshore gradients are similar to 24 hours ago. Current temperatures range from the 40s in the mountain valleys to the 60s across the Central Valley.

Isolated late-day thunderstorms will be possible again today in the Sierra south of Lake Tahoe, otherwise warm and dry weather will continue across the region. Temperatures are expected to warm a bit toward the end of the week as ridging from the eastern Pacific extends into NorCal.

With area fires continuing to burn, expect smoke and haze to be present, especially for the northern Sacramento valley and surrounding locations.

Extended Discussion (Sunday through Wednesday)

Confidence is growing in a cooling pattern during the extended period with ECMWF and GFS now both going with a slow trough development over the eastern Pacific and west coast Sunday through Tuesday.

Daytime highs start out just a bit above normal Sunday dropping to a little below normal by Tuesday. Stable southwest flow aloft should keep any shower activity out of the forecast area during this time.

Temperatures may cool a bit more on Wednesday as the upper trough digs in along the west coast. ECMWF and GFS both paint in some light precipitation over the north state as a shortwave disturbance pivots around the base of the main trough. Have put in some ghost pops across the northern CWA for now but will keep an eye on this time period as models develop.