August 22, 2018 – Gradual cooling with dry conditions expected through the week. Areas of smoke and haze will continue, especially near wildfires.
Discussion
Overnight water vapor imagery and model analysis showed a positively tilted trough over northern California with plenty of dry air in place. Temperatures in the valley ranged from the mid 50s to mid 60s, while locations in the mountains were in the low to mid 40s. Latest model trends have the current trough positioned over the interior to move off to the northeast today with a shortwave ridge of high pressure positioned overnight tonight through early Thursday. Another trough will be moving southward Thursday night into the weekend. The pattern of disturbances will bring increasing onshore flow and cooler than normal conditions ranging from 5 to 10 degrees below normal for this time in August. Dry weather will continue.
Smoke and haze, especially near the area wildfires, will continue as well. The increasing flow through the delta will bring chances for increasing clouds through the delta and into Sacramento and surrounding communities for the next several mornings.
Extended Discussion (Sunday through Wednesday)
Troughing is expected to linger over NorCal through the extended period. At the moment, the main impacts with this troughing expected to be cooler temperature as moisture seems limited over our forecast area.
Daytime temperatures are expected to gradually cool, ranging from 5 to 10 degrees below normal through midweek next week. Local breezy conditions possible Sunday and Monday as shortwave troughs move over NorCal.