June 26, 2019 – Unseasonably cool daytime temperatures today and Thursday, then a warming trend returns for the weekend. No precipitation expected except for a small chance of showers or thunderstorms over the mountains of Shasta County. Occasionally breezy winds through the Delta and over the higher terrain during the next few days.
Discussion
Clear to partly cloudy skies across the region early this morning as a band of mid and high clouds spreads southward ahead of the approaching trough. Current temperatures range from the mid 30s to mid 40s in the mountain valleys to the 60s to lower 70s across the Central Valley, around 3-8 degrees cooler across most of the area compared to 24 hours ago.
Synoptic pattern over the area will be dominated by a trough the next several days resulting in unseasonably cool temperatures along with breezy conditions at times. Temperatures will be significantly cooler today, then are forecast to cool a bit further on Thursday before beginning to edge upward heading into the weekend as the trough weakens.
The closed low is forecast to approach the southwest Oregon coast later today and may provide enough lift to pop a few late day showers or thunderstorms over Shasta County and near Mt Lassen. In addition, gusty southerly winds will likely pick up across the Sacramento Valley and over the high Sierra today.
Extended Discussion (Sunday through Wednesday)
Upper level low pressure system remains over the Pacific Northwest early next week bringing below normal temperatures and breezy west winds. Models differ on details but at this time, the general consensus is that a troughing pattern will remain over the west coast through the extended period. Any precipitation with this pattern still appears will remain north of the forecast area. Seems to be some movement towards weakening the trough through the first half of next week allowing for a slight warm up. Current forecast warms temperatures to near normal Monday with slightly above normal temperatures expected Tuesday and Wednesday.