April 29, 2020 – Dry weather with above normal temperatures continue through the week, though with a cooling trend. Near normal temperatures are expected by the weekend, with a slight chance of showers north of I-80.
Discussion
After some locations with record heat on Tuesday, cooler weather is expected as the upper ridge axis shifts eastward and a shortwave brushes by to the north. Onshore flow has developed with some cooling spreading through the Delta into the Sacramento metro area. Davis and Mather Airfield were 5 degrees cooler than yesterday at 3 am, and this should spread further into the Sacramento metro area this morning, where lows should drop into the upper 50s. The rest of the Valley should be in the lower 60s, mid 60s in the foothills. The area will see widespread cooler afternoon highs today, about 5 to 10 degrees cooler than Tuesday, in the mid to upper 80s. A stronger Delta breeze this evening is expected bringing further cooling.
As the shortwave passes to the north later today into Thursday, precipitation is currently expected to stay north of Shasta County, though some convective clouds could develop in the afternoon. Increased cloud cover and further cooling will be the main effects across the forecast area. Thursday will see more airmass cooling,but more sunshine should keep temperatures about the same as today.
Friday is expected to see Valley highs in the low 80s as a deeper trough from the Gulf of Alaska approaches. This trough will continue to influence our weather through the weekend. The potential for light rain showers will move into western Shasta County Saturday afternoon, spreading across the county overnight and into western Tehama County. Valley highs will reach around 80. EK
Extended Discussion (Sunday through Wednesday)
Pacific frontal system moves through over the weekend bringing cooler unsettled weather with some breezy wind. Best precip chances look to occur on Sunday, but model discrepancies exist with QPF. Overall precipitation totals are light with the primary threat of showers being over the mountains north of I-80. Warmer and drier weather returns early next week under building high pressure.