High pressure ridging brought hot temperatures across the area, 5 to 10 degrees above normal. Some locations had high temperatures reaching 105-110, with temperatures remaining in the mid to upper 70s overnight. Heat Warnings and Advisories were issued. Heat Risk Criteria reached Moderate levels across the forecast area, with some areas in the northern Sacramento Valley and adjacent foothills reaching High to Very High levels.
Isolated nocturnal thunderstorms brought locally heavy rain to the mountains, causing a rock slide.
A period of less extreme heat came earlier in the month. A 2 year old boy died in a hot car on July 7 in south Sacramento. The high temperature in downtown Sacramento reached 100 that day.

Heat in SHASTA LAKE/NORTH SHASTA COUNTY, CALIFORNIA
From 15-JUL-18 11:00:00 to 20-JUL-18 19:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The NWS Experimental Heat Risk reached Moderate to High readings for several days prompting a Heat Advisory for northern Shasta County.

Heat in CENTRAL SACRAMENTO VALLEY, CALIFORNIA
From 15-JUL-18 11:00:00 to 20-JUL-18 19:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The NWS Experimental Heat Risk reached Moderate to High readings for several days prompting a Heat Advisory for the Central Sacramento Valley. The hottest day was the 18th, when the temperature reached 104 at Marysville.

Heat in MOUNTAINS SOUTHWEST SHASTA COUNTY TO NORTHERN LAKE COUNTY, CALIFORNIA
From 15-JUL-18 11:00:00 to 20-JUL-18 19:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The NWS Experimental Heat Risk reached Moderate to High readings for several days prompting a Heat Advisory for the mountains of southwest Shasta County to northern Lake County.

Heat in CLEAR LAKE/SOUTHERN LAKE COUNTY, CALIFORNIA
From 15-JUL-18 11:00:00 to 20-JUL-18 19:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The NWS Experimental Heat Risk reached Moderate to High readings for several days prompting a Heat Advisory for southern Lake County.

Heat in NORTHEAST FOOTHILLS/SACRAMENTO VALLEY, CALIFORNIA
From 15-JUL-18 11:00:00 to 20-JUL-18 19:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The NWS Experimental Heat Risk reached High readings for several days prompting a Heat Advisory for the northeast foothills adjacent to Sacramento County.

Heat in MOTHERLODE/CAMPTONVILLE TO GROVELAND, CALIFORNIA
From 15-JUL-18 11:00:00 to 20-JUL-18 19:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The NWS Experimental Heat Risk reached Moderate to High readings for several days prompting a Heat Advisory for the Motherlode.

Heavy Rain in PLUMAS, CALIFORNIA
From 15-JUL-18 03:00:00 to 15-JUL-18 03:58:00 (PST-8)
Location: CAMP RODGERS
Crop damage: 0.00K
Reported by: Law Enforcement

Heavy rain from an isolated thunderstorm brought a rock slide covering the west bound lane of Highway 70. Radar estimates suggested locally 0.45 of rain within 1 hour.

Excessive Heat in NORTHERN SACRAMENTO VALLEY, CALIFORNIA
From 15-JUL-18 11:00:00 to 20-JUL-18 19:00:00 (PST-8)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The NWS Experimental Heat Risk reached High to Very High readings that prompted an  Excessive Heat Warning for the northern Sacramento Valley. Redding highs were 108 on the 16th, then reached 109 for 3 days in a row, from the 17th to the 19th. Lows were in the 70s, peaking at 75 on the 16th.