Hot temperatures through this evening with Moderate to locally Major HeatRisk north of I-80. Temperatures will trend cooler late-week and over the weekend. Isolated shower/thunderstorms over the Sierra Crest south of Highway 50 Thursday afternoon. Elevated fire weather conditions this weekend into early next week.

Key Points

  • Hot temperatures continue through this evening, mainly north of I- 80 where there is widespread Moderate HeatRisk with local Major HeatRisk today
  • Cooler Thursday, with closer to normal temperatures through the weekend
  • Slight chance of shower/thunderstorm over the Sierra Crest south of Highway 50 Thursday afternoon
  • Elevated Fire Weather Conditions later this weekend into early next week from gusty northerly wind and low RH - Local waterways are still running cold and fast from snowmelt

Short-Term Discussion (Today through Saturday)

Maybe she's born with it… Or maybe it's the high pressure over the area that's keeping skies clear on GOES West Satellite imagery of interior NorCal today. The ridge that brought the anomalously high temperatures the last couple of days is moving east today/tonight, leaving us with warm but more seasonable temperatures for the remainder of the week.

Excessive heat warning

Until then, the Excessive Heat Warning remains in effect for lower elevations north of I-80 through 8 PM this evening. Westerly flow remains over the area the next couple of days, though temperatures will still be quite warm with the seasonal norms.

HeatRisk falls to Minor across the majority of the area, with small areas of Moderate, through the start of the weekend.

High temperatures in the Valley will range from the 80s to 90s starting Thursday. Subsequently, the foothills and mountains will range from the 80s and 60s to 70s respectively. Thursday afternoon brings some slight chances for isolated thunderstorms (~10-20% probability) at higher elevations south of HWY 50 as well.

Fire wx safety. the tl;dr Don't do anything stupid

Saturday sees a drying trend in RH, with north to northeasterly winds picking up more as we move into the late weekend, with elevated fire weather conditions expected in the extended forecast period.

To view the latest HeatRisk, please visit www.wpc.ncep.noaa.gov/heatrisk/

To view current water temperatures, please visit www.cnrfc.noaa.gov

Extended Discussion (Sunday through Wednesday)

Confidence is increasing in winds continuing to build over the weekend, into Sunday and Monday. There is a 30 to 80% probability of gusts at or over 40 mph in the Valley, primarily along the western side. Strongest gusts are expected to occur along the I-5 corridor between Red Bluff and Woodland.

Fire weather June 15-17

These winds, combined with RH values in the low to mid teens, will cause elevated fire weather concerns on Sunday and Monday. Tuesday sees calmer winds, and by Wednesday, RH should begin to go up as well.

Onshore flow will keep temperatures near seasonable levels throughout the extended period, with highs in the Valley expected to be in the upper 80s to lower 90s, and at higher elevations between the 60s and 80s.