Includes Yosemite National Park
July 9, 2021 - The National Weather Service Hanford Office reports a few thunderstorms are possible along the Sierra Nevada this afternoon and evening hours.Small hail and wind gusts near 40 miles per hour are associated with strong thunderstorms.
In addition to dangerous cloud to ground lightning strikes, any thunderstorm can produce intense rainfall rates, leading to localized flooding.
Area Forecast Discussion National Weather Service Hanford CA 433 AM PDT Fri Jul 9 2021 .SYNOPSIS... Dangerous heat returns to the forecast area over the next several days due to a strong ridge of high pressure building overhead. Daily record high temperatures are likely to be broken through Monday. Slightly cooler by the middle of next week as the high pressure ridge erodes. && .DISCUSSION... Some mid level clouds moving across the central CA interior. Monsoon moisture from NW Mexico has been on the increase due to a SE flow around a ridge over the SW. A couple of showers occured over the high sierra yesterday. Soundings show an increase in mid level moisture. Models show precipitable water increasing to 175-200 percent of normal late today across the central CA interior. This should result in an increase potential for convective showers over the high sierra during the afternoon. Southeast flow will continue bringing surges of moisture into the weekend. Thus the threat of convective storms will continue each afternoon over the sierra through Monday. A significant warm up is expected starting today as a strong ridge of high pressure over the Four Corners area strengthens and shifts west towards CA. The center of the high will be over S NV with 598DM hights over central CA on Saturday. The strong ridge will slowly shift over central CA Sunday and remain anchored over California Monday. Ensemble models show a the ridge start to weaken Tuesday as trough of low pressure pushes through the PacNW. Models indicate the ridge will continue a weakening trend through the end of next week. A southwest flow aloft due to the Pac NW trough will bring a drier flow across north CA and shunt any remnant moisture east of the sierra during mid week. Very hot temperatures with near records are expected through Monday. 105-113 degrees are forecasted across the San Joaquin Valley Friday through Monday with the hottest day possibly being Sunday. Very high risk will continue through Monday with an excessive heat warning in affect for the entire area. New record high temperatures will be possible next few days. There may be little night time temperature recoveries especially in the high desert and lower foothills and elevated valleys within the thermal belt. && .AVIATION... VFR conditions can be expected throughout the central California interior for at least the next 24 hours. && .AIR QUALITY ISSUES... On Friday July 9 2021... Unhealthy in Sequoia National Park and Forest. Unhealthy for sensitive groups in Fresno... Kern... Kings and Tulare Counties. Further information is available at Valleyair.orgSource: NWS
