A red flag warning signifying a high risk of wildfire will go into effect this morning in parts of Riverside and San Bernardino counties -- though not the Coachella Valley -- because of high heat, gusty Santa Ana winds and low humidity.
The National Weather Service issued a red flag warning set to take effect at 8 a.m. today and extend until 5 p.m. Thursday for the Riverside County valleys and the San Bernardino County mountains, including the Mountain Top and Front Country ranger districts of the San Bernardino National Forest.
"A red flag warning means that critical fire weather conditions are either occurring now, or will shortly," according to the NWS. "A combination of strong winds, low relative humidity and warm temperatures will create explosive fire growth potential."
Northeast winds of 15 to 25 mph with gusts of up to 55 mph are expected in the warning areas, along with low humidity.
Temperatures are expected to reach 70 above 6,000 feet and up to 80 degrees between 3,000 and 6,000 feet, according to the weather service. Inland Empire highs of between 80 and 90 degrees are expected today and highs of up to 96 are expected Thursday.
Winds in Riverside and San Bernardino county valleys and mountains are expected to pick up to between 20 and 30 mph with gusts of up to 55 mph late tonight. The NWS issued a wind advisory that will take effect at midnight and extend to 5 p.m. Thursday.
A wind advisory was also issued for the Coachella Valley, where northeast winds of 20 to 30 mph are expected and gusts could reach 45 mph mainly north and east of Interstate 10 after midnight. The advisory will expire at 1 p.m. Thursday.
Forecasters said the winds could make driving difficult, especially for motorists in high profile vehicles, and areas of blowing sand and dust could reduce visibility.
A less severe fire weather watch will take effect at 5 a.m. Thursday and extend until 5 p.m. Thursday in mountain areas of Riverside County.
"A fire weather watch means that critical fire weather conditions are forecast to occur," according to the weather service.
High temperatures on Thursday are expected to reach up to 75 above 6,000 feet and up to 85 degrees between 3,000 and 6,000 feet, according to the weather service.
Wind gusts should weaken to less than 25 mph Thursday evening, but warm weather and low humidity are expected to continue into Friday, according to the NWS.