Thursday is expected to be the hottest day of this week’s extreme temperature swing in San Diego, elevated by a Santa Ana weather pattern that is creating dangerous fire conditions.
Highs on Thursday could reach 15 to 25 degrees above seasonal averages based on 30 years of forecast history, according to Meteorologist Dagmar Midcap.
Midcap forecasted coastal and desert highs in the mid to low-90s and said inland zones could get as hot as the upper 90s. Mountain areas should see the high 70s.
The National Weather Service in San Diego said there is a 60% chance the average high temperature in the county will be above 100 degrees.
A heat advisory will last until at least 6 p.m. Friday in coastal areas including Vista, Carlsbad, Encinitas, Chula Vista, National City, San Diego Escondido, El Cajon, San Marcos, La Mesa, Santee and Poway.
There is also a wind advisory in the foothills and inland valleys issued from 6 a.m. Wednesday until 8 p.m. on Thursday as Santa Ana winds pick up. Some isolated gusts could reach 45 mph.
Humidity will also drop to about 15% inland and 20% along the coast, according to the National Weather Service, and the combination of hot temperatures, strong wind and low humidity could create dangerous fire weather conditions.
Popular hiking trails including ones in the San Diego River Gorge, Cedar Creek Falls, Three Sisters and Eagle peak areas were closed to prevent public safety issues during the heatwave.
On Wednesday, coastal and mountain zones were expected to see highs in the mid-70s, but morning and afternoon fog along the coast helped keep temperatures down, the NWS said. Inland and desert communities saw highs creep into the low 90s.
Thursday started with some morning fog, too.
The National Weather Service called San Diego’s weather pattern this week a temperature "rollercoaster ride.
The region went from mist and cool temperatures last weekend to extreme heat mid-week. By this weekend, the heatwave is expected to break and by Monday, cooler temperatures and the chance of rain returns.
A heat advisory goes into effect when hot temperatures can cause illness and other safety issues.
Here are some tips to stay safe in the heat:
- Drink plenty of fluids
- Stay out of direct sunlight
- Reschedule outdoor activities for the morning and evenings
- Weare loose fighting clothing
- Don't leave pets or children in vehicles unattended
- Know the signs of heatstroke, including confusion, slurred speech, profuse sweating and very high body temperatures