SAN DIEGO (FOX 5/KUSI) — An early arrival of monsoon moisture and a return of warmer temperatures heading into the weekend means afternoon thunderstorms are more likely in San Diego County’s mountains and deserts through Friday.
As of Wednesday morning, a variety of clouds were visible, with low clouds clinging to the coast and altocumulus clouds appearing over the desert.
A stray air current or two has been developing near Mount Laguna, bringing brief showers, but monsoon moisture is expected to surge Thursday afternoon. More thunderstorms are expected during that time than over the weekend. The weekend will be mainly dry for these areas with only a slight chance of thunderstorms.
Over the weekend and into early next week, a ridge of high pressure will spread out from the Four Corners region, bringing warmer temperatures all the way to the coast.
Inland areas could see temperatures up to 10 degrees above normal during the afternoon, while coastal areas could see temperatures a few degrees above the seasonal average.
Daytime high temperatures on Thursday are expected to be in the mid 70s Fahrenheit, inland valleys in the mid 80s Fahrenheit, mountain areas in the low 90s Fahrenheit and around 110 Fahrenheit in the desert.
Heat advisories are in effect for all deserts this weekend, with an enhanced watch in Borrego Springs on Friday and Saturday.
The marine surface layer shrinks as high pressure develops, but it never disappears completely. Low clouds spread along the coast in the morning and evening, but do not remain there for long.
The ridge of high pressure is not expected to move, so hotter than normal summer temperatures are expected through the third week of July.
