San Diego's Weather Forecast for Aug. 17, 2021: Cooling Trend Begins

Sunny beach
Posted at 4:57 AM, Aug 17, 2021

A cooling trend begins today with temperatures coming down 1 to 4 degrees for the coast and valleys and 3 to 7 degrees in the mountains and deserts. Noticeably cooler tomorrow as temperatures plummet another 5 to 10 degrees!

Monsoon flow continues for one last day with only a slight chance for any showers or thunderstorms over the mountains and deserts this afternoon and evening.

A trough of low pressure will develop to our north ushering in the cooler air that will drop temperatures 5 to nearly 15 degrees below normal. Wednesday and Thursday will be the coolest days with thicker marine layer clouds, something we typically see in May or June!

The marine layer may be able to squeeze out some drizzle to a few light showers in the overnight and morning hours tonight through Thursday. Below normal temperatures will last through the weekend.

In addition to the cool-down, the humidity will also be trending downward making it feel a lot more comfortable across the county. The driest air will be away from the coast.

This trough will not only usher in cooler and drier air from the north but also smoke from wildfires burning in the Northwest leading to hazy skies. The smoke will be at the higher elevations and at this point shouldn't impact air quality.

Winds will pick up in the mountains and deserts over the coming days with westerly winds of 20 to 45mph.

Temperatures start to go back up Sunday into next week.

Tuesday's Highs:
Coast: 74-79°
Inland: 83-88°
Mountains: 77-90°
Deserts: 103-107°

Follow ABC 10News Meteorologist Megan Parry on Facebook at Megan Parry 10News, Instagram @mis_meg_wx and Twitter @10NewsParry