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Heat backs off at the coast Thursday but inland temps stay warm

Paso Robles night
Posted at 1:36 PM, Jun 16, 2021

It takes a lot for the Central Coast to see intense heat in June. The typical ingredients were all there today: high pressure, offshore winds and dry air.

However these are complicated in a microclimate sense. The most critical factor is the strength and duration of offshore winds and for some places like Morro Bay, Los Osos and San Luis Obispo there was enough to drive temps to the 100 range.

However there were places it was clear early that the offshore component was not pushing strong enough, like Pismo Beach and into Santa Maria. Temperatures did well, and much above average for some but not the triple digits.

Why? Well, water temperatures at this point of the year are in the mid-50s. Even a neutral or weak offshore isn't enough to push out the cooler and more dense influence (even if skies are clear). The other element is the daily turn of the wind. When inland temps heat up, it creates localized rising air and this weakens or reverses offshore flow.

Timing this in a microclimate (city by city) way is very challenging but critical to nail temps close to the water. Interestingly, there were towns that had both cool and hit temps simultaneously but just depending on elevation. The very narrow marine layer was producing temps around the AG area of only the 70s but up in the hills it was around 100. So, no town has only one temperature either.

Just thought I'd take a second to explain what makes these such challenging events to forecast, now on to what is next.

It seems pretty clear that the offshore driver for high heat is gone but coastal valleys should still see plenty of 80s. Beaches return quickly into the 60s, and the Southcoast in the 70s.

The interior looks to stay warm. The larger upper level ridge is still massive and 100 plus heat looks to be around until Saturday if not Sunday as well.

Next week it looks like a more typical June pattern returns of night and morning marine clouds at the coast with afternoon clearing and mild temps. Even inland temps return into the 80s.