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Believe it or not there is a rain chance this weekend

Morro Bay Coastline
Posted at 4:39 PM, Jul 16, 2021
and last updated 2021-07-16 23:37:43-04

The Central Coast saw a very mild week with interior temperatures running below average. At the coast, temperatures hugged the averages all week. We will see some changes over the course of the weekend. High pressure is building over the Utah, Arizona, New Mexico, and Colorado borders.

This feature in this area is called a "4 corners high". When this feature develops in the mid-levels it can pump unstable sub-tropical air into California. In this case, much of the moisture is stuck at the mid-levels, and when it interacts with heat (injected at mid-levels thru the warm mountain topography) it can cause thunderstorm activity. In this case, lacking low-level moisture we can get "dry lightning" storms which are energetic electrical features but don't put down the helpful rain. In fact, the dry lighting is more of a threat to wildfire risk.

This is pretty much the set-up late Saturday into early next week. I've been saying all week the potential locally was low but couldn't be eliminated. Well, late today modeling started to indicate potential local activity early Sunday. This is not unheard-of but definitely more rare than common.

Outside of interior and higher elevation instability, the weekend will see inland temps start creeping up again. Near-average temperatures are possible Saturday but Sunday thru next week could be near 100 each day inland. While above average it is short of extreme or record-setting levels.

At the coast a mild temperature bump is possible as well as coastal valleys move from the lower 70s to the upper 70s and lower 80s with beaches also perhaps getting a few degree bump but generally staying in the 60s with a few spots into the lower 70s.

Some continuing night and morning low cloud cover with clearing is likely. Some mid-level clouds are also possible as a minor sun filter.

I think the "4-corners high" stays put much of next week, which means the door is open to the mid-level moisture and possibly slightly higher dew points at the surface, in other words it might feel slightly muggier than average. Inland temps might back off a few degrees later in the week but not really a strong indicator on that.