The Central Coast and much of California look to roast a bit over the next week. A strong ridge of high pressure is setting up and there are only a few places to beat the heat, fortunately, some of those places are also here on the Central Coast.
This is a well-forecasted event: showing up on some modeling weeks ago.
Well, now it is here. Already today the Central Coast interior was experiencing warmer weather and the ridge of high pressure is building in from the east.
This is a heat event largely driven by the position of the upper atmospheric features. The large mid and upper-level ridge does promote high-pressure development. The high pressure will squish out marine influence from the interior valleys and limit the cooler and more dense air to beaches and near coastal valleys. Those locations also warm but there will be night and morning marine cloud potential and afternoon onshore winds will also help to limit how high those numbers can get. That said, I still think some coastal valleys can see 90+ late this week and thru the weekend.
As a result of this forecast, the National Weather Service has issued an excessive heat warning for the interior of the Central Coast, the Southcoast and some coastal mountain areas. These are all locations where temps can top 100 from tomorrow into early next week, and the advisories could be extended if relief doesn't develop.
There is some potential to see dips in the heat. Friday there is a little wave that runs thru the jet stream to the north which could back temps off a few degrees from Thursday's highs. But Thursday's highs look HOT with some interior valleys possibly seeing 110 (or warmer) potential. So, if temps back off 3-5 degrees Friday it would still be very hot. The problem is that Saturday-Monday (the holiday weekend) looks extremely hot with 110-115 in the forecast for the interior valleys. Paso Robles's all-time high is 117 from September 2020, looks like we will be VERY close to that.
The next dip potential is Tuesday next week, but the issue is the same in that Monday looks to be 110-115 and a 5-degree drop still leaves us in the 105-110 range. This is why I think the excessive heat warning could continue.
Beaches and very near coastal valleys look to offer heat relief from the interior but less so by day especially later in the weekend into early next week when beaches could see 80, and coastal valleys in the 80s and 90s (even some upper 90s).
To me, it looks like the ridge axis (the center of the feature creating the heat) should roll east a bit mid to late next week and put the Central Coast in some SW flow aloft which should bring relief. We also may have to watch hurricane activity near the Baja. Models like an active East Pacific. Looks like it might be possible that some SE-E flow could bring up some humidity relating to the tropics but this far out it is just something to watch as that part of the forecast is vastly more complex than what we face over the next few days. The latter is basically a slam dunk, there looks to be little quarter from this heat wave.
While it is common sense, I think it is always worth reminding folks to take precautions in a forecast like this. Avoid peak heat, stay hydrated, be very well aware of your medical condition and that of others around you. Plan and limit outdoor activities to the coolest hours of the day. Have a plan in case power were to be out for any period of time. Be aware of fire threats and report any activity quickly. Don't forget about your neighbors, pets, children and the elderly. This heat wave looks to last a while and many issues are cumulative as heat stress rises during such events.