There are some very minor changes to the forecast, and nothing unforeseen. The first changes are to the advisory situation. The excessive warning was extended into Wednesday for the interior where temps near 110 are possible in the forecast.
This was expected based on modeling and analysis. While that same modeling shows lingering heat, it is possible we avoid 115 in the interior. The last few days we were forecast 115 in the Paso Robles area over the weekend, but it looks like temps should stay a few degrees below that.
Elsewhere, the change that most folks will want to know about is the conversion of the excessive heat watch to a heat advisory. This is a lower level of an advisory so extreme temps are less likely but weather hot enough to plan for is likely. Additionally, the heat advisory area does NOT include beaches. The watch that was retired did show that possibility, however, it appears that a minor change in the intensity of the overall heat wave should keep beaches under advisory numbers for heat (in fact it is looking rather inviting). I should mention the beaches are always filled for this holiday weekend and folks should plan for even larger crowds based on this weather outlook.
The modeling for the heat wave has been very consistent however the devil is truly in the details. There is a wave moving thru the upper air on Friday. I had been saying this should drop temps Friday but now I think that wave acts to just stop warming rather than initialize cooling. This is still a dangerous potential situation for the weekend with 110 on the table inland. There will be a huge chunk of the day where precautions will need to be taken in the warmest locations to avoid heat stress.
After the Friday minor disturbance to the jet, ridging rebuilds for the weekend into next week. It appears that 100+ is likely in the interior into Thursday with more significant cooling Friday into the following weekend.
Another key factor in this forecast is the temps in the coastal valleys for the weekend: 80s and 90s. I think we likely avoid 100 degrees in these places with just enough marine presence and afternoon onshore flow to control the situation. That said, SLO will be very close to 100 on Saturday with Santa Maria and Santa Barbara closer to 90. This is why these locations are in the heat watch, that's definitely warm enough in places where most folks don't have air conditioning. Again, plan ahead.
Like the interior, a slow fade takes place on temps next week with near average temps holding off until Thursday or Friday.
Beaches warm from the 60s and low 70s Friday to the 70s and low 80s Saturday-Monday. Near-average temps recover by Tuesday or Wednesday we should be back in the lower 70s and ultimately the 60s by late next week.
Please have a weather app downloaded with notifications on for any critical information during the heat wave. Be mindful of the environment around you, monitor children, the elderly, and pets, and use common sense by avoiding peak heat and drinking plenty of liquids.
Today is the day we look at drought and lakes. The drought status actually got slightly better, but very minor changes statewide in the 3 worst categories of drought. Locally no changes at all. 100% of California remains in drought. The rate of water drop at lakes has increased week to week.