A huge ridge of high pressure has developed and over the next few days will fuel hot weather not only in the interior valleys but in the coastal valleys as well. Coastal valleys will already see temperatures in the mid 80s to mid 90s Saturday and in the mid 90s to 100 on Sunday, very slight if any temperature reduction Monday.
Inland high temperatures will crack 100 on Friday and 110-116 degree temperatures are likely over the weekend perhaps backing off to the 100-105 degree range Monday.
This forecast has prompted excessive heat advisories Saturday and Sunday for the coastal areas and Friday thru Monday inland.
The record highs at the Paso Robles Airport are Saturday 109 degrees set in 1988, Sunday 107 set in 2008 and Monday 108 all the way back in 1957. I think we'll be close to the record Saturday, Sunday looks like we'll top the daily record and perhaps threaten the all-time high.
The all-time high in Paso Robles is 115 degrees set back on July 20, 1960 and again on September 2, 2017.
The ridge should weaken Monday but more significantly Tuesday with onshore winds resuming. While breezy Monday and Tuesday the winds likely slacken mid-week to help the marine layer re-develop.