After a cold morning Saturday, temperatures trend upwards each day over the weekend through Monday. Fair, dry, and warm weather likely persists through next week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
Today through tomorrow night,
High pressure continues to build in across the region, which is allowing for continued clearing and weak offshore winds to become persistent throughout the night. This will keep any low clouds from forming at least through tomorrow night, with only a less than 20 percent chance of low clouds penetrating the coastal areas through then. It will also become quite cold for a lot of inner valleys, with some temperatures dropping down near the freezing mark within the IE. Due to this, there could be some areas of patchy frost, especially within the win-protected areas. There could also be some patchy fog/freezing fog developing, as there already is being reported at the Ramona airport (KRNM). There could also be some areas of fog developing along the I-15 corridor. Tomorrow will be notably warmer, but still on the cooler side. There will be a slightly better chance for low clouds to return to the coastal areas tomorrow night, although confidence is still low.
Monday through Friday,
The ridge is going to continue to strengthen over the inner western states and prevent any systems from moving over the region as these systems are deflected to the north of the region. Temperatures will continue to gradually through the mid part of the week, with only slight cooling as a trough passes to the north on Tuesday. By Thursday through Friday, ensembles have continued to trend drier in recent days, and the axis of the ridge has continued to strengthen. Both Thursday and Friday will be quite warm, and there could even be come locations flirting with the daily record for either day. Looking a little beyond the forecast, it does appear that the ridge should begin to break down by the following weekend, and should allow some relief with temperatures returning to values closer to the seasonal average for this time of year.
210930z, Mostly VFR conditions will prevail through the TAF period. Patchy radiation FG/FZFG and BR in wind-sheltered valleys (i.e. KRNM, KL18) to reduce vis below 1SM at times through 16z. Modest east winds gusting up to 35 kts over the west-facing coastal slopes and west of the Banning Pass 14-22z this morning and afternoon. SCT- BKN high clouds around 25kft after 00Z Sun.
No marine hazards are expected through Thursday morning.
Ca, None. PZ, None.
