It will be warmer through Saturday with moderate HeatRisk on Friday and Saturday for some coastal and western valley areas. There is also a slight chance of showers and thunderstorms for the mountains on Thursday afternoon. A low pressure system moving inland along the West Coast and mid and high clouds from tropical moisture to the south will bring cooling for Sunday and Monday. Then warmer under high pressure for next Tuesday.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, UPDATED AVIATION DISCUSSION,
(today through Friday), A weak upper level low pressure system off the coast of northern Baja will bring weak easterly winds to the mountains for this morning and again Thursday morning with gusts less than 25 mph. This will also bring some mid-level monsoonal moisture northward into the area for this afternoon and Thursday afternoon with the precipitable water values higher on Thursday. This will bring some clouds to the mountains for this afternoon and a less than 20 percent chance of showers and thunderstorms for the mountains for Thursday afternoon. The HRRR also shows some convective development along the Elsinore convergence zone in the Inland Empire on Thursday afternoon. This will be followed by some drying on Friday.
High temperatures today will warm as much as 5 to 10 degrees for the inland valleys with high temperatures as much as 4 to 8 degrees above average for the valleys and inland Orange County with high temperatures within a few degrees of average elsewhere. High temperatures for today will range from the mid 70s to lower 80s near the coast to the 90s for the Inland Empire with 100 to 104 for the lower deserts. Not much change is expected on Thursday.
On Friday, both high and low temperatures will warm slightly with moderate HeatRisk for the coastal areas and portions of the western valleys in San Diego County and in portions of inland Orange County.
The marine layer has decreased in depth to around 2500 feet. It will continue to slowly decrease in depth into Friday with night and morning coastal low clouds not spreading inland past the western valleys.
(Saturday through Tuesday), Friday night will be slightly warmer with not much change in high temperatures on Saturday. Moderate HeatRisk will continue on Saturday for the same areas as on Friday, coastal areas and portions of the western valleys in San Diego County and in portions of inland Orange County.
Mid and high clouds from tropical moisture and a low pressure system moving inland along the West Coast will spread cooling inland on Sunday and Monday. High temperatures on Sunday will cool a few degrees near the coast to as much as 4 to 8 degrees for the inland valleys with high temperatures cooling a few more degrees on Monday. With the cooling, high temperatures on Monday will be as much as 5 degrees below average for the mountains, inland valleys, and high desert. High temperatures on Monday will range from the 70s near the coast to the 80s for the Inland Empire with the lower deserts in the mid 90s. On Tuesday, high pressure over southern California will bring warming with decreasing mid and high clouds.
Any surf impacts to the coast of Orange and San Diego Counties from Hurricane Polo would most likely be after the weekend. The current track forecast through the weekend would most be outside of the the swell window the coast of Orange and San Diego Counties. There is greater spread in the track forecast beyond the weekend and any resulting potential swell and surf impacts along the coast for early next week.
231130z, Coast/Valleys, Areas of low clouds based around 1500 feet MSL this morning mainly in San Diego County. Any cigs to scatter out 16- 17Z. Low clouds based around 1500 feet MSL to gradually increase after 02Z this eve, becoming rather uniform after 10Z.
Otherwise, mostly clear skies with unrestricted vis today and tonight.
No hazardous marine conditions are expected through Sunday.
Ca, None. PZ, None.
