Still very warm conditions are in place with a subtle cooldown through the middle of the week. Monsoonal moisture is expected to increase by the middle and end of the week, but chances for rainfall remain small. Temperatures will continue to be near to slightly above average as well.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, UPDATED AVIATION DISCUSSION,
High pressure has began to weaken across the Desert Southwest. This will begin to bring subtle increases in cooling and onshore flow over the next few days. Temperatures will not be as hot for areas west of the mountains this afternoon, though the desert regions will be similar to yesterday. Onshore winds will slightly stronger across the mountain desert slopes and adjacent deserts later this afternoon and evening nearing 25-40 MPH. These winds will occur again on Monday. The marine layer will remain thinner, with patchy clouds and fog closer to the coast each morning.
A few degrees of cooling can be expected into the middle of the week as subtle changes in high's movement occur. Temperatures will still remain on the warmer side with highs slightly above normal for inland valleys, mountains, and deserts with areas of moderate heat risk. Models indicate an increase in monsoonal moisture moving into the area during this time period as well with the largest increase expected on Wednesday, so we can expect more humid conditions by this time onward. Cumulus clouds are likely to form over the mountains each afternoon starting Wednesday through later in the week. Chances for rainfall still look minimal near 20% or less each day over the higher terrain. Other areas look to see highs near to slightly above normal with dry weather.
010000z. Coasts/Valleys, Low clouds based 800-1200 ft MSL have started to develop along the immediate SD coastline; expect clouds to move into coastal regions after 03Z, increasing in coverage and moving in to 15-20 miles inland through 13Z. Vis 2-5 SM for higher coastal terrain. Low clouds will begin to clear from inland areas 15- 16Z Monday then from the coast 16-17Z. Similar based clouds will develop and move inland again after 02-03Z Mon.
.Mountains/Deserts, VFR conditions expected through the TAF period with predominantly clear skies.
No hazardous marine conditions are expected through Wednesday.
Ca, Heat Advisory until 8 PM PDT this evening for Orange County Coastal Areas-San Diego County Coastal Areas.
Extreme Heat Warning until 8 PM PDT Monday for Coachella Valley- Riverside County Mountains-San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Deserts- San Diego County Mountains-San Gorgonio Pass near Banning.
Extreme Heat Warning until 8 PM PDT this evening for Apple and Lucerne Valleys-Orange County Inland Areas-San Diego County Valleys-Santa Ana Mountains and Foothills.
Heat Advisory until 8 PM PDT Monday for San Bernardino County Mountains.
PZ, None.
