Ation DISCUSSION,
This morning, The marine layer is around 1500 ft deep with low clouds increasing in coverage over the coastal areas and western portions of the inland valleys. Due to the decreasing depth of the marine layer, low clouds are not expected to reach into the Inland Empire this morning. A large mass of mid and high clouds is moving over the region from the southwest. This is mostly moisture from the remnants of Post-Tropical Cyclone Douglas. There are convective elements embedded in the cloud mass but if any precipitation is produced, it's unlikely to reach the ground due to the deep and dry sub-cloud layer. The widespread cloud cover will inhibit heating today and high temperatures this afternoon could be lower than expected in the mountains and deserts.
By Monday, the upper level disturbance will have moved to the northeast into the Great Basin taking with it the elevated moisture and cloud cover. For Monday through the middle of next week, the warming trend will become more noticeable as the high pressure to our southeast expands westward into SoCal. The marine layer will become even shallower restricting the night and morning low clouds and fog mostly to the coastal areas. Wednesday and Thursday are likely to be the warmest days, with daytime high temperatures 5-10 degrees above normal in the inland valleys, mountains and deserts. Parts of the Inland Empire and the high desert could experience moderate HeatRisk Tue-Thu and the lower deserts could experience moderate to high HeatRsk.
As we approach the end of next week, Fair weather will continue but stronger onshore flow could spread the marine layer influence farther inland resulting in a slight lowering of temperatures west of the mountains along with more low cloud cover during the nights and mornings.
Fair and seasonal weather will continue for the coming week, with a gradual warming trend. The marine layer will gradually decrease in depth with night and morning low clouds not spreading as far inland nor lasting as long into the late mornings. Subtropical moisture will bring some high clouds this holiday weekend, but with seasonal temperatures.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, UPDATED AVIATION DISCUSSION,
This morning, The marine layer is around 1500 ft deep with low clouds increasing in coverage over the coastal areas and western portions of the inland valleys. Due to the decreasing depth of the marine layer, low clouds are not expected to reach into the Inland Empire this morning. A large mass of mid and high clouds is moving over the region from the southwest. This is mostly moisture from the remnants of Post-Tropical Cyclone Douglas. There are convective elements embedded in the cloud mass but if any precipitation is produced, it's unlikely to reach the ground due to the deep and dry sub-cloud layer. The widespread cloud cover will inhibit heating today and high temperatures this afternoon could be lower than expected in the mountains and deserts.
By Monday, the upper level disturbance will have moved to the northeast into the Great Basin taking with it the elevated moisture and cloud cover. For Monday through the middle of next week, the warming trend will become more noticeable as the high pressure to our southeast expands westward into SoCal. The marine layer will become even shallower restricting the night and morning low clouds and fog mostly to the coastal areas. Wednesday and Thursday are likely to be the warmest days, with daytime high temperatures 5-10 degrees above normal in the inland valleys, mountains and deserts. Parts of the Inland Empire and the high desert could experience moderate HeatRisk Tue-Thu and the lower deserts could experience moderate to high HeatRsk.
As we approach the end of next week, Fair weather will continue but stronger onshore flow could spread the marine layer influence farther inland resulting in a slight lowering of temperatures west of the mountains along with more low cloud cover during the nights and mornings.
040930z. Coast/Valleys, Patchy low clouds with bases 1000-1500 ft MSL continuing along the coast and locally up to 15-20 mi, with the greatest coverage in San Diego County. Low clouds clearing 14-17Z, then returning to the coast after 05/06Z with similar bases, spreading 15-20 mi inland by 12Z Sunday.
Otherwise, SCT-BKN high clouds at/above 20,000 ft MSL, thickening and lowering to 15,000 feet MSL later this morning. High clouds decreasing in coverage this evening. Local and brief 4-6 mi vis restrictions 04-07Z due to fireworks smoke this evening.
No hazardous marine conditions are expected through next Wednesday.
Ca, None. PZ, None.
