Ation Discussion,
This morning, the marine layer is about 3,000 ft deep and satellite imagery shows low clouds already as far inland as the coastal mtn slopes. Westerly winds are gusting 25-45 mph in portions of the deserts and desert mtn slopes. The strongest wind gust reported in the last hour is 59 mph at Whitewater (2500 ft) on the north side of the San Gorgonio Pass a few miles northwest of Palm Springs.
A large low pressure system moving into the Pacific Northwest will dominate our weather pattern through next week. It will bring stronger onshore flow resulting in gusty westerly winds in the deserts and on the desert mtn slopes along with well below average temperatures, and a deep marine layer. By Sunday, daytime high temperatures will be 7 to 9 degrees below average near the coast and low deserts, and 15 to 20 degrees below average in the valleys, mountains, and High Desert. As the marine layer deepens, there is also a potential for patchy drizzle west of the mountains Sunday morning.
The strong winds and low relative humidity will create periods of near critical to locally critical fire weather conditions in the deserts and on the desert slopes of the mountains. For more information on fire weather concerns, see the Fire Weather section below. Winds will become more widespread and peak in strength this afternoon and evening, with peak gusts 50 to 65 mph below the San Gorgonio Pass. Winds will weaken Sunday into next week.
Model guidance is in good agreement through the middle of next week with respect to the synoptic pattern. Even beyond Wednesday, it seems likely that SoCal will remain under the influence of a (weakening) trough of low pressure. Forecast details are more uncertain for later next week but it is more likely than not that we will remain cooler than normal with a significant marine layer presence each night and morning through the end of next week. The current solutions indicate that high temperatures next Saturday will be slightly to as much as 12 degrees below normal.
Windy on the desert mountain slopes and into the deserts, well below average temperatures across Southern California, and a deeper marine layer this weekend. Areas of drizzle are possible Sunday morning. Conditions will gradually warm through next week but daytime high temperatures will likely remain below seasonal averages for most of next week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
, Updated Aviation Discussion,
This morning, the marine layer is about 3,000 ft deep and satellite imagery shows low clouds already as far inland as the coastal mtn slopes. Westerly winds are gusting 25-45 mph in portions of the deserts and desert mtn slopes. The strongest wind gust reported in the last hour is 59 mph at Whitewater (2500 ft) on the north side of the San Gorgonio Pass a few miles northwest of Palm Springs.
A large low pressure system moving into the Pacific Northwest will dominate our weather pattern through next week. It will bring stronger onshore flow resulting in gusty westerly winds in the deserts and on the desert mtn slopes along with well below average temperatures, and a deep marine layer. By Sunday, daytime high temperatures will be 7 to 9 degrees below average near the coast and low deserts, and 15 to 20 degrees below average in the valleys, mountains, and High Desert. As the marine layer deepens, there is also a potential for patchy drizzle west of the mountains Sunday morning.
The strong winds and low relative humidity will create periods of near critical to locally critical fire weather conditions in the deserts and on the desert slopes of the mountains. For more information on fire weather concerns, see the Fire Weather section below. Winds will become more widespread and peak in strength this afternoon and evening, with peak gusts 50 to 65 mph below the San Gorgonio Pass. Winds will weaken Sunday into next week.
Model guidance is in good agreement through the middle of next week with respect to the synoptic pattern. Even beyond Wednesday, it seems likely that SoCal will remain under the influence of a (weakening) trough of low pressure. Forecast details are more uncertain for later next week but it is more likely than not that we will remain cooler than normal with a significant marine layer presence each night and morning through the end of next week. The current solutions indicate that high temperatures next Saturday will be slightly to as much as 12 degrees below normal.
270900z, Coast/Valleys, Low clouds based 2000-2500 ft MSL have expanded to the valley foothills and are filling into the Inland Empire. Patchy vis reductions (3-6SM) for highest inland valleys (Hemet, Ramona, ) and foothills. Model guidance suggests a 60% chance that clouds in SD Co. begin scattering out from inland to the coast very early - starting around 11z and being mostly scattered out by 15z. Clouds scatter out elsewhere in the coastal basin 14- 18z. Low clouds begin redeveloping along the SD County coast after 00z Sun with bases 2-3 kft MSL, expanding into the rest of the coastal basin 03-08z. VIS reductions mainly along foothills.
Mountains/Deserts, Reduced vis and fog where clouds meet terrain along mountain foothills up to 5 kft MSL tonight and Saturday night. Otherwise, mostly clear and VFR conditions for higher mountains, desert slopes and lower deserts through early Sunday.
Locally strong westerly wind gusts 20-35 kts (up to 50 kts through the Banning Pass) persist along desert slopes. West winds increase once again after 21z Sat. Top gusts peak Saturday evening and night, reaching 35-55 kts along desert slopes and up to 65 kts through the Banning Pass. MOD up/downdrafts in lee of mountains.
Breezy NW winds gusting over 20 kts this afternoon and evening near San Clemente Island may create hazardous conditions to small craft. Otherwise, no additional hazardous marine conditions are expected through Thursday.
Ca, Wind Advisory until 5 AM PDT Sunday for Apple and Lucerne Valleys.
Wind Advisory until 11 AM PDT Sunday for San Diego County Deserts.
Wind Advisory until 5 PM PDT Sunday for San Gorgonio Pass near Banning.
PZ, None.
