Clear skies and dry weather prevails for much of the week, with increasing temperatures as high pressure builds. Moderate HeatRisk returns for the deserts as early as Monday, with highs likely peaking Wednesday/Thursday reigon-wide. A shallower marine layer will allow for coastal and marine fog and less inland spread through the end of the week.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
The marine layer burned off efficiently this morning, with clouds clearing all inland areas by 9:30AM. Mid-level water vapor imagery shows drier air funneling into Southern California and the deserts, with the moisture being shunted further north into Nevada and northern Arizona. Temperatures will be free to warm this afternoon under generally clear skies, and highs should be at or slightly above where they were on Saturday. The moisture will continue to be pushed out of the region as high pressure builds over the Four Corners on Monday, and moderate HeatRisk will return for the low deserts as high temperatures push to 110+. The warming trend will continue through the week as high pressure elongates into Southern California and the marine layer continues to become compressed each morning, allowing for more coastal fog and less inland spread. The thermal ridge axis will shift over CA by mid to late week, with temperatures likely peaking Thursday. Afternoon highs in the High Desert may be above 105F and low deserts potentially up to 115F, while mountains and inland valleys look to be in the 90s to low 100s if the upper level pattern stays on track.
Temperatures late week into next weekend should cool a bit with an approaching low off the coast of CA forcing the high back towards the Four Corner region, potentially even further north into Wyoming. Should this occur, the Great Basin would see very hot and dry temperatures while subtropical moisture will be allowed to move back up into Arizona and California, potentially kicking off some monsoon storms. Stay tuned.
051730z. Coast/Valleys, Low clouds have quickly cleared to the coast with just a few lingering along the OC coast. Low clouds are expected to redevelop after 02-04Z Monday, increasing in coverage and pushing 15 miles inland after 05-07Z in SD County and after 10Z for OC. Bases are expected to be around 800-1200ft MSL. Low clouds will begin retreating to the coast after 15Z Monday, clearing the area by 17-18Z.
Otherwise, Localized 3-5 SM in HZ/FU from fireworks smoke expected through 20Z, then unrestricted vis and decreasing cloud cover at/above 20,000 ft MSL through the end of the TAF period.
Gusts near 20 kts will be possible at times in the afternoons near San Clemente Island today through Wednesday. Otherwise, no hazardous marine conditions are expected through Thursday.
Ca, None. PZ, None.
