Quiet weather with slightly below normal temperatures through Wednesday and a lackluster marine layer. Warmer and drier weather returns late week, with well-above-normal temperatures and Santa Ana winds for the weekend.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
The deep trough responsible for our rainy and cold Halloween weekend has moved into the Great Basin, evident on mid-level water vapor satellite imagery. On the back side, a thermal ridge axis sets up over California as temperatures warm today around 5-10 degrees over Sunday with clear skies. This upper level ridge is somewhat compressed, situated between the aforementioned trough over the Great Basin and a deepening low off the coast of Oregon. This ridge will likely be pushed out before it can be too helpful, with the Oregon low moving into Northern California by Tuesday night. Despite the significant warm up today, temperatures will hold steady with a lackluster marine layer into Wednesday given the quick changes in the upper level pattern.
Gusty onshore winds accompany the Oregon low on Tuesday as the gradient tightens over SoCal. Winds will pick up over the coastal waters as early as late morning on Tuesday, with inland spread through the afternoon. Gusts will reach up to 25-30 mph over the waters and as high as 20 mph for coastal and valley areas. Winds will decrease a bit as the low moves inland, likely calming by sunrise Wednesday morning. Some models continue to support light rainfall Wednesday morning for far southern San Diego County as this trough moves across, but chances only sit around 15-25% at this point. Still, it wouldn't be surprising if some light wetting rain was observed early Wednesday morning, primarily for SD County south of the 56.
As previously mentioned, temperatures won't be impacted much by the low as it swings across, likely out of California by peak heating Wednesday afternoon. As the low moves off, a positively tilted ridge will move ashore, bringing subsidence for Thursday/Friday as areas west of the mountains finally warm back above normal. Late week into early weekend, another significant pattern change will affect much of the western United States, with a very large ridge stretching from northern Canada down into the Desert Southwest. As high pressure moves over the Four Corners Saturday, offshore winds will increase for most of California, bringing about well- above-normal temperatures for areas west of the mountains. These dry, downsloping winds will push temperatures to the 80s for even coastal communities, around 10-15 degrees above normal, and minor to moderate HeaRisk will return for the western portions of the area. Current forecast indicates that by Saturday, temperatures near the coast may be even hotter than the Coachella Valley. Humidity will plummet, potentially as low as 15% for Saturday and Sunday afternoons. While there is still some disagreement in the placement of the ridge for the weekend, which will drastically influence the Santa Ana wind strength, most models remain in favor of the significant warming and stronger easterly winds this weekend. Should this pan out, it will be quite the contrast to the past gloomy Halloween weekend.
011830, VFR conditions expected through the period with increasing clouds AOA 20kft this afternoon and evening. Weakly offshore winds will very likely keep any low clouds offshore into Tue AM.
Weak winds expected through Tuesday morning, followed by more elevated onshore winds Tuesday afternoon and evening, with gusts in the outer coastal waters potentially exceeding 20 knots.
Southwesterly swell (3 ft at 15 seconds from 200 degrees) will bring elevated surf through today, with breaking wave heights 3 to 6 feet. Surf combined with a high tide near 6 ft will continue the potential for minor tidal overflow during today's high tide around 3:30 PM.
Tides are expected to increase for the end of the week, with tides reaching 7 ft as early as Thursday in Orange County and Friday in San Diego County. Tides will peak over the weekend into early next week at 7.5-7.7 ft. Minor coastal flooding is possible. We're monitoring the potential for an incoming west swell of 3 ft from 290 with a 14-16 second period. If this swell materializes, max surf of 6 to 7 feet are possible, which would increase the flood potential on west facing beaches.
Reminder, tides mentioned have been corrected to reflect the current trends in actual tide observations.
Ca, Beach Hazards Statement until 6 PM PST this evening for Orange County Coastal Areas-San Diego County Coastal Areas.
PZ, None.
