The long duration heatwave is past its halfway point, but extreme heat will persist through tomorrow for the coasts and valleys, and through Friday for the lower deserts. Cooling temperatures are expected for the weekend onward. A low pressure system will combine with tropical moisture, bringing showers Sunday into Tuesday, with the greatest chances of rain on Sunday into Monday.
For extreme southwestern California including Orange, San Diego, western Riverside and southwestern San Bernardino counties,
the cooling trend will continue into early next week, with high temperatures falling to as much as 10 to 15 degrees below average for the mountains, deserts, and inland valleys. High temperatures Monday through Wednesday will be mostly in the upper 60s to low 70s for the coast and valleys, with the lower deserts in the lower to mid 80s. This will make for temperatures 20-30 degrees cooler than observed just a few days earlier during the heatwave.
A low pressure system will absorb the moisture from what is left of former Hurricane Rachel, then move northeastward into extreme southern California and northern Baja. This will bring showers chances for Sunday through Tuesday with the greatest chances of rain Sunday into Monday. Rain totals for the whole event may as high as around 0.50 to 2.00 inches (highest in the mountains) for portions of the forecast area. There could be a few inches of snowfall on the very highest mountain peaks above 9000 feet for Monday night and Tuesday as snow levels may briefly fall as low as 8000 feet.
Onshore winds will strengthen for Sunday and Monday with southwest to west winds for Sunday afternoon through Monday morning gusting to 20 to 30 mph for the coastal waters to the valleys and to 35 to 45 mph for the mountains and deserts with gusts to 55 to 65 mph for the northern Coachella Valley below the San Gorgonio Pass. There is the potential for strong wind from the coastal waters to the deserts Sunday into Monday.
Please continue to monitor the forecast for the dynamic impacts due to remnants of Rachel.
(today through Saturday),
The long-duration heatwave will continue for the coast and valleys through Thursday, and through Friday for the lower deserts. Inland areas will warm a few degrees today, while the coast into the western San Diego County valleys cools a few degrees. There will be High to locally Extreme HeatRisk for the beaches and far inland valleys today, dropping to Moderate to locally Major HeatRisk tomorrow. There will be areas of Major to locally Extreme HeatRisk for the lower deserts today through Friday. High temperatures will range from the upper 70s to mid 80s near the coast to the 90s for the Inland Empire with 102 to 106 for the lower deserts for the duration of the heat. By Saturday, cooling will be very noticeable and only minor to locally moderate HeatRisk is expected.
Low clouds and locally dense fog over the coastal waters this evening will spread inland along the coast for late tonight into Thursday morning. Followed by a little farther inland spread of the low clouds into coastal areas for late Thursday night into Friday morning as the marine layer slowly deepens.
(Sunday through Wednesday),
KEY POINTS
1. Coastal flooding and beach erosion from high tides 6.5 to 7 ft and elevated surf at times is expected through next week.
2. Rain chances increase for Sunday through Tuesday across the area. Highest chances of rain are Sunday into Monday. We're monitoring the potential for flash and urban flooding.
3. There is a potential for increased winds from the coastal waters to the deserts Sunday into Monday
DISCUSSION
The cooling trend will continue into early next week, with high temperatures falling to as much as 10 to 15 degrees below average for the mountains, deserts, and inland valleys. High temperatures Monday through Wednesday will be mostly in the upper 60s to low 70s for the coast and valleys, with the lower deserts in the lower to mid 80s. This will make for temperatures 20-30 degrees cooler than observed just a few days earlier during the heatwave.
A low pressure system will absorb the moisture from what is left of former Hurricane Rachel, then move northeastward into extreme southern California and northern Baja. This will bring showers chances for Sunday through Tuesday with the greatest chances of rain Sunday into Monday. Rain totals for the whole event may as high as around 0.50 to 2.00 inches (highest in the mountains) for portions of the forecast area. There could be a few inches of snowfall on the very highest mountain peaks above 9000 feet for Monday night and Tuesday as snow levels may briefly fall as low as 8000 feet.
Onshore winds will strengthen for Sunday and Monday with southwest to west winds for Sunday afternoon through Monday morning gusting to 20 to 30 mph for the coastal waters to the valleys and to 35 to 45 mph for the mountains and deserts with gusts to 55 to 65 mph for the northern Coachella Valley below the San Gorgonio Pass. There is the potential for strong wind from the coastal waters to the deserts Sunday into Monday.
Please continue to monitor the forecast for the dynamic impacts due to remnants of Rachel.
071130z, Coast: Isolated and intermittent patches of low clouds and fog may occur from 03Z-10Z Thu. Any cigs would be around 200-600 feet MSL with vis possibly falling as low as 1SM. Greater coverage of low clouds and fog more likely after 10Z Thursday. Bases would be 200-600 feet MSL and vis likely 3-6SM.
Otherwise, clear skies except for cumulus based around 10 kft over mountains 19-01Z.
No hazardous marine conditions are expected through Saturday. Gusty winds and choppy seas are expected Sunday into early next week. Please stay tuned for more details in the coming days.
Increasing south swells due to current Hurricane Rachel will create surf of 3-5 feet with sets to 6 feet on south and southwest facing beaches through at least Friday. Additionally, elevated surf is expected to return for beaches from Sunday into early next week. Swimming conditions will be hazardous especially for inexperienced swimmers due to both the surf and rip current risk.
High tides and associated minor coastal flooding and beach erosion will continue into Tuesday, with Sunday being the main day to watch with the greatest impacts. Tides will be high during both the mornings and evenings through Friday, then Saturday onward the morning tides will be the highest. Please see the Beach Hazards Statement and Coastal Flood Advisory contain the details. Stay tuned for more details in the coming days.
Ca, Beach Hazards Statement through Friday evening for Orange County Coastal Areas-San Diego County Coastal Areas.
Coastal Flood Advisory until 2 PM PDT Tuesday for Orange County Coastal Areas-San Diego County Coastal Areas.
Extreme Heat Warning until 8 PM PDT Thursday for Orange County Coastal Areas-Orange County Inland Areas-San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Coastal Areas-San Diego County Valleys-Santa Ana Mountains and Foothills.
Extreme Heat Warning until 8 PM PDT Friday for Coachella Valley- San Diego County Deserts-San Gorgonio Pass near Banning.
PZ, None.
