textproduct: San Diego

SYNOPSIS

High pressure aloft will strengthen into the weekend with high temperatures for inland areas around 10 degrees above average through Saturday. Nights will be quite warm with low temperatures for the deserts as much as 10 to 15 degrees above average. Gradual drying and slight cooling for the early and middle of next week with high temperatures for the middle of next week still around 5 degrees above average for inland areas. There is some model guidance that has a brief surge of moisture into the area on Sunday which would result in more clouds, high temperatures not as high for some inland areas, and a slight chance of afternoon thunderstorms for the mountains.

SHORT TERM (Today through Saturday)

High pressure aloft to the east will expand and strengthen across southern California into the weekend. High temperatures for today will warm a few degrees near the coast to as much as 10 to 15 degrees for the inland valleys onto the lower coastal slopes of the mountains with not much change for Friday and Saturday.

High temperatures for today will be around 5 degrees above average near the coast and around 8 to 12 degrees above average for inland areas. High temperatures for today will range from around 80 near the coast to the upper 90s to 110 for the Inland Empire with 114 to 118 for the lower deserts.

Low temperatures will be quite warm as well for tonight, Friday night, and Saturday night with low temperatures for the coast and valleys mostly in the upper 60s to mid 70s, mostly in the 90s for the lower deserts, and in the mid 70s to mid 80s for the Apple and Lucerne Valleys. That is around 5 degrees above average for coastal areas, 5 to 10 degrees above average for the inland valleys, and 10 to 15 degrees above average for the deserts.

HeatRisk is expected to peak on Friday and Saturday with widespread extreme HeatRisk for the lower deserts, major to extreme Heat Risk for the Inland Empire, the Apple and Lucerne Valleys, and for the San Diego County mountains. Most areas will have moderate or greater HeatRisk except at the beaches and for mountain elevations above around 8000 feet.

While high temperatures will remain mostly below record levels, there could be a large number of daily records tied or broken for warmest low temperature for Friday, Saturday, and Sunday.

The marine layer will remain around 1200 to 1500 feet deep with night and morning coastal low clouds spreading no farther inland than the far western valleys.

LONG TERM (Sunday through Wednesday)

There are meaningful model differences in the southern extent of stronger high pressure on Sunday over the southwest states into northern Mexico and the resulting differences in the amount of moisture that may spread into portions of southern California. Those model solutions that maintain stronger high pressure farther into northern Mexico have less moisture transport into southern California while those that are weaker with high pressure across northern Mexico allow for a greater transport of moisture and clouds into portions of southern California on Sunday.

The current forecast shows less cooling of high temperatures and less increase in clouds and chances for afternoon thunderstorms over the mountains for Sunday with continued slow cooling into Monday. Beyond the moisture surge and resulting cooling of high temperatures that could occur on Sunday, gradual cooling and drying will continue into the middle of next week, but with high temperatures still around 5 degrees above average for inland areas. High temperatures for next Wednesday would range from the mid 70s to around 80 near the coast to the 90s to 102 for the Inland Empire with 108 to 112 for the lower deserts.

High pressure for the end of next week could be even stronger than for the end of this week.

AVIATION

230945Z....Coast/Valleys...Low clouds based near 700-1100 ft MSL across San Diego County may locally reach areas of Orange County after 11z. Patchy vis reductions 4-6SM (locally 0-3SM) over elevated coastal terrain and valleys along the I-15 corridor clearing mid morning. VCTY KSNA may see brief cigs near 1000 ft MSL 12-15z before clearing.

Clouds scatter out 15-17z. Cigs developing late again after 07z Fri across San Diego County, with increasing confidence of mostly clear conditions across much of Orange County. Cigs slightly higher near 1000 ft MSL.

Mountains/Deserts...Mostly clear through the morning. Areas of flatter cumulus over mountain peaks after 20z Thu. Otherwise, VFR conditions prevail through the TAF period.

MARINE

Northwesterly winds with gusts 20-25 kts in the outer waters near San Clemente Island to continue this afternoon and evening. Additionally, a mixed swell will cause steep and choppy seas 6 to 7 feet on Thursday and Friday in the outer waters.

BEACHES

A 3 to 4 feet south swell from 190 degrees with 13 second period will bring surf of 5 to 7 feet to area beaches Thursday through Sunday. Highest surf will be on south-southwest facing beaches. In addition to elevated surf, tides are expected to increase starting Friday peaking at 5.5 to 6.5 feet MLLW by early next week. The combination of surf and tides will result in minor coastal flooding during high tides.

SKYWARN

Skywarn activation is not requested. However weather spotters are encouraged to report significant weather conditions.

SGX WATCHES/WARNINGS/ADVISORIES

CA...Beach Hazards Statement through Sunday evening for Orange County Coastal Areas-San Diego County Coastal Areas.

Heat Advisory from 10 AM this morning to 8 PM PDT Monday for Orange County Coastal Areas-San Diego County Coastal Areas.

Extreme Heat Warning until 8 PM PDT Monday for Coachella Valley- San Bernardino and Riverside County Valleys-The Inland Empire-San Diego County Deserts-San Diego County Mountains- San Gorgonio Pass near Banning.

Heat Advisory until 8 PM PDT Monday for Orange County Inland Areas-Riverside County Mountains-San Bernardino County Mountains-San Diego County Valleys-Santa Ana Mountains and Foothills.

Extreme Heat Warning from 10 AM this morning to 8 PM PDT Monday for Apple and Lucerne Valleys.

PZ...Small Craft Advisory until 9 PM PDT this evening for Waters from San Mateo Point to the Mexican Border Extending 10 to 60 nm out including San Clemente Island.