textproduct: San Diego

SYNOPSIS

Strengthening high pressure aloft will bring a warming trend with a long-duration heat wave likely for this weekend through much of next week into the following weekend. The highest HeatRisk is expected for the coast and valleys with widespread Moderate or greater HeatRisk for the coast and valleys for Friday through next week with widespread Major to Extreme HeatRisk for the weekend into next week for inland coastal areas into the western valleys.

SHORT TERM (Today through Friday)

High pressure aloft will strengthen across California through Friday with 500 mb heights rising to near or slightly above the 90th percentile. This will bring a warming trend into the weekend with warming for today ranging from a few degrees near the coast to around 10 degrees for the mountains. The warming for Thursday and Friday will be mainly for the coast and valleys.

High temperatures for today will be mostly a few to around 5 degrees above average, ranging from the mid to upper 70s near the coast to the upper 80s to mid 90s for the Inland Empire with the lower deserts in the upper 90s. On Friday, high temperatures for the coast and valleys will be 10 to 15 degrees above average to locally 15 to 20 degrees above average for portions of the western valleys in San Diego County. High temperatures on Friday will range from the 80s near the coast to the upper 90s to 105 for the Inland Empire with the lower deserts around 100. This will result in Moderate to Major HeatRisk for the coast and valleys on Friday.

There could also be weak easterly offshore winds on Friday with gusts to 20 to 30 mph along the coastal slopes of the mountains into the adjacent inland valleys in Riverside and San Diego Counties. Areas of late night and early morning low clouds for coastal areas will become much patchier by the weekend.

LONG TERM (Saturday through Tuesday)

A weak trough of low pressure moving inland into northern and central California on Sunday and Monday could bring slight cooling for coastal areas for Sunday through Tuesday followed by weaker onshore flow near the coast returning by Wednesday.

ECMWF ensemble output for Campo is strongest with the offshore winds on Saturday with uncalibrated gusts to around 40 mph. High temperatures on Saturday could be another 5 or so degrees warmer for coastal areas into the western valleys with high temperatures ranging from around 90 near the coast to the upper 90s to 108 for the valleys with the lower deserts around 100. Low temperatures on Saturday will be mostly in the lower 70s for coastal areas, around 10 degrees above average. Widespread Major HeatRisk is expected for the coast and valleys on Saturday.

For Sunday through Tuesday, low temperatures for the coast into the western valleys will warm into the lower to mid 70s, 10 to 15 degrees above average. Moderate HeatRisk will continue for the far inland valleys with Major to Extreme HeatRisk for inland coastal areas into the western valleys.

This long-dursation heat wave, with highest HeatRisk for the coast and valleys, may continue through much of next week into the following weekend.

AVIATION

301130Z...Coast/western valleys: Low clouds based at around 1000- 1200 feet MSL will continue this morning, most uniform in San Diego County, more patchy in Orange County. Scatter out should occur by 16- 18Z. Low clouds based around 1000 feet MSL to move ashore 03-08Z this eve and locally into western valleys by sunrise Thursday.

Otherwise...clear skies today and tonight.

MARINE

No hazardous marine conditions are expected through Sunday.

BEACHES

High tides will peak at 6.8-7.1 feet between 11 AM and 1 PM today, leading to minor coastal flooding in low-lying areas and coastal erosion. A Coastal Flood Advisory is in effect through this afternoon.

Please note: mentioned tide predictions in the Advisory have been adjusted to reflect actual measured tide observations.

SKYWARN

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

SGX WATCHES/WARNINGS/ADVISORIES

CA...Coastal Flood Advisory until 5 PM PDT this afternoon for Orange County Coastal Areas-San Diego County Coastal Areas.

Extreme Heat Watch from Friday morning through Wednesday evening 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.

PZ...None.