textproduct: San Diego

SYNOPSIS

There will be cooling and drying for inland areas for early this week with high temperatures cooling to around 5 degrees below average for inland areas on Wednesday. Southwest to west winds for the mountains and deserts during the afternoons and evenings will gust to 25 to 35 mph through mid week. For next weekend, there could be some influx of monsoonal and possibly tropical moisture from an area of disturbed weather well to the south of southern Mexico that may develop this week and track towards the northwest.

..UPDATED AVIATION DISCUSSION

Today through Wednesday...

Current satellite and 500mb analysis reveals the upper ridge remains in control across the southeastern US with weak southwesterly flow aloft across southern California. The further displacement of the upper ridge allows for the continuation of the cooling trend observed through the last few days. High temperatures this afternoon are expected to be about 3-5 degrees cooler compared to yesterday. This has high temperatures running around average to 5 degrees below climatological averages - a much welcome change from the heat seen last week. Dewpoints and humidity remain high for the coastal areas, keeping overnight temperatures on the mild side while portions of the inland valleys will be allowed to fall into upper 50s.

Moving into Tuesday, an embedded shortwave trough within a much larger upper trough across the northeast Pacific is progged to eject into central California. This will bring around 40 kts of southwest flow at 500mb for Tuesday-Wednesday, leading to breezy conditions in the mountains and adjacent deserts each afternoon. West to southwest winds generally 25-35 mph for the mountains and deserts, locally up to 45-50 mph within major mountain passes. While this is largely sub- advisory or headline levels, the main concern will be elevated to near-critical fire weather conditions in the mountains and deserts where afternoon humidity is expected to fall into the 20-25% range for the mountains and near 15% in the deserts. Temperatures will remain on the cool side through midweek, with highs a degree or two cooler than today.

Thursday into early next week...

Following the shortwave passing through Tuesday/Wednesday, southwesterly flow aloft stays in place as the large-scale trough remains in place across the western US. This will likely keep the below normal temperatures and breezy onshore wind in place through the end of the week. However, the evolution of this large upper trough and embedded shortwaves will play a pivotal role in the steering flow of a potential tropical cyclone. This potential storm is currently only Invest 95E as a cluster of disorganized thunderstorms off the far southern Mexican coast. There remains a significant amount of uncertainty in the expected evolution of this system, especially as a storm has yet to officially develop. The current spread of the grand ensemble favors 2 main clusters, one with a more westward track out to sea, and the other as a more northward track which could bring any remnants towards southern California. Latest ensembles are favoring more of the westward track, with only a ~5% chance of more direct/significant impacts to the region. Despite this uncertainty and the potential track of this storm, chances of precipitation increase as early as Saturday evening with the potential for an influx of tropical moisture aloft. Even still, plenty of cards need to fall in the right way for this to occur, so stay tuned over the next few days as the forecast becomes more refined and details become more clear.

Mountains/Deserts

Mostly clear skies today and tonight. Breezy westerly winds mainly through mountain passes and desert slopes through 07Z this evening. Gusts 25-40 kts with pockets of moderate up/downdrafts over and in lee of ridges.

MARINE

No hazardous marine conditions are expected through Friday, except for gusts around 20 knots expected each afternoon through Thursday in the vicinity of San Clemente Island.

BEACHES

A southerly swell from Hurricane Karina will maintain elevated surf on south and southwest facing beaches with sets up to 6 feet today and 5 feet Tuesday. Swells from tropical cyclones will continue to arrive much of this week.

SGX WATCHES/WARNINGS/ADVISORIES

CA...None. PZ...None.