textproduct: San Diego

SYNOPSIS

Warmer weather moves into the region through Saturday with low clouds and patchy fog closer to the coast each morning. Tropical mid and high level moisture will bring more clouds and cooler temperature, along with a slight chance of showers for much of our area by Sunday and Monday. Weak high pressure moves into the area by next Tuesday, bringing warming and drying.

..UPDATED AVIATION DISCUSSION

Low clouds are still struggling to form early this morning over the coastal waters. The marine layer will remain thin over the next couple of days, bringing low clouds and patchy fog to areas within around 10 miles of the coast each late night and morning. One of the reasons for this will be high pressure aloft over Mexico beginning to expand further into our region during this time, bringing slightly warmer weather. With highs in the 90s for the lower deserts yesterday, there is a very high chance (85+ %) to see highs eclipse 100 degrees today and Saturday. Valleys west of the mountains will see the largest warm up of around 5 degrees with highs in the 90s from Escondido to Temecula to Ontario.

Model trends beginning to come together on a deep trough dropping in from the north by Sunday and becoming a closed low by Monday. As it does so, Hurricane Polo moves north on Sunday and northeastward on Monday, where it is expected to make landfall somewhere in southern Baja California later on Monday. The troughing pattern will act as a mechanism to help pull in some of this tropical moisture, mainly in the form of clouds and humidity.

The key will be where exactly our low pressure system sets up. Models continue to push the system slightly further to the south, which would not entrain as much moisture. Two things look more certain however: increased humidity (though high temperatures will not be as hot as today and Saturday), and increased swell and coastal flooding/erosion. Warmer nights can be expected near the coast with some places staying above 70 degrees. Monday will be the coolest day overall with highs in the 70s and 80s from the coastal to the foothills as well as the high desert. NBM gives Palm Springs only a 50-50 chance to reach over 90 degrees on Monday as well.

Though moisture increases are seen with PWAT values exceeding one inch, the low's track will be important on determining any accumulating rainfall for area. Moisture in the form of high clouds may spread over SoCal during this time, but lack of forcing mechanisms may only provide us cloudier, humid days. These clouds may also inhibit max temperatures as well.

The area of low pressure should begin to move out of the region by Tuesday. Depending on its location, offshore flow may accompany this exit. The strength is still uncertain as well as how hot we become by Tuesday and Wednesday. This is seen in quite the large spread in temperature guidance. Take the Miramar Base in San Diego: near a 15 degree spread in high temperatures from 25th-75th percentiles with highs in the upper 70s to lower 90s. With these factors, confidence is high that there will be less humidity and warmer temperatures, just not sure how warm. Weak high pressure looks to stick around into at least the middle of next week, keeping temperatures slightly above normal west of the mountains and closer to normal for the mountains and deserts.

AVIATION

251130Z...Coast/Valleys...Low clouds based around 700-1000 feet MSL will reach into far western valleys this morning. Local vis reduced 3-5SM on mesas or inland. Scatter out 16-18Z. Patchy low clouds to redevelop after 05Z, based at around 600-900 feet MSL, but will continue rather patchy and intermittent mainly in coastal areas through 10Z Saturday.

Mountains/Deserts...Clear skies this morning. Cumulus and isolated CBs to develop over mountains and lead to isolated SHRA/TSRA 20-00Z.

Regionwide...Increasing SCT-BKN clouds around 20 kft after 00Z.

MARINE

No hazardous marine conditions are expected through Tuesday.

BEACHES

Southwesterly swell (3-4 ft at 13 seconds from ~210 degrees) from Hurricane Odalys increases today, bringing surf up to 2-4 feet with sets up to 5 feet to most beaches. This swell from Odalys is expected to persist into this weekend. Given tides are already observed over 6 feet and are expected to gradually increase into this weekend, a Beach Hazard Statement is in effect through Sunday evening. Minor tidal overflow and minor coastal erosion are the primary impacts during this period.

The swell from Hurricane Polo (3-4 ft at 14 seconds from ~170 degrees) increases on Monday. Given this direction, most of San Diego County beaches will be largely sheltered from this swell, but Orange County beaches especially in north county should be impacted. Meanwhile, a northwesterly swell (3-4 ft at 8 seconds from ~290 degrees) arrives late Sunday and Monday. Between these two swells, surf of 3-5 feet with sets to 6 feet look probable especially along south or southwest facing beaches. Tides peak Monday-Wednesday mornings near 7.0 ft. Higher tides and elevated surf will combine to generate a risk for minor-moderate coastal flooding during the late morning/early afternoon high tides. Stay tuned as details continue to become more clear in the coming days.

Please note - listed tide predictions 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...Beach Hazards Statement through Sunday afternoon for Orange County Coastal Areas-San Diego County Coastal Areas.

PZ...None.