textproduct: San Diego

SYNOPSIS

Near seasonal temperatures through the first half of the week with an increase in both high and low temperatures for the middle to end of the week. An isolated shower or two may develop over the highest mountain peaks this afternoon and Monday afternoon, no impacts expected. Drier conditions expected Tuesday and Wednesday, with increased chances for afternoon/evening showers and thunderstorms over the mountains Thursday and Friday. Through the week the marine layer will remain mostly confined to the coast, reaching into portions of the valleys at times.

..UPDATED AVIATION DISCUSSION FOR 00Z TAF ISSUANCE

Highs today will be within a few degrees of Saturday, maintaining conditions that are within 3 degrees of normal for inland areas, and up to 7 degrees above average for the coast. The atmosphere is quite stable this morning based on the 12Z KNKX sounding. An isolated slight chance of showers has been maintained over the San Bernardino mountains this afternoon and Monday afternoon, but no thunderstorm development is expected. The forecast has trended drier for Tuesday and Wednesday so slight chances have been removed from the forecast.

The first half of the week will see minor day to day changes in temperatures with highs remaining near to slightly above normal. For the latter half of the week, the upper level high is forecast to shift south towards Oklahoma/Texas Wednesday/Thursday, then will slowly shift westward into next weekend. The forecast position of the ridge indicates at least a modest warming for the latter half of the week. Thursday is currently forecast to be the warmest day with high temperatures 5 to 10 degrees above average. Widespread moderate HeatRisk is expected west of the mountains with areas of major HeatRisk in the deserts, mainly due to elevated low temperatures. Limited overnight cooling will exacerbate impacts from the heat, especially for vulnerable populations and those without air conditioning. Similar levels of HeatRisk are expected to be maintained through the upcoming weekend.

The position of the upper level ridge looks most favorable to support an increase in precipitation for Thursday and Friday. Current forecast follows the NBM which has increased chances of precipitation Thursday and Friday afternoons (20 to 40 percent chance). NBM is supported by global ensemble guidance showing modest increases in precipitable water and instability. A limiting factor is the position of the upper level ridge's axis. If the axis ends up directly over us, that would limit our shower/thunderstorm chances.

AVIATION

200000Z....Coast/Valleys...FEW low clouds along the beaches at this hour with bases around 1500 ft MSL. Low clouds expected to begin increasing in coverage and spreading inland around 03Z Mon extending 5-10 miles inland by 15Z Mon. Bases will likely be 1000-1400 ft MSL with CIG impacts at KSAN and KCRQ between 04Z and 17Z Mon. CIGs will likely arrive around 06Z at KSNA. Patchy fog with VIS around 3 miles on elevated coastal terrain during this period. Expect clearing to the coast 15Z-17z Mon.

Mountains/Deserts...VFR conditions expected through the period with FEW-SCT clouds generally AOA 15,000ft MSL. FEW-SCT clouds based 10- 12 kft MSL likely to clear by 03Z Mon. West winds gusting 20-35 kts along desert slopes and up to 45 kts through the Banning Pass expected from 00Z-09z Mon.

MARINE

Wednesday afternoon, there is around a 50% chance for northwesterly wind gusts to exceed 20 kts in the outer waters near San Clemente Island. Otherwise, no hazardous marine conditions are expected through Thursday morning.

BEACHES

Southerly swell of 4-5 ft with a period of 11-13 seconds will likely bring elevated to high surf and strong rip and longshore currents through Tuesday. Surf generally 5-7 feet with sets to 8 feet is expected through Tuesday, with the highest surf focused on south and southwest facing beaches of Orange County. Surf sets up to 8 feet were reported across Orange County this morning and a High Surf Advisory is currently in effect. This High Surf Advisory remains in effect until 11 PM Tuesday.

The southerly swell and surf falls through the day on Tuesday, remaining low into Wednesday. Another round of elevated southerly swell from a tropical cyclone well off the coast is expected later this week. This swell is expected to be around 4-5 ft with a period of about 15 seconds which would once again bring high surf of 6-8 feet, especially for south-southwest facing beaches.

SKYWARN

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

SGX WATCHES/WARNINGS/ADVISORIES

CA...High Surf Advisory until 11 PM PDT Tuesday for Orange County Coastal Areas-San Diego County Coastal Areas.

PZ...None.