textproduct: Los Angeles

SYNOPSIS

08/143 PM.

Moderate heat impacts will continue through Friday away from the coast in response to a strong ridge over the region. Temperatures will decrease slightly over the weekend as the ridge breaks down. Monsoonal showers or thunderstorms will be possible starting Saturday. Temperatures will begin to build once again on Tuesday, potentially reaching Major HeatRisk levels, with the monsoonal moisture adding to the discomfort from the heat.

LONG TERM (SUN-WED)

08/139 PM.

As previously mentioned, the upper level high pressure will shift NE late Friday through Sunday, and eventually reach the Dakotas. This northeastward shift will open the door for SE flow into Southern California. Meanwhile, at the surface, moderate to strong onshore flow will continue both to the north and east.

With the SE flow, monsoonal moisture will move into the region Sunday night, lasting through basically all of the next week. While the moisture won't reach the region until Sunday night, there is still instability that will bring a 10-20% chance of dry thunderstorms on Sunday. However, once the moisture moves in Sunday night, PWATs will raise to 1-1.5 inches across most of the region (even up to Paso Robles) through at least Tuesday, bringing a 10-20% chance of showers and isolated thunderstorms to Southern California.

As for the heat, another warming trend will start up Tuesday through Thursday, with widespread Moderate HeatRisk, and a 30% chance of Major HeatRisk to most of the region during those days. Thus, an Extreme Heat Watch has been issued for the majority of the region, with temperatures of 90-112 degrees possible away from the coast. Additionally, the monsoonal moisture will add to the discomfort of the heat.

AVIATION

08/1711Z.

At 1606z at KLAX, the marine layer was 800 ft deep. The top of the inversion was at 1400 ft deep with a temperature of 22 C.

High confidence in TAFs for KSBA, KBUR, KVNY, KPMD and KWJF.

Fair confidence in TAFs for KSBP and KSMX with a 25 percent chc of IFR conds redeveloping this evening around 5-7z and lasting through 16Z. VFR conds could occur +/- 1 hour from fcst.

Good confidence in TAFs for KOXR and KCMA with a 15 percent chc of IFR cigs 13Z-16Z.

Low confidence in TAFs for KSMO, KLAX, KPRB (40 percent chc of IFR cigs 10Z-17Z) and KLGB (40 percent chc of no cigs)

KLAX...Low confidence in TAF. There is a 40 percent chc of OVC008 conds 12Z-17Z). Good confidence that any east wind component will be AOB 5kt.

KBUR...High confidence in TAF.

MARINE

08/104 PM.

High confidence in Small Craft Advisory (SCA) level NW winds persisting through at least Friday morning across the Outer Waters. There is a 50-70% chance of Gale Force winds this afternoon and evening into Friday morning. Winds will likely be strongest near Point Conception and the Channel Islands, extending south to San Nicolas Island. Short- period, advisory level, choppy seas will gradually increase in height, reaching around 10 ft by mid- week and then subsiding below advisory levels Friday into the weekend.

SCA level NW-W winds will affect the inner waters along the Central Coast and the Santa Barbara Channel greatest during the afternoon and evening hours through at least Thursday. There is a 40% chance of Gales across the nearshore waters along the Central Coast and the Santa Barbara Channel in the afternoons/evenings through Thursday morning.

For the inner waters adjacent to Los Angeles County, moderate confidence in SCA level gusts through tonight. Otherwise, conditions are expected to remain below SCA levels.

BEACHES

08/104 PM.

A south to southwest swell will continue to affect the coastal waters through next week. With the swell, the potential for larger surf and greater risk for rip currents will continue. High tides are expected to increase this weekend going into next week with Monday expected to be the highest tide of 7.0 to 7.6 ft above MLLW. There is the potential for some minor coastal flooding next week with the high tides and south swell. One thing that will need to be watched into next week will be the potential of a greater south to southwest swell from potential tropical development.

Thunderstorms are also possible starting Sunday and going through next week with a 10-20% chance.

LOX WATCHES/WARNINGS/ADVISORIES

CA...Heat Advisory now in effect until 10 AM PDT Tuesday for zones 38-88-343>345-353-368-372-373-375>380-548. (See LAXNPWLOX). Extreme Heat Watch in effect from Tuesday morning through Thursday evening for zones 38-88-341>345-347>358-362-366>376-378>383-548. (See LAXNPWLOX). Wind Advisory in effect until 8 AM PDT Thursday for zones 349-351. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 5 AM PDT Friday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Thursday for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect until 3 PM PDT this afternoon for zones 670-673-676. (See LAXMWWLOX). Gale Warning in effect until 3 AM PDT Thursday for zones 670-673-676. (See LAXMWWLOX). Small Craft Advisory in effect from 3 AM Thursday to 5 AM PDT Friday for zones 670-673-676. (See LAXMWWLOX).