textproduct: Los Angeles

SYNOPSIS

07/1247 PM.

Night through morning low clouds and patchy dense fog will be common over coastal areas and the coastal valleys through the weekend. Over the interior areas, hazardous heat will continue through this weekend and expand into the coastal valleys, with near to above normal temperatures around the beaches. Other than a small chance for mountain showers during the afternoon and evening hours through Sunday, dry conditions will prevail.

LONG TERM (TUE-FRI)

07/1117 AM.

500 mb heights will continue to drop to at least 592 dam through Thursday, and maybe even lower. At the same time, onshore flow will increase both to the north and the east becoming strongly onshore in both directions in the afternoons. The marine layer will respond to this and low clouds will likely begin to extend into the valleys. Look for slower than normal clearing and some west facing beaches may see only limited clearing each afternoon and evening.

The combination of a deeper marine layer, stronger onshore flow, and falling heights will bring 2 to 3 degrees of cooling each day through Thursday. Maximum temps will approach normals on Tuesday and then most areas will see below normal maximum temps on Wednesday and Thursday, with valley temps in the mid 80s to lower 90s.

PWs will remain elevated through the period, however. In combination with warmer than normal ocean temperatures off the immediate coast, conditions will continue to feel a little more humid than normal. It will also keep overnight lows a little warmer than normal. The region will remain on the fringe of the monsoonal moisture through at least Wednesday, with the elevated moisture and increased instability keeping the low chance (10 to 15 percent) of afternoon mountain convection going. By the end of next week, medium-range model guidance indicates the potential for an upper low to develop off the Central California Coast, east of which large-scale ascent and convective chances could modestly increase next Thursday and Friday.

Additionally, the strong onshore flow to the east will produce near advisory level wind gusts across the western Antelope Valley and the western foothills each afternoon and evening. Gusty sundowner winds will also be possible early next week in southern Santa Barbara County.

AVIATION

08/0001Z.

At 2209Z at KLAX, the marine layer was 900 feet deep. The top of the inversion was at 1800 feet with a temperature of 27 C.

High confidence in VFR TAFs for KPRB, KBUR, KVNY, KPMD & KWJF.

Low to moderate confidence in remaining TAFs after 05Z Sat. Mid-level moisture and warm SSTs will disrupt the formation of Marine layer. This will likely result in intermittent CIGs especially for KLAX, KSMO, & KLGB. CIG heights accurate within +/- 200 ft of current forecast.

KLAX...Fair confidence in TAF. Intermittent CIGs (007-010) possible 07Z-15Z Fri. No significant east wind component expected.

KBUR...High confidence in VFR TAF. No wind issues expected.

MARINE

07/748 PM.

Winds and seas are expected to remain largely below Small Craft Advisory (SCA) criteria across the coastal waters thru Wednesday night. However, northwest winds could locally gust 20-25 kt around and to the south of Point Conception each afternoon/evening thru Saturday. Local gusts may reach or exceed 21 kt nearshore Point Dume (Saturday evening) and across NW portions of PZZ670 (Sunday evening).

Dense fog may affect portions of the coastal waters each night through morning this weekend and possibly into early next week.

BEACHES

07/110 PM.

High astronomical tides are expected to affect low-lying beaches south of Point Conception with the possibility of minor coastal flooding starting with the evening high tide Monday and continuing through at least Wednesday.

Predicted tide heights of up to 7.5 feet are expected between about 8 and 10 PM each evening. These tides, combined with an increase in a long-period southerly swell, could result in flooding of sea water around the time of high tide over low-lying coastal areas such as parking lots, beaches, and walkways. Beaches most susceptible to potential minor coastal flooding issues include those around Point Dume and near Long Beach.

LOX WATCHES/WARNINGS/ADVISORIES

CA...Extreme Heat Warning in effect until 8 PM PDT Sunday for zones 38-377-381>383. (See LAXNPWLOX). Heat Advisory in effect from 10 AM Saturday to 8 PM PDT Sunday for zones 88-342-343-348-349-351-352-356>358-367>374-548. (See LAXNPWLOX). Heat Advisory in effect until 8 PM PDT Sunday for zones 344-345-353-375-376-378>380. (See LAXNPWLOX). PZ...NONE.