textproduct: Los Angeles

SYNOPSIS

17/1222 PM.

Steady cooling through Friday with below normal temperatures through the weekend. Ample low clouds each morning through the weekend, with patches of drizzle possible Thursday and Friday. Gusty onshore winds will impact interior areas through the week. A significant warming trend remains on track for next week with heat impacts expected.

LONG TERM (SUN-WED)

17/216 PM.

Good consensus across deterministic and ensemble suites among global models that an anomalous ridge will begin building across southwest California on Monday. This ridge is expected to peak in strength mid-week with the most reliable guidance showing 597 dm.

This change in pattern will also result in significant reduction in onshore flow. It will also result in shrinking of the marine layer and will limit the valley penetration. However, the increase in heights will strengthen the inversion which could make coastal clearing a little more stubborn (esp. immediate coastline and more confidence early in the week).

(PLEASE READ IMPORTANT)

If current trends continue, a EXTREME HEAT WATCH will likely be needed for Mid-week to highlight a significant heat risk across the area. This product will likely be issued by tomorrow morning (Thursday). It is important that travelers and locals are weather aware and ready during this time. Heat impacts will not be limited just to sensitive populations during this timeframe (such as heat exhaustion and stroke).

There is potential for triple digit heat across the warmest valleys and downtown LA could possibly reach 90F. Due to the onshore flow component, immediate coastal sections will remain cooler with less concern for heat impacts. Heat impacts are likely to linger in some fashion into the weekend, but confidence is lower on the magnitude & details.

AVIATION

17/2354Z.

At 23Z at KLAX, the marine layer was 1800 ft deep. The top of the inversion was near 4800 ft with a temperature of 21 Celsius.

High confidence in KPMD & KWJF staying VFR with gusty southwest winds.

High confidence in ceilings at all other airports. Moderate confidence in timing (+/- 3 hours) and flight categories (+/- 500 feet ceilings).

KLAX...High confidence in IFR/MVFR ceilings for the majority of the night and morning. Moderate confidence in timing (+/- 3 hours). No significant east wind component expected.

KBUR...Moderate confidence in IFR ceilings forming tonight with slightly stronger than usual onshore winds in the afternoon and evening hours.

MARINE

17/715 PM.

Fairly high confidence in winds and seas staying below Small Craft Advisory (SCA) criteria through Saturday, but typically gusty winds of 15 to 20 knots will form each afternoon and evening over several nearshore spots.

BEACHES

17/715 PM.

A long period south to southwest swell (14 seconds and 17 seconds) will continue to affect the coastal waters through at least Friday. A Beach Hazard Statement is in effect through Thursday evening due to elevated surf of 3 to 6 feet on south- facing beaches of Ventura County Beaches, Malibu Coast, and Los Angeles County Beaches. Portions of the Southern Santa Barbara County Beaches could see surf to 2 to 4 feet.

High tides will continue to lower and should stay below 7.0 feet MLLW. The coastal flooding risk has lowered significantly as a result.

LOX WATCHES/WARNINGS/ADVISORIES

CA...Beach Hazards Statement in effect through late Thursday night for zones 349-350-354-362-366. (See LAXCFWLOX). PZ...NONE.