textproduct: Los Angeles

SYNOPSIS

28/112 PM.

Temperatures will peak this weekend, then a significant cool-down is expected to begin Monday, with close to normal temperatures through much of the week. There is a chance for coastal dense fog tonight into Sunday morning. Much cooler conditions expected Tuesday through at least Thursday, along with gusty winds and a chance of rain at times.

LONG TERM (WED-SAT)

28/112 PM.

A cool period is on tap for the middle of next week across much of the region on Tuesday as 500 mb heights continue to decrease and onshore flow slightly increases. Additionally, a fairly deep and expansive marine layer will be common through at least Thursday. Little change will be felt and temperatures will hover near normal for this time of year. An increase in temperatures is expected as early as Friday of next week when 500 mb heights rebound some under weak ridging, and highs will likely increase to 5-10 degrees above seasonal normals by next weekend.

The upper level low swinging across the Pacific Northwest next week that will influence the noticeable cool-down has shown a slight chance to chance of rain across the region Tuesday- Thursday over the past week or so. However, the downward trend in rain totals is continuing, and the chances for any rain greater than 0.25 inches have become quite bleak, and rain totals, if any, will likely be less than 0.25 inches, trending more towards 0.10 inches or less.

Onshore flow will increase slightly under the influence of the trough's passage to the north through Thursday. The Antelope Valley (AV) and foothills and interior mountains of Los Angeles County will see the strongest winds during this period, but overall wind speeds are still favored to be just under advisory levels. However, this will need to be monitored as we move more into the higher resolution data timeframe. Additionally, temps across the AV may increase slightly with the compressional heating due to downsloping flow. By Friday, both the EC and GFS indicate light offshore flow, ushering in dryer air to the region.

AVIATION

28/2358Z.

At 23Z over KLAX, the marine layer was 900 ft deep. The top of the inversion was at 2000 feet with a temperature of 23 Celsius.

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

Chances for LIFR/IFR ceilings at KSBP (60%) KSMX (90%) KSBA (60%) KOXR (80%) KCMA (60%) KSMO (50%) KLAX (50%) KLGB (50%). Moderate confidence on timing (plus or minus 3 hours), except low confidence for KSBA (plus or minus 6 hours).

KLAX...Low confidence on if ceilings will form and when. High confidence in any east winds staying under 8 knots.

KBUR...High confidence in VFR TAF with typical winds.

MARINE

28/742 AM.

High confidence in winds and seas staying under Small Craft Advisory (SCA) levels through at least Monday, except for a 30-50% chance of low-end SCA winds beyond 20 NM from the Central Coast Sunday evening through Monday night.

Moderate risk of dense fog with visibility under one mile will continue in the near-term (night through morning).

There is a growing risk for widespread strong SCA or low-end Gale Force winds over most coastal waters (including nearshore and the Santa Barbara Channel) late Thursday through Friday of next week.

LOX WATCHES/WARNINGS/ADVISORIES

CA...NONE. PZ...NONE.