textproduct: Los Angeles

SYNOPSIS

28/1034 PM.

Gradual cooling will continue through the week as will coastal flooding issues due to very high tides. The next storm system is expected to bring rain to the area from as early as Friday through Sunday, likely peaking Saturday evening into Sunday morning.

LONG TERM (SAT-TUE)

28/130 PM.

For the extended, main storm action for the area looks to be Saturday night and Sunday morning with rain chances diminishing Sunday afternoon and evening. Based on model trends the last few days, the highest rain totals are expected to remain south of LA county. For our area, storm totals through Sunday are expected to range between 0.50 and 1.50 inches for most areas with local amounts up to 2.50 inches across south-facing mountain slopes. Rainfall rates are expected to be in the 0.10 to 0.33 inch/hour range. However, based on a continued wide range of solutions in the ensemble members, there is moderate confidence at best in the above numbers. There is a 20% chance of totals/rates double the expected numbers and a 20% chance of totals/rates half of the expected numbers. As for thunderstorm chances, the odds are pretty low (10% or less) as the best instability is forecast to remain south of LA county.

Once this storm moves eastward Sunday afternoon/evening, an upper level ridge will develop over the area Monday and Tuesday. This will bring dry and warmer conditions to the area. Additionally, there will be some offshore flow at the surface, but the offshore winds look to be on the weak side.

On Wednesday, the upper level ridge is nudged eastward as a low tracks northeastward into northern California. This will likely bring some increase in high-level clouds and some slight cooling as offshore flow decreases. As for rain chances, models indicate a low chance (less than 15%) of any showers across the area.

AVIATION

29/0533Z.

At 0455Z at KLAX, the marine layer was 3600 ft deep. The top of the inversion was at 5800 ft with a temperature of 12 C.

High confidence in VFR TAFs for KPMD and KWJF.

Moderate confidence in remaining TAFs with VFR mid and high level clouds likely through the period. Periods of SCT-OVC 020-030 are possible through the TAF period, especially from 06Z-18Z for coastal and coastal valley sites.

KLAX...Moderate to high confidence in TAF. BKN to OVC020-030 cigs possible through the period, especially 06Z-18Z. Any east wind component is expected to remain under 8 kt.

KBUR...Moderate to high confidence in TAF. BKN to OVC020-030 cigs possible through the period, especially 06Z-18Z.

MARINE

28/855 PM.

Conditions are expected to remain below Small Craft Advisory (SCA) levels through Saturday. Southwest flow aloft will produce chances for drizzle and isolated light rain showers Thursday night and Friday.

A storm system is expected to impact the coastal waters this weekend. There is a wide range of outcomes, but there is at least a low threat of a 12-24 hour period of strong winds and steep seas. Worst conditions look to be focused south of Pt Conception.

LOX WATCHES/WARNINGS/ADVISORIES

CA...Coastal Flood Advisory in effect until 2 PM PDT Friday for zones 87-340-346-349-350-354-362-366. (See LAXCFWLOX). PZ...NONE.