textproduct: Los Angeles

SYNOPSIS

12/1244 PM.

Below normal temperatures prevail through at least Wednesday, with coastal morning clouds and gusty onshore winds. Warming likely to return towards the end of next week.

LONG TERM (WED-SAT)

12/1243 PM.

Little change expected Tuesday-Wednesday with a fairly stagnant upper pattern and persistent moderate to strong onshore flow. There may be slight cooling each day, but the fairly mild mid- September should continue. The marine layer will likely become more robust across all coasts and maybe some lower valleys.

The consensus in models for Thursday through the end of next week is for warming, as high pressure builds in from the southeast and onshore flow weakens. The magnitude of that building high pressure and the offshore trends are still to be settled, which means the magnitude of the warming is uncertain. Temperatures pushing above normal look very likely, with a low but non-zero chance of Heat Hazard-level hotness. Peering down to the south, there are a couple of tropical systems that could provide some moisture, but the signal is weak at this point.

AVIATION

12/1645Z.

At 1630Z at KLAX, the marine layer was 1600 feet deep. The top of the inversion was at 4400 feet with a temperature of 24 degrees Celsius.

For 18Z TAF package, high confidence in CAVU conditions for KPRB, KSBA, KWJF and KPMD.

For all other sites, moderate confidence in 18Z TAFs due to uncertainties in behavior of marine layer overnight. There is a 40% chance of MVFR/IFR conditions at KOXR/KCMA/KSBP after 08Z. For LA Basin TAFs, timing of flight category changes could be +/- 4 hours of current forecasts.

KLAX...Overall, moderate confidence in 18Z TAF. High confidence in CAVU conditions this afternoon. For tonight, timing of return of MVFR conditions could be +/- 4 hours of current forecasts. No significant easterly wind component is expected.

KBUR...Overall, moderate confidence in 18Z TAF. High confidence in CAVU conditions through this evening. For tonight, timing of return of CIG/VSBY restrictions could be +/- 3 hours of current 10Z forecast. There is an equal chance of either CIGs coming in at MVFR or IFR levels overnight.

MARINE

12/1139 AM.

For the Outer Waters, high confidence in current forecast. Tonight through Sunday night, GALE FORCE winds are expected and GALE WARNINGS remain in effect. For Monday and Tuesday, winds will decrease to Small Craft Advisory (SCA) levels and drop below SCA levels on Wednesday and Thursday. Seas near SCA levels (7-10 feet) are also expected through Sunday night.

For the Inner Waters north of Point Sal, high confidence in current forecast. Tonight through Monday night, SCA level winds are expected in the afternoon and evening hours. For Tuesday through Thursday, winds and seas are expected to remain below SCA levels.

For the Inner Waters south of Point Conception, high confidence in current forecast. For a majority of the southern Inner Waters, winds and seas will remain below SCA levels through Thursday. The only exception will be the western half of the Santa Barbara Channel where SCA level winds can be expected today through Monday, mainly in the late afternoon and evening hours.

LOX WATCHES/WARNINGS/ADVISORIES

CA...Wind Advisory in effect from 6 PM this evening to 6 AM PDT Monday for zones 349-351-352. (See LAXNPWLOX). PZ...Small Craft Advisory in effect until 9 PM PDT this evening for zones 645-670-673-676. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Sunday for zone 650. (See LAXMWWLOX). Gale Warning in effect from 9 PM this evening to 6 AM PDT Monday for zones 670-673-676. (See LAXMWWLOX).