textproduct: Los Angeles

SYNOPSIS

17/201 PM.

Well above normal temperatures will continue away from the coast through Friday. Unsettled weather is possible this weekend along the Central Coast, spreading to all areas with a potentially significant storm near the middle part of next week.

LONG TERM (SUN-WED)

18/258 AM.

Sunday and Monday will be fairly similar days. The upper flow pattern will slowly tilt more and more into a SW to NE direction on Sunday as the AR system sags a little more to the south. A slight chc or chc (20 to 30 percent) of rain will develop over SLO and Western SBA counties. Other areas will just see increasing clouds. Rainfall totals during the two day period will most likely be under a tenth of an inch with perhaps the exception of the far NW tip of SLO county which could see more. Skies will turn mostly cloudy Sunday and will persist through Monday. Max temps will fall 2 to 4 degrees across almost all of the area Sunday and then will change little on Monday. Max temps will remain 3 to 6 degrees over normals for the csts and vlys.

Tuesday romaines the day of transition. The AR will sag south and the flow will become even more southwesterly. Rain chances will overspread the entire area. Rain chances have increased with the latest forecast and now sit around 40 percent for LA county, 50 percent for VTA county, 50 to 60 percent for SBA county and 60 to 70 percent for SLO county. The forecast rainfall amounts have also been increased. SBA and SLO counties will now likely see a half inch to an inch of rain, while a quarter inch to a half inch is possible for VTA and LA counties.

There has been a slight change in the current thinking for the Wed/Thu storm. Both the EC and esp the GFS (as well as most ensembles and the AI enhanced mdls) are now speeding up the system (hence the wetter Tuesday fcst). This forecast (Which very well might change since it is 7 to 8 days away) now call for the bulk of the rain to fall Wednesday through Thursday (Christmas) morning. Very preliminary (and subject to change) rainfall totals for the Wed/Thu time period call for 2 to 4 inches of rain csts/vlys, 4 to 6 inches across the mtns and 1 to 2 inches for the interior sections. It is too early to get a handle on rainfall rate predictions. Snow levels will be over 8000 ft but will start to fall later Thursday.

Model agreement falls off pretty rapidly after Thursday, but there is a potential for another system over the weekend of the 27th and 28th.

AVIATION

18/1701Z.

At 1630Z at KLAX, the marine layer depth was around 500 feet. The top of the inversion was 2600 feet with a temperature of 24 degrees Celsius.

For 18Z TAF package, high confidence in KSBP...KSBA...KOXR...KCMA KBUR...KVNY...KPMD and KWJF. For KSMX...KLAX...KLGB and KLGB, moderate confidence in 18Z TAFs as timing of flight category changes with marine layer could be +/- 3 hours of current forecasts.

KLAX...Overall...moderate confidence in 18Z TAF. Timing of flight category changes could be +/- 3 hours of current forecasts. No significant easterly wind component is expected.

KBUR...High confidence in 18Z TAF.

MARINE

18/720 AM.

For the Outer Waters, moderate to high confidence in current forecast. Today through Friday evening, Small Craft Advisory (SCA) level winds will continue across all of the Outer Waters. For Friday night and Saturday, the SCA level winds will continue across PZZ673/676. Additionally, there will be 20-30% chance of Gale force wind gusts around Point Conception today through Saturday. For Sunday through Monday, winds and seas will remain below SCA levels for all of the Outer Waters.

For the Inner Waters north of Point Sal, high confidence in current forecast. SCA level winds will develop today and Friday during the afternoon and evening hours. For Saturday through Sunday, winds and seas will remain below SCA levels.

For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Today through Friday, there is a 30-40% chance of SCA level winds across the western half of the Santa Barbara Channel. Otherwise, high confidence in winds and seas remaining below SCA for the southern Inner Waters through Monday.

LOX WATCHES/WARNINGS/ADVISORIES

CA...NONE. PZ...Small Craft Advisory in effect until 9 PM PST this evening for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 9 PM PST Friday for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PST Saturday for zones 673-676. (See LAXMWWLOX).