28/403 AM.
Mostly clear skies are expected through Tuesday with a warming trend. A 3 day Santa Ana wind event will start Sunday. It will peak on Monday with strong and gusty winds likely. The winds will not be as strong Sunday and Tuesday. Clouds will increase and a chance of rain will develop Wednesday. The new year will likely start off with quite a bit of rain.
(tdy-Tue), 28/403 AM.
Have issued Wind advisories beginning at 6PM leading up to the HIGH WIND WATCH for the Western San Gabriels, I-5 Corridor, western Santa Monicas and the Santa Susana mountains. Will let the day shift handle the upgrade to a HIGH WIND WARNING for the favored areas, and any additional advisories that may be needed.
The main concern in the short-term is a three day Santa Ana wind event starting Today. A fast moving shortwave trough embedded in 100kt 250mb flow is expected to cut off into a low offshore Mon into Tuesday. This key feature will result in the increase of offshore flow.
EC/NAM indicate offshore LAX-DAG gradients increasing to -3.5mb to -5.5mb on Sunday then into the -5.0 to -8.0 range Monday and Tuesday. High resolution models indicate 950mb winds increasing to near 50 kts on Monday with a slight decrease on Tuesday.
A major caveat to this event will be the saturated soils from the Christmas Week storm. This will make trees more susceptible to blowing down in gusty winds. Thus, residents across Ventura and LA Counties need to be aware of possible downed trees, resulting in power outages.
Otherwise, forecast will be rather benign. Skies are expected to remain mostly clear. Offshore flow will result in warming temps. By Tuesday, most coastal and coastal valley areas will be in the upper 60s to mid 70s. A few favored spots could approach the 80s.
(Wed-Sat), 28/403 AM.
The GFS, ECMWF/AI and their ensembles indicate another round of wet weather on New Years Eve and New Years Day. All guidance has trended a bit faster and amounts have increased somewhat as well. The GFS per usual is playing catchup. Thus, leaning more towards the euro solutions. Although not set in stone, general thoughts are .5 to 1.5 inches for coasts/valleys and 1.5 to 2.5 inches for foothills with somewhat less expected across the interior areas. Do not anticipate any significant hydrologic issues, but the Rose Parade looks to be wet. Snow levels are forecasted to remain above 8000 feet through Thursday.
A trough swings in from the west on Friday and Saturday. Current thinking is that this system will bring generally 0.25 to 1 inch with favored mtn areas across SLO county up to 1.5 inches. Snow levels will drop in the 6000 to 7500 foot range, so additional snowfall for resorts is possible. This is still fairly far out so stay tuned to the National Weather Service as the forecast is subject to change.
28/1137z.
At 0953Z at KLAX, there was no marine layer. There was a sfc- based inversion with a top of 900 ft and temp of 12 deg C.
High confidence in most TAFs, with moderate confidence in KPRB and KLGB. There may be periods of brief IFR-MVFR vis overnight at any TAF location due to wet runways. There is a 30% chc that KPRB remains VFR, and a 20% of VV002 cigs and 1/4-1/2 SM vis at KLGB and KSBP through 16Z Sun.
KLAX, High confidence in TAF. High confidence in any east wind component at or less than 6 kt.
KBUR, High confidence in TAF.
28/222 AM.
Have extended Small Craft Advisories (SCA) until 9 AM Today due to lingering Large, steep seas across the Outer waters (670/673). Seas will remain below SCA at least through Wednesday.
Offshore winds are expected to ramp up on Sunday affecting waters typically prone to Santa Ana wind events. These winds are expected to persist at least through Tuesday morning, if not Wednesday. Hazardous boating conditions are expected from Ventura to Santa Monica and out past the Channel Islands. Winds and steep seas are likely to affect PZZ676 thus have issued a SCA for the timeframe.
NE winds will be the strongest nearshore from Port Hueneme to Point Dume with gusts up to 40 kt. Have issued a GALE warning from Sunday evening to Monday afternoon to reflect this (PZZ650/676).
Please see CWFLOX for a breakdown of these zones as conditions will vary greatly with distance.
Ca, Wind Advisory in effect from 6 PM to 10 PM PST this evening for zones 369-375-378-379. (See LAXNPWLOX). High Wind Watch remains in effect from this evening through Monday afternoon for zones 369-375-378-379. (See LAXNPWLOX). PZ, Small Craft Advisory in effect from 3 PM this afternoon to 9 PM PST this evening for zones 650-655. (See LAXMWWLOX). Gale Warning in effect from 9 PM this evening to 3 PM PST Monday for zones 650-655. (See LAXMWWLOX).
