Santa Cruz Island to San Clemente Island to 60 NM offshore including San Nicolas and Santa Barbara Islands Marine Forecast
20 - 30
20 - 30
10 - 15
10 - 15
10 - 15
10 - 15
|Today...Nw Winds 20 To 30 Kt. Combined Seas 11 To 14 Ft Dominant Period 9 Seconds.|
|Tonight...Nw Winds 20 To 30 Kt In The Evening, Becoming N 15 To 25 Kt. Strongest Nw Of San Nicolas Island. Combined Seas 9 To 12 Ft Dominant Period 9 Seconds, Subsiding To 7 To 10 Ft After Midnight.|
|Mon...N Winds 10 To 15 Kt. Wind Waves 2 Ft Or Less. Nw Swell 6 To 8 Ft At 9 Seconds, Subsiding To 3 To 5 Ft In The Afternoon.|
|Mon Night...Nw Winds 10 To 15 Kt. Wind Waves 2 Ft Or Less. Nw Swell 3 To 5 Ft At 10 Seconds.|
|Tue...W Winds 10 To 15 Kt. Wind Waves 2 Ft Or Less. W Swell 3 To 5 Ft At 11 Seconds. A Slight Chance Of Rain In The Afternoon.|
|Tue Night...W Winds 10 To 15 Kt. Wind Waves 2 Ft Or Less. W Swell 5 To 7 Ft At 10 Seconds. Rain Likely.|
|Wed...W Winds 10 To 15 Kt. Wind Waves 2 Ft. W Swell 6 To 8 Ft. A Chance Of Rain.|
|Thu...Nw Winds 10 To 15 Kt. Wind Waves 2 Ft Or Less. Nw Swell 6 To 8 Ft. A Chance Of Rain.|
| Area Forecast Discussion|
National Weather Service Los Angeles/Oxnard CA
441am PDT Sunday Mar 26 2023
Updated Aviation Discussion
Drier and warmer weather will develop through Monday as a northerly flow today transition to offshore flow tonight. Gusty north to northeast winds are possible across portions of southwest California through Monday. A cold storm system originating from the Gulf of Alaska will bring rain and mountain snow along with gusty winds to the region late Tuesday through Wednesday. Showers will linger into Thursday, then drier but cool conditions are expected for late week.
Short Term - Today through Tuesday
A zonal flow continues over the area this morning as broad upper- level troughing remains in place over the Western States. A tight northerly gradient in place across the area last night is relaxing this morning. Wind advisories remain in effect for the Transverse mountains and the adjacent foothill areas this morning for gusty northwest to north winds. The gradient will relax enough late this morning and this afternoon for the wind advisory to be let go, but the gradient looks to tighten again this evening, and a wind advisory will likely be needed again.
Isolated snow showers cannot be ruled out along the northern slopes of the mountains this morning as high-resolution ensemble members suggest. A marginal amount of moisture can be seen in the 850 mb mixing ratio data to support isolated showers, especially on high peaks. Any amounts will likely amount to a dusting of snow this morning.
Ridging aloft developing over eastern Pacific Ocean will build into the region tonight through Monday. An offshore flow pattern will develop and gusty Santa Ana winds will develop across portion of the Southland late tonight through early Monday morning. The latest deterministic NAM-WRF solutions suggest KLAX- KDAG surface pressure gradients tightening to -5.4 mb and KLAX- KTPH to -9.6 mb. EPS ensemble members advertise K3A6 wind gusts getting solidly into advisory criteria and getting close to advisory criteria at KCMA on Monday morning. Local 3-km WRF and HRRR (High-Resolution Rapid Refresh) solutions fall very close inline with short-range multi-model ensemble members in advertising a greater than 60 percent chance of advisory level wind gusts across the usual Santa Ana wind corridor across the Southland. Wind advisories will likely be needed between late tonight and Monday morning for gusty Santa Ana winds.
With the offshore pattern developing, daytime temperatures were warmed over the forecast guidance over the coastal and valley areas. Sites like Downtown Los Angeles and Camarillo will warm to several degrees above normal. In fact, some sites will warm above 70 degrees for only the second time this month as March has been below normal across the region.
A vigorous storm system will arrive on the heels of the ridge on Tuesday. A developing storm system over the Gulf of Alaska and west of British Columbia this morning will dig into the region through Thursday. Rain will develop quickly across the region between Tuesday and Wednesday. High confidence remains in the forecast during this period as all EPS, GEFS, and CMC ensemble members suggest rainfall across the region. Probability of Precipitation has been nudged over NBM values for Tuesday and Tuesday night to mention categorical rain over most of the area. As the cold frontal boundary weakens at its moves south, the highest rainfall totals are expected for areas north of Point Conception. The latest rainfall totals range from 0.50 to 1.00 inch across the coast and valleys up to 1.00 to 2.00 inches across the foothills, mountains, and northwestern San Luis Obispo County.
While Quantitative Precipitation Forecast amounts have a little more uncertainty for the region, high confidence exists in widespread rain. WPC has highlighted a slight risk of excessive rainfall from KSBA northward along the Central Coast and a marginal area stretching into Ventura County. This aligns well with a difluent flow pattern developing on Tuesday night across San Luis Obispo, Santa Barbara, and Ventura Counties. Moisture parameters are decent with precipitable water values around 1 inch, or about two to three standard deviations above the mean. Mixing ratios are a little healthier, around 3 standard deviations above the mean. While the moisture parameters are not as high as the last several system, there is a concern that a Flood Watch will be needed with this storm as the system possess a great deal of instability. Heavy downpours are of greater concern with this storm system due to the colder air mass aloft.
With the colder air mass with this storm, gusty winds will also develop along the frontal boundary and wind headlines will be needed as we draw closer to the event. Snow levels start out near 6000 to 7000 feet on Tuesday and Tuesday night but crash down thereafter.
Long Term - Wednesday through Saturday
Snow levels will likely crash down to between 2500 and 3500 feet on Wednesday. A showery weather pattern will linger through Wednesday and Wednesday night as the colder air aloft punches in across the region. A -30 degree Celsius 500 mb cold pocket will move across the region between Wednesday night and Thursday. Isolated thunderstorms could develop over the region, some with gusty winds and small hail. This portions of the storm bears watching as this is where the convective threat for heavier rainfall could develop.
A cold air mass with drier conditions will linger across the region for late week, but a warming trend looks to shape up across the region for next weekend.
High confidence in Gale Warning conditions ending by sunrise everywhere. High confidence in Small Craft Advisory (SCA) conditions for onshore winds or steep seas over all coastal waters by Sunday afternoon. This includes the nearshore waters, although there may be a weaker winds in the morning, but seas will remain steep and wind wave-like. These conditions will be hazardous for most vessels. High confidence in rapidly improving seas Sunday night into Monday as winds turn offshore. There is a 30 percent chance for low-end SCA (Small Craft Advisory) northeast winds from Ventura to Santa Monica Sunday morning, but will be brief. High confidence in any northeast winds over Avalon and Two harbors staying under 15 knots. A storm system will impact the area Tuesday and Wednesday, with near SCA (Small Craft Advisory) southwest winds at times, and a potential for thunderstorms (especially Wednesday).
NOAA Los Angeles/Oxnard CA Office: Watches - Warnings - Advisories
CA...Wind Advisory in effect until 9am PDT this morning for zones 88-350-352-353-370-372-375>379-381.
High Surf Advisory in effect until 3pm PDT this afternoon for zones 340-346. (See LAXCFWLOX). Frost Advisory in effect from 1am to 9am PDT Monday for zones 346-347-357.
PZ...Small Craft Advisory in effect until 3am PDT Monday for zones 645-650-655-670-673-676.