01/630 PM.
A cooling trend will continue through Monday with night to morning low clouds and fog. Gusty west to north winds will continue through early Tuesday. Widespread moderate to locally strong northwest to northeast winds are likely Wednesday through Saturday.
(Sun-Wed), 01/758 PM.
***UPDATE***
Latest satellite and surface observations indicate partly cloudy skies across the district as high clouds drift overhead. Additionally, some stratus/fog is blanketing the Central Coast. Current sounding data indicates marine inversion ranging between 500 and 1000 feet in depth. As for winds, northerly winds, gusting 30-35 MPH, are observed across southern Santa Barbara county.
Forecast-wise for the immediate short term, no significant issues are expected. Northerly winds are expected to increase later this evening and into early Monday morning. So, current WIND ADVISORIES for the SBA South Coast look good. As for marine layer stratus, Central Coast will remain blanketed overnight. South of Point Conception, current forecast has stratus/fog developing overnight across the coasts and valleys. Overall, think this stratus forecast may be a bit overdone, but not enough confidence to make any significant changes to current forecast.
Overall, current forecast has good handle on the immediate short term. So, no significant updates are anticipated.
***From Previous Discussion***
A trough will swing through California fairly quickly today, moving east out of California by Monday evening. This trough will help facilitate a fairly dramatic cooldown region- wide, with further cooling occurring Monday as the trough moves through the state. By Monday, high temperatures in the high 60’s to mid 70’s will be common across Southwest California. As the trough swings through Monday, southwest flow will turn sharply northwest, save for localized northeast winds across Santa Barbara and San Luis Obispo interior mountains. Gusts of 25 to 45 mph will be common across interior mountains to southwest Santa Barbara County with Wind Advisories across these areas by Monday evening (except this evening for southwest Santa Barbara County). There may be some light precipitation on the north slopes of northern Los Angeles and Ventura County at the border of Kern County with the upslope flow. Then fairly weak offshore flow, with some localized areas of 20-35 mph, will take over on Tuesday as the trough begins to weaken near the Rockies. Offshore flow combined with a weak pop up ridge will contribute to a few to several degrees of warming, with the San Fernando Valley potentially touching the low 80’s again. A more expansive blanket of low clouds will likely return tonight into Monday, potentially extending into coastal valleys. A deeper marine layer should limit dense fog concerns.
A second, inside slider trough approaching from the north will begin to boost northerly winds again by Wednesday evening to at least as strong and widespread as Mondays winds.
(Thu-Sun), 01/108 PM.
High confidence in stronger than normal winds at least for Thursday and Friday, although lower confidence in how strong, widespread, and long lasting they may be. Model trends have been towards a stronger, slower moving system, increasing the coverage and duration of winds, possibly even into the weekend.
Advisory level winds are likely to continue Thursday through at least Saturday, although the coverage will likely change from impacting areas prone to north winds to more of a Santa Ana wind set up by the weekend with more widespread winds into coastal valleys to coasts of Los Angeles and Ventura Counties. There is a 30-40 percent chance for warning level winds at times late Wednesday through the Friday or Saturday time frame, focused across interior mountains into the Antelope Valley. Fortunately, somewhat recent rains greatly limit fire weather concerns despite the potential for strong winds.
A warming trend is likely by the weekend with warmer valleys potentially pushing back into the 80s.
Still looking mostly dry through at least the next 10 days.
02/0540z.
At 0510Z at KLAX, the marine layer depth was around 500 ft. The top of the inversion was at 2900 ft with a temperature of 20 C.
High confidence in VFR TAFs for KPMD and KWJF.
Low to moderate confidence in coastal and valley TAFs. Lower confidence in flight categories, with LIFR to IFR conds most likely and a 10-30% chance of VLIFR conds, highest at KSMX, KSBP, and KPRB. South of Point Conception, status may be disorganized and bounce between SCT and BKN, due top upper level clouds somewhat inhibiting stratus formation. Timing of flight cat may be off by 3 hours. 10-20% chance VFR conds prevail at LA Coastal sites.
Low confidence in winds at KSBA through 16Z. North winds may gusts to 20 kt, or they may not occur at all.
KLAX, Low to moderate confidence in TAF. Timing of flight cat changes may be off by +/- 3 hours. In addition, there is a 10% chance of conds lowering to LIFR overnight. 15% chance VFR conds prevail. No significant east wind component expected.
KBUR, Moderate confidence in TAF, with VFR conds expected. However, there is a 30% chance of LIFR conds from 10Z to 17Z.
01/804 PM.
For the Outer waters, Small Craft Advisory (SCA) level NW winds will continue across the waters near/south of Point Conception through Monday. These winds will increase in coverage and speed. Local gusts to GALE force (35 kts) is possible Monday afternoon/eve near the Channel Islands. The axis of strongest winds will shift westward and expand to the north during this time frame. Resulting in low- end SCA winds across northern waters. SCA level NW winds of 20-30 kts will be common across all Outer Waters by Tuesday evening. Winds will become strongest Wednesday morning through late Thursday night, especially during the afternoon/eve hours. During this period, there is a 60% chance of GALES across the outer waters, and a 30% chance for the nearshore waters along the Central Coast. There is a non- zero chance of Storm Force winds, but the more likely outcome is moderate to high end GALES. SCA winds will likely linger through the weekend. SCA seas expected Wednesday through possibly Saturday morning.
For the inner waters south of Point Conception, SCA level W winds up to 25 kt are expected across much of the area. Winds will increase on Monday, especially across the SB Channel where there is a 50-60% chance of low-end GALES during the afternoon/eve hours focused near the Channel Islands. Tuesday looks to be the calmest day where winds could drop below SCA levels for much of the waters excluding the western portion of the SB Channel Tuesday evening. Wednesday afternoon through Friday morning SCA winds are likely across the SB Channel. There is a moderate chance (40%) of Gales Wednesday afternoon/eve across western portion of the SB Channel. Offshore flow will shift the wind to a northeasterly direction starting Friday, thus waters typically impacted by Santa Ana Winds will potentially see more SCA winds over the weekend.
Ca, Wind Advisory remains in effect until 3 AM PST Tuesday for zones 349-351. (See LAXNPWLOX). Wind Advisory in effect from 3 PM Monday to 3 AM PST Tuesday for zones 352-353-376>378-381. (See LAXNPWLOX). PZ, Small Craft Advisory in effect from noon Monday to 3 AM PST Tuesday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until 3 PM PST Monday for zones 650-673-676. (See LAXMWWLOX). Gale Watch in effect from Monday afternoon through late Monday night for zones 650-673-676. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PST Tuesday for zone 655. (See LAXMWWLOX). Small Craft Advisory in effect from 3 PM Monday to 3 AM PST Tuesday for zone 670. (See LAXMWWLOX).
