Marine Weather and Tide Forecast for Rancho Palos Verdes, CA

.SHORT TERM (TUE-FRI)...29/929 PM.

***UPDATE***

No significant changes were needed to the forecast database this evening. The marine layer induced stratus clouds have rapidly spread across much of the coast and making progress moving inland this evening. A Catalina Eddy should continue to deepen overnight helping to push stratus further inland and lift the base of the clouds.

***From Previous Discussion***

High confidence in seasonally low impact weather through Friday with relatively small day to day changes in temperatures. Some buildups have already developed across the mountains with a 10 to 20 percent chance of showers across the higher mountains, especially the Ventura County mountains today and continuing each day through Friday.

A weak trough will pass through the region Wednesday and Thursday, leading to a much deeper marine layer with low clouds pushing well into coastal valleys if not lower mountain passes during this timeframe with patchy fog and drizzle possible, especially for valleys and south facing foothills. This type of pattern will support gusty but probably sub advisory winds focused across the interior Wednesday and Thursday afternoon in particular. A reverse clearing pattern is possible Wednesday and Thursday where low clouds linger in the valleys and especially foothills longer than at the coast on those days.

.LONG TERM (SAT-TUE)...29/137 PM.

High confidence in an unseasonably strong storm to push through the region this weekend with gusty northwest to onshore winds, but low confidence in precipitation amounts (if any) and timing.
Widespread advisory level winds will be possible sometime Saturday into Sunday including many coastal areas. Where precipitation does occur it will likely be under a quarter of an inch (except up to around a half of an inch in the mountains), with the Central Coast to mountains the most favorable to receive light amounts. Snow levels will largely be between 5000-7000 feet, although may dip to around 4000 feet Saturday night into Sunday morning with light accumulations generally above 5000 feet. The unusually cold (but moisture starved) system for this time of year will support a 10 percent chance of a thunderstorm over the mountains and deserts.
Any thunderstorms that do form could be slow moving, leading to locally heavier rainfall with embedded hail or graupel. It will feel much like a mid winter storm temperature wide with highs only in the 50s to low 60s for most (10-20 degrees below normal). A late season frost is possible for the coldest interior valleys Sunday or Monday mornings. Otherwise seasonably quiet weather with rebounding temperatures is likely early next week, although there’s a 20 percent chance of some shower activity lingering into early Monday.

AVIATION
30/0650Z.

At 0545Z at KLAX, the marine layer was 1700 feet deep. The top of the inversion was at 3200 feet with a temperature of 18 C.

High confidence in TAFs for KWJF, and KPMD. There is a 20% chance for LIFR to IFR conds at KPRB after 10Z.

Moderate confidence in TAFs for remaining sites. There is a 20 percent chc of SCT conds 21Z-02Z at all coastal sites. Flight Cat changes may be off by +/- 90 minutes.

KLAX...Moderate confidence in TAF. There is a 20 percent chc of SCT015 cond 21Z-02Z. OVC006 conds may not arrive until 1730Z. There is a 10% chance of an 8kt east wind component 12Z-16Z.

KBUR...Moderate confidence in TAF. There is a 30 percent chance cigs remaining AOA OVC006. There is a 25 percent chc of SCT conds not arriving until 1930Z.

MARINE
29/1029 PM.

In the outer waters, good confidence in ongoing Small Craft Advisory (SCA) conds thru Wed morning in the northern zone (PZZ670) and through tonight in the southern two zones (PZZ673/676). SCA conds are not expected across the outer waters Wed night thru early Fri. SCA conds are likely (>80% chance) Fri afternoon thru Sun night, with a 50% chance of GALE force winds Sat afternoon/night.

In the inner waters N of Pt Sal, SCA conds have ended . There is a 40% chance of SCA level winds Wed afternoon/eve. SCA conds are not expected Wed night thru Fri morning. SCA conds are likely (70% chance) in the afternoon/eve hours Fri through Sun, with a 40% chance GALES Sat afternoon/eve.

In the Santa Barbara Channel, there is a 10-20% chance of SCA level winds in western portions during the afternoon/eve hours Wed. SCA conds are not expected late Wed night thru Fri morning.
SCA conds are likely (70% chance) during the afternoon thru late night hours Fri through Sun, with a 40% chance of GALES across western sections Sat afternoon/eve.

In the southern inner waters, SCA conds are not expected thru Sat morning, then are likely (70% chance) beginning in the the afternoon Sat and continuing thru Sun.

LOX WATCHES/WARNINGS/ADVISORIES
CA...Beach Hazards Statement in effect through Wednesday evening for zones 362-366. (See LAXCFWLOX).
PZ...Small Craft Advisory in effect until 9 AM PDT Wednesday for zone 670. (See LAXMWWLOX).
Small Craft Advisory in effect until 3 AM PDT Wednesday for zones 673-676. (See LAXMWWLOX).