27/147 PM.
Gradual cooling will continue through the week as will coastal flooding issues due to very high tides. The next storm system is expected to arrive late Friday or Saturday with rain chances continuing into Sunday.
(Tue-Fri), 27/703 PM.
***UPDATE***
Another very quiet weather day saw max temperatures a few degrees cooler in many areas compared to yesterday. Further cooling is expected across most of the area tomorrow as well. Mid and high clouds will expand over the area leading to partly to mostly cloudy skies. Some marine layer stratus clouds will try to form in some areas like the LA Basin, but the higher clouds will likely disrupt the marine layer's formation by limiting the radiational cooling.
***From Previous Discussion***
Dry and mild conditions are expected through at least Thursday as a trough pattern develops along the West coast. Increasing low clouds and fog are possible through the week as onshore flow increases ahead of the next upper low. Otherwise, minimal if any weather impacts through the short range period. Temperatures will lower 1-2 degrees each day, and by Friday highs will mostly be in the 60s, except some lower 70s in the warmer valleys. There are still a few ensemble solutions indicating some very light rain as early as Friday afternoon, mainly along the Central Coast.
(Sat-Tue), 27/238 PM.
The 12z models today continued to indicate a weakening trend with the approaching system in terms of expected rain amounts. This has been a tricky system as it's following under the main upper low moving into the Pac NW. The one interesting aspect are the PW's which increase to around 1.2" Saturday night which could support some brief heavier shower at times. However, the upper low has been trending a little farther south with each run. So there remains still quite a bit of uncertainty but trends are generally favoring a system that should mostly just provide a beneficial rain. And given the current trajectory of the storm snow levels are expected to be no lower than 9000 feet.
27/2329z.
At 2157Z at KLAX, the marine layer was 1500 feet deep. The top of the weak inversion was 2500 feet with a temperature of 16 degrees Celsius. There was another inversion aloft.
Moderate to high confidence in VFR TAFs, There is a 15-30% chance of MVFR cigs at coastal/valley sites south of Point Conception 06Z-18Z, highest for LA County coastal sites and a 20% chance of VLIFR-LIFR conds at KPRB 10Z-17Z. If low clouds form, mid to high level clouds will likely make any marine layer stratus disorganized, leading to flight cats bouncing between VFR and lower flight cats.
KLAX, Moderate confidence in TAF. There is a 30% chance for BKN020-030 cigs from 06Z-18Z. Flight cats may bounce between VFR and MVFR if low clouds form. Any east wind component is expected to remain under 8 kt.
KBUR, High confidence in TAF. There is a 15% chance for BKN015-025 cigs from 08Z-18Z. Flight cats may bounce between VFR and MVFR if low clouds form.
27/940 PM.
For the Outer Waters, moderate to high confidence in current forecast. High confidence in Small Craft Advisory (SCA) level winds overnight, ending Wednesday morning. From Wednesday afternoon through Saturday, moderate confidence in winds and seas remaining below SCA levels. There is a 30% chance for SCA winds Wednesday evening for the waters north of Point Sal. On Sunday, there is a 50-60% chance of SCA level winds.
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. For Wednesday through Saturday, high confidence in winds and seas remaining below SCA levels. On Sunday, there is a 50% chance of SCA level winds in the afternoon and evening hours.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. High confidence in winds and seas remaining below SCA levels through Saturday. There is a 50% chance for SCA level winds Sunday from the Santa Barbara Channel to the southern inner waters.
A significant storm system will impact the area sometime in the Saturday to Sunday timeframe. There is a wide range of outcomes, but there is at least a low threat of a 12-24 hour period of strong winds and step seas.
Ca, Coastal Flood Advisory in effect until 1 PM PDT Thursday for zones 87-340-346-349-350-354-362-366. (See LAXCFWLOX). PZ, Small Craft Advisory in effect until 9 AM PDT Wednesday for zones 670-673-676. (See LAXMWWLOX).
