20/151 PM.
A significant cooling trend is expected to begin Wednesday, with light rain or drizzle possible Thursday into Friday. We to moderate offshore flow and sunny skies will bring warming and drying trends into next week.
(Tue-Fri), 20/148 PM.
Onshore trends to the east and north have fueled the resurgence of marine layer low clouds and fog across the beaches today focused south of Point Conception. Low clouds and fog (potentially dense) will likely extend into coastal areas tonight, possibly as early as early this evening with a 10-20 percent chance of overlapping with the back end of rush hour, especially across LA County.
A slow moving cut-off low pressure system will be the main weather player Wednesday through Friday. These systems are notoriously difficult to forecast. The current expected track along or just offshore our coast from northwest to southeast will support a 30-50 percent chance of rain at some point between Wednesday night and Friday morning, with the greatest chances for the Central Coast on the front end of that time frame and LA County on the back end.
Most showers will be on the light to moderate side, although there is less than a 10 percent chance of a heavier shower or thunderstorm with peak rainfall rates of 0.25 to 0.5 inches per hour. Given the very dry stretch we have had, we expect little to no flood impacts, even if these rates materialize locally. Rainfall amounts will be highly variable, but mostly under 0.25 inches with some arbitrary areas likely seeing no rain. Snow levels will generally be above 6500 feet with light snow accumulations possible at the ski resort levels. The cloud cover and rain at times will keep temperatures in the 60s outside of the mountains for much of this stretch.
(Sat-Tue), 20/149 PM.
Weak to moderate offshore flow will likely return by Sunday and continue into early next week with mostly sunny skies and downslope flow off of the mountains supporting warming trends focused west of the mountains. Advisory level Santa Ana winds will be possible for typical areas of Los Angeles and during this stretch, especially Monday or Tuesday of next week with the potential arrival of better upper level support.
Dry weather will likely prevail through the end of the month with a return of rain possible into early February.
21/0247z.
At 2334Z at KLAX, the marine layer was 600 ft deep. The inversion top was 600 ft with a temperature of 21 C.
High confidence for desert TAFs. Moderate to low confidence for remaining TAF sites due to uncertainty in cigs. Chances are 50-80% for VLIFR/LIFR conditions for coastal TAFs. Cigs may reach KVNY and KBUR briefly around 12Z. If CIGs do arrive, timing could be off +/- 2 hours earlier than forecast.
KLAX, Moderate to low confidence in TAF due to cigs. There is a 50% chance for VLIFR/LIFR conditions after 08Z. No significant east wind component expected.
KBUR, High confidence in TAF.
20/147 PM.
Winds and seas are expected to remain relatively calm through Wednesday, then there is a 30% chance for Small Craft Advisory (SCA) winds across the Outer Waters and into the western Santa Barbara Channel Thursday and Friday.
A cut off low will move over the coastal waters bringing rain showers Wednesday afternoon or evening into Thursday. Showers may linger into Friday across the waters adjacent to Los Angeles and Orange Counties.
Patchy dense fog with visibilities less than 1 NM is expected to increase in coverage late tonight into Wednesday, likely impacting nearshore waters.
Ca, NONE. PZ, NONE.
