25/212 AM.
Marine layer clouds with patchy fog will reoccur each night from the coasts to the coastal valleys, expanding into the valleys into this weekend. Temperatures will trend cooler, with below normal temperatures through the weekend.
(tdy-Sat), 25/821 AM.
***UPDATE***
Morning satellite imagery shows marine stratus layer solidly in place this morning with observations indicating the top of it sitting around 2K ft currently. High resolution models show it receding by around Noon PDT and filling back into coastal valleys beginning around 6 PM PDT.
Onshore flow in quasi-zonal flow aloft will result in deepening of the marine layer over the next several days which will continue to limit daytime heating during the early afternoons. High temperatures today are expected to warm to within a few degrees of yesterday's max temps.
Mid- to high- level clouds will begin to descend through CA early Friday morning as pressure heights continue to fall due to the deepening PacNW low pressure system. Increasing cloud cover will further limit daytime warming throughout the week with today marking the beginning of a cooling trend through early next week.
Winds will remain light today but will gradually turn more northerly and increase beginning Friday evening as the pressure gradient tightens.
***From Previous Discussion***
The flow overhead will become more and more cyclonic as a very large upper low works its way into and thru the PACNW. Hgts will fall from 590 dam to 584 dam by Saturday afternoon. Moderate to strong onshore flow will be present for all three day as well. The onshore flow will be strongest (8-9 mb) to the east and in the afternoons.
Look for three similar days today through Saturday. There will be plenty of low clouds and fog covering almost all of the csts and much of the vlys. Clearing will be slower than normal and a few beaches will see no clearing at all. The low clouds will also arrive earlier than normal as well. The only exception will be the western portion of the SBA south cst where local north winds will likely keep the region cloud free.
Max temps will fall 1 to 2 locally 3 to 4 degrees per day across most of the area. By Saturday even the vlys will be in the 70s. These max temps will be 3 to 6 degrees blo normal across the csts and 6 to 12 degrees across the vlys.
There will be gusty west winds across the Antelope Vly in the afternoons with peak gusts approaching advisory levels. There will also be gusty NW winds across the SW portion of SBA county in the evenings and overnight. These gusts will likely reach advisory levels Friday evening.
(Sun-Wed), 25/237 AM.
June Gloom will continue unabated through at least the 1st of July. A series of upper lows will rotate through the PACNW and keep cyclonic flow over the state. Strong onshore flow to the east will continue through the period. There will be moderate onshore flow to the N in the afternoon, but only weak onshore flow in the mornings.
Night through morning low clouds and fog will continue through the period pushing over the csts and deep into the vlys. Clearing will be on the slow side with some west facing beaches not clearing at all.
Strong near advisory west wind gusts will affect the Antelope Vly each afternoon due to the strong onshore push. NW winds will likely continue to affect the SW corner of SBA County in the evenings.
Max temps will not change much through the period. Looks for mid and upper 60s at the beaches; lower to mid 70s across the rest of the csts and mid and upper 70s across the vlys. These temps are 3 to 6 degrees under normal for the csts and 6 to 12 degrees cooler than normal for the vlys.
25/1757z.
At 1715Z at KLAX, the marine layer was 2200 ft deep. The top of the inversion was at 3900 feet with a temperature of 19 C.
High confidence in VFR TAFs for desert airfields (KPMD & KWJF).
Moderate confidence in the remainder of the TAFs. Timing of flight cat changes could be off +/- 3 hours and CIG heights +/- 300 ft.
KLAX, Moderate confidence in TAF. There is a 15% chance that CIGs do not clear, and a 30% chance of intermittent CIGs from 25/21Z through 26/01Z. Generally expecting MVFR CIGs 010-018, but likely CIGs fall to around IFR 008 from 26/05Z-10Z. No significant east wind component expected.
KBUR, Moderate confidence in TAF. Arrival of IFR CIGs should be accurate within +/- 2 hours of current forecast. No wind issues expected.
25/705 AM.
NW winds will increase to Small Craft Advisory (SCA) levels Thursday evening across the northern waters and will expand to the south Friday into the weekend. SCA winds will be strongest on Saturday, and will reach into the nearshore waters along the Central Coast and Santa Barbara Channel at times. Seas will near 10 ft Saturday evening through Monday morning. Beyond, conditions look to quiet down a bit through mid next week.
Ca, NONE. PZ, Small Craft Advisory in effect from 6 PM this evening to 9 AM PDT Monday for zone 670. (See LAXMWWLOX). Small Craft Advisory in effect from 9 PM this evening to 9 AM PDT Monday for zone 673. (See LAXMWWLOX). Small Craft Advisory in effect from 3 AM Friday to 9 AM PDT Monday for zone 676. (See LAXMWWLOX).
