04/730 AM.
Temperatures will be slightly above normal inland and near normal along the coast through Friday, then dropping below normal over the weekend and into next week as a large low pressure system develops over the West coast. Skies will be mostly clear except for night and morning low clouds and fog across the coast and valley areas.
(tdy-Sat), 04/757 AM.
***UPDATE***
Pretty standard June day across southwest California. Satellite imagery shows several tiny eddies embedded in a larger overall eddy centered near Catalina. The marine layer depth remains around 2000 feet this morning over LA and sloping down to around 600 ft along the Central Coast. Surprisingly no dense fog reported at the airport sites there but there is likely some reduced visibilities in the hills.
Overall, today should look and feel a lot like yesterday. Low clouds and fog may linger near some of the beaches well into the afternoon but will clear elsewhere by noon. Highs again in the low 90s in the warmest valleys and 60s near the coast.
***From Previous Discussion***
Fairly typical June day on tap today. A little ridge is poking in over Srn CA from the west and hgts are near 588 dam. At the sfc the gradients will follow the diurnal curve with the E/W grad mdt onshore in the morning and strongly onshore in the afternoon. The N/S grad will be weakly onshore in the AM and moderately onshore in the afternoon. The north flow coming off of the ridge is bringing north winds to the mtns and local NE winds to the Central coast. An eddy will bring low clouds to the csts south and east of KSBA, while westerly flow will bring some low clouds into western SBA county. Whether or not the low clouds will make it into the vlys is a still a question mark given the north push aloft and the high hgts. If low clouds do make it into the vlys they will be short lived. It will be another story for the west facing beaches across VTA and LA counties where the clearing will be slow or non existent. Max temps will be similar to ydy's readings with max temps mostly 3 to 6 degrees above normal everywhere across the csts and vlys save for the beaches. The mtns and far interior will again end up 6 to 12 degrees warmer than normal.
The ridge is now forecast to hold its own a little better on Friday. The eddy will remain intact so the low cloud pattern will hold. The onshore flow will remain strong in the afternoon and some beach may again not clear. Slightly lower hgts and stronger onshore flow will lower most max temps will fall by about 2 degrees. The strong onshore flow will bring gusty afternoon winds to the Antelope Vly.
Cyclonic flow arrive Friday night and Saturday as a large upper low moves into WA state. The cyclonic turning aloft, falling hgts and strong onshore flow will all combine to bring a deep marine layer with clouds covering the csts and almost all of the vlys. Clearing times will be later than normal and many beaches will stay cloudy all day. The coasts will only cool a couple of degrees, but the vlys will see 3 to 6 degrees of cooling and the far interior will cool by 4 to 8 degrees.
(Sun-Wed), 04/240 AM.
June gloom will be in full swing from Saturday into Wednesday and likely through the end of the week. A series of upper lows will parade through the PacNW and will keep fairly sharp cyclonic turning over Srn CA. This coupled with mdt to strong onshore flow to the east will bring day after day of early arriving and late to leave low clouds to the area. The beaches will be in danger of zero clearing each afternoon. There may be a slight reduction in low clouds towards the end of the week as weak offshore flow does develop from the north. The area that will be the exception to the June Gloom rule will be the SBA south coast where local offshore flow from the north will minimizes the clouds and keep max temps running above normal. Max temps will fall by up to 6 degrees on Sunday and then will not change much Monday through Wednesday.
04/1742z.
At 1705Z at KLAX, the marine layer was 1900 feet deep. The top of the inversion was near 4700 feet with a temperature of 22 degrees Celsius.
For 18Z TAF package, high confidence in TAFs for KPMD and KWJF. For all other sites, moderate confidence due to uncertainties with the marine layer. Timing of flight category changes could be +/- 3 hours of current forecasts.
KLAX, Moderate confidence in 18Z TAF. Timing of flight category changes could be +/- 3 hours of current forecasts. No significant easterly wind component is expected.
KBUR, Moderate confidence in 18Z TAF. Timing of flight category changes could be +/- 3 hours of current forecasts. There is a 30% chance that CIG/VSBY restrictions do not develop tonight.
04/721 AM.
For the Outer Waters, moderate to high confidence in current forecast. Through this evening, high confidence in combinations of Small Craft Advisory (SCA) level winds and seas. The SCA level winds and seas are expected to continue through Monday. On Saturday and Sunday, there is a 20-30% chance of GALE force winds, especially across PZZ670.
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Through this evening, high confidence in SCA level winds. On Friday, moderate confidence in winds and seas remaining below SCA levels. For Saturday through Monday, there is a 60-80% chance of SCA level winds in the afternoon and evening hours with seas approaching SCA levels at times.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. For a majority of the southern Inner Waters, high confidence in winds and seas remaining below SCA levels through Monday. The only exception will be the western half of the Santa Barbara Channel, where there is a 30-40% chance of SCA level winds Saturday through Monday.
Ca, NONE. PZ, Small Craft Advisory in effect until 9 PM PDT this evening for zones 645-670-673-676. (See LAXMWWLOX).
