14/1152 AM.
Slight warming is expected through Friday, then cooler over the weekend before a warming trend moves in for Monday through Wednesday. Gusty winds are expected at times across the mountains and deserts through the weekend. Hazardous seas are expected for the coastal waters over the next several days.
(Thu-Sun), 14/809 PM.
Overall, latest models exhibit good synoptic agreement through the short term period. At upper levels, broad northwest flow will prevail through Friday then an inside slider will drop into the Great Basin on Saturday/Sunday. At the surface, moderate onshore flow will prevail through Friday then moderate to locally strong northwesterly flow develops Friday night through Sunday.
Forecast-wise, main concern in the short term will be the winds, more specifically the northwesterly winds. Current models remain very consistent, indicating moderate northerly offshore gradients and some decent upper level support. So, will expect northwesterly winds to increase during the day on Friday across the usual spots (I-5 Corridor, northwestern Antelope Valley and the Santa Ynez Range) and continue through Sunday (with Friday night and Saturday likely the strongest time period). In these areas, high resolution ensembles indicated at least a 70% chance of advisory-level gusts (40-55 MPH) and even a 20% chance of warning-level gusts (60+ MPH). Additionally, the Central Coast will likely also experience advisory-level gusts (30-40 MPH) on both Saturday and Sunday. Future shifts will likely need to issue various wind products.
Other than the winds, no significant issues are expected. With the upper level pattern, the marine inversion will remain on the deep side, but the increasing northwesterly flow will help to limit the areal extent of the marine layer stratus. So, somewhat low confidence in the current stratus forecast through the weekend. Other than any stratus west of the mountains, skies should remain mostly clear through Sunday.
As for temperatures, will expect near persistence temperatures on Friday. However for Saturday and Sunday, there will be some cooling area-wide as the inside slider brings in some colder air to the region.
(Mon-Thu), 14/809 PM.
For the extended, models remain in decent agreement with the upper level pattern. Broad cyclonic flow is forecast to continue the period with a gradual increase in H5 heights. However at the surface, the models differ with the ECMWF and its ensembles indicate weak diurnal flow while the GFS and its ensembles indicate persistent weak to moderate onshore flow.
Forecast-wise, either model forecast indicates continued dry conditions for the region through next week. There will be some amount of marine layer stratus clouds each day, but the areal coverage will be at the whims of the surface gradients. Other than any marine layer stratus, skies should remain mostly clear through the period.
With this overall pattern, a warming trend can be expected for the area through the week. However if the ECMWF is correct with its surface pressure gradients, temperatures west of the mountains could be warmer than currently forecast. ill be possible each day across the coast and valleys.
15/0102z.
At 0040Z at KLAX, the marine layer was 1800 ft deep. The top of the inversion was at 5000 ft with a temperature of 17 C.
High confidence in VFR TAFs for desert airfields (KPMD & KWJF).
Moderate confidence in remaining TAFs. Timing of CIG/VSBY restrictions may be off +/- 2 hours and flight minimums off by one category.
KLAX, Moderate confidence in TAF. CIGs near 010-012 should return 08Z Fri (+/- 2 hours). There is a 20% chance of east wind component reaching 7-8kts 12Z-16Z Friday.
KBUR, Moderate confidence in TAF. Timing of flight cat changes could be off by +/- 2 hours. No wind issues expected.
14/844 PM.
GALE WARNINGS are in effect for the inner waters along the Central Coast, all the outer waters, and the Santa Barbara Channel this weekend. Please refer to MWWLOX for further details.
For the outer waters from the Central Coast to San Nicolas Island, high confidence forecast. Small Craft Advisory (SCA) level winds are expected to increase overnight into tomorrow to GALE FORCE levels. These winds will become high-end, STRONG GALES over the weekend. SCA level seas will continue to build through the weekend, becoming large 10-15+ foot steep seas.
SCA level winds will diminish overnight, however SCA level seas will continue through the weekend for the nearshore Central Coast waters. After a brief lull in winds for the nearshore Central Coast Waters, winds will increase to high-end, STRONG GALE FORCE levels Friday afternoon and continue through Sunday evening.
The GALE WATCH has been converted to a GALE WARNING for the Santa Barbara Channel for Saturday afternoon through late night, with a high chance of GALE FORCE winds again Sunday afternoon and evening. For the southern inner waters adjacent to the L.A. Coast, SCA level winds are possible across the western portion each afternoon and evening over the weekend.
These dangerous sea conditions could capsize or damage small and large vessels. Mariners should adjust plans NOW to remain in safe harbor.
14/838 PM.
A combination of strong winds, large seas, and moderately high evening high tides may lead to high surf with coastal flooding possible this weekend. High Surf advisories and Beach Hazard statements have been issued across the entire coastline. Please refer to CFWLOX for more details for your area.
In general, hazardous surfing and swimming conditions are expected. Minor beach erosion and coastal flooding is possible, mainly during the evening high tides.
Ca, High Surf Advisory in effect from 3 PM Friday to 9 AM PDT Monday for zones 340-346. (See LAXCFWLOX). Beach Hazards Statement in effect from Saturday afternoon through Monday morning for zones 349-350. (See LAXCFWLOX). High Surf Advisory in effect from 3 PM Saturday to 9 AM PDT Monday for zone 354. (See LAXCFWLOX). Beach Hazards Statement in effect from Saturday evening through Monday morning for zones 362-366. (See LAXCFWLOX). PZ, Small Craft Advisory in effect until 3 PM PDT Friday for zones 645-673. (See LAXMWWLOX). Gale Warning in effect from 3 PM Friday to 9 PM PDT Sunday for zone 645. (See LAXMWWLOX). Gale Warning in effect from noon Saturday to 5 AM PDT Sunday for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Friday for zone 670. (See LAXMWWLOX). Gale Warning in effect from 3 AM Friday to 3 AM PDT Monday for zone 670. (See LAXMWWLOX). Gale Warning in effect from 3 PM Friday to 3 AM PDT Monday for zone 673. (See LAXMWWLOX). Small Craft Advisory in effect until 6 PM PDT Friday for zone 676. (See LAXMWWLOX). Gale Warning in effect from 6 PM Friday to 3 AM PDT Monday for zone 676. (See LAXMWWLOX).
