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.
(tdy-Sun), 14/1149 AM.
The marine inversion deepened to near 3000 ft at LAX this morning. Low clouds were fairly extensive over portions of the coast and adjacent vlys this morning but are forecast to clear off the coast by this afternoon. Otherwise, mostly sunny skies will prevail today as an H5 580-582 dam ridge parks itself over the forecast area. Breezy to locally gusty SW-W winds can be expected by this afternoon across the region. Temps today are forecast to be from a few degrees below normal along the coast into the adjacent vlys to several degrees above normal for the interior vlys, mtns and deserts.
The weak upper level ridge will be replaced by a broad WNW flow aloft thru the day Fri, then lowering H5 heights will move into CA over the weekend as a fairly potent inside upper level trof moves into the Great Basin. An upper level low at the base of the upper level trof should move into central NV by late in the day on Sun. By then, H5 heights over SW CA will lower to around 568-570 dam with strong NW flow aloft.
Marine layer clouds will move back into the coast and vlys tonight and Fri morning, affect the coast and vlys mainly over VTU/L.A. Counties Fri night into Sat morning, and cover most coast/vlys except the SBA County S coast for Sat night into Sun morning. Otherwise, mostly clear skies will prevail across the forecast area thru Sun.
The main wx impacts over the next few days will be the winds. Strong and gusty NW winds will begin to affect the L.A. County mtns especially along the I-5 Corridor Fri night into Sat morning, where winds could approach Advisory levels at times.
NAM fcst pressure gradients for SBA-SMX for 00Z Sun (5 PM Sat) is -4.0 mb. With these pressure gradients and upper level support, it looks like northerly winds will increase over the VTU County mtns into the SBA County mtns including the Santa Ynez Mtns late Sat into Sat night, where Advisory-level winds are expected. In fact, the latest indications are that high-end Advisory-level wind gusts up to 55 mph cannot be ruled out for the wind-favored passes and canyons of the Santa Ynez Mtns Sat evening. Wind Advisories for this area will likely be needed at some point and would likely be issued on Friday. In addition, another round of strong and gusty N winds should affect this area late Sun into Sun night with more Advisory-level winds.
Temps will turn warmer inland on Friday but remain slightly below normal closer to the coast. Near-normal temps can be expected on Sat followed by a cool-down to several degrees below normal for most areas on Sun.
(Mon-Thu), 14/1150 AM.
Early next week, as the trough moves out the area to the east, 500 mb heights will gradually trend upwards. Additionally there is around a 30 percent chance of periods of weak offshore flow, particularly Monday and Tuesday mornings. Northeast wind gusts of around 20 to 30 mph will be possible across the wind prone mountains. If offshore flow does occur, coastal temperatures have the potential to warm into the upper 70s and low 80s, otherwise highs in the 60s will be favored. Overall a warming trend is expected Monday through Wednesday, with the highest confidence for inland areas. Away from the beaches, highs will increase from mid 70s to low 80s on Monday to the 80s to around 90 by Wednesay (5 to 10 degrees above normal) then turn only slightly cooler on Thursday. Marine layer low clouds and fog will be possible each day across the coast and valleys.
14/1736z.
At 1638Z at KLAX, the marine layer was 2500 ft deep. The top of the inversion was at 4000 ft with a temperature of 15 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. Clearing of MVFR CIGs 020-025 expected 19Z-21Z Thursday. CIGs near 010-012 should return 08Z Friday (+/- 2 hours). CIGs expected to gradually lift reaching 020 threshold by mid-morning Friday. There is a 20% chance of east wind component reaching 7-8kts 12Z-16Z Friday.
KBUR, Moderate confidence in TAF. No wind issues expected.
14/823 AM.
GALE WARNINGS have been issued. Refer to MWWLOX for details.
For the outer waters from the Central Coast to San Nicolas Island, high confidence in Small Craft Advisory (SCA) winds and seas lasting through tonight. STRONG GALES are expected Friday through the weekend with large 10-15+ foot steep seas.
Periods of SCA conditions are expected for the nearshore Central Coast waters through Friday morning. STRONG GALES are expected from Friday afternoon through Sunday evening. There is also a moderate chance for GALES across the Santa Barbara Channel and the western portion of the southern waters Saturday into Sunday.
These dangerous sea conditions could capsize or damage small and large vessels. Mariners should adjust plans NOW to remain in safe harbor.
14/824 AM.
Over the weekend, the combination of high winds and seas could result in hazardous surfing conditions and minor coastal flooding especially across more unprotected west-facing beaches such as along the Ventura coastline. Stay tuned for future updates.
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 from 3 PM this afternoon to 9 PM PDT this evening for zone 645. (See LAXMWWLOX). Gale Warning in effect from 3 PM Friday to 9 PM PDT Sunday for zone 645. (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). Small Craft Advisory in effect until 3 PM PDT Friday for zone 673. (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).
