20/154 PM.
Hot conditions with an increased risk of heat illness will continue through Thursday before cooling to near normal by the holiday weekend. Breezy and dry conditions focused across the interior will lead to heightened fire weather concerns.
(tdy-Fri), 20/154 PM.
Heat away from the coast and night to morning dense fog near the coast look to be the main weather hazards through Thursday. We have below normal confidence in the Heat Advisory described in some detail below, especially near the coast, including Downtown Los Angeles, with the increasing potential for nature’s air conditioning via the marine layer potentially sheltering these areas from the worst of the heat Wednesday and especially Thursday.
The warming trend continued today with temperatures already around 90 degrees by noon across warmer valleys with daytime highs expected for these areas in the 90-95+ range, focused in the San Fernando Valley and some adjacent areas where a Heat Advisory is in effect starting today. A few degrees of additional warming is likely into Wednesday, focused away from immediate coastal areas, which may see their warmest day today. The Heat Advisory expands to most coasts and and coastal valleys as well as southern Salinas Valley including Paso Robles into Wednesday and Thursday.
Breezy Sundowner winds and increasing northwest to onshore winds across the interior by Thursday may near advisory levels, but perhaps more importantly will lead to elevated fire weather concerns where the grass has already dried out, focused across the mountains and interior valleys. Please take care with fire ignition sources in these areas in particular.
(Sat-Tue), 20/154 PM.
The weak ridge responsible for the warmup breaks down by Friday and with limited weather impacts on the horizon and near to slightly above normal temperatures and winds likely prevailing through at least this weekend. Night to morning low clouds may more widespread with less dense fog concerns, especially in coastal areas. We may see near advisory level northwest Sundowner winds for southwest Santa Barbara County and interior mountains especially near the I-5 corridor in the Friday/Saturday time frame. Fire weather concerns will continue, especially across the far interior mountains and valleys.
20/1911z.
At 1747Z at KLAX, the marine layer was around 800 feet deep. The top of the inversion was 1800 feet with a temperature of 22 C.
High confidence in L.A. desert and valley TAFs, moderate confidence for the remainder of TAFs. There is a 30% chc of LIFR conds at KPRB, KSBP, KSMX 10Z-16Z. There is a 20% chance of IFR to MVFR conds at KSBA, KOXR, KCMA 10-16Z. There is a 40% chance of KSMO, KLAX, KLGB remaining VFR through the period.
KLAX, Moderate confidence in TAF. There is a 40% chance of VFR conds through the period. If cigs do arrive, there is a 30% chc of 1/4SM-1/2SM FG BKN002 conds 10Z-16Z Wed. Any east wind component should remain less than 7 knots.
KBUR, High confidence in TAF.
20/155 PM.
Moderate to high confidence in the current forecast. Higher confidence exists in the forecast for seas relative to the forecast for winds.
For the Outer Waters and the nearshore waters along the Central Coast, conditions will be at least Small Craft Advisory (SCA) levels through Wednesday night, except for lulls nearshore along the Central Coast during late night and early morning hours. There is a 60-90 percent chance for GALE Force winds late this afternoon through late tonight. The highest chances for Gale Force winds will be for the majority of the Outer Waters, while the lowest chances will be for the nearshore waters along the Central Coast and the for southern Outer Waters. There is a moderate chance for GALE Force winds for Thursday and Friday.
Across the Santa Barbara Channel, there is a 30-50 percent chance of SCA conditions this afternoon and evening, with the highest chances across the western portion. Local SCA wind gusts are possible across the far western portion during the afternoon and evening hours. Chances for SCA conditions lessen Wednesday through Friday.
South of Point Mugu, into the Santa Monica Bay, and the San Pedro Channel, winds and seas are expected to remain below SCA levels through at least Friday.
Ca, Heat Advisory remains in effect from 11 AM Wednesday to 9 PM PDT Thursday for zones 88-343-348-351>353-356>358-368-374-375-548. (See LAXNPWLOX). Heat Advisory remains in effect until 9 PM PDT Thursday for zones 369>373. (See LAXNPWLOX). PZ, Small Craft Advisory in effect until 3 AM PDT Wednesday for zone 645. (See LAXMWWLOX). Gale Warning in effect until 3 AM PDT Wednesday for zones 670-673-676. (See LAXMWWLOX).
