08/835 PM.
A warming trend will continue into early next week. Temperatures will warm to the 80s and 90s over the weekend through Tuesday. 100 degree readings may occur locally in the warmest valleys on Sunday and Monday. Coastal clouds will reoccur each night through the weekend.
(Fri-Mon), 08/905 PM.
***UPDATE***
Marine layer clouds were quite expansive today, limiting warming from the coasts into the valleys. High temperatures for sunny locations warmed better, reaching the upper 70s to mid 80s, with highs in the 90s for portions of the interior. Low clouds have expanded again tonight, and will likely see low clouds and patchy fog for most of the coastline, with clouds reaching into the valleys. Therefore, adjusted high temperatures down near the coasts where marine layer clouds will likely inhibit warming for Saturday. Will likely need to cool coastal and coastal plains for Sunday as well due to marine layer clouds. Otherwise, the forecast looks on track with warming away from the coast through the weekend.
***From Previous Discussion***
Moderate heat risk is possible Sunday through Monday or Tuesday with an expected peak Monday except near the coast which will likely be sheltered by a stubborn but shrinking marine layer. There is only a 20-30 percent chance that Heat Advisories will be needed for coastal valleys to interior as this will be short duration heat wave and most areas will experience comfortable overnight temperatures.
Persistent warming is anticipated each day through Monday as a stout ridge for May will build and peak by Monday with 500 mb heights near 588 dm. Moderate offshore trends with actual neutral to slightly offshore gradients will allow the heat to build into many coastal valleys Sunday into Monday. Peak heat of 90-100 will become common away from the coast during this period. The thermal belt below the ridge will support overnight lows only 65 to 75 at elevations of roughly 1500-3500 feet. Generally light winds during the peak of the heat will allow better temperature recoveries across valley floors with lows 55-60 common even where daytime highs are well into the 90s.
Breezy northwest to northeast winds will generally be below advisory levels but lead to heightened fire weather in combination with the warming and drying trends. The one exception is a low end wind advisory for this afternoon to evening for southwest Santa Barbara County.
The northwest winds will likely kick off another eddy tonight and maybe again into Sunday. This will somewhat offset the squashing effects of the building ridge and offshore trends to maintain marine layer presence, especially through Sunday. Dense fog may become more of a concern into Sunday or Monday where low clouds do form.
(Tue-Fri), 08/1207 PM.
Cooling is expected in most areas Tuesday as the high pressure aloft weakens, which in turn will increase onshore flow. The onshore push may be strong enough for winds nearing advisory levels for the far interior, leading to heightened fire weather concerns. Highs will drop 4-8 degrees most areas, though desert areas may need to wait for Wednesday for more significant cooling. By that time highs area- wide will be within a few degrees of normal.
Forecast confidence is below normal for later next week, although impacts will likely be low regardless with temperatures likely within 5 degrees of normal with night to morning low clouds and fog near the coast.
09/0309z.
At 2353Z at KLAX, the marine layer was 1800 ft deep. The top of the inversion was at 4000 ft with a temperature of 20 C.
High confidence in VFR TAFs for desert airfields (KPMD & KWJF).
Moderate confidence in remaining TAFs. Timing of CIG/VSBY restrictions may be off +/- 3 hours and flight minimums by one category. Lowest confidence for KVNY & KBUR which has a 30% chance low-IFR CIGs do not arrive. Lower confidence in arrival and clearing times.
KLAX, Moderate confidence in TAF. Better coverage expected at 09Z (+/- 2 hours) with IFR CIGs 008. CIGs likely to lift to low MVFR around 15Z Sat. There is a 30% chance CIGs 010 linger through fcst pd. No significant east wind component expected.
KBUR, Low to moderate confidence in TAF. VFR conditions expected through at least 09Z Sat. Confidence is low with a 30% chance of VFR conditions. No wind issues expected.
08/826 PM.
SCA level NW winds are expected to strengthen through Saturday for the outer waters. Winds will likely reach GALE Force locally across the far northern waters this evening. There is a 40-60% chance of GALES Saturday afternoon and evening over the northern two zones, near and NW of Point Conception. For the southern outer zone PZZ676, SCA winds are likely through early Sunday morning.
For the nearshore waters, SCA level winds are likely during the afternoon and evening hours through Sunday, especially along the Central Coast and to a lesser extent near the Channel islands.
Short period seas will build during this timeframe especially across the outer waters - peaking 10 to 13 ft through Saturday night.
Winds and seas should diminish throughout the day on Sunday. By Monday, conditions should be much calmer and likely below SCA levels.
Ca, Wind Advisory remains in effect until 2 AM PDT Saturday for zones 349-351. (See LAXNPWLOX). PZ, Small Craft Advisory in effect until 3 AM PDT Saturday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect from 2 AM to 3 AM PDT Saturday for zone 650. (See LAXMWWLOX). Small Craft Advisory in effect until 2 PM PDT Saturday for zones 670-673. (See LAXMWWLOX). Gale Watch in effect from Saturday afternoon through Saturday evening for zones 670-673. (See LAXMWWLOX). Small Craft Advisory in effect until 3 AM PDT Sunday for zone 676. (See LAXMWWLOX).
