04/650 PM.
Breezy Santa Ana Winds will continue to taper off through late this evening, with sub advisory northerly winds continuing into Friday morning across mountain areas. Freezing conditions will occur across some interior areas Friday morning. A significant warming trend will begin this weekend with temperatures well above normal through next Thursday, peaking next Tuesday and Wednesday.
(Thu-Sun), 04/850 PM.
***UPDATE***
Offshore winds are diminishing across the area this evening, with many sites shifting from northeast to a more northerly direction. A couple of standouts in the Santa Monica Mountains are still gusting 30 to 40 mph but most sites in the Santa Ana wind corridor are gusting 15 to 25 mph as of 700 PM. Winds may pick up again for a few hours later tonight, but should begin to weaken more substantially between 800 to 1000 AM Friday morning.
Clear skies are expected for most areas tonight, except for the Salinas Valley where light winds may allow for another night of dense fog for a few hours after midnight through around 900 AM. However, there is a chance the fog will not materialize, making this a lower confidence forecast.
Chilly overnight temperatures are expected across the area tonight thanks to efficient radiational cooling, in particular the wind sheltered interior valleys, including the Antelope Valley. See below for details on the Freeze Warnings in effect for tonight. A Frost Advisory was added for the Ojai Valley based on last night's low of 32 degrees and similar to slightly warmer lows expected there tonight.
***From Previous Discussion***
Another chilly night is on tap. The coasts and coastal valleys, especially south of Point Conception, will cool a couple degrees as the weakening offshore winds have less of downslope warming affect on these areas. This will likely be the last night that Frost/Freeze products will be needed for the forecast period. The Freeze Watch for the Antelope Valley, southern Salinas Valley, and Interior San Luis Obispo County valleys has been converted to a Freeze Warning. The Freeze Warning is somewhat marginal for the southern Salinas Valley, with temperatures likely in the 30-35 degree range. Higher confidence in widespread freezing temperatures across the Antelope Valley and interior SLO County valleys tonight with lows in the 25-32 degree range common.
High temperatures will be anything but remarkable into Saturday, with some minor fluctuations day to day. Weaker offshore flow and eventually weak onshore flow Friday and Saturday afternoons will lead to a few degrees of cooling at the coasts though. Highs across coastal valleys will yo-yo a degree or two here and there through Saturday, depending on how far inland the marine influence makes it. Interior portions including the Antelope Valley will see the largest increase in temps, where an increase up to 10 degrees over the next couple of days will be common.
A significant warming trend will begin Sunday as a very powerful (for this time of year) ridge overhead builds across the West Coast, sending most of the coastal valleys into the 70’s, while the coasts and interior valleys will top out in the mid to high 60’s.
(Mon-Thu), 04/153 PM.
Focus will shift to high temperatures next week as Monday through Thursday are looking very warm for this time of year. The upper level ridge will be fully parked along the west coast, with the highest 500 mb heights just off of the Central California coast. Over Southwest California, 500 mb heights will likely reach the 95th-97th percentile during this period. In addition to the synoptic pattern favoring a warm and dry spell, offshore winds will increase from the east and particularly the north Monday and Tuesday, with northerly flow continuing into Thursday. As of right now, the most likely outcome would be weak to occasionally moderate north-northeast winds.
Temperatures will be 10 to 15 and locally 20 degrees above normal through Thursday except for 5 to 10 degrees above normal near the coasts. Widespread upper 70’s to at least low 80’s will be common across coastal valleys, while coasts will likely top out in the low to mid 70’s. Mid 80's cannot be ruled out for warmest valley locations. There is considerable agreement amongst ensembles that the ridge will persist through the work week, but begin to break down into more zonal flow over the weekend. It might be a good idea to keep those winter coats in the closet next week.
05/0609z.
At 0512Z at KLAX, there was no marine layer. There was a sfc based inversion with a top of 300 ft and a temp of 17 C.
High confidence in all TAFs except for KPRB. For KPRB there is a 40% chance that low clouds will not form.
KLAX, High confidence in TAF. There is a 20% chance of a 7 kt east wind component 09Z-15Z.
KBUR, High confidence in TAF.
04/927 PM.
Across the Outer Waters, Small Craft Advisory (SCA) level winds are likely from Friday afternoon through late Saturday, especially north of the Channel Islands. There is a 50% chance that SCA winds may persist through Sunday and Monday.
For the Inner Waters, there is a 30 percent chance of SCA winds briefly returning tonight through Friday morning for Rincon Point to Santa Monica and into the San Pedro Channel. Breezy offshore winds are also possible near Morro Bay Friday morning. Nearshore north of Point Sal, there is a 20-40% chance of SCA winds during the afternoons/evenings Friday through Monday. Otherwise, winds and seas will likely remain below SCA levels through the weekend.
Ca, Beach Hazards Statement in effect through Saturday morning for zones 87-349-350-354-362-366. (See LAXCFWLOX). Freeze Warning remains in effect from 2 AM to 8 AM PST Friday for zones 343-344-383. (See LAXNPWLOX). Frost Advisory in effect from 2 AM to 8 AM PST Friday for zone 357. (See LAXNPWLOX). PZ, Small Craft Advisory in effect from 3 PM Friday to 3 AM PST Sunday for zones 670-673. (See LAXMWWLOX).
