02/1010 PM.
Warm and dry conditions can be expected through most of this week. There will be some coastal low clouds and fog at times, but otherwise skies will remain mostly clear. Developing northerly winds will affect areas of southern CA into Wednesday night, with Sundowner winds expected tonight and Wednesday night.
(Tue-Fri), 02/1004 PM.
***UPDATE***
Highs today climbed into the upper 70s to low 90s throughout the area, with cooler 60s common near the coasts. Marine layer clouds played a role in limiting warming near the coasts, and lingered through most of the day for quite a few areas. Expecting warmer temperatures tomorrow, with a shallower marine layer as high pressure builds over the area. In addition, north winds have developed tonight, especially over the western Santa Ynez Range. These northerly winds will continue through Wednesday night, peaking during the evening hours. Could need wind advisories for the entire Santa Ynez mountain range, and near the I-5 corridor with gusts up to about 45-50 mph possible. Otherwise, the forecast looks on track with reoccurring low clouds and patchy fog, and warm temperatures for the interior.
***From Previous Discussion***
Overall, 12Z models in good synoptic agreement through the short term period. At upper levels, ridge noses in from the west through Thursday then weakens slightly on Friday. At the surface, moderate onshore will prevail to the east with some increase in northerly offshore flow through Thursday.
Forecast-wise for the short term, main issue will be the winds, more specifically northerly winds. Based on high resolution model data, northerly offshore pressure gradients (especially SBA-SMX) gradually increase through Wednesday night along with increasing northerly winds aloft. So, gusty northerly winds will be an issue across the usual locations (Santa Ynez Range and the I-5 Corridor). Looking at HREF data, there is a 30-40% chance of advisory-level winds tonight and about a 50-70% chance Wednesday night. So, will not issue any advisories for tonight, expecting any advisory-level winds to remain localized. However, some advisories will be a definite possibility Wednesday night. Otherwise, will expect the usual gusty southwesterly winds across interior sections during the afternoon and evening hours.
Other than winds, no significant issues are expected. Marine layer stratus/fog will continue to be an "issue" during the night and morning hours. With rising H5 heights and the northerly winds, will expect a gradual decrease in areal coverage of stratus/fog through Wednesday night/Thursday morning. However for Thursday night and Friday morning, will expect stratus coverage to increase a bit. Other than marine layer stratus, skies should remain mostly clear through Friday.
As for temperatures, will expect a warming trend through Thursday with less marine influence and higher thicknesses as upper ridge noses in overhead. By Thursday, areas away from the coast will have highs in the mid 80s to mid 90s. However on Friday, will expect some slight cooling as ridge weakens and marine influence increases a bit.
(Sat-Tue), 02/138 PM.
For the extended, 12Z models continue to be on the same synoptic page. At upper levels, ridge breaks down on Saturday and a trough settles in Sunday through the middle of next week. At the surface, moderate to strong onshore flow will continue to the east with some increase in northerly offshore flow early next week.
Forecast-wise, typical June conditions are expected through the period. Marine layer stratus/fog will remain persistent, and rather extensive, through the weekend with the possibility of some drizzle. For early next week, there will likely be some decrease in areal stratus coverage as northerly flow develops. Other than the marine layer, skies should remain mostly clear to partly cloudy, depending on if any high clouds move over the area in the cyclonic flow.
As for winds, no major issues are expected. For the upcoming weekend, the moderate to strong onshore gradients could cause afternoon/evening winds to flirt with advisory levels across interior sections (mainly the Antelope Valley foothills). For early next week, any advisory-level northerly winds look to remain localized.
Finally with respect to temperatures, a noticeable cooling is expected through with weekend with developing trough and increased onshore flow, although highs will still be hovering around seasonal normals. For early next week, temperatures will rebound a few degrees, but no significant heat is expected.
03/0332z.
At 0050Z at KLAX, the marine layer was 1900 feet deep. The top of the inversion was near 4700 feet with a temperature of 21 C.
High confidence in VFR TAFs for KPMD, KWJF, and KPRB.
Moderate confidence in remaining TAFs due to uncertainty in cigs timing. Timing of CIG/VSBY restrictions may be off +/- 2 hours and flight minimums by one category. Expecting earlier clearing times tomorrow with a 20% chance for LIFR conditions for most TAF sites.
KLAX, Moderate confidence in TAF. Lower confidence in clearing times. Cigs may lift with MVFR conditions lingering a few hours later than forecast. No significant east wind component expected.
KBUR, Moderate confidence in TAF. There is 20-30% chc of LIFR CIGs overnight. No wind issues expected.
02/813 PM.
For the Outer Waters from the Central Coast to San Nicolas Island, moderate to high confidence in current forecast. GALE WARNINGS have been issued starting Wednesday afternoon through Thursday morning. Winds will be the strongest across the northern waters (gusts to 40 kt). Seas will peak 12-15 ft during this timeframe. There is a 30-40% chance that Gales may linger Thursday afternoon through Saturday across the northern waters. Otherwise, SCA conditions (winds and/or seas) are likely to persist through the weekend.
For the Inner Waters north of Point Sal, moderate to high confidence in current forecast. Local gusts of 20-25 kt is possible later this evening across the northern portion. Winds will increase to SCA levels early Wednesday afternoon, with a 70% chance of Gales Wednesday afternoon/evening into late night hours. Otherwise, SCA winds are likely to persist through Thursday evening. After decreasing some Friday, winds may increase to SCA levels again Saturday, and seas will hover near advisory levels across the western portion.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. There is a 50 percent chance of SCA winds Wednesday late afternoon and evening, and again Thursday, and Sunday across the western portion of the Santa Barbara Channel.
Ca, Wind Advisory in effect until 3 AM PDT Wednesday for zones 349-351. (See LAXNPWLOX). PZ, Gale Warning in effect from noon to 11 PM PDT Wednesday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect from 11 PM Wednesday to 9 PM PDT Thursday for zone 645. (See LAXMWWLOX). Small Craft Advisory in effect until noon PDT Wednesday for zones 670-673. (See LAXMWWLOX). Gale Warning in effect from noon Wednesday to 9 AM PDT Thursday for zones 670-673. (See LAXMWWLOX). Small Craft Advisory in effect from 9 AM to 9 PM PDT Thursday for zones 670-673-676. (See LAXMWWLOX). Small Craft Advisory in effect until 6 PM PDT Wednesday for zone 676. (See LAXMWWLOX). Gale Warning in effect from 6 PM Wednesday to 9 AM PDT Thursday for zone 676. (See LAXMWWLOX).
