20/1227 PM.
A cooling trend will begin in most areas Thursday as onshore flow returns and strengthens into the weekend. Night and morning low clouds and fog will return to coastal areas and eventually the valleys. By the weekend temperatures will generally within a few degrees of normal, and next week they will be 5 to 10 degrees below normal.
(tdy-Sat), 21/126 AM.
Overall, 00Z models in good synoptic agreement through the short term period. At upper levels, weak low, currently spinning southwest of the Channel Islands will move southeastward into northern Baja by Friday with a weak ridge nosing across the area on Saturday. At the surface, moderate onshore flow is expected through the period.
Forecast-wis, no significant issues are expected through the short term. With the increasing onshore pressure gradients and some lowering of H5 heights, the marine layer should become more established with increasing areal coverage from day-to-day. However, the inversion will likely stay on the shallow side, so most any stratus/fog will likely be confined to the coastal plain with some patchy dense fog possible. Other than any marine layer stratus, skies are expected to remain mostly clear through Saturday.
As for temperatures, the combination of increased onshore flow, marine layer influence and some lowering of thicknesses will bring a cooling trend for all areas through the period. By Saturday, high temperatures will be hovering around seasonal normals for all areas.
Finally with respect to winds, no significant winds are anticipated. With the moderate onshore pressure gradients, there will be some gusty southwesterly winds across interior sections each afternoon/evening. However, speeds are anticipated to remain below advisory levels.
(Sun-Wed), 21/126 AM.
For the extended, models continue to exhibit decent synoptic agreement. At upper levels, weak low will move across the area on Sunday then general troughing will remain over the area Monday through Wednesday. At the surface, moderate to strong onshore pressure gradients are expected.
Forecast-wise, very benign and typical May weather can be expected. The combination of the upper level pattern and the onshore surface flow will allow for the marine layer to deepen and stratus/fog to become more widespread each day, pushing into the coastal valleys next week. Other than the marine layer stratus, skies are expected to remain mostly clear through the middle of next week. As for temperatures, there will be a cooling trend for all areas through the period with the increased marine influence and lower thicknesses/H5 heights.
As for winds, will expect continued onshore flow through the period. Given the forecast strength of the onshore pressure gradients, southwesterly winds across interior sections could reach advisory level each afternoon/evening by Tuesday and Wednesday.
21/1129z.
At 1100Z at KLAX, the marine layer was 900 feet deep. The top of the inversion was 2700 feet with a temperature of 23 degrees Celsius.
For 12Z TAFs, high confidence in KPRB, KVNY, KBUR and KPMD.
For coastal sites, moderate confidence in 12Z TAFs as timing of flight category changes could be +/- 2 hours of current forecasts.
KLAX, Moderate confidence in 12Z TAF. Timing of flight category changes could be +/- 2 hours of current forecasts. There is a 30% chance that CIG/VSBY restrictions do not develop this morning. No significant easterly wind component is expected.
KBUR, High confidence in 12Z TAF as CAVU conditions are expected through the period.
21/126 AM.
For the Outer Waters, moderate to high confidence in current forecast. Today through Sunday, high confidence in winds and seas remaining below Small Craft Advisory (SCA) levels. On Monday, there is a 20-30% chance of SCA level winds developing in the afternoon and evening hours.
For the Inner Waters north of Point Sal, high confidence in current forecast. Today through Monday, winds and seas are expected to remain below SCA levels.
For the Inner Waters south of Point Conception, moderate to high confidence in current forecast. Today through Sunday, high confidence in winds and seas remaining below SCA levels. On Monday, there is a 20-30% chance of SCA level winds in the afternoon and evening hours across the western half of the Santa Barbara Channel.
Ca, NONE. PZ, NONE.
