| Day | Date | High/Low | Forecast |
| Fri | 29th | 68/57 | Mostly sunny remainder of day with scattered, morning low clouds; Possibly breezy at times in the afternoon. Chance of late evening low clouds. |
| Sat | 30th | 71/58 | Mostly sunny day except chance of early morning low clouds. Mostly clear evening. |
| Sun | 31st | 75/59 | Mostly sunny day except chance of some early morning low clouds. Mostly clear evening. |
| Mon | 1st Jun | 75/59 | Mostly sunny day except chance of some early morning low clouds. Mostly clear evening. |
| Tue | 2nd | 74/58 | Mostly sunny day except chance of some early morning low clouds. Chance of evening low clouds. |
Synopsis
A large, upper level low pressure is exiting the state this afternoon (a little later than what most computer models predicted). It brought some showers (nothing more than sprinkles in some cases) to parts of southern California (relevant rainfall only in San Luis Obispo County). For most people, occasionally breezy, cool conditions were noticed.
High pressure aloft will slowly build into the state through the weekend. A deep marine layer exists today (more diluted this afternoon in L.A. County, water vapor-wise). The high pressure will weaken the on-shore flow (sea breezes should be less brisk after today), and the marine layer depth should shrink over next few days. I’m unsure if widespread, low clouds will occur in the coastal plain tomorrow (diluted marine layer would suggest partly cloudy skies at best). By Sunday, a marginal but weak off-shore flow should limit areal coverage of coastal low clouds further. Assuming the off-shore flow verifies, slightly warmer than normal temperatures should prevail in most areas. Little change in the weather is expected on Monday.
There are some computer model forecasts for a very weak, upper level trough near the Southland by Tuesday. This could strengthen the on-shore flow slightly (marine layer coverage may in turn increase). For now, I’m leaning toward a minor cooling in the Tuesday-Wednesday period (back to seasonable temperatures). A number of model forecasts show high pressure nosing back over the state late next week (only for 2 to 3 days). Minor to modest warming would occur with this scenario (far from certain as model agreement not the best). For what it’s worth, another minor cooling cycle may occur over the subsequent weekend. Potentially, there is a chance that a moderate strength high pressure aloft will prevail over the state in the week of June 8th. If that verifies (??), much warmer than normal weather can be expected in the state.
Next issued forecast/synopsis should be on Monday, 1 June.