| Day | Date | High/Low | Forecast |
| Fri | 16th | 80/59 | Sunny remainder of day. Mostly clear evening. |
| Sat | 17th | 84/62 | Mostly sunny day with some high clouds. Some evening high clouds. |
| Sun | 18th | 82/57 | Mostly sunny day with scattered high clouds. Scattered evening high clouds. |
| Mon | 19th | 77/56 | Mostly sunny day with scattered high clouds. Scattered evening high clouds. |
| Tue | 20th | 73/53 | Sunny day. Chance of evening fog/low clouds. |
Synopsis
Off-shore flow continues, but wind gusts in Santa Ana wind prone areas are generally less than what it was several days ago (peak gusts no more than 40 mph this afternoon). Areal coverage is also a bit less than at the beginning of the week. Still, the computer models predict a small uptick in winds tonight into tomorrow morning. A more general decrease in wind should occur starting Sunday. A marginal, on-shore flow may develop as early as Tuesday (full fledged, albeit weak, on-shore flow expected for second half of next week).
High pressure aloft covers most of the West Coast (includes British Columbia). With the center circulation just west of the Pacific Northwest states, the off-shore flow weakened just enough to allow some fog patches to reach the coast early today (closest patch affected Ventura County). All the models show a secondary high pressure center forming over the Southland this weekend. This should help boost temperatures a little tomorrow (leveling off inland areas Sunday…a bit cooler closer to the coast as off-shore flow weakens). A steady cooling trend should develop early next week as the models predict weakening of high pressure aloft.
With the expected changes in the wind flow pattern early next week, a general increase in coastal fog/low clouds are likely (patchy coverage as early as MLK, Jr Day). Areas of dense fog should increase in coverage on Tuesday/Wednesday. Should on-shore flow turn out stronger than currently expected, low clouds may be more prevalent than dense fog near the coast. Regardless, this long stretch of very dry air in the coastal plain will be coming to an end sometime next week.
Well, the longer range models continue to back pedal on when a relevant chance for wet weather will occur in the state (at one time, it was predicted to start on the 17th…that’s tomorrow…not going to happen). Most of the model solutions now show an upper level trough reaching the Southland late next Friday (23rd) or a day later. If some solutions verify, widespread but modest rains will reach the Southland . Because it’s of sub-tropical origin, it will be a relatively warm storm. Most models also depict it as southern California only storm (northern California left high and dry). There is also some chance that the center of the storm will pass too far to the south (making landfall central Baja California) for widespread, relevant, wet weather (storm totals well under a quarter inch). Of course, I wouldn’t be surprised if the model consensus delays this storm for yet another day.
Most of the models show high pressure aloft rebounding temporarily on the 26th. A storm or two may reach the state sometime in the final days of January (29th or later), but for now, it’s far from clear if wet weather will reach the Southland (wet weather may stay over the north half of the state). Even amongst the wet scenarios, only modest storms are predicted to reach southern California (flooding type storms very unlikely at this time). The one thing likely in the last week of the month is that no warm, off-shore flow is predicted.
Next issued forecast/synopsis should be on Tuesday, 20 January.