| Day | Date | High/Low | Forecast |
| Fri | 7th | 61/49 | Chance of light showers remainder of morning; Possible partial afternoon clearing. Partly cloudy evening. |
| Sat | 8th | 64/48 | Variable high clouds but mostly sunny day. Variable evening high clouds. |
| Sun | 9th | 65/49 | Variable high clouds but mostly sunny day. Variable evening high clouds. |
| Mon | 10th | 60/47 | Chance of some morning low clouds; Otherwise, scattered high clouds. Scattered evening high clouds. |
| Tue | 11th | 59/47 | Partly cloudy day. Partly to mostly cloudy evening. |
Synopsis
The latest storm has essentially passed. Only some isolated, light showers remain around some locales (mostly around/over the mountains). This one stayed more organized than what the computer models had predicted. So, it turned out to a be a decent, soaking storm for many areas west of the mountains. Rainfall from yesterday through today was over a half an inch in many lowland areas away from the mountains. Some areas around foothills/mountains received over two inches (incomplete storm totals, as of this writing). The campus, auto-gauge recorded just over two inches (two-thirds with the first storm earlier in the week), but based on past recordings, the auto-gauge has a high bias (1.6 inches may be closer to the truth…official measurements slated for this weekend).
A dry weather weekend in on tap, but a return to widespread, seasonable or warmer than normal weather isn’t expected. A weak, but marginal, off-shore flow is predicted, but it should decay by Sunday afternoon. Little or no low clouds are anticipated for the weekend, but variable high clouds should preclude clear skies. Temperature-wise, nights should cool off noticeably from recent days (some polar air influx associated with the marginal, off-shore flow). High pressure aloft should be fairly weak, as high pressures go. So, subsidence warming by the off-shore flow shouldn’t yield a lot of warming (at best, seasonable temperatures in some areas west of the mountains on Sunday).
All the models predict a general tough pattern over the West by Monday. Increasing on-shore flow that starts Sunday afternoon should promote a return of marine layer clouds (not necessarily with an extensive overcast, however). By Tuesday morning, some model solutions show a chance for scattered, light showers over/adjacent to the higher mountains. Any warming cycle that occurs over the weekend should get reversed early next week (nothing drastic at first).
Depending on which model solution is right, rain from new Pacific storm could start in southern California (San Luis Obispo/Santa Barbara Counties) on Wednesday. This predicted storm, while it should be a more typical, cold storm, is forecast to be tapped into an atmospheric river (a substantial one, according to many models). Unlike last week’s systems where the Southland was largely left dry, the one predicted for next week may orient the atmospheric river more squarely over southern California. IF true, significant precipitation is likely (potential for widespread 2 to 3 inch rains away from the mountains…twice as much for coastal facing foothill communities). Of course, this also assumes some models are right placing the thrust of storm dynamics over the southern third of the state.
The timing for this predicted storm is still uncertain. Wet weather could begin west of L.A. County Wednesday morning, but there are model solutions delaying that by up to half a day (i.e. beginning Wednesday evening). Some model scenarios today include precipitation nearly all day on Thursday (13th). Periodic heavy to intense rain would be possible. Snow levels should begin around 7000 feet but lower to 6000 feet during the height of the storm (near 5000 feet with post-frontal showers). With good storm dynamics, the weather will likely be breezy for a time (not just ahead of the storm due to strong, on-shore flow). Based on many model solutions, inclement weather should be winding down on Valentine’s Day (pretty much all gone by evening).
I should caution that all of the above is based on current, model trends. It’s possible that the rain timeline will change in the coming days. While preparations for a very strong storm are prudent, it’s not a certainty as of yet (also a possibility for intense precipitation to fall over just a narrow portion of the Southland…yet to be determined). At this point, I’m confident in cooler than normal weather next week and at least some wet weather sometime in the second half of the week. Details remain to be resolved. Oh, for anyone interested, the subsequent Presidents’ Day weekend looks dry and warmer.
Next issued forecast/synopsis should be on Monday, 10 February.