| Day | Date | High/Low | Forecast |
| Mon | 15th | 76/63 | Some mid/high clouds possible, but mostly sunny remainder of day. Chance of evening low clouds. |
| Tue | 16th | 76/63 | Chance of early morning low clouds; Otherwise, mostly sunny day with some mid/high clouds possible. Chance of late evening low clouds. |
| Wed | 17th | 76/64 | Chance of early morning low clouds; Otherwise, mostly sunny day with some mid/high clouds possible. Chance of late evening low clouds. |
| Thu | 18th | 77/64 | Chance of early morning low clouds; Otherwise, mostly sunny day with some mid/high clouds possible. Chance of late evening low clouds. |
| Fri | 19th | 79/64 | Chance of early morning low clouds; Otherwise, mostly sunny day with some mid/high clouds possible. Chance of late evening low clouds. |
Synopsis
High pressure aloft resides over western New Mexico this afternoon. As is common in summer, the high pressure center is predicted to meander somewhere around one of the Four Corners states (Utah, Colorado, Arizona, New Mexico) for much of the season. On occasion though, it’s center may migrate as far west as Nevada or as far south as northern Mexico (former usually promotes the most warming for interior sections of southern California). The position and strength of the high pressure aloft influences the strength of the low level on-shore flow in the Southland (complicated process as one location doesn’t always result in a particular on-shore flow strength). That, in turn, can have an influence on the areal coverage/persistence of the local, low cloud field. This applies to temperature changes encompassed by the marine layer too.
The numerical models don’t always predict accurately the subtleties with the wind flow that affect Southland weather. The models are not predicting any significant changes to the marine layer this week or next (remaining on the shallow side…areal coverage coastal plain though not necessarily all of the coastal plain). Low clouds may persist much of the day at some beaches, but day to day changes in areal coverage are possible. In general, however, don’t expect relevant changes to the low cloud pattern this week (possibly less coverage by the weekend).
Since the aforementioned high pressure is forecast to expand westward later this weekend, some renewed warming is likely for well inland areas (possibly comparable to last week for the interior). This should last well into next week. As with the previous warming cycle, I don’t anticipate major warming near the coast (as reflected in this week’s forecast). The one thing that could promote more significant warming close to the coast is if the marine layer gets disrupted by the “monsoon” flow.
Unlike what was predicted last week, upper level moisture with the Southwest Monsoon isn’t expected to leave the state now. Varying amounts of mid/high clouds are forecast for this week (possibly next week too). Sufficient moisture and atmospheric instability are promoting scattered showers and thunderstorms today (higher mountains including the Sierras and portions of the Southland deserts). Some day to day variability in areal coverage is expected (less active tomorrow but probably picking up again late in the week). At this point, none of the shower activity is predicted to get west of the mountains this week (unexpectedly happened over the past weekend).
Next issued forecast/synopsis should be on Monday, 22 July.