A slight warming trend began Monday and is expected to persist through midweek as a weak upper ridge approaches, according to the National Weather Service.

High temperatures Tuesday are forecast to be 68 to 73 near the coast, 74 inland, 76 in the western valleys, 76 to 81 near the foothills, 73 to 81 in the mountains and 94 to 99 in the deserts, according to the weather agency.

Forecasters said the warmest days look to be Wednesday and Thursday, when inland areas will see high temperatures several degrees above average.

The marine layer will also get shallower through midweek as a result of the upper ridge building in, according to meteorologists.

Another upper-level trough then approaches the West Coast toward the end of the week, bringing another brief stretch of cooler and cloudier weather.