SAN DIEGO (KGTV) \u2014 San Diego County is heading into another stretch of warmer and increasingly humid weather this week as high pressure builds over Southern California.<\/p>\n
The week begins relatively mild, with temperatures near or slightly below seasonal averages. Highs are expected to reach the mid to upper 70s along the coast, the mid-80s in western valleys and the low to mid-90s across the inland valleys.<\/p>\n
Temperatures will gradually climb through the middle of the week as a broad area of high pressure expands westward. By Wednesday and Thursday, some communities could be running about 3 to 7 degrees warmer than normal.<\/p>\n
The National Weather Service expects widespread moderate HeatRisk across inland valleys, lower-elevation mountains and deserts from Wednesday through Friday. The hottest conditions will remain in the deserts, where temperatures could reach or exceed 110 degrees in some locations.<\/p>\n
Hotter days and warmer nights<\/p>\n
Humidity will also remain elevated throughout the week, making the heat feel more noticeable and limiting how much temperatures can cool overnight.<\/p>\n
Higher dew points are expected to keep nighttime temperatures several degrees above normal, especially away from the immediate coastline.<\/p>\n
For San Diego County, that means another stretch of hot and muggy afternoons inland, followed by relatively warm nights.<\/p>\n
Marine layer becomes shallower<\/p>\n
Coastal communities will continue to get some relief from the marine layer, although it is expected to become increasingly shallow as high pressure strengthens.<\/p>\n
Areas of low clouds and fog will develop during the overnight and morning hours, but the clouds will have a harder time reaching farther inland as the week progresses.<\/p>\n
Most of the marine layer will eventually become confined to the coast and far western valleys before clearing during the morning and afternoon.<\/p>\n
Monsoon thunderstorms could return<\/p>\n
Another change arrives toward the end of the week.<\/p>\n
As the center of high pressure shifts toward the Four Corners region, monsoonal moisture is expected to begin moving back into Southern California.<\/p>\n
That will bring about a 15% to 20% chance of afternoon showers and thunderstorms across the mountains and high desert Thursday through Saturday.<\/p>\n
Most coastal and valley communities in San Diego County are expected to remain dry, but anyone heading into the mountains later this week should keep an eye on changing conditions.<\/p>\n
Temperatures could also ease slightly toward the weekend as the high-pressure system moves farther east.<\/p>\n
What to expect this week<\/p>\n
San Diego’s weather pattern will largely be defined by gradually rising temperatures, increasing inland heat, muggy conditions and a shrinking marine layer through the middle of the week.<\/p>\n
By Thursday, attention turns to the mountains, where the return of monsoonal moisture could once again produce isolated afternoon thunderstorms.<\/p>\n
For most of the county, however, the main story will be the heat and humidity \u2014 particularly across inland communities.<\/p>\n
Sunday\u2019s high temperatures<\/p>\n
Here\u2019s what to expect across the region Sunday:<\/p>\n