SAN DIEGO (FOX 5/KUSI) -- Tuesday's temperatures in Southern California, both maximum highs and overnight lows, broke records amid an early October heat wave. The area could see record-breaking temperatures through Sunday in some places, especially inland valleys, mountains and deserts dealing with extreme risk of heat. Temperatures are running 10 to up to 20 degrees warmer than normal for this time of year.  Excessive Heat Warnings for San Diego County valleys and deserts have been extended through Monday evening as an area of high pressure parks itself over California. Pilot flying Helene rescue missions in NC ordered out, threatened with arrest A Heat Advisory for the mountains has also been extended over the next several days.  It is a very different story for those at the immediate coast, where lifeguards are reporting less than a mile visibility as of 1 p.m. Wednesday afternoon due to dense fog.  The coastal marine layer will deepen going into Thursday, which will keep the foggy conditions at the beach and possibly even bring tough driving conditions farther inland into coastal mesas and higher terrain for the morning commute.  There's a slight dip in temperatures heading into Friday as the heat dome shifts a bit to the east, but it looks like it will change its mind and return to California for the weekend.