Daytime temperatures Monday in parts of San Diego County could reach as high as 24 degrees above average as an early-spring heat wave is expected to ratchet temperatures up into the low 90s on what should be the hottest day so far in 2018, forecasters said.
Ramona is expected to see a high of 92 degrees Monday, which would be 24 degrees above the average temperature for this date, the National Weather Service said. Escondido is also forecast to hit 92 Monday, which would be 18 degrees above average for the city.
A predicted high of 90 degrees in Alpine Monday would be 21 degrees above average, while the forecast high of 87 in Miramar would be 19 degrees above average, the NWS said. Downtown San Diego could see temperatures close to 80 degrees, which would be about 12 degrees above average.
A high-pressure system is causing the heat and is expected to be accompanied by mostly light winds and clear, sunny skies, forecasters said. The flow of onshore air from over the ocean will be very weak Monday, allowing the high pressure aloft to heat things up without a cooling influence.
Temperatures near the coast should dip significantly on Tuesday as the onshore flow strengthens, though the cooling isn't expected to reach inland until later in the week. Gusty winds will bring cooler air and clouds to the region by Wednesday or Thursday.
Another warm period is expected to begin Friday and last through at least the early parts of next week.
