Heat wave triggers weather by zip code -- 105 in Fairfield, 68 in Half Moon Bay

SAN FRANCISCO (CBS SF) -- A high pressure system will send waves of heat into the San Francisco Bay Area Friday, triggering a wide range of temperatures from Half Moon Bay on the coast to dangerous conditions in Fairfield to the east. 

The National Weather Service has issued an excessive heat warning for Solano County, a heat advisory for inland communities and a small craft advisory off the coast.

The comfort level of the day will very much depend on your zip code as the classic Bay Area micro-climate spread will be in full force.

The extreme heat has triggered a First Alert Weather Day away from the coast while residents on in beach communities like Half Moon Bay will be watching a fog bank build offshore and kicking up a cooling breeze.

"Of course high pressure off the coast and over the Four-Corners is bulging northward into Norcal spreading the warm dome of air across the region," the weather service said.

"This is far from a classic heat spell pattern in numerous ways," forecasters added. 

And it will be quick hitting. Temperatures will tumble back toward normal on the weekend as a low pressure system moves in from the Pacific Northwest.

"The onshore flow will increase in response to the extreme heating over the Central Valley today so it's clear that temps along the coast and bays will stay warm with refreshing breezes," the weather service said. "Will have to keep our eyes on the offshore fog bank today but should it make it towards the coast."

Even though the heat wave will be short lived, it will still be intense enough and the humidity levels low enough, to further dry out the parched, drought stricken hillsides.

Wildfire danger will be high and local fire crews on alert.

On Thursday afternoon, a fire ignited near Brentwood in Eastern Contra Costa County. Initially reported as 15 acres, it quickly grew to 200 acres before fire crews began getting a handle on it.

Fire officials hoped it wasn't a sign for what may happen on Friday.

The Bay Area Air Quality Management District has issued a Spare The Air alert in anticipation of the incoming heat. The alert asks that drivers limit their time in their cars to prevent unhealthy ozone or smog accumulation in the Bay Area.