[2] The city of San Francisco became an important port during the 1850s, when the California gold rush in the Sierra Nevada mountains brought a huge influx of European and Chinese immigrants, in search of fortune.

It was around this time that European grape varieties began to be planted throughout the Santa Clara Valley, Contra Costa County and other California regions to supply the demand of the thirsty population.

[11] Geyser Peak had a Montgomery St. facility and legendary vintner Louis Petri got his start moving barrels in his family's San Francisco warehouse.

[14] George Taber, the sole journalist who attended the event, penned the article "Judgment of Paris" in Time magazine reporting the shocking results when the local judges ranked the California vintages, from Napa and Monterey, higher than the primer French labels in both Chardonnay (white) and Cabernet Sauvignon (red) categories.

San Francisco Bay is widely recognized as the well-known body of water by that name and, by inference, the land areas that surround it.

Although sources differ in how broadly they define the San Francisco Bay region, the various definitions, without exception, include the counties mentioned above.

The following sources were cited by the petitioner as being representative of the consensus among experts that the petitioned area is widely known by the name San Francisco Bay.

Also, climatologist Clyde Patton studied the same region in his definitive work "Climatology of Summer Fogs in the San Francisco Bay Area".

[1] The weather in the Bay region is a product of the modification of the onshore marine air masses by the topography of the Coast Ranges, a double chain of mountains running north-northwest to south-southeast.

These inland areas are, however, somewhat protected from the Pacific fogs, which are evaporated as the flow is warmed by passage over the warmer land surfaces.

Several smaller mountain pass gaps (San Bruno and Crystal Springs) sometimes also allow for the inland spread of coastal climate in the Bay Area when the elevated inversion base is high enough.

Marine air exits the San Francisco Bay (without having experienced the normal drying and heating effects associated with over-land travel) in several directions.

The predominant outflow is carried by the onshore northwesterly winds toward the south through the Santa Clara Valley to Morgan Hill and to the east via the Hayward Pass and Niles Canyon.

During winter months, its location south of San Francisco allows the passage of westward moving, rain producing, low pressure storms through the area.

When moist marine air from the Pacific High flows onshore over this cold water, it cools, producing fog and/or stratus cloud areas which are transported inland by wind.

The onshore prevailing northwesterly flow direction, in combination with the coastal range topographic features of counties north of the Bay and the pressure differential of the Central Valley, minimize a northward influence from the air that enters the Golden Gate.

This effect is illustrated by Hamilton Air Force Base on the northwest shore of the San Pablo Bay in Marin County.

The base gets 25 percent more rain in a season than does San Mateo, which has a corresponding bay shore location 34 miles (55 km) to the south.

These factors lead to significant temperature, humidity and precipitation differences between the areas east and west of the eastern boundary.

[1] The regional northwestern prevailing wind flow direction generally prevents the Monterey Bay influence from affecting the climate in the viticultural area.

Fog and ocean air traveling along the Pajaro River do on rare occasions reach the south end of the Santa Clara Valley to the north, but most of the Monterey Bay influence travels to the east and south (borne by the prevailing northwest wind) into the Salinas Valley and up against the eastern coastal hills.

The warming trend reverses, however, at the point where the south end of the Santa Clara Valley meets the Pajaro River.

Here wind and fog from the Monterey Bay, flowing westward through the Pajaro River gap, begins to assert a cooling influence.

Thus, it is logical to draw the northern boundary of the proposed area at the point where the Golden Gate Bridge and San Francisco Bay separate the northern counties, i.e., Marin, Napa, Solano, and Sonoma of the North Coast viticultural area from the counties of San Francisco and Contra Costa.

East of the Diablo Range lies the Central Valley, distinguished from the "San Francisco Bay" viticultural area by its higher temperature, lower humidity, and decreased rainfall.

A statement in Mr. Johnson’s book points out that the area just south and east of San Francisco Bay is wine country as old as the Napa Valley.

[21] Another writer, Robert Lawrence Balzer, devotes a chapter to "Vineyards and Wineries: Bay Area and Central Coast Counties" in his book "Wines of California".

The vineyard domain south of San Francisco is as rich and colorful in its vintage history as the more celebrated regions north of the Bay Area."