Although its one of the drier places in the world, the west coast of the Baja Peninsula is plagued by a persistent low level cloudiness and fog. The dull grey skies, mostly in the morning, come courtesy of the high pressure system which camps in the eastern Pacific. Wind circulations around the high build a strong temperature inversion which traps moisture in the lowest 2000 meters of the atmosphere.
A cold California Current flows southward along the coast, lowering the air temperature, and bringing the atmosphere to saturation. Winds, mostly out of northwest, carry the cloud onshore to plague eclipse chasers (as many discovered in July 1991). The sun is usually able to burn this cloud away by noon, but that will be much too late for this eclipse. Depending on the lie of the coast, some areas are more prone than others to intercept the flow of moist air from the ocean. First among these is the prominent fishhook peninsula jutting from the Baja coast, terminating at Punta Eugenia. The hook creates a large bay - Bahia Sebastian Vizcaino - which scoops the moist northwest flow from the ocean and directs it inland. And it's here that the eclipse first comes ashore.
Satellite pictures show that low cloud and fog often fill the entire Desierto de Vizcaino which lies at the bottom of the Bay. Statistics collected over a 30 year period show that the cloud does not usually penetrate as far as San Ignacio but it doesn't miss by much. Nearby El Alamo records fog nearly 6 days of the month. Some of the cloudiest areas along the Baja coast report fog on one day out of three. If there were a station on the coast of the Bahia Sebastian Vizcaino it is likely that it would be a strong challenger for the foggiest location.
Those who wish to challenge the statistics and be the first to greet the ringed sun on the west side of the Baja should keep a weather eye peeled for evidence of impending cloudiness. While fog and low cloud are obvious, even a feeling of humidity or mugginess may signal that cloud will form once the sun rises. Be wary of cloud and fog in the distance, for the rising sun will quickly warm the ground and strengthen the onshore breezes which will carry the cloud inland.
All-in-all, eclipse chasers would do well to avoid much of western Baja, and seek better weather prospects elsewhere. And better prospects are only a short distance away, on the east slopes of the peninsula and along its mountain spine.
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