{"id":2339,"date":"2021-03-01T10:08:24","date_gmt":"2021-03-01T18:08:24","guid":{"rendered":"http:\/\/tradewindssailing.com\/wordpress\/?p=2339"},"modified":"2021-03-01T10:08:29","modified_gmt":"2021-03-01T18:08:29","slug":"nautical-terminator-small-craft-advisory","status":"publish","type":"post","link":"https:\/\/www.tradewindssailing.com\/wordpress\/nautical-terminator\/nautical-terminator-small-craft-advisory\/","title":{"rendered":"Nautical Terminator – Small Craft Advisory"},"content":{"rendered":"\n

<\/p>\n\n\n\n

\"Small<\/figure>\n\n\n\n

The forecast calls for a \u201csmall craft advisory.\u201d Latitude 38<\/em> once made the comment that these don\u2019t really mean anything. This is false, but I can understand how one might come to that conclusion. <\/p>\n\n\n\n

First, there\u2019s no legal definition of \u201csmall craft.\u201d However, this means you. <\/p>\n\n\n\n

Secondly, none of the many websites of the National Weather Service offers an explanation specifically applicable to our unique San Francisco Bay conditions. But a phone call or two to the NWS elicited the following thresholds for the three types of small craft advisory for our local waters:<\/p>\n\n\n\n

1) A small craft advisory<\/em> is issued if current or forecast sustained\nwinds are 21-33 knots, or frequent gusts of 21-33 knots lasting more than two\nhours are predicted.<\/p>\n\n\n\n

Outside the Gate:<\/p>\n\n\n\n

2) A small craft advisory for hazardous seas<\/em> is issued if the period of\nthe combined seas measured in seconds is less than or equal to the wave height\nin feet, except when the wave height is less than 5 feet.<\/p>\n\n\n\n

3) A small craft advisory for rough bar conditions<\/em> is issued if breaking\nwaves and\/or combined seas of 10 feet or greater are expected on the San\nFrancisco Bar.<\/p>\n\n\n\n

The confusion over this advisory results partly from the difference between our summer conditions and winter conditions. In summer, a daily thermal low in California\u2019s central valley pulls wind from the sea through the path of least resistance, which is the Golden Gate. A venturi effect amplifies the velocity in the \u201cslot,\u201d and from there the wind fans out and its speed diminishes. So in the summer, a sailor in the Oakland Estuary may see 10 mellow knots while a boat near Alcatraz may be well reefed down in 30 knots.<\/p>\n\n\n\n

In the winter, however, wind velocity is generated by Pacific weather systems that can have massive fronts of over 1000 miles in length. These sweep over the entire bay and may generate sizable waves, so there will be no place to hide. <\/p>\n\n\n\n

Since the NWS makes predictions for the highest wind anywhere within the forecast area<\/em> on a given day, and does not slice our area any smaller than \u201cSan Francisco, San Pablo, Suisun Bay and the West Delta,\u201d you need to know summer from winter patterns to interpret this advisory. In fall and spring, take a closer look at the local weather reports, as winds can be generated by either dynamic.<\/p>\n","protected":false},"excerpt":{"rendered":"

The forecast calls for a \u201csmall craft advisory.\u201d Latitude 38 once made the comment that these don\u2019t really mean anything. This is false, but I can understand how one might come to that conclusion. First, there\u2019s no legal definition of … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":13,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[31],"tags":[],"class_list":["post-2339","post","type-post","status-publish","format-standard","hentry","category-nautical-terminator"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_likes_enabled":true,"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/posts\/2339","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/users\/13"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/comments?post=2339"}],"version-history":[{"count":2,"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/posts\/2339\/revisions"}],"predecessor-version":[{"id":2710,"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/posts\/2339\/revisions\/2710"}],"wp:attachment":[{"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/media?parent=2339"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/categories?post=2339"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tradewindssailing.com\/wordpress\/wp-json\/wp\/v2\/tags?post=2339"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}