Halifax, Long Island, San Francisco

 Bedford Institute, Halifax, Nova Scotia, Canada:




Long Island, NY:




San Francisco:




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Maui Tide Patterns Table of Contents

Why are Maui's high tides so weak during winter days?  When are the highest tides?  Are new moon high tides stronger than full moon tides?  Is the Moon always overhead at high tide?  Does the Moon really lift up the ocean to create the tidal bulge?  How are the tides predicted?  If you've always been curious about the tides, you've come to the right place: Maui's Weak High Tides in Winter Anatomy of a Hole Harmonic Tide Analysis King Tides, New Moons vs Full Moons Does the Moon Lift the Ocean to Create the Tidal Bulge? Tide Lagging and Priming Halifax, Long Island, San Francisco References, Acknowledgements, Contact Info
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Maui's Weak High Tides in Winter

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 Here is a plot of NOAA high tide predictions for Kahului Harbor, Maui, in 2023: Watersport folks know that the shallow reefs in Kanaha Beach Park become problematic during winter, and this plot shows clearly how different winter is from summer in Maui in the mid-day. Terminology: " Diurnal" means a once daily tide.  Semi-diurnal means twice per day.   One might think that a word that begins "di-" would mean twice per day, since the Greek root prefix "di-" implies twice.  However, the etymology for diurnal is Latin, from dies (day), diurnus (daily). Many US ports have mainly semi-diurnal tides.  That means there will usually be two unequal high tides and two low tides.  The highest high tide is known as the "high high water (HHW)", and the lower high tide is the "low high water (LHW)".  Maui has been classified as "mixed, mainly semi-diurnal."  In 2024 Maui will have 286 days with two high tides.  On semi-diurnal days, there i
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Does the Moon Lift the Ocean to Create the Tides?

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We tend to think of the Moon's gravity "lifting" up the ocean underneath the moon in order to create the tidal bulge.  This is not how it works.  The earth's gravity is far too strong, and the ocean is too heavy, to be "lifted" by the Moon, 240,000 miles away.  Do you feel lighter when the moon is overhead?  Probably not, since the Moon's vertical force has been calculated to be one ten millionth of the Earth's gravity at points directly underneath the Moon. At points directly under the moon, such as point Z in the figure below, the gravity vector caused by the moon is perpendicular to the Earth's surface and has zero effect on the tides.  However at points not directly underneath the Moon, the gravity vector towards the Moon has a horizontal component which produces a "tractive force."  This force operates horizontally along the surface of the sea, and the sea presents relatively little resistance.  The sea is pulled from both sides to
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