Subject: Tide Prediction Web Sites
Date: Aug 9 21:41:16 2000
From: Douglas Canning - dcanning at igc.org


In response to the request to repost web URLs for on-line tide prediction...

There are two tide prediction web sites I prefer.

One is saltwatertides.com at, of course, http://www.saltwatertides.com --
or if you want to go directly to the Washington state page,
http://www.saltwatertides.com/dynamic.dir/washingtonsites.html -- here you
can select any one of the approximately 180 tide gages in the state, and
print a tide table covering up to 14 days. At any time their database
covers 12 months -- one month into the past and 11 months into the future.
No graphics; just standard tide tables.

The other is Nautical Software's web site at http://www.tides.com --
Nautical Software publishes Tides and Currents Pro, the software I normally
rely on. At their web site you can call up a tide prediction graphic for
"today" or "tomorrow" for any of the Washington tide gages which includes
both the two daily highs and lows, plus a table of hourly tide levels.
Unfortunately, the web site interface is kinda clunky. Their software
product, however, is very good.

Another option is WWW Tide and Current Predictor at
http://tbone.biol.sc.edu/tide/sitesel.html which offers versatile choices
for tables of graphical plots but inexplicably and randomly provides tide
levels in feet or meters for different tide gages.

Finally, if you want to find out what the tides *actually* were during the
past day try Tides Online at http://tidesonline.nos.noaa.gov/ and select
"State Maps" and then click on Washington. You can select a plot of the
predicted and recorded tide for any of the eight primary tide gages. In
Data Listing mode you can get a table of predicted and recorded tide levels
at a 6 minute interval.

Why would anyone care about predicted vs recorded tides? While normal
variation from the predicted is only a few tenths of a foot, during days of
unusually low atmospheric pressure, and during El Nino winters, the
variation can be a foot or more. During the 1997-98 El Nino, tides were
running about a foot above the predicted most of the winter, and up to
three feet above predicted when low pressure systems and storms moved
onshore. That's largely why we had so much beach erosion at Ocean Shores
that winter. The recent erosion which closed Damon Point Road and our
access to Damon Point itself is quite possibly related to after effects of
the El Nino erosion of two years ago.

****************
Douglas Canning
Olympia, Washington
dcanning at igc.org
****************