Starting with January we are using a different tide location for our prediction charts. For as many years as we can remember we have been using the NOAA Nummy Island tide predictions for our official tide predictions. Nummy Island tide predictions like most tide predictions in our area are based off a reference station which in our case is Cape May and a difference is added or subtracted to come up with a prediction for Nummy Island. After several years of posting the Water By the Numbers posts on Facebook it was clear that Nummy Island tide times were different that what we were seeing. For those that don’t know Nummy Island is located between North Wildwood and Stone Harbor (Ocean Drive takes you over it). The next nearest location and probably better suited for the back bay areas of North Wildwood is the West Wildwood tide prediction. So starting on January 1st, 2020 we will be using the tide prediction times for Grassy Sounds – West Wildwood as our tide predictions. While adopting a new prediction location really doesn’t change anything that happens with the physical tides the only real change is that the high and low tides will happen a half hour later than it previously was predicted. Most people will not notice the change and the only people that might have to do some thing are those with tide clocks or phone applications they use to track the tide and once they are changed nothing else is needed.
Next in November a staff member had the opportunity to meet one of the meteorologist from the Mount Holly – Philadelphia office of the National Weather Service. As a result of that meeting and a series of back and forth emails we learned the following regarding our understanding of the tide heights and what the NWS minor / moderate / major flooding mean to our area. For years because the NWS in their text version of Coastal Flood Warning provides predictions for both Cape May and Ocean City we used the tide heights of 6.7 feet as minor, 7.7 feet as moderate and 8.7 as major they were listed with Cape May. (measurement are feet above MLLW). In response to our inquiry the NWS responded “The values 6.7 (minor), 7.7 (moderate) and 8.7 (major) were developed specifically for the Cape May Ferry tide gauge. They were never meant to be used for the North Wildwood gauge due to the variability in MLLW from location to location. We at the NWS think that 6.0 (minor), 7.0 (moderate), and 8.0 (major) are more suitable values for North Wildwood. Those values would put you in synch category-wise with all the other oceanside gauges in Cape May County. When we issue a Coastal Flood Advisory you can expect water levels in the 6.3 to 7.0 foot range at North Wildwood. (We don’t issue advisories for low end minor events). When we issue a Coastal Flood Warning you can expect water levels of 7.0 feet or greater at North Wildwood. A warning would indicate that moderate to major flooding is forecast.”
Going forward we will be taking the recommendation of the National Weather Service and will incorporate the minor / moderate / major tide heights. This doesn’t change the tide and tide heights that we have been observing for years however it will give us a better understanding of what to expect when we hear a National Weather Service Coast Flood Advisory / Watch / Warning. Currently we see water at several locations around storm drains on Delaware Avenue when the tide reaches 6.0 and this height will vary from 5.9 to 6.2 depending on the wind speed and direction. So when we or the NWS says “minor” flooding for our area you can expect water from 6.0 to 6.9 feet which is generally water in the gutters of Delaware Avenue and adjacent side streets. Moderate is 7.0 to 7.9 feet which is generally water some areas of Delaware Avenue, New York Avenue, 400 West Spruce Avenue, North Delaware Avenue and adjacent side streets. Major Flooding starts at 8.0 feet and water will be from the west side up and onto sections of New Jersey Avenue and in some areas water will continue into the 100 block East of the adjacent side streets.
For those that follow the tide heights on the municipal tide gauge and know what the tide heights are when water is around your property there is no change. For those that key in on the NWS terminology of minor – moderate – major rather than numbers all of us are now on the same page. As far as the tide predictions the new location should bring us closer to the time when the tide will crest and start going down. The 2020 Tide Charts listing the high and low tides for the year are available by clicking the link called 2020 Tide Charts in the left hand column of this page.