OK, so as it turns out I have been doing someting wrong. I love looking at the data for things like storm surge. I previously have been using an incorrect asumption. NOAA predicts storm surge but when the do their calculations they define the surge as that which is added to what is called the Mean High High Water (MHHW). If one looks at the tide gauge information near your house you will see this as the blue line on the tide graph. The red line is what the actual tide is and it usually HIGHER that the calculated blue line.
My method is conservative and I’m OK with that but still, when NOAA predicts an 8′ surge they are saying they THINK the surge will be 8′ above the calculated MHHW. So, for the East Bay tide station in Tampa the MHHM line is +0.86′ by the NAVD, say +1′ NAVD 88. With a 10′ storm surge, if the finished floor of your house is +11′ or lower by the NAVD datum then your wet.
