| cieldumort |
| (Moderator) |
| Thu Aug 24 2017 05:26 PM |
|
Re: Harvey Regenerates for Gulf Watches/Warnings up for Western Gulf
|
Quote:
Sorry cieldumort, but I wanted to verify how the storm surge is being calculated now? Is it using a straight ESTIMATION of the surge or does it include NOAA buoy information as well? With or without, since Harvey is going to be spinning up so quickly, I'm predicting less storm surge as it'll have less time really push the surf. How is storm surge observed and measured?
From NHC (May not answer your question, which is probably best directed to @NHC)
Quote:
"Storm surge is water from the ocean that is pushed onshore by the force of the winds. Flooding from storm surge depends on many factors, such as the track, intensity, size, and forward speed of the tropical cyclone and the characteristics of the coastline where it comes ashore or passes nearby. These factors are difficult to predict far in advance of a tropical cyclone affecting a particular area."
Tide Stations (NOAA): A network of 175 long-term, continuously operating water level stations throughout the U.S. serving as the foundation for NOAA's tide prediction products and providing data for storm surge estimates.
Storm Surge Tide Station
NOAA Tide Station
Measure still water (e.g., no waves)
Traditionally most reliable
Limited stations
FEMA/USGS High Water Marks (HWM): These marks are lines found on trees and other structures marking the highest elevation (peak) of the water surface for a flood event created by foam, seed, or other debris. Survey crews are deployed after a storm to locate and record reliable HWMs. GPS methods are used to determine location for coastal HWMs, which are then mapped relative to a vertical reference datum such as NAVD88.
Storm Surge High Water
High Water Marks Inside A Building
Perishable
Traditionally best method for capturing highest surge
Subjective and often include impacts of waves
Pressure Sensors (USGS): These are temporary water-level and barometric-pressure sensors which provide information about storm surge duration, times of surge arrival/retreat, and maximum depths.
Storm Surge Pressure Sensor
USGS Pressure Sensor
Relatively new method
Deployed in advance of storms at expected location of highest surge
Can contain impacts of waves
With regard to Harvey's potential storm surge, it could have the potential to be greater than you'd expect, because the system will be drawing in the ocean for a long time - even once well inland.