National Weather Service United States Department of Commerce


GUIDANCE from the Probabilistic Tropical Storm Surge (P-Surge) model

For NWS' official FORECAST please go here

P-Surge v2.7

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Archive data HERE

Storm and Year Storm Name & Year
Since names for tropical cyclones can repeat years later, the storms here are identified with the year in which they occurred.

The storms are sorted with the most recent storm first.

Advisory Advisory
During a Tropical Storm or Hurricane, the National Hurricane Center produces advisories (aka advisories) typically every 6 hours. These advisories are referenced by number starting with 1 for a storm's first advisory.

The P-Surge model is intiated when a hurricane watch is in effect for the Continental US, which is within 48 hrs of the onset of tropical storm force winds. This means that not all advisories for a given storm have P-Surge results.

The P-Surge results are valid for a time range as discussed below in the Time Grouping tool-tip.

Type Exceedance or Probability
Exceedance products show the maximum height, in feet, that will be exceeded by a given percentage of possible storms. For example, there is a 10% chance that a location will have water levels higher than the corresponding value in the 10% exceedance product.

Probability products show the likelihood of water above a chosen height for the area. So a 3 ft probability map will show the probability that there will be 3 ft of water throughout the entire area.

Datum Datum
A vertical datum is an established surface that serves as a reference to measure or model heights and depths. All water level observations, including modeled storm surge heights, are referenced as height above a vertical reference datum.

P-Surge can be displayed either above the model datum of NAVD-88, or as water depth above ground level, aka "inundation heights".

For more information, see the National Ocean Service's page on datums.

Time Grouping Incremental or Cumulative
Above Ground Only

P-Surge above ground results are split into 6-hourly chunks which can be displayed as either the incremental water level increase for every timestep, or as the total water height increase shown every 6 hours (cumulative).

This splitting of results helps inform when the maximum threat from storm surge will occur for a given region.

Start | Stop Animate
Above Ground Only

The above ground P-Surge results show surge every 6 hours, frame 1 as the first 6 hours, frame 2 the next 6, and so on until the final frame, 17.

The Above Ground product, cumulative, frame 17, is comparable to the Above Datum product, since it is a cumulative snapshot of the entire forecast period (102 hours).


Download Data Data File Formats
P-Surge results are available 2 formats:

SHP - geospatial vector data format for geographic information systems (GIS)
GRIB2 - binary data format commonly used in meteorology to store historical and forecast weather data

Files available for download for the storm, advisory, type, datum, and time grouping chosen above.

download shp files download grib file

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