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NOAA Atlas 14 Precipitation Frequency Estimates
in GIS Compatible Format

This web page provides access to NOAA Atlas 14 precipitation frequency estimates with upper and lower bounds of the 90% confidence interval in GIS compatible format. For Volumes 2 and 3, only partial duration series (PDS)-based grids are available for download; annual maximum series (AMS)-based grids can be calculated by applying ratios from Table 4.6.2 from corresponding NOAA Atlas 14 documents. For NOAA Atlas 14 Volume 1, and Volume 4 and above, both, AMS- and PDS-based grids are available for download. Please note that the precipitation frequency estimates for each volume of NOAA Atlas 14 were computed independently using all available data at the time. Some discrepancies between volumes at project boundaries are inevitable and they will generally be more pronounced for rarer frequencies.


To display and interpret the data, two separate files are needed:
  1. File with zipped ASCII grids - This file contains the final, spatially interpolated, high-resolution NOAA Atlas 14 precipitation frequency estimates with confidence limits, and is the basis for the PFDS interface results.

  2. Grid metadata file - This file contains information on projection, grid resolution, precipitation units, and other details relevant to data shown in ASCII grid files. The grid metadata file is in the XML format and is automatically downloaded with zipped ASCII grids. The grid metadata file can also be viewed and downloaded separately below (left-click to view, right-click/Save As to download):
         Volume 1: Semiarid Southwest (sw)
         Volume 2: Ohio River Basin and Surrounding States (orb)
         Volume 3: Puerto Rico and the U.S. Virgin Islands (pr)
         Volume 4: Hawaiian Islands (hi)
         Volume 5: Selected Pacific Islands - click to see sub regions
  3.      Volume 6: California (sw)
         Volume 7: Alaska (ak)
         Volume 8: Midwestern States (mw)
         Volume 9: Southeastern States (se)
         Volume 10: Northeastern States (ne)
         Volume 11: Texas (tx)

The files either can be downloaded 1) via pull-down menu, 2) by anonymous ftp or 3) via web browser. Ftp is recommended for multiple-file downloads. To obtain precipitation frequency estimates without downloading files, please visit the PFDS interface.

1) Via pull-down menu:

2) By anonymous ftp:

Action Type this
Open ftp to the server ftp
Login as anonymous user anonymous
Give the password "your e-mail address"
Switch to binary mode binary
Change directory cd pub/hdsc/data/xx/ (replace "xx" with an abbreviation, abbreviations can be found at the top of the page in parenthesis, e.g. "ak" for Alaska)
Get one file Example: mget (this will download the 100-year 24-hour data for the Volume 7: Alaska)
Get several files Example: mget ak* (the wildcard '*' in this case will get Alaska data for all frequencies for the 24-hour duration)
Quit ftp quit

3) Via web browser: alternatively you can peruse the ftp directory via a browser.

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Page Author: HDSC webmaster
Page last modified: April 21, 2017
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