Wisconsin State Climatology Office

USEFUL INSTRUCTIONS FOR PRECIPITATION FREQUENCY ESTIMATES
Using NOAA-14 ATLAS for WISCONSIN

Precipitation frequency (PF) estimates and associated information for Wisconsin have been produced as part of the NOAA-14 Atlas. These data have been made available through a point-and-click interface on the Precipitation Frequency Data Server (PFDS). The following instructions are meant to help in the navigation of this website.

For Precipitation Frequency at Wisconsin Locations:

The PF estimates for selected "point locations" or stations in Wisconsin can be obtained by starting on the Wisconsin page at https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_map_cont.html?bkmrk=wi

• Step 1: Select Data Type (Precipitation Depth or Precipitation Intensity), along with units and time series type (partial duration* vs. annual maximum**).
• Step 2: Select Location of point (choice of three ways):
• Latitude-Longitude entry
• Station from the pull-down list in the window; a list of Wisconsin stations used in the analysis with additional information is available.
• Use of map
• Step 3: Select PF Estimates Choose 1 of 3 tabs:
• Left= Tables
• Middle= Graphical,
• Right= Supplemental
• Step 4: For Graphical PF, further choose
• Left tab=Depth-Duration Frequency (DDF) Curves or
• Right tab=PF Estimates with 90% Confidence Intervals (choose Duration by clicking button)

* Partial duration -- Time series that includes all precipitation amounts for a specified duration at a given station above a pre-defined threshold regardless of year; it can include more than one event in any particular year.

** Annual maximum -- Time series of largest precipitation amounts in a continuous 12-month period (calendar or water year) for a specified duration at a given station.

For Wisconsin Precipitation Frequency Maps:

Color cartographic maps showing the PF estimates of precipitation frequency estimates for selected average recurrence intervals and durations across Wisconsin and sections of adjacent states are available from the NOAA Atlas 14 site. These maps are in pdf format.

• Step 1: Go to https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_maps.html
• Step 2: Select Wisconsin from state list
• Step 3: Using the accompanying table, choose Average Recurrence Interval (years) and Duration (60-min to 60-days), then submit on gray bar below.

An example would be the Wisconsin map showing the isopluvials (lines of equal precipitation quantity) for a 60-minute precipitation event with a two-year recurrence interval: ftp://hdsc.nws.noaa.gov/pub/hdsc/data/mw/mi2y60m.pdf

REFERENCE:

"Precipitation-Frequency Atlas of the United States" NOAA Atlas 14, Volume 8, Version 3.0, NOAA, National Weather Service, Silver Spring, Maryland, 2013. To be released in June 2013. https://www.nws.noaa.gov/oh/hdsc/PF_documents/Atlas14_Volume8.pdf