Arizona Summer Monsoon Season Precipitation Mapping

The maps below are focused on capturing unique elements of the summer monsoon season across Arizona including total precipitation, intensity, and frequency of precipitation events. Maps are updated once a day from June 15 - September 30th using gridded precipitation data (nominally 4km by 4km) provided by the National Weather Service Advanced Hydrologic Prediction Service. The gridded data provide a spatial estimate of true precipitation amounts across the region and should be interpreted with caution at very fine scales. More information on how the gridded data are produced can be found here.

-- Check out new Southwest U.S. Monsoon Maps here!! --

A companion site of station level plots can be found here

[New Mexico maps here]

Email Mike Crimmins with questions and/or suggestions on how to improve these plots or ideas for additional variables 
Total Precip
Total precipitation: Daily precipitation data summed from 6/15 to present.

Alternate extended colormap version here

Percent of Avg
Percent of average precipitation: A measure of the difference from expected precipitation over the period of 6/15 to present calculated against a long-term mean. 100% is equal to average for the time period shown on the map. (Seasonal Average Total Precipitation)
Days with Rain
Percent of days with rain: A count of days observing greater than or equal to 0.01" of rain divided by the number of days between 6/15 and the current date. A value of 50% indicates that rain was observed on half of the days between 6/15 and the current date.

Daily intensity index: This index is the simple ratio between the total precipitation over the time period and the number of days observing rain with units in 'inches/day'. A high value indicates that most of the total precipitation came in a small number of large or intense events.
Max Precip
Max 1-day precipitation: This maps shows the single maximum 1-day precipitation amount observed in each data grid cell between 6/15 and the current date.

Days since rain
Days since 0.05" rain event: This map indicates the number of days since at least a precipitation amount of 0.05" was observed in each data grid cell. Higher values indicate a longer time period or break since at least light rainfall was observed.
Recent precipitation: This map is the most recent one-day total precipitation. This will often be the total from yesterday through 12Z of the current day.

All daily precip maps here

Daily change in precipitation anomaly coverage: This figure depicts the daily change in the coverage of different categories of precipitation anomalies or differences from average. It is calculated by counting the number of grid cells in each anomaly category (e.g. below or above average) each day and then dividing it by the total number of grid cells for Arizona. For example, if the brown or below average category is greatest for any given day, then that indicates most of the state was observing below average precipitation.

Other SW monsoon season resources:

Climate Science Applications Program - University of Arizona Cooperative Extension

Last Updated: 5/31/19 2019 The Arizona Board of Regents. All contents copyrighted. All rights reserved.