DROUGHT: The Weekly Drill behind the U.S. Drought Monitor

March 26, 2013 U.S. Drought Monitor Map

The U.S. Drought Monitor (USDM) is created by following a well-established series of events. Each week and on a rotating basis, one author from the U.S. Department of Agriculture, the National Oceanic and Atmospheric Administration, the National Drought Mitigation Center at the University of Nebraska–Lincoln or the Western Regional Climate Center assumes responsibility for preparing the map and accompanying narrative. With each author rotation, the previous author informs the current author about ”hot spots”  where conditions have been getting progressively worse, or better, but they have not yet tipped the USDM into a more, or less, severe category in the previous week’s report. This transition conversation between authors serves as a way to prioritize the development of the map by focusing first on obvious changes.

That initial discussion leads into a well-defined set of steps, which form a weekly timeline for the entire process:

Friday: The author begins examining all the indicators since the previous Tuesday and looks for places that have reported precipitation, which might lead to drought relief, and places that already had been or have become dry, which might support drought development or intensification.

Sunday: Another look at the indicators since the last map.  This fresh look helps the author set up his “game plan” for proposing and implementing changes to the weekly analysis.

Monday: Begin in-depth analysis of the data through the use of a Geographic Information System  and personal observations, and start making physical changes to the map. The author for each week is in charge of synthesizing the drought indicators including temperature, precipitation, soil moisture, fire danger, streamflow, and a slew of others. In a common week, an author will look at literally hundreds of indicators for different geographic regions as well as for specific points (station data), in order to create the national map. 

Each author also examines impact information especially in data-sparse locations because the physical indicators will not adequately represent the severity of a drought. Impact information can come from a news article or from a personal observation, such as from a farmer who reports that he had to sell cattle because of lack of feed or water.

Synthesizing all of the information, the author generates the first draft of the USDM map for circulation.

Tuesday: The last day of data ingest. The data cutoff for Drought Monitor maps is Tuesday at 7:00 a.m. (Eastern Time). Changes to the map are made as needed based on the data since the prior Tuesday. Often, a second draft, and occasionally a third, is provided to about 300 climatologists, extension agents, and other experts across the Nation for review and for what we call “ground truthing,” which is to substantiate the information from the field compared to the evidence from the data.

Wednesday: Comments from reviewers flow in up until about noon. Once comments about the working version of the map have been considered and addressed, the narrative to accompany the report is developed and circulated for additional review, again incorporating comments to update the text as needed.

Thursday: The weekly map and narrative are released to the public at 8:30 a.m. (Eastern Time).

This is part of a series of articles about monitoring and assessing drought conditions across the United States. Check back next week to learn more about the importance of drought indicators and check out the history and function of the drought monitoring system in the United States.