Saturday, April 16, 2022

Drought: A Small Ray of Hope?

Wheat field, April 16, 2022. central Butler County, Kansas
I went out to take a look at a few wheat fields myself this afternoon and the crop probably looks the worst I've seen it in my 40+ years. While I am certainly no expert, the reports of poor crop conditions appear to be correct.

Over the next two weeks, the extended range computer models are indicating the possibility that sufficient rains may fall that could slightly ease the drought in the winter wheat belt.

How Much Rain is Needed?
Based on the Palmer Drought Index, the following amounts are what are needed to ease the drought. Note: these amounts are in addition to the "normal" rainfall amount (i.e., if normal is 2 inches and the map shows 3 inches, then 5 inches are needed).

NOAA has helpfully calculated the amounts needed.

The black areas had insufficient data to make an estimate this week. The states are broken into NOAA's "climate divisions." 

The Forecasts
Among the products produced by the major global meteorological modeling systems are "ensembles" where the model is run over and over using slightly different initial conditions. For example, we may not know the precise location of a low pressure system in the middle of the Pacific Ocean. So, that uncertainty is taken into account by running the ensembles. 

All of the major modeling systems are indicating significant rains over much of the region the next two weeks:

European Global Model Ensemble (statistically, the world's most accurate)
Canadian Global Model (medium accuracy, statistically)

United States' Global Model
(statistically least accurate)

Please do not focus on the details but rather that all three model ensembles, of varying statistical accuracy, have surprisingly similar forecasts. 

It is important to realize that, in most areas, there is little to no "excess" (e.g., more than normal) rainfall forecasted. Returning to the European ensemble, below is a forecast of which areas will have below or above normal amounts if the forecast is "perfect" (they never are).
Still, if these forecasts are correct, this will be the first two week period in quite a while the wheat belt hasn't lost ground. 

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