Commodity markets closely follow the American (GFS) and the European (EC) weather models, and it is important to understand their variations, especially at this time of year. The four-times-daily GFS forecasts out 15 days while the twice-per-day EC evaluates a 10-day period. Both models’ precipitation output has deviated significantly enough from the actuals to warrant higher levels of uncertainty in precipitation forecasts versus temperature ones. Both the GFS and EC precipitation output for the first half of July was overly optimistic on precipitation, which has generally been the case for the past six months. Despite the GFS’s recent temperature reliability, it has more often leaned too cool versus too warm in the last couple of months.

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Persons: Tuesday’s GFS, Karen Braun, Matthew Lewis Organizations: European, Midwest, EC, Crop Watch, Reuters, Thomson Locations: NAPERVILLE , Illinois, Midwest, U.S