Rainfall variability and spatial patterns for the southeast

The southeastern region of the USA holds significant agricultural and hydrologic importance. Rainfall patterns, although highly variable from year to year, show rainfall to be greatest in the midsummer months with high intensity, convective thunderstorms. Thirty years of rainfall data from the Little River Watershed near Tifton, GA, have been analyzed. The summer storms were found to be more intense, shorter, yield less volume, and occur more frequently. For summer storms, gages separated by 1.9 km or less are likely to be highly correlated (R greater than or equal to 0.9) while this increases to 9.2 km for the winter. The seasonal data provided here will be useful in planning planting times and agrichemical management. This analysis indicates that extrapolation of precipitation data collected at off-site locations will have little utility for prediction or modeling purposes unless the off-site gage is located closer than 2 km to the site of interest.