The January NRCS Rio Grande runoff forecast is lousy: a mid-point forecast of 65 percent of average at Otowi (upstream of Albuquerque) and 37 percent of average at San Marcial (downstream of Albuquerque). Based on the current snowpack, I expected worse. Forecaster Karl Wetlaufer, in the email distributing the numbers, explains:
After a wet start to the water year conditions have become drier as of late in the Rio Grande basin. In general January forecasts are for below normal volumes across much of the basin with the exception of some headwaters points in Colorado. This temporal pattern of moisture accumulation has also led to a large discrepancy between water year precipitation and snowpack, as much of the precipitation for the water year was received before the primary snowpack began to accumulate. Forecast models utilize both precipitation and snowpack for forecast values may be higher than you would anticipate in looking at snowpack alone. Particularly in much of New Mexico. It is worth bearing in mind that early season precipitation adds to the soil moisture which can in turn aid in springtime runoff efficiency.
Wetlaufer also reminds us that there’s a lot of snowpack season ahead of us. The numbers above are the median forecast. The one-in-ten wettest side (10 percent exceedence) is ~115% of average at Otowi, and the one-in-ten dry (90 percent exceedence) is less than 20% of average.