The weather outside isn’t frightful.And that could be a problem if it continues.A ridge of high pressure in the Pacific Northwest is keeping December unusually dry in California prompting water managers to take notice.While no one is ready to warn about a possible drought year, the numbers do point to a dry trend.For the Central Sierra that covers the Stanislaus River watershed that Manteca, Ripon, and Lathrop rely on as well as the drainage basin for the Tuolumne and Merced rivers December rainfall is 4 percent of normal and the snowpack is at 40 percent of average for this time of year. “It points to how we always have to be mindful of how we use water,” noted South San Joaquin Irrigation District General Manager Peter Rietkerk. The dry weather and above average temperatures has triggered some farmers to inquiry about the possibility of an early winter irrigation run if conditions persist.