New Mexico's spring runoff forecast for March through July is looking good, according to a water-supply report released Friday.

The New Mexico portion of the Rio Grande Basin sports the fifth-best snowpack in 16 years, said Wayne Sleep, snow surveyor for the federal Natural Resources Conservation Service.

Northern reservoirs, except for Navajo Lake, are still behind their 30-year average levels for this time of year, but the main spring runoff is still a few weeks away. Navajo Lake is at 99 percent of normal and 96 percent of last year's capacity.

New Mexico owes its wet winter to the El Niño weather phenomenon, a pattern in which warmer ocean temperatures near the equator mean more moisture for the southwestern U.S.

Good snowpack in the mountains with a lot of water content usually means good river flows when the snow melts in springtime. In New Mexico, farmers, water managers, anglers, rafting companies and other water watchers eagerly await the monthly spring forecast reports from the federal agency, part of the U.S. Department of Agriculture. Those forecasts give them a heads-up about what kind of summer and fall might lie ahead.

The monthly water supply forecasts have some uncertainties. Warmer temperatures and rain can melt off snowpacks too quickly. The snowpack data snow surveyors gather remotely from mountain telemetry sites can have errors. So the runoff forecast is set up to give water watchers a range of values from the highest probability to the lowest.

Friday's forecast predicts a near normal spring snowmelt for most New Mexico river basins. The forecast says the Zuni, Gila, Mimbres and Rio Ruidoso river basins will have a stellar, above normal runoff season.

Meanwhile, Santa Fe's municipal reservoirs east of the city — Nichols and McClure — are at a combined 52 percent capacity. Last year at this time the two reservoirs were at 74 percent capacity. The reservoirs are fed by snowmelt from the Sangre de Cristo Mountains. Snow telemetry sites measure snowpack above the reservoirs at 55 inches (Santa Fe site) and 22 inches at the lower elevation Elk Mountain site.

Cochiti and Elephant Butte lakes are likely to receive near normal flows from the Rio Grande into July. Elephant Butte Lake's water storage, the largest in the state, is closely watched by the State Engineer's Office and farmers in southern New Mexico and Texas. The reservoirs' water levels determine how much water the farmers will receive and can impact the water use and storage in other northern lakes along the Rio Grande and Chama rivers.

New Mexico overall received near normal to above normal precipitation in February, according to the water supply report. The state's eastern plains, suffering under a crushing drought the last couple of years, finally received respite from two to four times the normal precipitation last month.

Weather forecasters say more snow could still be in the picture for New Mexico's mountains in the next couple of weeks. The National Weather Service predicts partly to mostly cloudy weather from Sunday through the week with a slight chance of rain or snow in the Santa Fe area.

Contact Staci Matlock at 986-3055 or smatlock@sfnewmexican.com.