WATER SUPPLY FORECAST – May 2009

Contact: NWS - Ed Polasko (505) 244-9147
NRCS - Wayne Sleep (505) 761-4431
NRCS – Richard Armijo (505) 761-4428

Coordinated Release: National Weather Service and Natural Resources Conservation Service

The water supply forecast for early May 2009 ranges from near normal snowmelt runoff to well below normal snowmelt runoff through early summer.

Forecast flows for the Rio Grande include 86 percent of normal into Cochiti Lake and 84 percent of normal into Elephant Butte Lake. Other Rio Grande Basin reservoir forecast inflows range from 101 percent of normal at El Vado Lake to 43 percent of normal at Jemez Canyon Reservoir. Inflow to Santa Rosa Lake is expected to be 60 percent of normal while in the San Juan Basin, Navajo Reservoir is expecting 88 percent of normal inflow.

Inflow to Conchas Lake is forecast to be only 13 percent of normal.

Precipitation across New Mexico during April 2009 was near normal to above normal in the northern mountain regions but well below normal for the fourth consecutive month across much of the southern third of the state.

Seasonal precipitation, October 2008 through April 2009, ranged from far below average over most of southern New Mexico to near average in the northern mountains. Seasonal precipitation through April in the south central and southwest mountains of Colorado was near average.

Surveys by the U.S. Department of Agriculture’s Natural Resources Conservation Service indicate that snowpack water content in the Rio Grande basin as of May 1 was 86 percent of normal, and 81 percent of one year ago. In the San Juan Basin the snowpack water content is 73 percent of normal, but only 66 percent of the total of May 1, 2008.

In the Colorado high country headwaters of the Rio Grande Basin, snowpack water content as of May 1, 2009 was 95 percent of normal but only 81 percent of one year ago.

At the start of 2009, northern New Mexico snowpack water content was the best of the past 15 years at nearly 170 percent of normal. But three months of drier-than-normal and warmer-than-normal weather conditions had taken a significant toll on the snowpack.

La Niña cold water conditions in the equatorial central Pacific Ocean may have been a factor in shifting the storm track well to the north of New Mexico from January through March. The equatorial Pacific has since warmed and La Niña conditions are no longer in effect.

New Mexico reservoir storage is well below normal in the Rio Grande Basin, Canadian Basin, and Pecos Basin, but near normal at Navajo Lake. In the Rio Grande basin, storage is 67 percent of the 1971 to 2000 normal and 113 percent of last years storage at this time. In the San Juan basin, Navajo Reservoir storage is 103 percent of the 30 year normal, and 98 percent of the storage of one year ago.

Unseasonably warm temperatures in early May have accelerated the snowmelt runoff process and warmer-than-normal temperatures are expected to persist in the mountain regions of northern New Mexico and southern Colorado through at least the third week of May.

WATER SUPPLY FORECAST as of May 1, 2009

National Weather Service Office
Albuquerque, New Mexico

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