The moderate strength El Nino event continues in the Eastern Tropical Pacific. Its effect on the atmosphere has been negligible for a large part of this winter season. However, some changes in the atmospheric circulation were noted beginning in late December and into early January, characterized by reduced ridging in the western United States and more frequent disturbances traversing the southwest United States. However, while these changes brought cooler temperatures to the North and South Platte basin, precipitation was light. Overall, the South Platte basin tends to benefit more during El Nino events compared to the North Platte, and this effect is usually manifested later in the winter season.
North Platte and South Platte basin snowpack is currently tracking very close to seasonal norms, which is a positive sign given some dryness seen at lower elevations.
The latest forecast shows little change compared to December, with generally below normal flow expected in the North Platte basin and near normal flow projected in the South Platte. The Lewellen projected flow increased by about 25% from around 80K acre-feet to just over 100K acre-feet – a positive sign.