March 3, 2010

Eastern Nebraska is likely to see a major warm-up this weekend that could lead to significant runoff and increased ice action on local tributaries, according to several weather models released this week.

Current models indicate that a surface low will be over the Nebraska Panhandle this Friday morning and likely move into northern Wisconsin by Saturday evening. If this occurs, temperatures are likely to approach the mid 50s along the Nebraska-Kansas border and the low 40s across extreme northeast Nebraska.

Current models show much of the heavier moisture occurring across northern and western Nebraska, with lighter amounts across south central and southeast Nebraska. Precipitation forecasts are for 0.25-0.50 inch of rain across northern Nebraska and 0.10-0.35 inch  across extreme southern Nebraska. An isolated thunderstorm is possible across southwest Nebraska late Friday afternoon.

If forecasted temperatures occur, substantial snow melt can be expected with fields, ditches, roads, and creeks likely to experience rising water levels. The extent of flooding in the Blue, Elkhorn, and Platte river valleys will be determined by the extent of ice on these rivers. As of March 1, the main channel of the Platte River was open at Ashland, but 90% of the river still contained ice. Upstream ice accumulation is more significant and the flood risk from potential ice jams will remain high for at least the next week.

Osceola cooperative weather observer Tom Johnson recorded 4.21 inches of liquid water in the 12 inches of snow in his front yard on February 26. His location lies on the southwest quadrant of a deep snowpack extending east and north of Osceola.

To add insult to injury, weather models indicate a more potent system will move into the central U.S. March 8-10. The current track places the heaviest moisture across northern Kansas and southern Nebraska. It is projected to bring 0.5 to 1.5 inches of rain to southern Nebraska and 0.5 inch of rain or snow to northern Nebraska.

Another significant storm is expected to develop March 12-13. While it's too early to tell whether Nebraska will see snow or rain, the models do indicate significant snowfall accumulations in the central to northern plains.

Significant snowfall accumulations are also forecast for the Central Rockies, which would benefit moisture accumulations for the upper Plate River basin.

Al Dutcher
Extension State Climatologist