Because La Nina was so strong last year, the northern jet stream was especially active and winter storm activity was concentrated across the northern and north central Rockies eastward through the Great Lakes and northeast. In the last 30-45 days the jet stream has tended toward a split flow pattern with a portion of the energy moving into the northern Rockies and northern Plains and the remaining energy diving down into the southwest and the southern Great Basin.
What does this really mean? Essentially, the upper air lows moving across Texas are keeping moisture from moving north into the northern plains. As a result, the upper plains moisture patterns will depend on moisture from the Pacific Ocean rather than the Gulf of Mexico.
Source:; U.S. Climate Prediction CenterFigure 3. Three-month precipitation outlook for February to April 2012. What it Means for Nebraska
Nebraska has been caught between these two pieces of energy. If the low in the southern plains begins to lift northeastward before the northern Plains trough arrives, rain and/or snow could develop. If the northern Plains trough moves in first, a dry, cold pattern will develop and the moisture will go to the southern. The two competing pieces of energy eventually merge east into a strong upper air trough east of Nebraska, likely resulting in more rain/snow for the eastern Cornbelt.
As long as this pattern continues, areas of southwest through east central Nebraska will likely have the best opportunity to receive normal to above normal moisture. Unfortunately, north central and northeast Nebraska will likely be dry if it doesn’t see a big snowfall before the ground freezes, limiting moisture infiltration.
Without significant snowfall across the plains of Montana and the Dakota’s, I would rate the flooding potential for this spring as low. While the northern Rockies are getting snow, it’s not concentrated in a single region as it was last year. There is no runoff potential with the existing northern Plains snow pack, but this could certainly change before the spring melt begins.
Source: U.S. Climate Prediction CenterFigure 4. Three-month precipitation outlook for March to May 2012. Three-month Forecasts
The latest Climate Prediction Center (CPC) forecast for January-March indicates above normal temperatures for the southern Plains (Figure 1), extending north to the extreme southeastern Nebraska. The precipitation forecast indicates below normal moisture for the southern plains, extending north to the Kansas-Nebraska border (Figure 2), and moisture for the northern Rockies and eastern Cornbelt.