Wet or White Christmas
There is growing consensus for the transition to an active, stormy pattern as we head into the week of Christmas. Indeed the CPC is very bullish on moisture across the whole state and region for the period between 23-27 December. Right now it looks wet, perhaps quite wet, across the eastern third to half of Nebraska with snow probable across the western half of the state on the 24th with snow possible in the eastern section of the state between late on the 25th and early on the 27th. At a minimum, plan on an extended period of overcast starting this next weekend, particularly in the east.
What we know
A trough will move into the southwest later this week bringing needed moisture to that part of the country and will then move to the northeast into the central U.S. This trough will be bringing sub-tropical moisture via southwest flow aloft and will also be tapping moisture from the Gulf of Mexico in the lower levels of the atmosphere. At the surface an area of low pressure will be moving from the lee of the Rockies into the Southern Plains and then into the Midwest.
Meteorology to English translation: Precipitation is looking likely early next week in Nebraska.
What we don't know
Exact Track: The current forecast is for the surface low to slowly track from eastern CO east-southeast into the northern part of OK before turning to the northeast and heading into the Midwest. Changes in the track of the storm will dictate how much precipitation we get and what kind precipitation type certain places get. Current thinking is western NE will have a period of snow on Christmas Eve with rain in the eastern half of the state, with the main rain/snow line being somewhere between North Platte and Kearney. As the storm starts its northeastward movement, how far west it is will dictate whether eastern NE picks up some between Christmas night and early on the 27th. Worth keeping an eye from York and points east. If it tracks over Kansas City, the eastern third of the state would be in a favorable position to pick up snow. If it tracks closer to St. Louis, eastern NE will not have a snow threat.
Timing: Current projections are that precipitation will be affecting most, if not all, of the state on Christmas Eve, with additional precipitation over eastern NE possible later on the 25th into the 26th. A slower or faster evolution would affect the windows of time where travel might be more problematic.
Strength: This appears to be a potent trough with the possibility to being generous precipitation to a large section of the central U.S. and the possibility to disrupt travel. However, the sharp temperature gradient and "phasing of the polar and subtropical jets" needed to produce a very strong storm do not appear to be in place. Thus, the possibility of a storm resembling the 2009 Christmas blizzard or the March 2019 storm is low. It's also early to give precise projections on amounts of snow and rain. But my best guess now is 3-6" of snow across western NE on the 24th and between 0.50-1.50" of rain in the eastern half of the state on the 24th, with low confidence in 2-4" of snow in eastern NE post-Christmas.
Best Advice
Pay attention to the forecast as we get closer to the weekend and have a plan to adjust travel plans if necessary.
Eric Hunt, University of Nebraska Extension