Drier, Colder Weather Now, but Storms Likely in Late November

Two US maps, one showing departure from normal temperature for October 2018 and the other showing departure for October 2019.
Figure 1. Comparison of departure from normal temperatures in October 2018 (left) and October 2019. Note: Temperature ranges per color differ between the two maps. (Source: National Weather Service)

Drier, Colder Weather Now, but Storms Likely in Late November

Harvest activity across the state has made great strides over the past two weeks due to a lack of significant moisture chasing producers out of their fields. Nebraska Agricultural Statistics Service reported that 60% of the corn crop had been harvested as of Sunday, Nov. 3, an increase of 16 percentage points from the previous week. The soybean harvest is virtually complete at 94%.

Our saving grace during the month of October revolves around two major storm systems that dropped significant snow and rain accumulations to our north, south, and east. The first storm blanketed the Dakota’s with up to two feet of snow the second weekend of October. The second major event occurred the final weekend of October and brought widespread snow to the front range of the Rockies before heading northeast and slamming the central and eastern Corn Belt with heavy rain and wet snow.

In east central and southeast Nebraska, the first measurable snowfall for most locations occurred 14 days later than last year. However, looking at Figure 1, it is apparent that October 2019 has delivered more cold air into the region than we experienced in 2018. Whether this means anything is certainly up in the air, but it does indicate that cold air following fronts this fall are stronger at this point of the season than we experienced last fall.

Over the next two weeks, numerical weather models are in good agreement with each other and point to a drier- and colder-than-normal pattern for Nebraska. It appears this period will be dominated by an upper air trough over the eastern half of the country, with ridging over the southwest, southern Great Basin, and the Southern Rockies. Any precipitation events that occur will originate from the northwest, usually the source of fast-moving systems with dry snow, high winds, and cold temperatures.

As we enter this weekend, a beautiful fall day is in store for Saturday, as temperatures should reach the low 60s south to upper 50s north. A very strong cold front moves through the state on Sunday, bringing high winds, clouds, and possibly a brief snow flurry to light snow. Accumulating snowfall will likely be confined to the Dakota’s and Minnesota. This Arctic air looks to hold through the middle of next week, with Monday and Tuesday set to see highs in just the 20s and 30s. Temperatures may briefly move into the 40s Wednesday, before another cold front brings temperatures back into the 30s on Thursday.

By next Friday, weather models indicate that temperature will begin to moderate and approach the 50s due to the western U.S. upper air ridge pushing eastward. Another surge of Arctic air is forecast to move into Nebraska a week from Sunday (Nov. 17), but it is presently not expected to push as far south or last as long as next week’s event. By Tuesday, November 19, the western U.S. ridge expands eastward in response to a strong storm system entering the west coast of United States.

This system will need to be watched closely as there are signs that a stormy pattern will develop for the western U.S. during the final two weeks of November. If the models are correct, this heavy precipitation event should bring an end to the significant wildfire threat across the northern two-thirds of California. It usually takes about a week for upper air troughs to move from the west coast into the central U.S, so the last full week of November could be stormy across the central High Plains if the models have the correct interpretation of the jet stream pattern.

Bottom line, precipitation will be minimal to non-existent for most of the state over the next two weeks, but temperatures will be well below normal for most of this period. Arctic air usually means a dry air mass, so if corn moisture can continue to decrease under these conditions, much of the remaining corn across the state stands a decent chance of being harvested before inclement weather arrives.

What is certain is that with next week’s cold temperatures, soil surfaces in the Dakota’s, Minnesota, and Wisconsin will likely freeze, which could help support combines where fields have been too muddy to harvest. The biggest question for these producers will be if the ground remains frozen or thaws out after warmer air arrives across the region the third full week of this month.