Climate Summary
Above normal temperatures and below normal precipitation was the general rule for the month of November across Nebraska (Figure 1). Average temperatures were 4-8°F above normal and numerous daily maximum temperature records were set during the first and third week of the month. On average, there were three above normal temperature days to each below normal day.
Precipitation was below normal across the western two-thirds of the state and east central Nebraska. The remaining third of the state reported above normal moisture due to the impacts from two storm systems that crossed the state. The first system brought widespread rain and freezing rain to eastern Nebraska which resulted in localized tree and power line damage from central through northeastern Nebraska.
The second system passed through the state the 23-24th and brought rain to the southeast and snow to the northeast. Unfortunately, most of the western half of the state were fortunate if they received more than a tenth of an inch from this storm and the 9-10th system. Between summer drought and a very dry fall across western Nebraska, the fire danger continues to be elevated whenever warm, dry, and windy conditions develop.
The primary concern going into the winter is the poor fall moisture trend in building soil moisture reserves for the 2021 cropping season. Figure 3 shows that the precipitation departures from September through November (fall soil moisture recharge period) for Nebraska. No location in the state has received normal moisture this fall and accumulated precipitation deficits were greatest across the central third of the state, as well as northeast Nebraska.
Crop Progress and Impacts
Harvest activity of warm season crops wrapped up early in the month according to Nebraska Agricultural Statistics Service (NASS). This harvest proceeded at the fastest pace since 2012 with only two major storm systems delaying harvest activity. The first was in early September at the beginning of harvest and the second was the third week of October when less than 25% of the crops remained unharvested.
Warm and dry conditions during November continued to stress newly emerged wheat due to the lack of root zone moisture across western Nebraska. Cover crops finally emerged on dryland acres and the warm temperatures during November helped promote some growth, but far short of what would be expected if soil moisture during October would have supported stand emergence.
There were positive impacts from the warm and drier than normal conditions. The lack of precipitation activity gave producers a large window to work on fall fieldwork and provided good grazing weather for cattle without the need for supplemental feed due to excessive cold and wet conditions.
Drought conditions have deteriorated further across western Nebraska due to the accumulated dryness this fall. Extreme drought (D3) has now expanded into southwest and parts of south central Nebraska (Figure 4). Abnormally dry (D0) conditions across the Sandhill region in early November have shrunk significantly and have been replaced by Moderate drought (D1) as the month progressed.
The lack of normal moisture this fall after the development of drought this past summer can be seen in the crop report issued by Nebraska Agricultural Statistics Service (NASS). At the end of November, NASS indicated that 65% of topsoil (top one foot) and 71% of subsoil moisture (below one foot) was short to very short. Forty-five percent of the pastures across the state were rated poor to very poor, while 26% of the wheat acreage was given the same rating by NASS. With winter precipitation normally representing about 7% of our annual total, major improvement in these conditions will not likely occur before the end of this winter.
Outlook
The Climate Prediction Center (CPC) released their December temperature and precipitation outlooks November 30 (Figures 5 & 6). CPC projects above normal temperatures from the southwestern through northeastern United States, with the highest likelihood for these conditions assigned to the northern Plains and upper Midwest, including Nebraska. The Pacific Northwest and the southeastern United States have equal chances of above, normal, or below normal temperatures, except for southern Florida where below normal temperatures are expected.
Below normal precipitation is projected for the entire High Plains region, the Mississippi River valley, the western Great Lakes and the southern two-thirds of region west of the Rocky Mountains. The northeastern United States is projected to receive above normal moisture, while the remainder of the United States has equal chances for above normal, normal, or below normal precipitation.
La Niña conditions in the Equatorial Pacific are approaching the bottom range of a strong event. Of the 11 strong La Niña events in recorded history, seven of them resulted in below normal average temperatures for the winter season across Nebraska. At the beginning of December the GFS model indicated above normal temperatures were likely through the 10th of the month with no appreciable moisture. By mid-month, the GFS indicates that Arctic air will begin to move southward into the United States.
With colder air forecast to move in to the region during the middle of the month, there are signs that a stormy pattern will develop across the central United States. If this materializes it would help reinforce cold air and help offset some of the above normal temperatures predicted for the first half of the month. However, if the storm stays east of the region, upper level ridging from the western United States will likely build eastward and continue the trend of above normal temperatures and below normal moisture into the second half of December.
Source: Al Dutcher, Agricultural Extension Climatologist with the Nebraska State Climate Office