January 2021 Ag/Climate Update

December Temperature Trend
December Temperature Trend

December 2020 Average Temperature Departure From Normal Source: High Plains Regional Climate Center ACIS Mapping Tool

December Temperature Trend

December Precipitation
December Precipitation

December 2020 Precipitation Source: High Plains Regional Climate Center ACIS Mapping Tool

December Precipitation

December Precipitation Trend
December Precipitation Trend

December 2020 Departure From Normal Precipitation Source: High Plains Regional Climate Center ACIS Mapping Tool

December Precipitation Trend

Water Year Precipitation Trend
Water Year Precipitation Trend

October - December 2020 Departure From Normal Precipitation Source: High Plains Regional Climate Center ACIS Mapping Tool

Water Year Precipitation Trend

January Temperature Outlook
January Temperature Outlook

January 2021 Temperature Outlook Source: NOAA Climate Prediction Center

January Temperature Outlook

January Precipitation Outlook
January Precipitation Outlook

January 2021 Precipitation Outlook Source: NOAA Climate Prediction Center

January Precipitation Outlook

December Climate Impacts on Agriculture

Very warm, dry, and at times, windy conditions dominated the first three weeks of December. Producers were granted a favorable period for completing fall field work and other related projects. These conditions provided favorable grazing weather for cattle, helping to reduce supplemental feeding costs.

On the flip side, the continuing dry conditions are a concern for the winter wheat crop. Dry surface conditions make cold air penetration into the root zone when Artic air arrives prior to an established snow cover. Additionally, the lack of moisture coupled with high wind events puts the crop in a vulnerable position for wind erosion.

Some of these surface moisture concerns were alleviated temporarily during the final 10 days of the month as two weather systems brought snow, ice and rain to the eastern half of the state December 23rd and 29th. The December 29th event resulted in widespread snowfall of 3 to 8 inches and cool temperatures to end the month. With frost depths non-existent or very shallow, a low sun angle and cool temperatures should provide the perfect environment for the snow to melt slowly and infiltrate soil profiles.

Figure 1 shows the cumulative impacts of the warm conditions during the first three weeks of the month when snow cover was non-existent. Even with the return to winter-like conditions during the final week of the month, average temperature departures were 6-10 F above normal across northern Nebraska and 2-6 F above normal across southern areas of the state.

Figure 2 shows the actual moisture received during December, while Figure 3 depicts how much precipitation deviated from normal. A broad area of central through eastern Nebraska received above normal moisture, which was the first above normal moisture month for these areas since July or August (location dependent).

At the end of December, the Nebraska Agricultural Statistics Service indicated that 56% of topsoil (top one foot) and 63% of subsoil moisture (below one foot) was short to very short. Soil moisture conditions improved an average of 9% from the end of November, due in large part to the December 29th snow storm.

However, precipitation from October through December (fall soil moisture recharge period) was well below normal across southern and western Nebraska. Figure 4 indicates that precipitation deficits were greater than 1.50 inches over most areas south of I-80, with deficits of 2.25-3.00 inches across south central Nebraska. In order to make up these deficits before the end of winter, precipitation will need to average 300% of normal across south central Nebraska.

January Weather Outlook

The Climate Prediction Center (CPC) released their January temperature and precipitation outlooks December 31 (Figures 5 and 6). CPC projects above normal temperatures for the entire United States east and north or the southwestern desert region. The highest odds of receiving above normal temperatures are assigned to the Great Lakes region. For Nebraska, probabilities would suggest a moderate likelihood of above normal temperatures for January.

Above normal precipitation is projected to fall across the eastern half of the United States, along with the Pacific northwest southward through central California. The eastern half of Nebraska is favored for above normal precipitation according to CPC. Probabilities indicate a slight chance exists for above normal moisture for the eastern half of north central, central, and south central Nebraska. There is a moderate chance for above normal moisture for northeast, east central, and southeast Nebraska. Equal chances for above, normal, or below normal moisture are indicated for the western half of the state.

Below normal precipitation is projected for the entire High Plains region, the Mississippi River valley, the western Great Lakes and the southern 2/3 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.

Weather models at the beginning of January indicate that temperatures are likely to be below normal the first 5 days of the month, the fluctuating between below and above normal the second 5 days of the month. Above normal temperatures are likely to return from January 11-16, before a strong surge of Artic air is projected to slide into the northern United State from January 17-23.

Any significant moisture that develops will likely be tied to the transition to an Arctic air mass during the second half of the month. The GFS model indicates that a potential winter storm will develop during the January 21-23 period and actually supports accumulating snowfall across western Nebraska, which has seen little moisture from recent snow events. Since September, Nebraska has experienced one major snow event per month and this system appears to provide the best opportunity to continue that trend.

If the snowfall event projected by the GFS materializes, below normal temperatures would be supported due to the ability of fresh snow cover to reflect solar radiation. This in turn will slow the moderation of Arctic air masses that surge southward out of Canada. If the February temperature trend during the past decade is any indication of how the winter will end, then bitter temperatures may lie ahead.

Special Note

The Climate Prediction Center will issue their latest El Nino Southern Oscillation (ENSO) update on current La Nina conditions mid-January. A mid-month edition of the Ag Update will be issued to analyze CPC’s predictions, provide a drought update, and take a peek at thoughts on how the current La Nina event may impact weather trends during the upcoming year.

Al Dutcher, Agricultural Extension Climatologist, Nebraska State Climate Office

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