Weekly Agricultural Weather Update - November 2, 2021

Weekly Precipitation
Weekly Precipitation

October 26 - November 1, 2021 Precipitation Source: High Plains Regional Climate Center ACIS Mapping Tool

Weekly Precipitation

Weekly Precipitation Anomalies
Weekly Precipitation Anomalies

October 26 - November 1, 2021 Departure From Normal Precipitation Source: High Plains Regional Climate Center ACIS Mapping Tool

Weekly Precipitation Anomalies

October Temperature Anomalies
October Temperature Anomalies

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

October Temperature Anomalies

October Precipitaiton
October Precipitaiton

October 2021 Precipitation Source: High Plains Regional Climate Center ACIS Mapping Tool

October Precipitaiton

October Precipitation Anomalies
October Precipitation Anomalies

Departure From Normal Precipitation - October 2021 Source: High Plains Regional Climate Center ACIS Mapping Tool

October Precipitation Anomalies

Weather Update

As expected, the combination of storm systems impacting the state October 24-25 and 27-28 produced widespread rainfall of 1-5 inches across the eastern 1/3 of the state limited harvest activity last week. Western Nebraska did receive moisture from these two systems, but the accumulated precipitation from these events was under an inch at most locations and weather harvest delays were limited to 1-2 days versus the entire week for eastern Nebraska.

A storm system crossing the state during the second half of October 31 and dropped 3-6 inches of snowfall across the southern Panhandle eastward through North Platte. This event will be incorporated into next week’s crop progress report released by the Nebraska Agricultural Statistics Service (NASS). Preliminary snow to water ratios were in the range of 8-10 inches of snow for every inch of water equivalency. Areas that received 3-6 inches of snow reported liquid equivalent values of 0.25-0.50 inches of precipitation.

With the passage of these two storm systems, maximum temperatures October 25th were in the 60’s, warming into the mid 70’s to mid 80’s October 26th, only to drop into the upper 50’s to low 60’s October 27-28 as the second storm slowly crossed the state. As high pressure built across the central Plains, maximum temperatures pushed into the upper 60’s to mid 70’s October 29-30. A cold front pushed through the state on Halloween, with high temperatures statewide dropping into the 40’s, with just a few isolated low 50’s across extreme southeast Nebraska.

Even with cooler air invading the central Plains this past week, average temperature anomalies were above normal statewide as depicted in Figure 1. The vast majority of Nebraska average temperature anomalies this past week were normal to 2 F above normal. However, there were pockets of 2-4 F above normal anomalies across southwest, northwest, northeast, central and east central Nebraska.

Daily high/low temperatures reported during the past week are as follows: October 25 (Kimball: 70 / Imperial: 28), October 26 (Imperial: 86 / Kimball: 32), October 27 (Hebron and McCook: 63 / Scottsbluff: 36), October 28 (Grand Island, Hebron and McCook: 62 / Alliance: 33), October 29 (Chadron: 74 / Alliance: 24), October 30 (Lincoln: 73 / Alliance and 3 other locations: 29), October 31 (Falls City: 53 / Alliance and Chadron: 31).

Precipitation was widespread across the eastern half of the state with these two storm systems, with the first system producing strong thunderstorm activity and the second producing a long lived steady precipitation event. Thunderstorms across the eastern ¼ of the state October 24th led to flash flooding across southern Lancaster and northern Gage counties as radar indicated precipitation approached 5 inches. The October 27-28 system dropped 0.50 to 2.00 inches of rainfall from Grand Island eastward. Figure 2 depicts the accumulated precipitation from October 26 – November 1. Areas east of Grand Island received at least an inch of moisture, while north central and southwest Nebraska reported less than 0.30 inches of moisture.

Maximum reported daily precipitation from NERain observers are as follows: October 25 (Lincoln 8.5 ENE: 3.11 inches), October 26 (Filley 0.4 WNW: 0.55 inches), October 27 (Milford 0.4 WSW: 1.80), October 28 (Friend 2.6 SSE: 2.65), October 29 (Falls City 5.5 NE: 0.49), October 30 (Statewide: 0.00), October 31 (Hemingford 4 S: 0.21).

Even with cooler air invading the state this past week, October average temperature anomalies were above normal statewide due to temperatures the first half of the month averaging up to 10 F above normal. Figure 3 depicts the October average temperature anomalies for Nebraska and extreme eastern Nebraska, as well as the northwestern Sandhill region and parts of northeastern corner of the state were 3-5 F above normal. For the remainder of the state, average temperature anomalies were 2-3 F above normal.

Precipitation the final week of October precipitation brought monthly totals above 3 inches east of York, with 5-6 inches around the Omaha metropolitan area (Figure 4). Monthly precipitation totals were less than an inch across west central and southwest Nebraska, with less than 0.50 inches in areas in and around McCook and Ogallala.

Since October is traditionally the start of the soil water recharge period (October – April), precipitation activity the final week of the month resulted in surplus anomalies across eastern Nebraska and the northern half of the Panhandle, along with pockets in the northeast (Figure 5). Surplus moisture of 1.5-3.75 inches were common from Lincoln eastward, with normal precipitation to surpluses of 1.50 inches were observed across the northern half of the Panhandle. However, a broad area of precipitation deficits of 0.75-1.50 inches covered north central, central, south central, southwest and west central Nebraska.

Crop Progress

Harvest activity slowed to a crawl this past week due to widespread precipitation across the eastern half of the state. In areas receiving at least two inches of moisture, harvest activity came to a standstill this past week. However, due to the lack of widespread precipitation across the western half of the state, harvest activity delays were limited to less than 3 days.

According to NASS, the percentage of warm season crops estimated to be harvested as of October 31 stood at 72% for corn, 91% for soybeans and 78% for sorghum. Compared to the October 24 NASS crop report, 12% of the corn crop was harvested last week, while 3% of the soybeans and 6% of the sorghum were run through combines. The eastern 1/4 of the state accounts for over 80% of the soybeans produced, so it is not surprising that only 3 percent of the crop came out of the field last week with the abundance of rainfall.

The absence of widespread moisture for western Nebraska led to further declines in pasture ratings according to NASS. As of October 31, pasture and range conditions were rated 13% very poor, 21% poor, 30% fair, 15% good and 1% excellent. Compared to the October 24th numbers, the very poor category increased 1 percentage point and the poor category increased 2 percentage points. These increases came at the expense of the good category which declined 3 percentage points.

Topsoil and subsoil moisture estimates by NASS improved slightly with precipitation across eastern Nebraska, but the gains were tempered due to the persistent dryness across southwest and west central areas of the state. NASS indicates that topsoil ratings as of October 31 stood at 7% very short, 26% short, 62% adequate and 5% surplus. The weekly change from October 24 was to decrease the very short category 1 percentage point and the short category 6 percentage points. These decreases resulted in a 4 percentage point increase in the adequate category and a 3 percentage point increase in the surplus category.

Subsoil ratings stood at 11% very short, 37% short, 48% adequate and 4% surplus as of October 31st according to NASS. Although subsoil ratings also improved, weekly changes were not as dramatic as the changes in topsoil ratings. Compared to the October 24 NASS crop report, the very poor category shrank one percentage point and the short category declined 4 percentage points. This 5 percentage point change was offset by an increase of 3 percentage points in the adequate category and a 2 percentage point increase in the surplus category.

Weather Outlook

With the calendar turning to November, we are now beginning to enter the drier portion of the calendar year. Precipitation from November through March represents 20 percent or less of the annual total based upon the 1991-2020 climate normals. For November proper, normal monthly precipitation totals range from 0.70 inches across the northwestern Panhandle to 1.90 inches in the extreme southeastern corner of Nebraska.

Normal daily high temperatures range from the mid 50’s northwest to the upper 50’s southeast at the beginning of November and drop in low 40’s northwest to mid 40’s southeast by the end of the month. Low temperatures are normally in mid 20’s northwest to low 30’s southeast at the beginning of November and drop into the upper teens northwest to mid 20’s southeast by month’s end.

It does appear from the GFS model output from the morning of November 2 that producers will have an extended period of favorable harvest weather as an upper air ridge builds into the central United States this week. It appears that Indian summer conditions will prevail through early next week before an upper air trough begins to move eastward from the Pacific Northwest. In simple layman’s jargon, Indian summers are an extended period of above normal temperatures and dry weather following a hard freeze (minimum temperatures 28 F or lower).

The GFS model indicates that an upper air ridge will dominate the central United States through November 5 before an upper air trough crosses the northern Plains November 6. At present, the GFS models keeps precipitation with this trough to the north of Nebraska, but slightly cooler air will filter into Nebraska. High temperatures will warm from the 40’s November 2 to the 50’s by November 4, with 60’s likely November 5. Depending on the speed of the northern Plains trough, maximum temperatures may reach the 60’s November 6 before a cold front moves through the state.

High pressure will move into the central 1/3 of the United States November 7-9 and maximum temperatures should range from the mid 40’s northwest to mid 50’s south. Another quick moving trough is depicted by the GFS to cross the northern Plains November 10-12. The GFS is advertising that cold air with this system will surge southward into Nebraska and maximum temperatures are forecast to drop into the 40’s November 10-11 before warming into the 50’s November 12-13.

At this point in time, the GFS model is developing a powerful storm system November 14-15 as an upper air trough pushes eastward across the central and northern Rockies. The main upper air low is forecast to move into the eastern Dakota’s November 14 and heavy snowfall is possible across eastern Montana, northeastern Wyoming, the Dakota’s and western Minnesota. Currently, northeastern Nebraska is on the southern periphery of snow pattern currently forecast.

By November 15, the GFS model intensifies the northern Plains upper air low and pivots a piece of energy around its rear flank. It is this piece of energy that the GFS model indicates will build southward and increase the chances for accumulating snowfall across the northern half of the state. High temperatures will likely drop into the 20’s north to 30’s south. If the GFS model is correct, ranchers and producers should be aware that significant moisture is likely, including heavy snowfall accumulation (> 6 inches).

High pressure is then forecast to build into the central United States November 16-18 and high temperatures will depend on the extent of snowfall received across the northern and central Plains. Without snowfall, high temperatures will rebound into the upper 40’s to low 50’s. If snowfall matches the GFS forecast, high temperatures will likely run 5-10 F cooler.

To add insult to injury, the GFS indicates another powerful upper air trough will move into the central United States November 19-20, which increases the potential for another significant snow event for the northern half of the High Plains region, which includes Nebraska. Since this is at the end of the model forecast period, confidence is low. However, as this past week has shown, it is possible to have to strong storm systems in close proximity to each other.

Bottom line, over the next 16 days, the best harvest activity weather will be November 2-9, before a stormy weather pattern appears to return to the central Plains. If the GFS storm activity currently forecast materializes, what crops still remain in the field may be a challenge to harvest after we reach mid-month.

Al Dutcher, Agricultural Extension Climatologist, Nebraska State Climate Office

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