General Observations
Very dry and warm conditions (Figure 1 and 2) were reported statewide from October 6-10. A cold front finally pushed through the state on October 11, triggering a narrow line of thunderstorms that impacted a small area of northeast into east central Nebraska. Precipitation within this area was reported to be in the 0.75-1.25 inch range. Unfortunately, for the remainder of the state, precipitation totals were generally under 0.25 inches, with most of the western half of the state receiving less than a tenth of an inch of moisture.
Winds were the biggest issue during the past week. Very high winds were reported statewide on October 9 and coupled with high temperatures in the upper 80’s to low 90’s mimicked summer conditions instead of more typical mid-fall weather. Even stronger winds were reported on October 11 as a cold front moved through the state. Widespread wind gusts of 50-70 miles per hour were reported statewide, with significant field debris movement across harvested soybean acreage in southeast Nebraska.
Perhaps the most concerning issue this harvest season outside of the lack of moisture has been the high fire danger associated with the dry air masses that have been in place across the western corn belt over the past three weeks. Numerous combine related fires have been reported statewide this fall. Two particularly large fires broke out near Lexington and Stanton this past week. Over 100 large bales of hay were lost with the Lexington fire and 9 corn fields were destroyed with the Stanton fire.
When the upper air ridge builds eastward from the western U.S., warm and dry air has been moved northward toward the central Plains from the southwestern desert region and the southern Plains. When cold fronts move through the region, cool and dry Canadian air replaces the warm air masses. Until a significant upper air low can move eastward through the central Rockies, these conditions will continue into the foreseeable future.
Crop Progress
Nebraska Agricultural Statistics Service (NASS) indicates that for the period ending October 11 that there were 6.8 days of field work. The 0.2 day takes into consideration the rainfall that impacted eastern Nebraska the afternoon of the 11th. With warm, dry, and windy conditions, harvest activity proceeded virtually uninterrupted. Perhaps the biggest issues were low moisture content of harvested beans, high amounts of harvest dust, and excessively high fire dangers with relative humidity levels below 20% prior to the arrival of the cold front on Sunday.
Soybeans harvested stood at 82% on October 11 according to NASS. This compares to 24% last year and the 5-year average of 39%. Every extension specialist on the university crop extension call October 13 estimated soybean acreage harvested stood at 90% or greater. Dryland yields were consistently mentioned to be in the 30 to 60 bushels per acre(bu/ac), while irrigated yields were in the 70-90 bu/ac range.
NASS estimates that 34% of the corn had been harvested as of October 11, compared to 21% last week. The 5-year average is 22% and 18% was harvested at this point last year. With the soybean harvest virtually complete and no significant moisture events on the horizon, the corn harvest may be close to complete before the end of the month. Extension specialist on the university crop call indicated 25-50% of the area was harvested south of I-80 and around 25-35% north of I-80.
The sorghum harvest stands at 31% complete as of October 11 according to NASS. This compares to 8% last year and the 5-year average of 21%. Winter wheat seeding reached 90%, with 60% of the crop emerged. Dry soils were inhibiting proper germination and stand establishment due to the lack of top soil moisture.
The lack of top soil moisture is evident in this week’s crop report released by NASS. Topsoil moisture was rated at 73% short to very short. Subsoil moisture stood at 64% short to very short. Pastures continued to deteriorate with 38% rated poor to very poor. Only 36% of the acreage was rated as good, with none rated excellent.
The continued dryness has once again led to further drought expansion (Figure 3) into the Sandhill region and southern Nebraska. The drought has intensified significantly across the western third of the state. A large area of extreme drought (D3) now covers the central Panhandle region. Further expansion into the remainder of the Panhandle is probable this month if the dry forecast verifies.
Outlook
Opportunities for moisture appear limited during the next two weeks according to the latest GFS model issued the morning of October 13. As has been the case most of the past two months, temperatures and very limited precipitation chances will be determined by the battle between the upper air ridge over the western U.S. and the upper air trough located southern Ontario. It does appear that those areas across Nebraska that have failed to receive a killing freeze will see an end to the growing season early next week.
Warm and windy conditions are projected for October 13-14 prior to a cold front moving southward into Nebraska from the northern Plains during the overnight hours of October 14. High temperatures will cool from the 70’s into the 50’s to low 60’s on October 15. Temperatures are expected to warm about 5 F on October 16, then into the 70’s October 17.
Another cold front will dive southward out of the northern Plains on October 18 as the upper air trough over south central Canada and the western Great Lakes deepens and expands westward. The cold front is currently projected to move through the state during the second half of the day, with temperatures steadily dropping during the afternoon hours. The GFS model indicates that light rain and/or snow will develop during the overnight hours and should be south of the state by sunrise on October 19.
Very cold conditions are expected October 19-20 as cool Canadian high pressure settles across Nebraska. High temperatures will be confined to the 50’s both days, with overnight lows likely to reach the lower 20’s north to upper 20’s south. A gradual warming trend and precipitation free conditions are projected from October 21-26. High temperatures will warm from the 60’s October 21 to the low 80’s by October 26.
Another surge of cold air is projected at the end of the GFS model period as the western upper air ridge breaks down and allows energy entering the Pacific Northwest to move across the northern Rockies. This energy is then forecast to dive southeastward toward the central U.S. and pull another surge of below normal temperatures into the central Plains. At this point in time, the GFS model indicates that little moisture will occur with this system.
The Climate Prediction Center (CPC) will be releasing their official ENSO update and Winter Outlooks this week. If the past 3 months are any indication of CPC’s temperature trend, it should not be unexpected to see them pull below normal temperatures from the northern Plains (predicted last month) southward toward the central Plains. Precipitation is more uncertain, but with such a dry trend firmly entrenched across the southern and central Plains, substantial drought relief should not be expected in the December-February outlook.
Al Dutcher, Agricultural Extension Climatologist with the Nebraska State Climate Office