Weekly Agricultural Weather Update — Oct. 18, 2022
The only concentrated area of the state that received precipitation last week was southeast of a line from Omaha to Hardy when a cold front pushed through the state on Oct. 11. Showers and thunderstorm developed during the evening hours and pushed southeast of the state by daybreak on Oct. 12. NERain observers indicated broad based coverage of 0.25 to 0.75 inches, with isolated reports of 1.00-1.25 inches of moisture.
Although harvest activity across southeast Nebraska was likely delayed one to two days due to the precipitation, high daytime wind speeds and low relative humidity levels likely had a greater impact on slowing harvest activity across the northwestern four-fifths of the state. Wind gusts exceeded 40 mph from the south-southwest Oct. 10-11, before switching to the northwest behind the cold front. Although not as strong as the preceding two days, wind gusts were still consistently in the 30-40 mph range.
Coupled with a dry atmosphere, fire danger indices remained high through the first four days of last week. Many producers chose to delay harvest activity during this stretch due to the elevated risk of combine fires spreading uncontrollably to adjacent grassland areas. In addition, soybean producers also chose to park combines during the peak heating hours of the day because of the low moisture content of harvested grain. University of Nebraska Extension educators indicated producers were harvesting soybeans below 10%, with the lowest confirmed measurement being 6%.
Even with the slowdown in grain harvest activity due to high winds and low soybean moisture content, this harvest season is progressing ahead of the five-year average and is closely mirroring last year’s rapid harvest pace. Although current weather models indicate the potential for a system to produce widespread moisture across eastern Nebraska early next week, the soybean harvest should reach 85% completion and the corn harvest should push the 65% mark in next week’s NASS crop progress report.
The daily maximum temperature extremes for airport locations reported by the National Weather Service (NWS) are as follows: Oct. 10 — 84°F (Valentine), Oct. 11 — 88°F (Falls City, McCook), Oct. 12 — 71°F (Lexington, McCook), Oct. 13 — 66°F (McCook, Scottsbluff), Oct. 14 — 81°F (McCook), Oct. 15 — 76°F (Grand Island, Lincoln), Oct. 16 — 63°F (Beatrice, Falls City, Imperial, McCook, Scottsbluff).
The daily minimum temperature extremes for airport locations reported by the NWS are as follows: Oct. 10 — 27°F (Gordon), Oct. 11 — 37°F (Alliance, Chadron), Oct. 12 — 30°F (Gordon, Valentine), Oct. 13 — 29°F (North Platte), Oct. 14 — 27°F (Gordon), Oct. 15 — 20°F (Tekamah), Oct. 16 — 28°F (Alliance).
The daily maximum precipitation values reported from NERain observers are as follows: Oct. 10 — 0.03 inches (Sumner 3.7 ESE), Oct. 11 — 0.37 inches (Fort Calhoun 2.9 SSW), Oct. 12 — 1.29 inches (Barneston 0.1 E), Oct. 13 — 0.07 inches (Kearney 0.9 SW), Oct. 14 - Oct. 15 — 0.00 inches (all stations), Oct. 16 — 0.04 inches (Hay Springs 7.5 WSW, Gordon 12.6 NW).
Winter wheat planting for the 2023 production season is close to completion, according to the Nebraska Agricultural Statistics Service (NASS). As of Oct. 16, 94% of the crop is estimated to be planted, compared to 92% last year and the five-year average of 92%. NASS also estimates current emergence at 73%, which compares to 74% last year and the five-year average of 72%. The first wheat condition report of the 2022-23 cropping year by NASS estimates the winter wheat crop is currently 16% very poor, 19% poor, 36% fair, 28% good and 1% excellent.
Harvest activity proceeded at a robust pace last week, even with multiple high wind warning and high fire danger days. The only significant weather delays from precipitation occurred south and east of a line from Omaha to Hardy where 0.25 to 1.25 inches of moisture were reported through NERain observations. Precipitation in this area likely delayed harvest activity 1-2 days, but a larger issue is the low moisture content of soybeans during harvest. University of Nebraska Extension educators indicate that a lot of beans have been harvested below 10% this past week, with the lowest confirmed content coming in at 6% during a mid-afternoon harvest.
NASS estimates that as of Oct. 16, 46% of the corn had been harvested, compared to 39% last year and the five-year average of 32%. The 2022 soybean harvest is estimated to be 76% complete, which compares to 74% last year and the five-year average of 57%. The sorghum harvest is still proceeding at a slower pace than corn and soybeans with NASS estimating that 34% of the crop has harvested. At this point last year, 55% of the crop had been harvested, which compares to the five-year average of 36%.
Rainfall this past week was reported across southeast Nebraska but left the northwestern four-fifths of the state without measurable rainfall. Therefore, soil moisture and pasture health continue to show drought impacts from this past growing season. NASS estimates topsoil moisture as of Oct. 16 to be 46% very short, 36% short, 18% adequate and 0% surplus. Subsoil moisture is rated 47% very short, 37% short, 16% adequate and 0% surplus. Rangeland and pastures are rated 52% very poor, 31% poor, 14% fair, 3% good and 0% excellent. Until a widespread one to two precipitation event materializes, little improvement in soil moisture estimates and pasture conditions should be expected.
The cold air in place across Nebraska is the result of a Canadian air mass that was pulled southward through the High Plains on the backside of a strong upper air low that has been semi-stationary over the Great Lakes. This air mass brought a hard freeze to south-central and southwest Nebraska the morning of Oct. 17, which had escaped the hard freeze event that hit northern and eastern sections of the state the morning of Oct. 8. In general, the Oct. 8 hard freeze occurred seven to 10 days earlier than normal, while the Oct. 17 hard freeze occurred less than a week ahead of normal.
Dry weather is forecast for Nebraska through this coming weekend. The upper air trough over the Great Lakes is forecast to move toward the northeastern United States Thursday and Friday of this week. This will allow the upper air ridge centered over the western United States to build eastward into the High Plains. With a dry air mass in place, high temperatures will rapidly warm into the 70s east to lower 80s west by the end of this coming weekend.
More importantly, the upper air trough that the GFS model hinted at a week ago that might impact the central and northern Plains as early as this weekend has been delayed a couple of days. The GFS model run issued the morning of Oct. 17 indicates this upper air trough will begin to enter the Pacific Northwest by the end of this work week. It will then dive southeast toward the southern Great Basin by Oct. 21 before ejecting northeastward toward the central/northern High Plains on Oct. 23.
There still remains considerable uncertainty in regard to the overall strength of the upper air trough and the eventual path of the surface low associated with this feature. Currently, the GFS indicates the brunt of cold air associated with this system will remain north of Nebraska. The bigger question is whether precipitation will remain north of Nebraska and whether it will be in the form of accumulating snowfall.
Over the past week, the GFS models handling of next week's system has resulted in a hodge-podge of solutions including a potential snowstorm for eastern Montana and the Dakotas, dry and warmer than normal conditions for the northern/central Plains, a snowstorm for the Great Lakes and a rain/snow event spread out from Texas northward to the Canadian border. Currently, the GFS is promoting rain across eastern Nebraska with no measurable moisture across the western half of the state. Snowfall is forecast to remain north of the state in the Dakotas and Minnesota.
As mentioned last week, the overall path of this system is likely to change and readers should pay attention to the ever-changing forecast in case snow from this system is pulled further southward than currently depicted. The most current GFS model run indicates that eastern Nebraska has the best chance of receiving moisture with this system in the form of a cold rain, while the western half of the state remains in the storm system’s dry slot and remains precipitation-free. Current model forecasts for eastern Nebraska indicates the potential for 0.25-0.50 inches of liquid equivalent moisture, which may increase if the upper air troughs forward speed slows down compared to current depictions.
After this upper air trough passes east of Nebraska, the GFS model indicates that the upper air trough will stall out over the Great Lakes region, just like the current system. This will allow drier and colder Canadian air to move into the northern and central High Plains. High temperatures will likely drop back into the 50s, possibly cooler Oct. 25-29. The upper air ridge across the western United States is then forecast to push eastward during the week in response to another upper air trough pushing into the Pacific Northwest by Nov. 2.
In advance of the upper air trough moving into the western United States, the eastward building upper air ridge should allow high temperatures Oct. 30–Nov. 4 to warm into the upper 60s to middle 70s. The upper air trough over the northwestern United States should begin to impact the High Plains region the first full week of November, but it is too early to tell whether this event will produce precipitation across Nebraska or remain north and east of the state.