General Observations
Last weekend’s snow storm brought fall harvest activity and fieldwork to a halt during first half of last week due to the slow melt of the existing snow pack. Record low and record low high temperatures were reported statewide, with the most intense cold located over the western 1/3 of the state October 26-27. Alliance set a daily record of -14 F on the 27th, a full 15 degrees colder than the previous low record and likely set the coldest statewide October low temperature ever recorded.
Figures 1-3 show the impact of this record cold outbreak compared to normal for the past week. Temperatures returned to above normal from October 29 – November 1, but couldn’t compensate for the strong cold outbreak earlier in the week when average, maximum, and minimum temperatures were 20-40 F below normal, depending on location.
Minimum average temperature showed the greatest departures from normal from October 26 – November 1. Average minimum temperature departures (Figure 3) were 12-20 F below normal across the southwest and southern ¾ of the Panhandle. The remainder of the state experienced departures of 8-16 F below normal. Maximum temperature departures (Figure 2) averaged 2-4 F warmer than low temperature departures, but were still in a range of 6-18 F below normal.
The precipitation received during the October 26-November 1 period occurred during the morning through afternoon hours of October 26. Scattered light precipitation was reported across the southern 2 tiers of counties bordering Kansas. This area was on the extreme northern fringe of the storm that hit Nebraska, dropped south to the Texas panhandle, before moving eastward into the southeastern United States. According to NERain observations, trace to 0.10 inches of moisture was common, with a maximum of 0.24 inches reported in the Arapahoe area.
Crop Progress
Last weekend’s snowstorm dropped the heaviest accumulations over areas where the corn harvest was least advanced. Even with the brutal cold and slow snow melt, a return to warm, windy and dry weather late in the week allowed producer the opportunity to resume harvest activity. Nebraska Agricultural Statistic Service (NASS) indicated that 86% of the corn was harvested as of November 1, compared to 76% last week. Last year the corn harvest stood at 55% and the 5-year average for November 1 stands at 63 percent. With warm and dry weather expected this week, the corn harvest should be close to 95% by next week’s crop report release.
The sorghum harvest last week stood at 82% complete compared to 92% this week according to NASS. Last year the harvest stood at 50% compared to the 5-year average of 65 percent. With 8 percent of the crop remaining to be harvested coupled with a favorable harvest outlook this week, the sorghum harvest should be virtually complete by next week’s NASS crop report.
NASS reports that top soil moisture is rated 68% short to very short, 31% adequate, and 1% surplus. Subsoil moisture is rated at 66% short to very short, 33% adequate, and 1% surplus. Both top soil and subsoil ratings improved slightly due to the impacts of the snow melt. The amount of area in the very poor to poor rating was reduced 5 points for topsoil moisture and 3 points for subsoil moisture.
Pasture ratings continue to reflect the impacts of drought conditions and the minimal contribution of last week’s snowstorm on pasture growth. Since this event came so late in the grass season, it is unlikely that there will be much of a response in cool season growth this late in the season. As of November 1, NASS reports 18% of pastures were very poor, 22% poor, 26% fair, 33% good and 1% excellent.
Although the snowstorm provided valuable protection for the winter wheat crop from record cold October 26-27, crop condition ratings continues to point to a large percentage of the crop with rated no better than fair. According to NASS, 5% of the winter wheat was rated very poor, 17% poor, 37% fair, 37% good, and only 4% excellent. Additional moisture events will be need to see substantial improvement in these ratings before the crop goes dormant for the winter.
Outlook
The Climate Prediction Center (CPC) released their November temperature and precipitation outlooks October 31 (See Figures 4 and 5). CPC projects above normal temperatures for the United States, except for equal chances of above, normal, or below normal temperatures over the Pacific Northwest and northern Rockies. Below normal precipitation is projected for the southern Great Basin, southern and central Rocky Mountains, southern and central High Plains (including Nebraska), along with the southeastern United States. Above normal moisture is forecast for the Pacific Northwest and the northern half of the northern Rocky Mountains.
If the most current model run of the GFS used for this report and issued the morning of November 3 is correct, CPC’s temperature forecast may be too warm and dry for Nebraska. The GFS is hinting that a series of storm systems will roll across Nebraska over the next 16 days, offering our best potential for drought reducing precipitation since mid-summer. It appears that three potential storm systems will impact the state, with the first one slated to arrive November 8-9.
The GFS indicates that a trough will deepen over the northwestern United States November 3-6, before moving into the Rocky Mountain region November 7-8. Prior to its arrival in the central Plains, a strong upper air ridge will bring widespread 70’s to low 80’s to the central Plains November 3-6. As this major trough enters the western high Plains late on November 7, the GFS model is indicating the precipitation will move into western Nebraska overnight, with the bulk of the heaviest precipitation pushed into the northern High Plains.
As the surface front moves through the state, the GFS model indicates that light moisture will develop over the Nebraska Panhandle and push northeast into western South Dakota. Further east, the surface warm front is projected to develop light to moderate rainfall across central Nebraska and lift it northeast toward southern Minnesota. Most of central, north central, and northeast Nebraska should see precipitation, but coverage appears weaker for east central and southeast Nebraska .
The upper air trough deepens over the High Plains on October 9, stalling out the surface cold front over eastern Nebraska. A surface low is projected to develop over central Oklahoma and race rapidly northeast during the day. The current GFS depiction indicates that the surface front will move eastward during the day and bring moderate, to possibly heavy precipitation, to the eastern ¼ of the state. Near the end of the storm, enough cold air may be drawn southward to bring a quick shot of accumulating snowfall.
The upper air trough is projected to lift northeastward November 10-11 and broaden out across the north central United States. The GFS model indicates that a piece of energy will rotate around this trough and deepen over the northern high Plains November 12-13. At present, northern Nebraska lies on the southern periphery of the precipitation shield expected to move across South Dakota and the southern half of North Dakota in the form of snow. If the system deepens more than currently forecast, accumulating snowfall could be a distinct possibility across the northern half of the state.
More energy rotates around the northern Plains upper air trough November 14-15 and this energy is forecast to deepen across the central Plains. If the GFS model is correct in its depiction, a surface low will develop over northern Texas and track northeastward along the front side of the upper air trough. According to the GFS, the surface low will bring moderate rainfall to eastern Nebraska November 16-17, with accumulating snowfall for the western 2/3 of the state. At present, the central 1/3 of the state is depicted as having the greatest likelihood of receiving four or more inches of snowfall.
Al Dutcher, Agricultural Extension Climatologist, Nebraska State Climate Office