Weather Review

Record high and low temperatures were established over a four-day period last week as a strong upper air trough slowly worked its way across the western half of the United States. Before this upper air trough moved into the central Plains, high temperatures across Nebraska peaked out in the middle 70s to low 80s from Oct. 31 through Nov. 3. A quick records check of National Weather Service field office websites that serve Nebraska revealed that every airport location in the state set at least one maximum daily high temperature record Nov. 1-3. As the upper air trough pushed through the state on Nov. 3, a cold Canadian air mass brought record low minimum temperatures to the state Nov. 4-5. Low temperatures ranged from the mid-teens to lower 20s across the western half of the state, with low to upper 20s across eastern Nebraska.

High temperatures on Nov. 4 were primarily in the 40s, except for extreme southeast Nebraska, which reached the low 50s due to the surface cold front not clearing the area until the second half of the day. Temperatures rebounded statewide Nov. 5-6, with highs reaching the middle 60s to low 70s on Nov. 5. A reinforcing shot of cold air associated with the northern part of the upper air trough moving across the Dakotas and Minnesota, resulted in high temperatures dropping 5-10°F statewide on Nov. 6.

The daily maximum temperature extremes for airport locations reported by the National Weather Service (NWS) are as follows: Oct. 31 — 75°F (Grand Island, Ord), Nov. 1 — 80°F (Falls City, Offut AFB, O’Neill, Tekamah), Nov. 2 — 80°F (Lexington, McCook, Tekamah), Nov. 3 — 77°F (Falls City, Lincoln, Nebraska City), Nov. 4 — 52°F (Falls City), Nov. 5 — 72°F (McCook), Nov. 6 — 63°F (Falls City).

The daily minimum temperature extremes for airport locations reported by the NWS are as follows: Oct. 31 — 19°F (Alliance), Nov. 1 — 22°F (Alliance), Nov. 2 — 26°F (Alliance), Nov. 3 — 29°F (Kimball), Nov. 4 — 14°F (Chadron, Kimball), Nov. 5 — 15°F (Valentine), Nov. 6 — 22°F (Valentine).

Precipitation last week was associated with the cold frontal boundary passage Nov. 3-5. Scattered thunderstorms developed across the eastern third of the state after sunset on Nov. 3 and continued into the first half of Nov. 4. Most areas south of a line from Omaha to Fairbury received at least 0.25 inches of moisture from this storm system, with totals exceeding 0.75 inches southeast of a line from Beatrice to Nebraska City. Several NERain observers reported over an inch of moisture in Johnson, Nemaha, Pawnee and Richardson counties. The NERain observer at Falls City 5.5 NE reported 2.66 inches of precipitation in the 24-hour period ending at 0800 Central Daylight Time Nov. 5.

Unfortunately, a substantial portion of southwest, west-central, north-central and south-central Nebraska failed to receive measurable moisture with the late week storm system. There was enough moisture and cold air with this system across the northwestern half of the Panhandle to produce snowfall accumulations of 1-3 inches, with the heaviest totals across the northern third of Panhandle. Snowfall totals ranging from a trace to an inch in scattered pockets east of the Panhandle and west of a McCook–Lexington–Anselmo line. There were some minor snowfall accumulations reported across eastern Richardson County the morning of Nov. 5, enough to produce a skiff (less than 0.25 inches) of accumulation on grass surfaces.

The daily maximum precipitation values reported from NERain observers are as follows: Oct. 31-Nov. 2 — 0.00 inches (all stations), Nov. 3 — 0.45 inches (Filley 0.4 NNW), Nov. 4 — 1.50 inches (DeWitt 4.6 SSW), Nov. 5 — 2.66 inches (Falls City 5.5 NE), Nov. 6 — 0.05 inches (Scottsbluff 16.4 WNW).

Crop Progress

Even with the storm system crossing the state during the second half of last week, harvest progress continued at a rapid pace. Areas of east-central and southeast Nebraska that received more than a quarter of an inch of moisture had already completed harvest activity and were not impacted by weather delays. According to extension educators with the University of Nebraska, most of the unharvested crops were located across the western half of the state. Nebraska Agricultural Statistic Service (NASS) indicates that there was the equivalent of 6.2 days of favorable harvest weather last week, which includes the southeastern corner of the state where the vast majority of moisture fell with the late week storm system.

NASS estimates that as of Nov. 4, 90% of the state corn crop has been harvested, which compares to 81% last year and the five-year average of 75%. A week ago (Oct. 30) NASS estimated the corn harvest at 80% complete. The grain sorghum harvest is estimated at 87% complete, compared to 84% last year and the five-year average of 77%. A week ago NASS estimated that 75% of the sorghum crop had been harvested. NASS didn’t provide soybean harvest estimate numbers this week, which suggests that they believe the state harvest is virtually complete. Last week NASS estimated 97% of the crop had been harvested.

Dry conditions continue to plague the winter wheat crop, pastures and forage conditions, as well as topsoil and subsoil moisture estimates. The lack of widespread moisture the past 30 days across the western third of Nebraska has led to deteriorating conditions to newly established wheat fields. NASS estimates that the condition of the 2023 winter wheat crop at 17% very poor, 19% poor, 40% fair, 21% good and 3% excellent as of Nov. 6. Pastures and rangeland condition estimates continue to reflect the impacts of drought conditions and the lack of widespread fall moisture. NASS rates pasture and rangeland conditions across the state as 47% very poor, 30% poor, 18% fair, 4% good and 1% excellent.

Naturally, with such dismal wheat and rangeland condition rankings, topsoil and subsoil moisture estimates are going to reflect the impacts of below-normal growing season moisture, as well as the lack of widespread fall moisture across the state. NASS rates topsoil moisture supplies as of Nov. 6 as 46% very short, 38% short, 16% adequate and 0% surplus. Subsoil moisture supplies are rated 51% very short, 37% short, 12% adequate and 0% surplus. Even with the rainfall across southeastern Nebraska this past week, topsoil rated “very short to short” was 74% this week, compared to 75% last week. Subsoil moisture rated “very short to short” was 88% this week, which compares to 84% in last week’s NASS crop report.

Outlook

A strong upper air trough is forecast to impact the northern half of the High Plains region Nov. 8-10 and has the potential to deliver blizzard to near-blizzard conditions to parts of the Dakotas, Minnesota and Montana. Warm air being lifted northward ahead of the surface low is expected to trigger scattered showers and thunderstorms across the eastern third of Nebraska during the second half of Nov. 8 into the first half of Nov. 9. As the surface low develops over southeastern Colorado and lifts rapidly toward eastern North Dakota, a surface cold front is forecast to sweep through Nebraska and trigger a line of thunderstorms east of U.S. Highway 81 during the late afternoon to early evening hours. The best opportunity for widespread severe weather will be along the Missouri River into the western half of Iowa.

The latest GFS model indicates that this storm will contain a dry slot ahead of the surface low and it is likely that southwest and south-central Nebraska will be hard-pressed to receive measurable moisture. In fact, quantitative precipitation forecasts for this storm system indicate that the Panhandle and the northern fourth of Nebraska have the best chance of receiving 0.25-0.50 inches of moisture. Eastern Nebraska where thunderstorm development is most likely is currently forecast to receive less than 0.25 inches of general coverage according to the GFS model issued the morning of Nov. 8. The coldest air we have seen so far this fall is forecast to push southward behind the departing surface low. Therefore, snowfall accumulations are probable over northern Nebraska and could become significant if this storm takes a more southerly path than is currently forecast.

Northwest winds on the backside of the surface low will create visibility issues where snowfall accumulates, but bitter wind chill values are likely statewide on Nov. 11. Low temperatures the morning of Nov. 12 are forecast to drop into the single digits northwest to mid-teens southeast. As the upper air trough passes east of Nebraska, the GFS model links it up with the remnants of tropical system Linda which will be racing up the east coast of the United States. This will allow the upper air trough to broaden out and keep the central Plains in a northwest flow aloft regime through Nov. 13. High temperatures are forecast to be in the middle 20s west to middle 30s east Nov. 11, warming back into the 40s by Nov. 15.

A reinforcing shot of cold air is forecast to develop behind a short wave trough moving southeastward on the backside of the upper air trough over the Great Lakes Nov. 15. The GFS model currently indicates that this short wave will strengthen as it passes east of Nebraska and pull another round of cold air into the central Plains. Less than a quarter inch of moisture is forecast across the state with this shortwave trough, most likely in the form of snow. In meteorological terms, this is a fancy way of saying an Alberta Clipper system is forecast to cross the state next week. The GFS hints at two more potential clipper systems, Nov. 18 and 21, before the upper air trough pattern begins to break down. If correct, the GFS model indicates that high temperatures may return to the 50s by Thanksgiving as an upper air trough builds into the Pacific Northwest leading to upper air ridging over the central and southern High Plains region.