KIMBALL– Weather conditions continued to cool across the tri-state region last week as winter continued to approach.
Although cooler than the previous week, daytime and nighttime temperatures remained slightly warmer than the long-term average.
As upper air masses began to shift north and south, gusty winds developed across much of the northern Plains.
Warmer than average conditions and plenty of sunshine have kept fall-seeded winter wheat and weedy winter annual grasses actively transpiring and metabolizing deeper into December than is the norm. Depending on how the winter and spring unfold, this could presage some problems with the 2018 winter wheat crop, as actively transpiring wheat stands are using up soil moisture which was largely rather scant at planting. Also, a sudden cold snap could cause a great deal of mortality to wheat plants which have not yet gone dormant. Only time will tell, but many producers are watching their wheat
stands closely.
On Thursday, December 21 at 9:28 a.m. the sun will stop moving south and begin moving north. Thursday will be the shortest day of the year at 9 hours, 21 minutes and 22 seconds. Monday night will be the longest night of the year at 14 hours, 38 minutes and 38 seconds.
Celestial winter will have arrived at the point of winter solstice.
Friday, December 22 will be about two seconds longer than Monday, and Friday night about three seconds shorter. Once the solstice has passed this trend will continue, with days getting longer and nights shorter until on June 21, 2018 at 4:07 a.m., the sun will stop moving north and begin moving south once again. June 21 will be the longest day of the year at 14 hours, 59 minutes and 8 seconds. The night of June 21 will be the shortest of the year at only 9 hours and 52 seconds.
What causes the sun to move north and south with the seasons? The answer is that the Earth is tilted over at about 23.5 degrees in relation to the plane in which it orbits the sun. This plane is called “The Plane of the Ecliptic,” and is the same plane occupied by the other seven planets of our solar system as they orbit the sun.
For those Pluto fans out there who remain irritated at Pluto’s demotion from planet status, the former “ninth planet” actually orbits the sun in a plane tilted to the plane of the ecliptic. Therefore, reference to eight vs. nine planets refers only to orbital mechanics and not to planetary status (or lack thereof).
Now if the Earth stood vertical in the Plane of the Ecliptic, with the north pole straight up and south pole straight down, the sun would never appear to move north or south. It would rise each morning in precisely the same location on the eastern horizon and set each evening in precisely the same location on the western horizon. Each period of day and night would be the same from day to day, and those periods would be very close to 12 hours for most of the planet.
Earth’s axial tilt remains constant (at least in our very short temporal frame of reference) as the Earth orbits the sun. In the summer, the northern hemisphere is leaned over toward the sun, and the sun’s light shines more directly on the north half of the planet. In the winter, the northern hemisphere is leaned away from the sun, and the sun’s light shines less directly on the north half of the planet. If you live below the Equator, in Australia, say, the process is exactly reversed, and your summer begins in late December while your winter begins in late June.
Enjoy next Thursday and Friday, the shortest day and longest night of the year, with the certain knowledge that as our planet continues to orbit the sun, our trusty axial tilt will mean lengthening days. Before you know it, it will once again be spring, and life will begin anew across the lovely and majestic Great Plains.

Regional Forecast and Conditions
As of Tuesday morning (December 5), the temperature at sunrise was 35 degrees under clear skies. There was a northwesterly breeze at 15 mph, gusting to 30 mph. The day was expected to clear and remain breezy, with temperatures climbing to near 60 degrees.
The forecast through the weekend calls for continued seasonably warm and windy conditions. Daytime highs are expected to range from the low 40’s to mid-50’s with a persistent and sometimes stiff northwest breeze. Overnight lows are expected to fall into the teens throughout the weekend, and wind speeds should ease during the nighttime hours. Little if any widespread precipitation is anticipated.
Conditions are expected to remain much the same for the Monday-Wednesday period. There is little chance of precipitation in the forecast through Wednesday.
Daytime air temperatures cooled across the region last week. At Kimball the December 5-11 daytime high averaged 45.71, about 9.5 degrees cooler than the previous week. The weekly high temperature was 59 degrees on December 10. Overnight lows also cooled, averaging 19.14 degrees, about 3.5 degrees cooler than the previous week. The weekly low temperature was 8 degrees on December 5. The weekly mean temperature was 32.42 degrees, about 6 degrees cooler than the previous week, and about 4 degrees warmer than the December average of 28.4 degrees. The long term average high and low temperatures at Kimball for December are 41.7 and 15.0 degrees, respectively.
With the exception of widespread but very light snow showers on December 6 it was once again a very dry week across the region. Although 12 of 13 Panhandle stations reported precipitation during the December 5-11 period, only two stations reported more than a trace of liquid equivalent precipitation -- Dalton reported one-tenth and Gordon four one-hundredths of an inch. Sidney Municipal reported zero precipitation. Likewise, nearly all stations reported less than one tenth of an inch of snowfall, except for Dalton, Gordon, and Scottsbluff, which reported one inch, one-half inch, and three-tenths of an inch respectively. Liquid equivalent precipitation averaged 0.013 inches for the Panhandle, while snowfall averaged 0.22 inches.
Soil temperatures cooled across the Panhandle over the December 5-11 period: (this week/last week/change): Alliance 34.5/41.7 (-7.2) degrees; Gordon 34.4/36.8 (-2.2) degrees; Mitchell 36.2/41.3 (-5.1) degrees; Scottsbluff 34.5/38.5 (-3.0); and Sidney 33.7/38.5 (-4.8) degrees.
Winds near Kimball averaged north-northwesterly and quite breezy over the December 5-11 period. Gusts for the week averaged 40.14 mph. High gust for the week was 61 mph on December 15.

December 15 Weather Almanac
Here’s an overview of December 15 temperature and precipitation highs, lows, and averages over the preceding 123 years at Kimball. Data is taken from the High Plains Regional Climate Center (www.hprcc.unl.edu), where you can easily find and track data for your own particular location.
Last year (December 15, 2016): Daily high temperature 21 degrees, overnight low 9 degrees, average temperature 15 degrees. Precipitation 0.07 inches, snowfall one inch, snow depth
one inch.
The warmest December 15 on record was 69 degrees in 1998. The coolest December 15 high temperature was 0 degrees in 2008. The coldest December 15 overnight low was -13 degrees in 2008. The warmest December 15 overnight low was 37 degrees in 1934. Over the years since 1893 the high temperature on December 15 has averaged 39 degrees, the overnight low 13 degrees, the daily average 25.8 degrees, precipitation has averaged 0.01 inches, snowfall 0.2 inches, snow depth zero inches.
The highest December 15 precipitation total was 0.30 inches liquid equivalent in 1897. The greatest snowfall was 3.0 inches in 1989. Greatest snow depth was 8.0 inches in 1985.
Snow has fallen on December 15 at Kimball 17 times over the last 123 years, with quantities ranging from a trace to 3 inches.

U.S. Drought Monitor
(November 28) Northern Plains: This week conditions deteriorated in eastern portions of the Dakotas as well as in eastern Nebraska and Kansas.
In the Dakotas, areas of Abnormally Dry (D0) and Moderate Drought (D1) expanded as a result of unseasonably warm temperatures and below normal precipitation during the past 30-to-60 days. Moreover, the lack of snow cover and warm temperatures have raised concern in relation to the condition of the winter wheat crop. According to NOAA’s NCEI, North Dakota experienced its fourth driest October-November period on record.
In Nebraska and Kansas, below normal precipitation and above normal temperatures during the past 30 days led to the introduction of new areas of Abnormally Dry (D0). During the past week, the region was generally dry and temperatures were well above average (5-to-15 degrees).
West: During the past week, the region was dry with the exception of the Pacific Northwest where coastal areas of Oregon and Washington as well as the North Cascades received liquid accumulations ranging from 2-to-3.5 inches.
Lesser precipitation accumulations were observed in the northern Rockies where Water Year-to-Date precipitation accumulations are normal to slightly above normal.
In southern California, four rapidly spreading large wildfires exacerbated by strong Santa Ana winds broke out this week near Los Angeles and further north in Ventura County. Elsewhere in the region, the Southwest continued to be unseasonably warm and dry leading to expansion of areas of Moderate Drought (D1) across northern Arizona.
According to the National Weather Service in Flagstaff, several locations saw their Top-5 warmest autumns on record including: Flagstaff (fourth warmest), Prescott (warmest), Payson (second warmest), and Winslow (second warmest). As a region, the Southwest experienced its sixth driest and second warmest October-November period on record.
Further north in Montana, conditions have been improving in the western portion of the state leading to slight reductions in areas of Abnormally Dry (D0) and Moderate Drought (D1). During the past week, average temperatures were near normal in the Far West and above normal (5-to-15 degrees) across the remainder of the West.
National Summary: This week saw continued intensification and expansion of areas of drought across portions of the Southwest, Plains, lower Midwest, South, Southeast, and the Mid-Atlantic.
For the conterminous U.S., this past autumn (September-November) was the tenth warmest on record according to NOAA’s National Centers for Environmental Information (NCEI).
In terms of precipitation this fall, October and November were very dry in various regions with the South experiencing its eleventh driest on record and the Southwest its sixth driest.
Conversely, areas of the Midwest experienced above normal precipitation with Michigan having its second wettest and Ohio its fifth wettest on record.
Looking at changes in drought conditions nationwide during the past three months, the focal point of drought development has been centered over portions of the Desert Southwest, Deep South, and southern Plains while conditions have steadily improved across the Pacific Northwest.
For more information on the U.S. Drought Monitor visit: http://droughtmonitor.unl.edu

U.S. Conditions and Weather Report
(December 12) A sustained period of offshore (Santa Ana) winds fueled the spread of several wildfires across coastal southern California. The erratic and gusty winds were especially destructive in Ventura and Santa Barbara Counties, where the Thomas fire scorched more than 230,000 acres of vegetation and destroyed nearly 800 structures.
High pressure centered over northern sections of the Great Basin and Intermountain West led to poor air quality and cool, foggy conditions.
Farther east, mostly dry, breezy weather accompanied generally mild weather across the Plains.
Weekly temperatures averaged at least 10 degrees above normal across portions of the northern High Plains. In addition, the Plains’ winter wheat continued to experience varying degrees of stress due to poor establishment and diminishing soil moisture.
In the mid-South, light precipitation provided only temporary relief from an extremely dry autumn. In contrast, an early-season winter storm provided beneficial moisture across the Deep South and the lower Southeast.
The late-week storm also produced rare and significant snow in parts of southern Texas and from near the central Gulf Coast into the southern Mid-Atlantic region, causing travel and electrical disruptions.
At week’s end, snow fell along the middle and northern Atlantic Coast.
Elsewhere, Midwestern precipitation was mostly light, except for heavier snow showers downwind of the Great Lakes. Midwestern producers proceeded with any remaining harvest activities as fields dried out or as soils began to freeze.

USDA Weekly
Weather and Crop Reports

Nebraska
Weekly crop progress reports have ended for the growing season. Monthly reports will be issued during the first week of January, February, and March. Next year’s weekly reports will begin the first week of April 2018.

Wyoming
Weekly crop progress reports have ended for the growing season. Monthly reports will be issued during the first week of January, February, and March. Next year’s weekly reports will begin the first week of  April 2018.

Colorado
Weekly crop progress reports have ended for the growing season. Monthly reports will be issued during the first week of January and February. Next year’s weekly reports will begin the first week of March 2018.