December 2021 National Weather Summary

[James Munley]

NATIONAL WEATHER SUMMARY
DECEMBER 2021

1-4: By the morning of December 3, only 6 percent of the continental U.S. was covered by snow—lowest on record for that date going back to 2003. Late in the week, however, some snow blanketed the nation’s northern tier, accompanied by gusty winds and cooler conditions. Elsewhere, significant wetness was confined to the Pacific Northwest and the northernmost Rockies. Some additional flooding was noted in western Washington, which remained very wet in the wake of mid-November flooding. With record-setting warmth dominating areas from the Pacific Coast to the Mississippi Valley, weekly temperatures averaged at least 10 to 20°F above normal throughout the Rockies, Plains, interior Northwest, and western Corn Belt. In fact, anomalous warmth broadly covered the entire continental U.S., except for some lingering cool conditions in the East. Weekly temperatures averaged as much as 5°F below normal in peninsular Florida and northern New England. Historically warm weather developed across the western and central U.S. before spreading eastward, resulting in dozens of monthly record highs in early December. During the first wave of monthly records on December 1, high temperatures soared to 85°F in Salinas, CA; 74°F in Omak, WA, and Sidney, NE; and 71°F in Mobridge, SD, and Hettinger, ND. Hettinger also set a state record for December, eclipsing the longstanding mark of 70°F, set on December 12, 1894, in the community of Napoleon. Elsewhere on the 1st, Helena, MT (70°F), achieved its warmest winter day on record, surpassing 69°F on February 24, 1995, and broke its December record by 6°F. The parade of records continued through December 2, with highs rising to monthly record levels in locations such as Russell, KS (79°F); Sidney, NE (78°F); Sheridan, WY (77°F); and Rapid City, SD (75°F). Although warmth was slightly less anomalous after the 2nd, Greenville Spartanburg, SC, tied a monthly record with a high of 79°F on December 3. On the 4th, Galveston, TX (80°F), attained a reading of 80°F or higher in December for only the fifth time on record. In addition, hundreds of daily-record highs were established in late November and early December, with many sites setting records on multiple days. On November 29, highs surged to the 80-degree mark or higher as far north as Kansas, where Medicine Lodge posted a reading of 82°F. On the same date, Woodland Hills, CA, notched a high of 90°F. Woodland Hills collected another daily-record high (88°F) on November 30, while Palm Springs, CA, noted 91°F on the 30th and again on December 1. In Washington, Ephrata closed November with three consecutive daily record highs (61, 62, and 60°F), followed by a monthly record high of 69°F on December 1. Monthly records were shattered on the 1st by at least 5°F in Washington locations such as Ellensburg (66°F), Ephrata (69°F), Wenatchee (70°F), Yakima (72°F), and Omak (74°F). Late week warmth became prominent in the South, where daily-record highs for December 2 included 81°F in Gage, OK; 80°F in Batesville, AR; and 78°F in Poplar Bluff, MO. The following day, record-setting highs for December 3 rose to 88°F in San Angelo, TX; 82°F in Columbia, SC; and 81°F in Lumberton, NC; and 80°F in Harrison, AR. As markedly cooler air arrived on December 4 across the Plains and Midwest, lingering warmth was confined to the West and South; daily-record highs included 83°F in Yuma, AZ, and 81°F in Shreveport, LA.

5-11: Generally beneficial rain and snow showers dotted the West, although heavy precipitation was mostly confined to parts of the Pacific Northwest and northern Rockies. Despite the stormy weather, coast-to-coast warmth covered the country, except for cooler-than-normal conditions across the nation’s northern tier. Weekly temperatures averaged as much as 5°F below normal along and near the Canadian border from northern Montana to northern Wisconsin. In contrast, readings averaged at least 10°F above normal across much of the Deep South and in scattered locations as far north as the middle Mississippi Valley. Temperatures were up to 15°F above normal in the western Gulf Coast region. In fact, record setting warmth pushed temperatures to 80°F or higher from southern Oklahoma and central and eastern Texas to the southern Atlantic Coast. A few readings above 90°F were reported in southern Texas.

On December 5, a surge of warmth in advance of a cold front resulted in dailyrecord highs of 82°F in Hobart, OK, and Childress, TX. Very warm weather also covered the Desert Southwest, where Thermal, CA, posted a daily-record high (89°F) for the 5th. Farther north, however, the temperature in Denver, CO, fell 43°F (from 64 to 21°F) in a little over 8 hours on December 5, accompanied by blowing dust and a northeasterly wind gust to 46 mph. On the same date, wind gusts in New Mexico were clocked to 62 mph at Cannon AFB and 60 mph in Clovis. Meanwhile, Galveston, TX, reported highs of 80°F or greater on December 4, 6, and 9. Prior to this year, Galveston had reached or exceeded the 80-degree mark in December once apiece in 1918, 2007, 2016, and 2018. During the second half of the week, high temperatures soared in advance of a new Western storm system. On December 9 and 10, Houston, TX, tied a monthly record with highs of 85°F. Daily-record highs in Texas on the 9th included 89°F in Laredo and 88°F in Brownsville. Del Rio, TX, posted a daily-record high of 90°F on December 10. Elsewhere in Texas, consecutive daily-record highs occurred on December 9-10 in Abilene (83 and 84°F); Waco (82 and 84°F); and Wichita Falls (79 and 84°F). On December 10, the day of the tornado outbreak, dailyrecord highs surged to 85°F in Vicksburg and Greenwood, MS, and to 80°F in Pine Bluff, AR, and Memphis, TN. Warmth spread into the East on December 11, when daily-record high surged to 87°F in Fort Myers, FL; 82°F in Montgomery, AL; 77°F in New Bern, NC; 70°F in Washington, DC; and 69°F in Newark, NJ. High winds accompanied the Northeastern warmth; in New York, peak gusts of 74 mph in Niagara Falls and 66 mph in Buffalo were recorded on December 11.

12-18: Just 5 days after the deadly December 10 tornado outbreak across the mid-South and lower Midwest, extreme weather returned across the Plains and Midwest in the form of high winds and isolated tornadoes. Unrelated to thunderstorm activity, winds of 75 to 100 mph or greater raked the central Plains, raising dust, disrupting travel, fanning several grassfires, and blasting an already stressed winter wheat crop. Elsewhere on the 15th, high winds (60 to 80 mph or higher) associated with severe thunderstorms—a derecho—swept hundreds of miles across the Midwest, from central and eastern Kansas into Wisconsin, resulting in localized to widespread damage. Isolated tornadoes, including the first five (based on preliminary reports) ever noted during December in Minnesota, accompanied the outbreak.

Several days of record-smashing warmth across much of the central and eastern U.S. led to hundreds of daily-record highs and several monthly record highs. Weekly temperatures averaged 10 to 15°F above normal in many areas along and east of a line from Texas to Minnesota, excluding portions of the middle and southern Atlantic States. In contrast, cooler-than-normal conditions settled across parts of the West, holding temperatures more than 5°F below normal in parts of California. Cold weather also prevailed along and near the Canadian border in Montana and western North Dakota. During the early- to mid-week period, another wave of record-breaking high temperatures preceded the passage of a powerful cold front. Notably, December 15 featured monthly record-high temperatures in numerous Midwestern locations, including Columbia, MO (76°F); Ottumwa, IA (75°F); Moline, IL (75°F); Lincoln, NE (74°F); La Crosse, WI (69°F); and Rochester, MN (64°F). Readings of 80°F or higher briefly occurred as far north as western Oklahoma and were common in the western Gulf Coast region and across Florida’s peninsula. Tampa, FL, collected daily-record highs of 86°F on December 13, 16, and 17. Galveston, TX, reached or exceeded 80°F on December 4, 6, 9, and 16, compared with 4 such December days (one apiece in 1918, 2007, 2016, and 2018) in all years back to 1874. Prior to the historic, mid-week surge of warmth, above-normal temperatures were already in place across the nation’s mid-section. From December 12- 14, Borger, TX, tallied a trio of daily-record highs (76, 74, and 81°F). In addition, Borger last received a drop of rain on October 12, pushing its dry spell to 67 days by week’s end. Farther north, monthly record warmth lasted into early December 16 across Wisconsin, where highs included 65°F in Green Bay and 68°F (tying December 5, 2001) in Milwaukee. Green Bay’s previous December record of 64°F had been set on December 5, 2001, and December 15, 2021. The warmth briefly reached the Northeast on December 16-17, resulting in consecutive daily-record highs in locations such as Providence, RI (65 and 63°F), and Montpelier, VT (63°F both days). In contrast, daily-record lows in southern California dipped to daily-record levels on December 16 in Ramona (26°F) and San Diego (38°F). On December 18, Tonopah, NV, posted a daily-record low of -1°F. Warmth lingered at week’s end across the South, where record-setting highs for December 18 rose to 86°F in Naples, FL, and Harlingen, TX.

19-25: Meaningful snow east of the Rockies was limited to the North, leaving much of the central and eastern U.S. with no snow for the holidays. In fact, even with recent Western accumulations, less than 27 percent of the contiguous U.S. had snow on the ground on the morning of December 25—the fourth year in a row with Christmas Day coverage less than 30 percent. With a warm December pattern continuing, except across the North and the Far West, weekly temperatures averaged at least 10°F above normal on the High Plains as far north as Wyoming and western Nebraska. In contrast, readings averaged at least 5°F below normal in scattered Northern locations, especially in northern Montana. Record-shattering high temperatures continued in many areas of the country, notably from the central and southern Plains into the Southeast. On December 19, Vero Beach, FL, began the week with a monthly record high of 90°F (previously, 89°F on December 2 and 3, 2018). Subsequently, Wichita Falls, TX, posted a December record high with a reading of 91°F on the 24th. Wichita Falls had never reached or exceeded the 90-degree mark so late in the year; the monthly record had been 88°F on December 4, 1954. It was the warmest Christmas Day on record in dozens of locations across the South; record highs for December 25 included 84°F in Houston, TX; 80°F in Pine Bluff, AR; and 76°F in Nashville, TN. Rio Grande Village, TX, reported a high of 94°F, a U.S. record for December 25. Holiday warmth extended into the Midwest, where daily-record highs for December 25 rose to 77°F in Poplar Bluff, MO; 74°F in Carbondale, IL; and 72°F in Evansville, IN. Meanwhile, frigid conditions were limited to the nation’s northern tier, where readings below -10°F occurred from Montana to Maine. Shortly after reporting a monthly record-tying high of 69°F (on December 1), Glasgow, MT, registered sub-zero minimum temperatures on December 5-7, 15-18, 20-21, and 24-25. A handful of daily-record lows occurred in the West, where Ramona, CA (22°F), noted a record for December 20. The week ended (on December 24-25) with consecutive daily-record highs in several Southern locations, including Midland, TX (84 and 78°F), and Paducah, KY (70 and 74°F).

26-31: Dry weather dominated the southern Atlantic region, as well as large sections of the Plains.

Colder, drier air settled across the western U.S., starting in the Northwest. Prior to the arrival of drier weather, the average water content of the high-elevation Sierra Nevada snowpack climbed to 15 inches, more than 160 percent of the early-January normal and about 55 percent of the typical accumulation for an entire season, according to the California Department of Water Resources. With historic, lateDecember warmth prevailing across the South, East, and lower Midwest, several monthly record highs were established. In those regions, weekly temperatures broadly averaged at least 10 to 25°F above normal, capping the warmest December on record in numerous locations. In stark contrast, frigid conditions gripped the North, extending as far east as the upper Midwest. Weekly readings averaged 10 to 25°F or more below normal in many locations from Washington and Oregon eastward to Minnesota. Cold weather also dominated the remainder of the West. Scattered readings below -30°F were noted along and near the Canadian border from Montana to Minnesota. As 2021 ended and the New Year began, temperatures plunged to 0°F as far south as northern New Mexico, southeastern Colorado, and northwestern Kansas. A stunning array of daily- and monthly record highs spanned the South. In the latter category, Abilene, TX, notched a December record high on the 26th with a high of 90°F (previously, 89°F on December 4, 1954, and December 24, 1955). Two days later, on the 28th, a high of 82°F edged the monthly record of 81°F, set on December 13, 2016, and December 6, 2021. Galveston had experienced just 4 days of 80-degree warmth in December prior to this year. On December 30 in Alabama, highs of 85°F in Montgomery and 82°F in Mobile tied or broke monthly records. The record-smashing Southern warmth continued into the New Year. In fact, the warmest New Year’s Day and January day on record occurred in Texas locations such as Houston (85°F) and Galveston (81°F). Galveston’s former monthly record had been 79°F on January 3, 2017. Elsewhere in Texas, daily-record highs for January 1 included 94°F in Laredo and 92°F in McAllen, Corpus Christi, and Harlingen. In contrast, frigid weather gripped the northern Plains and Northwest, accompanied by some snow. In Washington, consecutive daily-record lows were set on December 26-27 in Seattle (20 and 17°F) and Bellingham (9 and 7°). In Montana, recordsetting lows for the 27th dipped to -28°F in Choteau and -26°F in Cut Bank. Later, Grand Forks, ND, closed the week on December 31 and January 1 with consecutive daily-record lows (-33 and -37°F, respectively).