Mixed-up month: November warm, cold, dry and snowy

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By Scot Johnson

November’s weather presented broad and interesting contrasts. The temperature plunge that began the day before Thanksgiving conveniently allowed celebrators to brine their turkeys outdoors, an impossibility for the refrigerator given the size of the pot.The snowstorm a day later added to the holiday enjoyment and broke the dry spell. The rain on the last day of the month turned a monthly precipitation deficit into a generous surplus.The average temperature of 42 degrees in Los Alamos was five degrees above normal. White Rock’s average of 40 degrees was only two degrees above normal.The difference was probably due to more than the usual cold nightly drainage flow common to White Rock; the average high temperatures in both towns and the average Los Alamos minimum temperature were all about five degrees above normal, while White Rock’s average night time low temperature was a degree colder than normal.High pressure throughout the southwest dominated in November, bringing sunny skies and unseasonable warmth. A backdoor cold front, so called because it comes from the northeast, dropped temps a bit around Nov. 15.More noteworthy than the temperature change, however, was that the inversion which always accompanies a front, whether a warm front or cold one, backdoor or not, caused smoke from controlled burns to linger close to the ground, causing much of the community to gag through the night.The reign of warmth ended Nov. 21 as a strong cold front swept from north to south across the nation. Record high maximum temperatures in Los Alamos of 62, 64 and 63 degrees Nov. 18, 19 and 20 and in White Rock of 68 and 67 degrees Nov. 19 and 20 plummeted to a record low maximum of 29 degrees in White Rock Nov. 23, and a record low minimum of 7 degrees Nov. 25. The first three weeks of November were bone dry. But moisture followed the strong cold front passage of Nov. 21 and the county enjoyed its first significant snowfall of the season, about six inches, Nov. 23.As the end of the month approached, so did an even more promising storm. Coming from the south, we expected plenty of moisture but unfortunately warm temperatures as well.Still, with a snow level pegged at 7,500 feet, there should have been a foot or more snow in the mountains and a few inches in town. Instead, as temperatures rose beyond those expected with the warm, moist advection from the tropics, little snow was seen anywhere in the county.Nonetheless, there was reason to celebrate as the 25-year storm brought about 2.5 inches of rain.The precipitation total for November rose to 1.61 inches (liquid equivalent), with another 1.25 inches on the tally for December, but I’ll talk about that next month. 1.61 inches in November is a third more than the normal 1.19 inches.The annual total so far is 17.57 inches, about half an inch below normal.White Rock’s November total was 1.42 inches, 50 percent more than the normal 0.93. The annual total there is 12.75 inches, right on schedule for a normal year.Winds were about normal in Los Alamos and White Rock during November. We experienced some 50-plus mph gusts with the rainstorm on Dec. 1, but that’s again a subject for next month.

Scot Johnson is a meteorologist with the Waste and Environmental Services Division, Geotechnical Services Group, Los Alamos National Laboratory.