|Above: Bucolic Saranac Lake, in the Adirondack Mountains of upstate New York, saw temperatures drop by a phenomenal 85°F in less than 48 hours on January 12-14, 2018. Image credit: Mwanner, via Wikimedia Commons.|
The U.S. winter of 2017-18 was one of wild temperature variations. After a frigid few weeks in late December and early January, people in the Midwest and Northeast saw the temperature suddenly vault upwards for a few days in mid-January before plummeting to frigid depths again later in the month. A dramatic example comes from Saranac Lake, in the Adirondack Mountains of upstate New York, where the temperature rose to 55°F (after being at -32°F on January 1) on the afternoon of January 12, only to plummet back to -30°F on the morning of January 14—a drop of some 85° in just 36 hours.
Some of the winter’s swings took place remarkably quickly. On February 20 in Oklahoma City, OK, a cold front sent the temperature down by an amazing 21.4° in just four minutes (from 64.4°F at 6:48 am to 43.0°F at 6:52 am) .
Here’s a look at some of the historical extremes of rapid U.S. temperature change.
From cold to warm
Montana holds the U.S. (and perhaps world) record for the fastest rise in temperature over a 24-hour period. A downslope chinook wind event pushed the temperature at the town of Loma from -54°F at 9 am on January 14, 1972, to 49°F by 8 am on January 15th. The 103°F (57.2°C) rise is the greatest change in temperature ever officially measured on earth within a 24-hour period. An AMS conference writeup in 2003 (see the “Extended Abstract” link) discusses the National Weather Service investigation of this event.
|Figure 1. NWS COOP observer Jim Wood and his instrument shelter at Loma, Montana where the famous (and officially investigated) world-record 103°F change of temperature occurred on January 14-15, 1972. At that time Mr. Wood was unaware of the significance of his observation. Image credit: Courtesy NWS/Great Falls.|
80°F rise in 15 hours: Kipp, MT, on December 1, 1896
42°F rise in 15 minutes: Fort Assiniboine, MT, on January 19, 1893
47°F rise in 7 minutes: Great Falls, MT, on January 11, 1980. The temperature ultimately rose 82°, from -30°F on the 10th to 52°F by the 14th, then dropped back to -26°F on the 29. On the same date, a site in central Montana named Roy 24 NE (near Mobridge) went from -25°F near midnight on the 11th to 53° on the afternoon of the 12th (in other words, a 78° rise in about 18 hours). It’s interesting to note that an intense storm with a central pressure below 952 mb (28.10”) slammed onto the coast of British Columbia at Prince Rupert on the night of January 11-12.
Heat bursts and rapid warm-ups
The rare phenomenon called a heat burst is known to raise temperatures dramatically in short periods of time. Most heat bursts are produced as thunderstorms collapse, typically during the late evening and overnight hours. Phillipsburg, Kansas saw a 19°F rise in 11 minutes (from 74.6°F to 93.5°F) during a heat burst on the morning of May 29, 2000.
There are many anecdotal (and apocryphal) stories surrounding heat bursts, but not much hard data. One very impressive study was published in 2011 in the International Journal of Climatology and led by Renee McPherson (University of Oklahoma). This study analyzed 207 heat bursts detected by the Oklahoma Mesonet from 1994 to 2009. One of these produced the most extreme heat-burst-related temperature change that appears valid at any location in the U.S. (that I am aware of): a temperature rise of 19.3° (from 74.1°F to 93.4°F) in just five minutes (between 8:40 am and 8:45 am) at Hobart, OK, on May 23, 2005.
|Figure 2. A verified heat burst brought the temperature from 74.1°F to 93.4°F in just five mintes on the morning of May 23, 2005, at Hobart, Oklahoma. Image credit: Oklahoma Mesonet, courtesy Renee McPherson.|
From warm to cold
Once again, Montana holds (perhaps) the world record for the sharpest drop in temperature as well as the sharpest increase. Browning, MT, saw its temperature drop 100°F, from 44°F to -56°F, in less than 24 hours as a result of a cold front passage on January 23-24, 1916. Fairfield, MT, saw an 84° drop (from 63°F to -21°F) in just 12 hours on December 24, 1924. This is generally credited as the record for any 12-hour period.
The most infamous cold frontal passage in U.S. history was that which occurred in the heart of the U.S. on November 10-11, 1911. No other frontal passage this intense has been documented in modern records anywhere in the United States (although a similar event may have occurred on Dec. 20, 1836, according to anecdotal evidence).
On November 9, 1911, a blast of arctic air invaded the northern plains, sending the temperature at Rapid City, South Dakota, from 55°F at 6 am to 3° by 8 am. The front pushed eastward on November 10 and 11, when a low pressure formed along the cold front over Missouri, sucking very warm and unstable air into the lower Great Lakes region. Violent tornadoes broke out in Iowa, Illinois, Indiana, Michigan, and Wisconsin. An F4 twister decimated Janesville, Wisconsin, killing 9 people and injuring 50. The Janesville tornado struck at 9 pm on November 11; by midnight, blizzard conditions raged and the temperature had fallen from 70°F to 7°F (as measured in nearby Madison).
|Figure 3. The U.S. Weather Bureau weather map for 8 am November 11, 1911. An area of low pressure has formed along the very sharp front over Missouri, infusing very warm and unstable air into the area just east of the front and resulting in multiple tornado events in Wisconsin, Illinois, Michigan and Indiana. This was and still remains the most violent tornado outbreak for so late in the season in the Great Lakes region. Image credit: NOAA.|
Aside from producing the tornadoes (the most violent so late in the season on record for the north-central states), the frontal passage was even more notorious for the incredible rapidity of the temperature change during its passage, especially on November 11 (or 11/11/11). The temperature at Kansas City, MO, dropped from a daily record high of 76° at noon on Nov. 11 to a daily record low of 11° by midnight. Oklahoma City, OK, fell from a record 83°F at 1 pm to 17°F by midnight. Chicago dropped from 74°F at 1 pm to 13°F by midnight, and the Monthly Weather Review quoted a local newspaper that "one man was overcome by heat and two others frozen to death in the short space of 24 hours" (which sounds like a little journalistic license!). Officially, Springfield, MO, dropped from a record 80°F at 3 pm to 13°F by midnight, but a look at the thermograph for that day (Figure 5 below) reveals that the actual drop was even more impressive.
|Figure 4. Monthly records for heat and cold set in various U.S. states from November 10 to 13, 1911. The warmest monthly readings for the month of November 1911 for each of the states listed occurred on either Nov. 10 or 11, whereas the coldest monthly temperatures for the month of November 1911 occurred just one or two days later, on Nov. 12 or 13.|
|Figure 5. Thermograph trace from Springfield, Missouri for November 11, 1911, with temperatures shown in Fahrenheit and hours of the day (in CST) along the top. Although the official temperature range for the day was quoted as 80°F to 13°F, the actual high (as shown in the thermograph) was 81°F at about 3:45 pm and the actual low 10°F just before midnight. The U.S. Weather Bureau office in Springfield only reported hourly observations at the top of each hour and did not include reports between hourly observations or at midnight. An almost instantaneous drop of at least 45° seems to have occurred around 4:00 pm. The 71° drop from 81°F at 3:45 pm to 10°F at midnight, in a bit over eight hours is almost unprecedented in meteorological records, although two locations in Arkansas (Rogers and Fayetteville) measured a 72° drop (from 81°F to 9°F) during the same period. Image credit: NWS/Springfield.|
The cold front passage of November 1911 also affected northern Texas, where Seymour saw its temperature fall from 87°F on the afternoon of November 11 to 10°F the following morning! In Texas, such fast-moving fronts are often colloquially known as “Blue Northers”. For details about some of the more extreme of these to affect Texas, see the blog I penned on the subject back in 2013.
Record highs and record lows set on the same day
As noted above, one striking aspect of the November 1911 event was how some cities recorded both daily record high temperatures and daily record low temperatures on the same day. This uncommon occurrence usually happens in the high-desert regions of the West where the air is dry and the sun intense, thus encouraging large diurnal temperature variations. Daily temperature ranges of 35°-40°F or more are the norm for many places in this region. For instance, Reno, Nevada, has an average annual diurnal temperature spread of around 35°F throughout the year. On August 29, 1962, the city established its coldest August temperature on record with a 24°F reading—and by the afternoon it was 82°F (a 58° rise). Another interesting example of this comes from Gavilan, New Mexico, where the following diurnal spread of temperatures occurred in January 1949:
Jan. 5: High of 29°F, low of -40°F (69° spread)
Jan. 6: High of 43°F, low of -31°F (74° spread)
Jan. 7: High of 43°F, low of -22°F (65° spread)
A truly outrageous (and most likely erroneous) instance of this was a daily temperature spread of 81° (low of 0°F and high of 81°F) reported at Juniper Lake, Oregon on May 2, 1968. Such an excursion is difficult to believe and, in fact, almost certainly in error. The low of 0°F on May 2 would be the coldest May temperature ever observed in the entire state of Oregon.
Although the Juniper Lake data is probably in error, there are a number of well-documented cases of daily record high and low temperatures happening on the same day. Below is a short list of some of such events I have researched. This list is incomplete, I’m sure.
|Figure 6. Towns and cities that have observed both their daily record high and daily record low on the same date.|
In the case of Alamosa, CO, the 30°F on August 25, 2002, was just 1° short of their all-time August monthly record minimum of 29°F, whereas the 88°F the following day was only 3° short of their all-time monthly August record maximum of 91°F. The POR (period of record) for Alamosa dates back to 1932. You may notice several of these types of records occurred in the West in 2002. That’s a result of a severe drought that was affecting the region with deadly wildfires and with exceptionally dry air, which encourages large diurnal temperature fluctuations.
Almost as amazing was the daily record low in Rapid City, SD, of 39°F (1° short of their monthly August record) on August 16, 2002, followed the next day (August 17) by a reading of 101°F, a daily record and just 5° short of their August monthly record at the time. Since 2002 Rapid City has seen a new record for the month of 107°F. In fact, as a result of global warming, these same-day high/low records seem to be getting less frequent, as new daily maximums outstrip daily minimums and subsume the old records.
The mystery of Sunrise Manor
As a footnote to this subject, there is another crazy set of diurnal temperature excursions that I’m not sure I can believe and should be taken with the proverbial grain of salt. Nevertheless, according to a publication by the Nevada Bureau of Mines and Geology titled Nevada’s Weather and Climate (Mackay School of Mines, University of Nevada, Reno, 1975 with one of the authors of the monograph being Clarence Sakamoto, the former Nevada State Climatologist), the North Las Vegas site known as Sunrise Manor measured a low of 48°F and a high of 119°F on July 13, 1972, a 71° daily spread.
The official Las Vegas site at the airport saw nothing like this with a range from 78°F to 114°F but the authors noted (on page 28) that “temperature ranges are much larger at Sunrise Manor than at the Las Vegas airport because of local topographic effects”. However, a low 30° cooler at a site just 15 miles northeast from the airport? Perhaps some local residents could chime in on this proposed anomaly (keeping in mind that Las Vegas in 1972 was quite a different city than it is now). The following day Sunrise Manor reported 121°F and Las Vegas Airport 116°F, one of their warmest temperatures on record, with lows of 61° at Sunrise Manor but 82° at the airport.
|Figure 7. The Black Hills of western South Dakota, viewed from Harney Peak. Image credit: Runner1928, via Wikimedia Commons.|
The “sloshing” temperatures of the Black Hills
Of special mention are the famed temperature antics that occasionally occur in the distinctive geography of South Dakota’s Black Hills. These happen when a stationary front drapes itself over the compact mountain range, and cold and warm pockets of air become trapped in the valleys, sloshing back and forth like water in a shallow bowl. This can result in dramatic changes of temperature measured in minutes rather than hours. The most dramatic example of this occurred on January 22, 1943, when the town of Spearfish saw its temperature rise from -4°F at 7:30 am to 45°F at 7:32 am—an almost unbelievable rise of 49° in just two minutes. By 9:00 am, the temperature had risen gradually to 54°F when it suddenly dropped again to -4°F just 27 minutes later. Rapid City experienced the same effect, as evidenced by the thermograph below.
|Figure 8. Temperature fluctuations in Rapid City, South Dakota from 9:00 am to 6:00 pm on January 22, 1943. Data from Monthly Weather Review, March 1943.|
The town of Lead, up in the Black Hills, experienced such a shocking change of temperature that plate-glass windows reportedly cracked. At one point, the town of Deadwood (in a canyon 600 feet lower than Lead, but only two miles away) had a temperature of -16°F at the same time it was 52°F in Lead! Wind gusts of 40-50 mph were whipping through the region. Motorists had to pull off the roads, as their windshields would suddenly frost over as they drove from a warm pocket to a cold one. Needless to say, the temperature excursions in the Black Hills that day are the most extreme observed and measured anywhere in the world. The March 1943 issue of Monthly Weather Review includes a complete summary of this extraordinary event.
Rapid City saw another crazy day temperature-wise on January 10, 1911 (yes, the same year as the infamous November temperature event), when temperature readings fell from 55°F at 7:00 am to 8°F fifteen minutes later. Two days later on January 12, temperatures rose back to 49°F only to fall back to -13°F in two hours later that day, a 62° swing.
If all this data from Rapid City is to be believed, then I think it fair to propose that Rapid City’s name ought to serve as a reference to its temperature anomalies!
KUDOS: Thanks to Mark Stroud at Moon Street Cartography for production of the last two graphics.
Christopher C. Burt