RodneyS

IAD has now recorded 16.0 inches of snow in March 2014, bringing the 2013-14 total to 49.0 inches vs. only 29.8 inches for DCA. Thus, the separation of 19.2 inches has now surpassed the previous record set in 1992-93.

I should have said "1.0 degrees below the 1981-2010 average of 38.4." For some reason, the normalization process shaves 0.2 degrees off the average at DCA, reducing the 1981-2010 meteorological winter normal there to 38.2 degrees. For purposes of comparing the current year with the baseline, I would argue that the average is a better measure to use, but perhaps some normalization guru can explain why I'm wrong. In any event, while the 2013-14 meteorological winter at DCA was 1.0 degrees below the 1981-2010 average, it was only 0.8 degrees below the 1981-2010 normal.

The same for IAD, except that today's minimum of -1 only tied the all-time low for March. The other time was after the 1993 "Storm of the Century," when -1 was recorded on March 15th.

I haven't checked every year in DC, but during the 1904-05 snow season, there were 21 days with measurable snow and 16 additional days with a trace of snow, for a total of 37 days on which at least a trace fell. During that same season, there was measurable snow on the ground on 55 days and a trace of snow on the ground on an additional 20 days, for a total of 75 days with at least a trace on the ground.

Another thing that marked the 2013-14 meteorological winter in this area was the average daily temperature change. At DCA, that average was 6.1 degrees, which was the highest since the 6.8 degree average daily change that occurred during the 1990-91 winter. However, 6.1 degrees is only tied for 31st all-time in DC. During the first 29 years of daily temperature records in DC (1872-1900), the average daily temperature change during the meteorological winter exceeded 6.1 degrees twelve times, including the all-time record of 7.6 degrees during the winter of 1889-90. That winter was also the second warmest in DC history, with an average temperature of 44.3 degrees vs 37.4 degrees this winter.

At IAD, it's tied for the 8th coldest so far out of 52 years, with a January-February average of 29.7 degrees vs a 1981-2010 normal of 34.7 degrees. It's interesting to note that the three coldest IAD first two months composites came back-to-back-to-back: 1977 (27.9), 1978 (27.0), and 1979 (27.25). In DC, it's tied for the 58th coldest so far out of 144 years, with a January-February average at DCA of 35.0 degrees vs a 1981-2010 normal of 37.5 degrees. The coldest DC first two months composite was 1904 (27.95), and the coldest DCA first two months composite was 1963 (31.2).

Winter precipitation this season was actually more impressive than temperature. IAD received 12.08 inches during December 2013 through February 2014 vs a 1981-2010 normal of 8.38 inches and a 1978-79 record of 15.94 inches -- good enough for 6th all-time (relative to 51 meteorological winters there ). DCA received 12.13 inches vs a 1981-2010 normal of 8.49 inches and a 1881-82 record of 18.30 inches -- good enough for 19th all-time (relative to 143 meteorological winters in DC).

IAD finished February at 32.2 degrees , bringing the meteorological winter average to 32.9 there. That is 2.4 degrees below the 1981-2010 normal of 35.3, which means that season tied for the 15th coldest winter, and the coldest since 2002-2003 (30.7). However, it was still far behind the back-to-back winters of 1976-77 and 1977-78, which each averaged 29.0.DCA finished February at 37.8 degrees , bringing the meteorological winter average to 37.4 there. That is 1.0 degrees below the 1981-2010 normal of 38.4. However, this season was actually the 56th warmest DC winter of 143, and the coldest only since 2010-2011 (36.7). Moreover, it trailed the all-time coldest winter by 8.4 degrees. That would be the winter of 1904-1905, which averaged 29.0.

During the 2013-14 snow season, DCA and IAD have now each exceeded their three most recent snow season totals combined. For DCA, this season has seen 15.5 inches vs. 15.2 inches for the prior three seasons; and for IAD, this season has seen 30.8 inches vs. 29.0 inches for the prior three seasons.

Speaking of Top Tens at Dulles, with yesterday's 0.3 inch snowfall IAD has now recorded 30.5 inches of snow this winter, tying this season for 10th on the all-time list. Further, IAD's snow total this season has exceeded DCA's total of 15.2 inches by 15.3 inches so far, putting it within striking distance of the all-time record separation of 18.6 inches set in the winter of 1992-93, when IAD recorded 30.3 inches and DCA recorded only 11.7 inches. That season -- also an ENSO-neutral one -- more than half of IAD's snow total was recorded in March.

IAD Top Ten: 1) February 5-6, 2010: 32.4 inches 2) January 6-8, 1996: 24.6 inches 3) February 10-11, 1983: 22.8 inches 4) February 15-17, 2003: 21.7 inches 5) December 18-19, 2009: 18.0 inches 6) February 18-19, 1979: 16.3 inches 7) December 31,1970-January 1, 1971: 15.4 inches 8) March 12-14, 1993: 14.1 inches 9) February 12-13, 2014: 13.3 inches 10) December 25-26, 1969: 12.1 inches

Dulles' snowfall of 13.3 inches on February 12-13, 2014 cracked the IAD Top Ten, at #9, displacing to # 10 the December 25-26, 1969 snowfall of 12.1 inches.

IAD finished at 27.2 degrees, which was indeed the 6th coldest January there, and 6.0 degrees below the 1981-2010 normal. DCA finished at 32.2 degrees, which tied for the 39th coldest January in DC, and 3.8 degrees below the 1981-2010 normal.

IAD looks as if it will finish January with an average temperature of around 27 degrees, which would make it the coldest January since 1994 and the 6th coldest all-time. The coldest IAD Januaries: 1977 (21.0), 1970 (23.9), 1984 (25.8), 1994 (26.1), and 1982 (26.2). Bear in mind, however, that the temperature record there dates only to November 1962, and so we're talking about only 52 Januaries. DCA has not been all that cold, and will likely finish January with an average temperature of around 32 degrees, which would not be even the coldest recent January. The coldest DCA Januaries over the past 20 years: 1994 (28.8), 2004 (30.6), 2003 (31.1), and 2009 (31.7). The all-time coldest DC January was 1918, with an average of 23.7, and there have been another 30 or so years in the 144-year January temperature record that have been colder than this one is likely to be.

I would say DCA no, but IAD yes.

In that case, you are definitely in the minority among sports fans. But let me ask you this: What would it take to convince you that something more than random fluctuations were taking place?

Rodney, have you split it out before and after the move to the river location? I have now done that. First, a slight error crept into my previous calculations, as during the most recent 31 years, January 13th had a lower average temperature than January 21st six -- rather than five -- times. Thus, the percentage changes slightly, from 16.1% to 19.4%. Sorry for the error, but 19.4% remains a long ways from 63.8%. Second, regarding your question, DCA became the official DC weather location on July 1, 1945, and so the first 74 Januaries reflect the previous 24th and M Street, NW location. During those 74 years, January 13th had a lower average temperature than January 21st 48 times (64.9%), with one tie (1.4%). In the next 38 years -- prior to the most recent 31 years -- January 13th had a lower average temperature than January 21st 22 times (57.9%), with two ties (5.3%). So, the percentage did lessen somewhat immediately following the location change, but not all that much. Overall, since the location change, January 13th has had a lower average temperature than January 21st 28 times (40.6%), with two ties (2.9%).

Thanks for your comment, but I think the question remains whether something has fundamentally changed in recent years. Consider that, during the first 112 years of DC temperature records, January 13th had a lower average daily temperature than January 21st 70 times (62.5%), with three ties (2.7%). However, during the most recent 31 years, January 13th had a lower average temperature than January 21st only five times (16.1%), with no ties. Think of this situation in a sports context: Suppose a baseball or hockey team had a winning percentage of .638 over its first 112 games (counting each of the three ties as half a win), and then plummeted to a winning percentage of only .161 over its most recent 31 games. Would you say that it's more likely that those sharply varying winning percentages can be explained by: (1) random fluctuations, or (2) a fundamental change in the team's performance?

The beat goes on. January 13th reached 61 degrees this year, and averaged 46.5, vs 29.0 on January 21st. January 13th -- once the coldest January day -- has now averaged 40.5 since 1984, vs 31.8 on January 21st. Why so warm in early January in recent years, and why do the January cold waves now occur around the 21st?

In DC, I believe that it is January 25th, with 24 events. So, perhaps we can make it 25 tomorrow. December 5th, by the way, has had only ten.

Here is an odd coincidence. From the beginning of the official DC snow record in the winter of 1884-85 through the winter of 1999-2000, there was measurable snow on January 21st in only three years (1917, 0.8 inches; 1976, 0.1 inches; and 1982, 3.5 inches). However, since then there has been measurable snow on January 21st in six years (2001, 1.1 inches; 2003, 0.7 inches; 2007, 1.2 inches; 2011, 0.1 inches; 2012, 0.6 inches; and 2014, 3.8 inches).

The 2-inch DC snow drought is over, at 1091 days between the storms of January 26, 2011 and today, January 21, 2014. The previous record was only 701 days, between the storms of February 4, 1975 and January 5, 1977.

Here is a mind-boggling statistic to put our area's volatility in perspective. Nowata, OK set the all-time low temperature record in the history of Oklahoma on February 10, 2011, with a reading of -31. Exactly one week later, it recorded a high of 79 -- a 110 degree rise not from winter to summer but from one Thursday to the next!

For DC, I believe it is 1881. The high of 104 on September 7th represented a 118 degree increase from the low of -14 on New Year's Day. For DCA, I believe it is 1994. The high of 101 on June 15th represented a 105 degree increase from the low of -4 on January 19th. For IAD, I believe it is 1987. The high of 100 on August 27th represented a 117 degree increase from the low of -17 on January 28th.

IAD easily broke the lowest daily maximum and minimum records for January 7th, with 18 and 1, respectively. The maximum was the lowest since January 16, 2009 (17), and the minimum was the lowest since January 17, 2009 (0). The daily average of 9.5 was the lowest since February 5, 1996 (5.0, consisting of a maximum of 20 and a minimum of -10).