RodneyS

Quite an historical contrast in June 2014 average minimum and maximum temperatures at DCA. The average minimum was 68.8 degrees, good enough for 6th warmest on the all-time DC list. The average maximum, on the other hand, was 85.6 degrees, tied for only 31st warmest on the all-time DC list. In June 1994, DCA recorded an average maximum of 90.0 degrees, the all-time DC high for June -- 4.4 degrees higher than this year. However, the average DCA minimum in June 1994 was only 68.7 degrees, 0.1 lower than this year.

IAD missed tying by a degree at 59 degrees -- record for May 29th there still stands at 58, also set in 1996. DC record for May 29th is 58, set in 1893; and DCA record is 60, also set in 1996. DCA recorded a maximum of 62 yesterday.

Is he talking about below the 1981-2010 normals? If so, I think that may be true with an asterisk. I haven't checked every year, but I know that in 1996 at BWI July, August, October, and November were all below normal, with September exactly at normal. So, that would be five consecutive months of normal and below, but only four of the five below. At IAD, I believe that the last year with four consecutive below normal months was 2000, when June-September were all below.

The temperature at IAD last night rose four degrees after I posted the above to peak at 58 right before midnight, causing April's average to tick up from 52.1 to 52.2, and the first four months average to tick up to 37.25. That is still the third coldest first third of the year ever at IAD, and the coldest April (tied with 2007) since 50.3 was recorded in 1997.

Same deal for January-April. The first four months of 2014 at IAD averaged 37.23 degrees, beaten for the coldest first third of the year only by 1970 at 36.73 and 1978 at 37.20.

Jan-Mar 2014 was third coldest (of 52 years) at IAD, with an average temperature of 32.27 degrees. Coldest was 1970, with an average of 31.47; and second coldest was 1978, with an average of 31.53.

I agree. DCA, on the other hand, was a not terribly cold 42.9 -- the coldest only since 1996, which also averaged 42.9.

It may have occurred to most in this area that March 2014 was a rather up and down month. How up and down? Since official daily temperature records began in DC in January 1872, there have now been a total of 1707 months recorded, listing the minimum and maximum temperature for each day of each month. According to my figures, with respect to the average daily change in maximum temperature, March 2014 month was -- drum roll, please -- number one! That's correct, with an average daily change in the maximum temperature of 12.4 degrees at DCA, March 2014 displaced long-time record-holder February 1900 (12.1). Also, with respect to the average daily change in the mean temperature, March 2014 was number three, at 9.1 degree. January 1916 remains the record-holder in that category, at 9.34 degrees, narrowly edging January 1950, at 9.32 degrees. Here are the top five months in each category: Average Daily Change in Maximum TemperatureMarch 2014, 12.4 February 1900, 12.1 March 1934, 11.9 March 1923, 11.71 February 1918, 11.68 Average Daily Change in Mean Temperature January 1916, 9.34 January 1950, 9.32 March 2014, 9.1 Febuary 1900, 8.8 March 1938, 8.7

True, and the March 2014 snow total at Dulles just increased to 19.8 inches. Also, the March 2014 snow total at Reagan is now 12.7 inches, which is the highest March total there since 1960. The respective IAD/DCA 2013-14 snow season totals are 52.8 and 32.0 inches, so the difference is a record-breaking 20.8 inches.

This season's astronomical winter averaged only 37.4 degrees at DCA, down 3.0 degrees from last year and 8.5 degrees below the record-setting pace of 2011-12. 2013-14 was the coldest astronomical winter at DCA since 2002-03 (35.8 degrees) and averaged slightly below the historical (1871 to the present) DC average of 37.7 degrees.

Thanks. In that case, the IAD/DCA snowfall separation for 2013-14 is 18.7 inches (49.0 vs 30.3), making this year #1 for separation.

The National Weather Service has upped DCA's snow accumulation for the March 16-17 storm from 6.7 to 7.7 inches, so now the IAD/DCA snowfall separation for 2013-14 is only 18.2 inches. So, for the moment at least, the 1992-93 snow season remains the kingpin for IAD/DCA snowfall separation, at 18.6 inches.

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.