RodneyS

And at least a dozen more somewhat obscure high average temperature records -- for the 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 months ending in March 2012, as well as the warmest 12 consecutive months irrespective of ending month. I believe that the March 2012 number is now finalized at 56.7 degrees, beating the 1945 record by 0.5 degrees. Additionally: February-March 2012 averaged 50.5* degrees, beating the 1976 record by 1.4; January-March 2012 averaged 47.2 degrees, beating the 1990 record by 0.9; December 2011-March 2012 averaged 46.7 degrees, beating the 2001/2002 record by 2.3; November 2011-March 2012 averaged 47.8 degrees, beating the 2001/2002 record by 1.4; October 2011-March 2012 averaged 49.6 degrees, beating the 2001/2002 record by 0.9; September 2011-March 2012 averaged 52.7 degrees, beating the 1931/1932 record by 0.8; August 2011-March 2012 averaged 56.1 degrees, beating the 1973/1974 record by 0.8; July 2011-March 2012 averaged 59.3 degrees, beating the 1973/1974 record by 1.4; June 2011-March 2012 averaged 61.2 degrees, beating the 1973/1974 record by 1.3; May 2011-March 2012 averaged 61.9 degrees, beating the 2007/2008 record by 1.5; and April 2011-March 2012 averaged 61.6 degrees, beating the 1980/1981 record by 1.7. The last record is particularly noteworthy, because it is also the highest temperature for any 12-month period in DC history, beating the October 1990-September 1991 record by 0.8. Of course, this new 12-month record may be short-lived, if the April 2012 average temperature exceeds the April 2011 average of 58.8 degrees. * Averages for more than one month (such as December, January, and February -- the three months of meteorological winter) have traditionally been calculated by assuming that each month has the same number of days, even though that method is slightly inaccurate because the months differ in length. For example, to calculate a true February-March 2012 average, the average temperature for each of those 60 days (29 in February and 31 in March) should be summed and divided by 60, rather than simply adding the average February temperature to the average March temperature and dividing by two. The true average for February-March 2012 is 50.8, rather than 50.5, but for consistency with traditional calculations, I have used the simpler method. Either way you do the calculations, all the above records were broken.

I don't have Baltimore data, but regarding DC, I stated on this thread -- http://www.americanw...h-on-record-dca -- "We are also locked in to the warmest astronomical winter (approximately December 21st to March 20th each season) and the warmest composite meteorological/astronomical winter (December 1st to March 20th each season). Each of these two measures of winter currently (through March 13th) show average temperatures of 44.4 degrees in DC, versus the previous astronomical winter record of 43.7 in 1989-90 and the previous composite winter record of 44.0 in 2001-02" The final figures in DC for both the 2011/12 astronomical and composite winters will be at least a degree higher than they were through March 13th -- I'll post them later today or early tomorrow on the above thread. Given by how much the DC records are going to be broken, I think it's pretty certain that the corresponding Baltimore records will also be broken.

I would throw in 10th wettest August (2011), which when combined with September 2011, produced the third wettest August-September.

August 12 has seen a trace of precipitation on 20 days, measurable precipitation on 51 days, at least an inch on 11 days, and at least two inches on 5 days; August 15 has seen a trace of precipitation on 15 days, measurable precipitation on 45 days, at least an inch on 4 days, and has never received two inches.

I was recently given historical weather data for Washington, DC. The data are very interesting in a number of respects, but I noted something particularly odd about two days in August that are only three days apart: During the period of record, 1871-2010, rainfall on August 12th has exceeded rainfall on August 15th by a factor of 3.7 -- 40.95 inches vs. 11.12 inches. Further, the differences have been quite consistent over the years. For example, consider these figures for 30-year periods (20 years for the most recent data): 1871-1900: 9.07 inches total on the 12th, 3.73 inches on the 15th. 1901-1930: 11.90 inches total on the 12th, 0.85 inches on the 15th. 1931-1960: 12.22 inches total on the 12th, 4.31 inches on the 15th. 1961-1990: 2.16 inches total on the 12th, 1.60 inches on the 15th. 1991-2010: 5.60 inches total on the 12th, 0.63 inches on the 15th. August 15th has never had more than 1.15 inches of precipitation, while August 12th has exceeded that amount nine times, and has exceeded two inches five times. In fact, two of the largest rainfalls in Washington, DC history occurred on the 12th -- 4.92 inches in 1898 and 5.44 inches in 1955. Is this just a random variation, or is there something more to it? In searching for an explanation, I came across this article on-line -- http://www.atmos.was...eteors_1956.pdf. That article suggests that there could be a correlation between rainfall and meteor showers -- specifically that rainfall peaks may occur about 30 days after meteor showers. While this hypothesis would not seem to directly relate to the difference in rainfall between August 12th and August 15th in Washington, DC, I find it interesting that more than 55 years ago a meteorologist was suggesting a correlation between rainfall and meteor showers. So, does anyone have any insight into this matter? For example, are there other areas where there are significant variations in rainfall on different days only a few days apart? If so, is there any evidence that meteor showers could play a role? Thanks.