Ian Posted February 26, 2015 Share Posted February 26, 2015 I think BWI will finish either 2nd or 3rd coldest February. That will also be a top 10 coldest month overall. Rodney or MN (or anyone), how does it look for DCA and IAD rankings? I don't keep spreadsheets of those. BWI should get 2nd as 1979 finished a bit mild. Dulles is close but seems it'll miss 1979 by a smidge for number 2? DC is like top 15. Link to comment Share on other sites More sharing options...
RodneyS Posted February 27, 2015 Share Posted February 27, 2015 BWI should get 2nd as 1979 finished a bit mild. Dulles is close but seems it'll miss 1979 by a smidge for number 2? DC is like top 15. Dulles is a lock for the second coldest February there, but 1979 is now out of reach due to the warm-up yesterday afternoon and today. As Ian notes, DCA will finish in the Top 15 coldest in DC history, but will also finish warmer than in 1979. However, DCA still has a chance for the coldest last half of February in DC history. Further, the second half of February at both IAD and DCA will finish way colder than in 1979. Link to comment Share on other sites More sharing options...
RodneyS Posted March 1, 2015 Share Posted March 1, 2015 Dulles is a lock for the second coldest February there, but 1979 is now out of reach due to the warm-up yesterday afternoon and today. As Ian notes, DCA will finish in the Top 15 coldest in DC history, but will also finish warmer than in 1979. However, DCA still has a chance for the coldest last half of February in DC history. Further, the second half of February at both IAD and DCA will finish way colder than in 1979. February 2015 appears to be finalized at 30.3 degrees for DCA and at 25.4 degrees for IAD. That makes each airport the coldest in February since 1979 (DCA: 28.4, IAD: 23.3), and it places DCA 14th coldest of 145 years in DC history and IAD second coldest of 53 years in Dulles history. February 2015 was also the coldest month experienced at DCA since January 1994 (28.8) and at IAD since December 1989 (23.1). For the meteorological winter as a whole, DCA averaged 36.5 -- pretty much in the middle at 68th coldest of 144 seasons and coldest only since 2009-10 (35.8). However, IAD averaged just 31.0 -- the 7th coldest of 53 seasons there and coldest since 2002-03 (30.7). Regarding the last half of February 2015, it was a case of "missed it by that much" at DCA. It averaged an even 25.0 degrees from the 15th to the 28th, which was just a tenth of a degree warmer than February 15-28, 1934, and 1934 also holds the record for the coldest February as a whole, at 24.6 degrees. However, the last half of February 2015 was 7.3 degrees colder than the last half of February 1979 at DCA, and IAD's February 2015 last half average of 19.5 degrees was 7.5 degrees colder than the last half of February 1979 there. Link to comment Share on other sites More sharing options...
PrinceFrederickWx Posted March 1, 2015 Share Posted March 1, 2015 BWI finished February at 25.3 degrees, making it the 2nd coldest February ever and 5th coldest month ever (top 10 coldest months are listed below): Jan. 1977 - 22.9 degrees Jan. 1918 - 24.2 degrees Feb. 1934 - 24.3 degrees Jan. 1893 - 24.3 degrees Feb. 2015 - 25.3 degrees Dec. 1989 -25.4 degrees Jan. 1982 - 25.5 degrees Feb. 1979 - 25.6 degrees Jan. 1912 - 25.8 degrees Jan. 1940 - 26 degrees This was also the 2nd coldest Jan-Feb period ever for BWI at a combined average of 28.1 degrees (the first was 1904 at 28.0 degrees). May be too soon but... could BWI try making a run for top 10 coldest year again this year? Edit: I forgot about Dec. 1989 so its been put in the list. I hadn't even bothered checking Dec. cause I figured it couldn't even compete. Wow... Link to comment Share on other sites More sharing options...
Deck Pic Posted March 2, 2015 Share Posted March 2, 2015 Link to comment Share on other sites More sharing options...
WxUSAF Posted March 3, 2015 Share Posted March 3, 2015 10 below normal months at BWI in the period of November 13-February 15. February 15, January 15, November 14, August 14, July 14, April 14, March 14, February 14, January 14, November 13 That's a pretty impressive run given climate and UHI both progressively working against below normal temps. Maybe some of the stat-minded folks can tell us how exceptional it is? Link to comment Share on other sites More sharing options...
RodneyS Posted March 3, 2015 Share Posted March 3, 2015 10 below normal months at BWI in the period of November 13-February 15. February 15, January 15, November 14, August 14, July 14, April 14, March 14, February 14, January 14, November 13 That's a pretty impressive run given climate and UHI both progressively working against below normal temps. Maybe some of the stat-minded folks can tell us how exceptional it is? That depends on what probability assumptions you make. For example, during February 2011-October 2012 inclusive, every month (21 straight) at BWI was above normal, leading some to believe that the probability of a below normal month there had fallen well below 50% -- possibly as low as only 20-30%. However, since then only 13 of 28 months have been above normal at BWI. If you do a straight binomial calculation, the odds of 10 of the last 16 months being below normal there are as follows, given these probabilities of a below normal month: 50% chance of below normal month: 22.7% chance of at least 10 months being below normal. 40% chance of below normal month: 5.8% chance of at least 10 months being below normal. 30% chance of below normal month: 0.7% chance of at least 10 months being below normal. 20% chance of below normal month: 0.02% chance of at least 10 months being below normal. So, I would conclude that the probability of a below normal month at present is much closer to 50% than it is to 20%. However, we could simply be in an unusual run of below normal months. Nonetheless, the probability of 21 straight months being above normal followed by only 13 of 28 months being above normal simply due to random factors is unlikely in the extreme. Link to comment Share on other sites More sharing options...
PrinceFrederickWx Posted March 3, 2015 Share Posted March 3, 2015 10 below normal months at BWI in the period of November 13-February 15. February 15, January 15, November 14, August 14, July 14, April 14, March 14, February 14, January 14, November 13 That's a pretty impressive run given climate and UHI both progressively working against below normal temps. Maybe some of the stat-minded folks can tell us how exceptional it is? If you're looking for a better stretch of below normal months at BWI (using the 1981-2010 normals), the most recent one I could find was the period between Jan. 2003 - Feb. 2004, which had 10 out of 14 months below normal. An even more impressive stretch would be the period between Oct. 2002 - Feb. 2004, which had 13 of 17 months below normal. Also, the period between Jan. 2009 - Feb. 2010 had 9 of 14 months below normal. By the way 2003, as a calendar year, actually finished colder than 2014- 2003 finished 13th coldest, whereas 2014 finished tied for 14th coldest. Link to comment Share on other sites More sharing options...
PrinceFrederickWx Posted March 4, 2015 Share Posted March 4, 2015 I didn't realize BWI had a low-hanging-fruit daily snow record for 3/5- only 4.0 inches (days before it and after it are much higher). We'll probably break that if everything goes as planned. Also, record low watch for 3/5 and 3/6. Link to comment Share on other sites More sharing options...
Ian Posted March 6, 2015 Share Posted March 6, 2015 Dulles has now seen two of its top three March snowstorms the past two years. 11.1" 16th-17th in 2014 and 9.5" Mar 5 this year (second greatest March daily total there). Link to comment Share on other sites More sharing options...
Ian Posted March 6, 2015 Share Posted March 6, 2015 Dulles up to 88.8" now for last two winters. Most for back-to-back winters there. Of course 09-10 and 10-11 are 2nd because 09-10 was almost as big on its own. Link to comment Share on other sites More sharing options...
Ji Posted March 6, 2015 Share Posted March 6, 2015 Dulles up to 88.8" now for last two winters. Most for back-to-back winters there. Of course 09-10 and 10-11 are 2nd because 09-10 was almost as big on its own. I should probably stop complaining about winter Link to comment Share on other sites More sharing options...
Ian Posted March 6, 2015 Share Posted March 6, 2015 I should probably stop complaining about winter That was your stat heads up initially.. just verified myself. Due for some fail now. Link to comment Share on other sites More sharing options...
PrinceFrederickWx Posted March 7, 2015 Share Posted March 7, 2015 I didn't realize BWI had a low-hanging-fruit daily snow record for 3/5- only 4.0 inches (days before it and after it are much higher). We'll probably break that if everything goes as planned. Also, record low watch for 3/5 and 3/6. All these records were indeed broken. Edit: Actually it was 3/6 and 3/7 Link to comment Share on other sites More sharing options...
RodneyS Posted March 8, 2015 Share Posted March 8, 2015 Regarding the last half of February 2015, it was a case of "missed it by that much" at DCA. It averaged an even 25.0 degrees from the 15th to the 28th, which was just a tenth of a degree warmer than February 15-28, 1934, and 1934 also holds the record for the coldest February as a whole, at 24.6 degrees. However, the last half of February 2015 was 7.3 degrees colder than the last half of February 1979 at DCA, and IAD's February 2015 last half average of 19.5 degrees was 7.5 degrees colder than the last half of February 1979 there. While DCA narrowly missed breaking the last half of February average low temperature record in DC, it has just narrowly broken the DC record for the lowest average temperature for the three weeks ending March 7th. February 15-March 7, 2015 averaged 28.1 degrees at DCA, breaking the record of 28.2 degrees set 101 years ago, February 15-March 7, 1914. Further, IAD averaged only 22.6 degrees during the last three weeks, shattering the previous record low average of 28.7 degrees for those three weeks set February 15-March 7, 1978. Link to comment Share on other sites More sharing options...
gymengineer Posted March 27, 2015 Share Posted March 27, 2015 Dulles up to 88.8" now for last two winters. Most for back-to-back winters there. Of course 09-10 and 10-11 are 2nd because 09-10 was almost as big on its own. And adding in the snow from last week, the two-season average for IAD is 44.9", which is crazy good. At the very least, we're done with "feast or famine" assumption of how winters work around here, which didn't really apply to much of the region anyway during the last 10 years. DCA's 18.3" total is obviously neither a feast nor a famine. Link to comment Share on other sites More sharing options...
PrinceFrederickWx Posted March 27, 2015 Share Posted March 27, 2015 The Jan.-Mar. period last year tied for 6th coldest at BWI- will be interesting to see where Jan.-Mar. this year ranks. I haven't done the math but I'm almost certain it'll beat last year. Also- record low watch for Sunday, March 29? The record is 18 (set in 1923), current forecast is 23, so its a long shot, but the forecast keeps trending colder. Link to comment Share on other sites More sharing options...
Bob Chill Posted March 27, 2015 Share Posted March 27, 2015 The Jan.-Mar. period last year tied for 6th coldest at BWI- will be interesting to see where Jan.-Mar. this year ranks. I haven't done the math but I'm almost certain it'll beat last year. Also- record low watch for Sunday, March 29? The record is 18 (set in 1923), current forecast is 23, so its a long shot, but the forecast keeps trending colder. If the month ended today, BWI would be -5.4 for the period. JFM last year was -4.5. Looks like a lock that last year gets beat by a pretty hefty margin. I just realized that BWI went -10.5 in Feb. Double digit neg monthly departures are very rare nowadays. Link to comment Share on other sites More sharing options...
PrinceFrederickWx Posted March 27, 2015 Share Posted March 27, 2015 Tomorrow's daily snowfall record for BWI is the lowest out of any day in DJFM- just 0.2 inches. Now, if we could get tomorrow's snow showers to accumulate just a little bit... (I'm just kidding!) Link to comment Share on other sites More sharing options...
RodneyS Posted April 1, 2015 Share Posted April 1, 2015 If the month ended today, BWI would be -5.4 for the period. JFM last year was -4.5. Looks like a lock that last year gets beat by a pretty hefty margin. I just realized that BWI went -10.5 in Feb. Double digit neg monthly departures are very rare nowadays. Not so dramatic at DCA, but this year's first quarter average of 37.1 degrees was the lowest since 36.9 in 1994. IAD's first quarter average of 31.6 degrees was the lowest since 31.5 in 1978. Link to comment Share on other sites More sharing options...
PrinceFrederickWx Posted April 1, 2015 Share Posted April 1, 2015 BWI just crushed the record for coldest Jan-Mar period ever. Below are the top five: 2015: 31.91904: 32.31912: 32.51895: 32.61885: 32.6 I'm tempted to start saying "top 10 coldest year on record watch" again since we're way out in front, but I said that last year and had the rug pulled out from under me in December. Also there seems to be more chatter now about a flip to warm for the rest of spring and summer... Rodney (or anyone) where did IAD rank? I had assumed it would be somewhere in the top five coldest? Link to comment Share on other sites More sharing options...
Fozz Posted April 1, 2015 Share Posted April 1, 2015 To get the first ever Jan-March that averaged below freezing is really impressive Link to comment Share on other sites More sharing options...
MN Transplant Posted April 1, 2015 Author Share Posted April 1, 2015 BWI just crushed the record for coldest Jan-Mar period ever. Below are the top five: 2015: 31.9 1904: 32.3 1912: 32.5 1895: 32.6 1885: 32.6 I'm tempted to start saying "top 10 coldest year on record watch" again since we're way out in front, but I said that last year and had the rug pulled out from under me in December. Also there seems to be more chatter now about a flip to warm for the rest of spring and summer... Rodney (or anyone) where did IAD rank? I had assumed it would be somewhere in the top five coldest? Looks like 3rd at IAD 1970: 31.5 1978: 31.5 2015: 31.8 2014: 32.3 1969: 33.4 Coldest Feb/Mar combo on record though. Link to comment Share on other sites More sharing options...
PrinceFrederickWx Posted April 1, 2015 Share Posted April 1, 2015 To get the first ever Jan-March that averaged below freezing is really impressive Speaking of which, DJF for BWI averaged exactly 32 degrees- 1 of the 15 winters to finish at or below freezing on average. Link to comment Share on other sites More sharing options...
RodneyS Posted April 1, 2015 Share Posted April 1, 2015 BWI just crushed the record for coldest Jan-Mar period ever. Below are the top five: 2015: 31.9 1904: 32.3 1912: 32.5 1895: 32.6 1885: 32.6 I'm tempted to start saying "top 10 coldest year on record watch" again since we're way out in front, but I said that last year and had the rug pulled out from under me in December. Also there seems to be more chatter now about a flip to warm for the rest of spring and summer... Rodney (or anyone) where did IAD rank? I had assumed it would be somewhere in the top five coldest? Looks like 3rd at IAD 1970: 31.5 1978: 31.5 2015: 31.8 2014: 32.3 1969: 33.4 Coldest Feb/Mar combo on record though. I agree with your figures (I previously misstated this year's 1Q at IAD as 31.6 degrees). Bear in mind, though that these figures are unweighted averages of January, February, and March average monthly temperatures, which gives too much weight to February, as it has only 28 days (29 in leap years), compared to 31 days each in January and March. Weighting each of the first 90 days of each year equally results in 1Q 1970 being colder than 1Q 1978 at IAD (31.4 vs. 31.7). 2015 would still be third coldest, but at 32.0 degrees, rather than 31.8. Perhaps some day weighted averages will be used to calculate quarterly and seasonal averages. Link to comment Share on other sites More sharing options...
PrinceFrederickWx Posted April 1, 2015 Share Posted April 1, 2015 I agree with your figures (I previously misstated this year's 1Q at IAD as 31.6 degrees). Bear in mind, though that these figures are unweighted averages of January, February, and March average monthly temperatures, which gives too much weight to February, as it has only 28 days (29 in leap years), compared to 31 days each in January and March. Weighting each of the first 90 days of each year equally results in 1Q 1970 being colder than 1Q 1978 at IAD (31.4 vs. 31.7). 2015 would still be third coldest, but at 32.0 degrees, rather than 31.8. Perhaps some day weighted averages will be used to calculate quarterly and seasonal averages. That's a good point and would skew the results; however, it doesn't look like LWX uses weighted averages for February or the 30-day months. I checked through their data to be sure. So my numbers are using their same methodology (whether its accurate or not). Link to comment Share on other sites More sharing options...
RodneyS Posted April 1, 2015 Share Posted April 1, 2015 That's a good point and would skew the results; however, it doesn't look like LWX uses weighted averages for February or the 30-day months. I checked through their data to be sure. So my numbers are using their same methodology (whether its accurate or not). I'm not sure that any meteorological organization uses weighted averages. Presumably, that is because in the old days -- prior to the widespread use of calculators -- it was a pain to compute anything but unweighted averages by hand, and the methodology was never updated. In general, this isn't a big deal, but when you have an abnormally cold or warm February, unweighted averages can result in slightly erroneous figures for both the first quarter and the meteorological winter. Link to comment Share on other sites More sharing options...
MN Transplant Posted April 1, 2015 Author Share Posted April 1, 2015 I agree with your figures (I previously misstated this year's 1Q at IAD as 31.6 degrees). Bear in mind, though that these figures are unweighted averages of January, February, and March average monthly temperatures, which gives too much weight to February, as it has only 28 days (29 in leap years), compared to 31 days each in January and March. Weighting each of the first 90 days of each year equally results in 1Q 1970 being colder than 1Q 1978 at IAD (31.4 vs. 31.7). 2015 would still be third coldest, but at 32.0 degrees, rather than 31.8. Perhaps some day weighted averages will be used to calculate quarterly and seasonal averages. Agree, I think we can give up a little simplicity for the sake of better accuracy. Link to comment Share on other sites More sharing options...
PrinceFrederickWx Posted April 3, 2015 Share Posted April 3, 2015 If they can hold it until midnight, BWI has tied the record highest minimum for today (60). Currently 66 now. Link to comment Share on other sites More sharing options...
PrinceFrederickWx Posted April 4, 2015 Share Posted April 4, 2015 Its a little unsettling how easily BWI tied that record highest min yesterday, just seemingly out of nowhere. I hope that's not an omen like 4/4/2011 or 4/5-6/2010... Link to comment Share on other sites More sharing options...
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