JBG Posted September 6, 2014 Share Posted September 6, 2014 At least at KNYC we exactly matched 1972 for first 90 degree day. I will point out that in those days KNYC had less vegetation and the high that day was 91. So in real world this first 90 day was probably a hotter day than 1972. In terms of 90+ days this summer has been notably cool. Though probably not as cool as suggested by the statistics. KNYC has been plagued by a reverse of the UHI effect. New York City's Central Park is actually man-made. Previously it was a mixture of slums, farms and slaughterhouses. It has been progressively getting more densely forested. New York City's weather station is also located there. Back in the 1970's the thirty-year moving average for summer temperatures included about a week where the mean was 78, implying a high of about 86 and a low of about 70. It could have been an 85/70 split since the practice is to round upwards. By the early 2000's the "78 degree" bulge was cut to two days and in the most recent thirty-year period eliminated. Now the average maximum high-low is rated as 84/69, for the period, roughly, July 10 through August 10. This works out to a 76.5 mean, or a full degree lower than the mean for most of the corresponding period historically. The number of 90+ days has also dropped at Central Park (KNYC), so that in the recent summer we have only touched 90 for 7 or 8 days (today may be the 8th day). This summer was considered a cool one. Summers with similar weather patterns, i.e. relatively cool ones, such as 1969, 1972 and 1979 had more 90+ days. 1969 did have a few 96 or 97 days that clearly would have topped 90 even now but nowadays the same situations that created 90-92 degree Central Park readings now create 87-89 degree readings. All you have to do is look at statistics for LaGuardia Airport (KLGA) to see the difference. I posted similar material separately as a comment on Sacrus' excellent 90 Degree days thread (link). Link to comment Share on other sites More sharing options...
uncle W Posted September 6, 2014 Share Posted September 6, 2014 the decade annual max temperature for KNYC... 1880-89...95.2 1890-99...96.7 1900-09...94.7 1910-19...97.3 1920-29...96.6 1930-39...99.3 1940-49...98.5 1950-59...98.1 1960-69...97.3 1970-79...96.5 1980-89...97.6 1990-99...97.9 2000-09...95.5 2010-14...99.2 ........................................................................... decade total 90 degree days... decade...90+days100+1870's...101.....0.....1880's.....81.....1.....1890's...138.....1.....1900's...101.....2.....1910's...115.....3.....1920's...128.....2.....1930's...189.....8.....1940's...202.....8.....1950's...175...12.....1960's...181.....4.....1970's...183.....3.....1980's...195.....2.....1990's...197.....8.....2000's...123.....1..... 2010's...100.....5.....as of 9/6...average 20 90's for the five years and one 100...1870-2009.....149.....4.....1980-2009.....172.....4..... Link to comment Share on other sites More sharing options...
JBG Posted September 6, 2014 Author Share Posted September 6, 2014 2010's...100.....5.....as of 9/6...average 20 90's for the five years and one 100... .. How many 88's or 89's do we think would have been 90's with earlier vegetative conditions applying? Link to comment Share on other sites More sharing options...
uncle W Posted September 7, 2014 Share Posted September 7, 2014 How many 88's or 89's do we think would have been 90's with earlier vegetative conditions applying? I think the vegetation is keeping night time lows higher also but that's for another post... Link to comment Share on other sites More sharing options...
JBG Posted September 7, 2014 Author Share Posted September 7, 2014 I think the vegetation is keeping night time lows higher also but that's for another post...Good point. Hadn't thought of that. Link to comment Share on other sites More sharing options...
IntenseBlizzard2014 Posted September 7, 2014 Share Posted September 7, 2014 I think the vegetation is keeping night time lows higher also but that's for another post... Sounds like the water in the vegetation is retaining heat and making it easier for the humid airmass to retain higher temps/dews? Link to comment Share on other sites More sharing options...
JBG Posted September 7, 2014 Author Share Posted September 7, 2014 Sounds like the water in the vegetation is retaining heat and making it easier for the humid airmass to retain higher temps/dews?But the number of 90+ days has dropped. Also the highest mean, albeit "smoothed" has dropped from 77.5 to 76.5. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.