Central Park Summer Cooling Since The 90's

[bluewave]

I just wanted to start a thread documenting the summer cooling that we have seen at Central Park

since the 90's. The easiest way to document this change is to make a comparison between

NYC and LGA using July temperatures going back to the 60's. The Julys were selected

for having above normal temperatures. The number of 90 degree days, monthly average

temperature, and rainfall is included. The NYC cooling pattern looks to be a result of

increased vegetation growth over the years. The recent wet Julys really show the 

contrast between LGA and NYC especially during July 2006. From the 60's to the 90's, NYC

typically had more 90 degree days than LGA in July. Now LGA has more July 90 degree days

and has higher average temperatures by a wider margin. Rainy July patterns in the past didn't

show this divergence that we see in recent years. The other question is whether the location

of the LGA sensors were moved to a different spot at the airport at some point in the past

to help contribute to this change?

 

 

July...station....90 degree days.....monthly average temperature....monthly rainfall

 

Higher station 90 degree days bolded

 

2012...NYC.....9...78.8....4.21"

...........LGA...14...80.5....3.77"

 

2011...NYC...13...80.3...3.03"

...........LGA...14...80.4...2.94"

 

2010...NYC...16...81.4...2.60"

...........LGA...18...82.8...2.52"

 

2008...NYC..6....78.4....2.84"

...........LGA..11..80.0....2.32"

 

2006...NYC..4...78.0.....6.16"

...........LGA.12...80.7....5.95"

 

2005...NYC...8...77.6....3.16"

...........LGA..10..78.6....2.33"

 

2002....NYC...12...78.8..1.05"

............LGA...14...79.5..1.47"

 

1999...NYC...18...81.4...0.44"

...........LGA...17...81.9...0.56"

 

1995...NYC..11....79.2...6.13"

...........LGA...8.....79.8...5.51"

 

1994.....NYC...9...79.4...3.86"

.............LGA...10..80.6..4.41"

 

1993....NYC...20..80.2...1.70"

............LGA...12..80.8...1.70"

 

1988...NYC...13...79.3...8.14"

...........LGA...8.....78.6...8.47"

 

1983....NYC...14..79.5...3.40"

............LGA...11..78.3...3.41"

 

1980....NYC...11...79.3...5.26"

............LGA....8....78.7...4.74"

 

1977....NYC....11...79.0...1.60"

............LGA.....9....77.2...1.53"

 

1966....NYC...16...79.7...1.25"

............LGA...12...80.8...1.12"

[uncle W]

ever since Central Park went aos in 1996 the totals have gone down...LGA had less 90 degrees on average before 1996...

monthly 90 degrees days......
Season.....Apr...May...June.July.Aug...Sept....total...LGA's totals...
1944..........0.......1.......5....17....11......3.........37.......................
1950..........0.......0.......4......2.....0.......0..........6..........8
1951..........0.......1.......0......5.....1.......0..........7.........11
1952..........0.......0.......6....14.....1.......3.........24........24
1953..........0.......1.......8....11.....8.......4.........32........30
1954..........0.......0.......3....12.....2.......0.........17........15
1955..........0.......1.......0....14....10......0.........25........29
1956..........0.......0.......5......2.....4.......0.........11........13
1957..........0.......0.......6....10.....3.......2.........21........19
1958..........0.......0.......0......4.....2.......0..........6.........10
1959..........0.......3.......5......3....13......3.........27........27
1960..........0.......0.......0......1.....3.......1..........5..........7
1961..........0.......0.......3....12.....6.......8.........29........14
1962..........1.......3.......5......7.....2.......0.........18.........9
1963..........0.......0.......5....11.....0.......0.........16........12
1964..........0.......2.......7......7.....4.......3.........23........16
1965..........0.......4.......5......4.....1.......1.........15........16
1966..........0.......0.....10....16.....8.......1.........35........25
1967..........0.......0.......5......3.....1.......0..........9..........6
1968..........0.......0.......3......6.....8.......0.........17........15
1969..........0.......2.......3......5.....5.......1.........16.........9
1970..........0.......2.......1......4.....8.......7.........22........22
1971..........0.......0.......5......6.....5.......2.........18..........9
1972..........0.......0.......0....11.....3.......1.........15..........4
1973..........0.......0.......4......4.....6.......4.........18........17
1974..........0.......1.......1....10.....5.......0.........17........13
1975..........0.......1.......1......2.....4.......0..........8..........7
1976..........3.......0.......6......2.....4.......0.........15........10
1977..........1.......2.......0....11.....7.......2.........23........14
1978..........0.......1.......2......3.....5.......0.........11..........4
1979..........0.......2.......0......7.....8.......1.........18........16
1980..........0.......2.......1....11....15......3.........32........22
1981..........0.......0.......2....10......4......0.........16........15
1982..........0.......0.......0....11......0......0.........11..........6
1983..........0.......0.......6....14......9......7.........36........31
1984..........0.......0.......6......1......3......0.........10..........9
1985..........0.......0.......0......4......2......3..........9..........8
1986..........0.......3.......2......6......0......0.........11.........9
1987..........0.......4.......5......9......4......0.........22........19
1988..........0.......1.......8....13....10......0.........32.........26
1989..........0.......0.......3......7......4......2.........16........17
1990..........2.......0.......0......6......4......0.........12........10
1991..........1.......5.......9....12....10......2.........39........34
1992..........0.......2.......0......4......3......0..........9..........9
1993..........0.......1.......5....20....10......3.........39........26
1994..........0.......1.......7......9......2......0.........19........22
1995..........0.......0.......3....11....13......2.........29........23
1996..........0.......2.......0......0......1......0..........3..........6
1997..........0.......0.......5......5......2......0.........12........17
1998..........0.......0.......2......3......2......1..........8........11
1999..........0.......0.......6....18......3......0.........27........26
2000..........0.......3.......3......0......1......0..........7........12
2001..........0.......3.......2......2......8......0.........15........17
2002..........3.......0.......1....12....14......2.........32........33
2003..........0.......0.......4......2......2......0..........8........17
2004..........0.......0.......1......0......1......0..........2..........7
2005..........0.......0.......4......8......9......2.........23........30
2006..........0.......0.......1......4......3......0..........8........22
2007..........0.......2.......2......2......4......0.........10........23
2008..........0.......0.......4......6......1......1.........12........19
2009..........2.......0.......0......0......5......0...........7.........8
2010..........1.......1.......4....16....12......3.........37........48
2011..........0.......0.......3....14......3......0.........20........19
2012..........0.......0.......5....10......3......1.........19........28
2013..........0.......2.......3......3

[ag3]

We went over this in the past.

The temp decrease strongly correlates to Central Park going aos in 1996.

The yearly average temps have only been affected by a tiny fraction but the 90 degree days have been moderately affected.

[bluewave]

We went over this in the past.

The temp decrease strongly correlates to Central Park going aos in 1996.

The yearly average temps have only been affected by a tiny fraction but the 90 degree days have been moderately affected.

 

The whole point is that the ASOS is too close to the cooling influence of the vegetation. The average temperatures

diverge more when the trees are leafed out during the warm season. We have never seen the July average

temperature so much lower in NYC than LGA since 2005. The 6 warm Julys since 2005 has LGA

running +1.4 over NYC for average temperature. The 6 warm Julys before 1996 NYC and LGA had

the same average temperature.

 

http://www.weather2000.com/ASOS/NYC_ASOS.html

Central Park Weather: Vegetative Overgrowth Affecting Weather Readings - WABC-TV(New York-WABC, August 22, 2003) - Forecasting the weather is not easy.Government equipment can often be blamed for giving faulty weatherinformation. As Bill Evans explains, a big culprit may be some of theequipment buried in Central Park.Rainfall, snowfall, and the temperature are all vital informationrecorded 24 hours a day at the weather station located in the heart ofCentral Park.But meteorologists like Michael Schlacter have serious concerns about theaccuracy of the stations data. It sits amid overgrown vegetation and hesays thats the problem. The leaves can trigger snow gauges and trees canwarp rain and wind measurements. On this hot day, a temperature gauge isin the shade instead of direct sunlight.Michael Schlacter, Weather 2000: "Its kind of like driving a carwithout a speedometer, odometer, and gas gauge. You are running withfalse information."The weather instruments at Belvedere Castle have long adorned the top.There used to be a government meteorologist here in the city to keep aneye on them. But now the nearest meteorologist is 60 miles that way.But National Weather Service meteorologists say they knew the weatherreadings in the park would never be as keenly accurate as the ones atthe airports where guidelines prevent foliage from being within 100 feetof the station.Schlacter: "We knew that at times we would have flaky readings, thatleaves would fall in gauges, that we would have problems withvisibility sensors."[NWS Meteorologist-in-Charge Michael] Wyllie says the weather station isthere because it was historically significant to maintain its presencein the park.He says theres been a lot of growth because of the wet spring at so muchin fact that temperatures have routinely been recorded lower in the parkthan at the airports.Wyllie: "We are actually having a micro climate system there because ofthe vegetation."Imperfect perhaps but nonetheless the system provides the official recordof weather for the country's largest city. And Michael Schlacter saysits a city that deserves better.Schlacter: "I think New Yorkers deserve a lot better, and I think theydeserve the best weather station money can buy."Copyright 2003 ABC Inc., WABC-TV Inc.

[Cfa]

I can't imagine that they're (NWS?) in the dark about this trend, they should really consider moving it out of that forest.

And move JFK's ASOS out of Jamaica Bay while they're at it.

[bluewave]

I can't imagine that they're (NWS?) in the dark about this trend, they should really consider moving it out of that forest.

And move JFK's ASOS out of Jamaica Bay while they're at it.

 

Or just focus more on LGA for official NYC summer temperatures and heat waves since it's more representative 

of conditions in NYC. 

 

2005,2006,2008,2010,2011,2012 July average temperature

 

NYC....79.1

LGA....80.5

 

1980,1983,1988,1993,1994,1995 July average temperature

 

NYC...79.5

LGA...79.5

[SACRUS]

Or just focus more on LGA for official NYC summer temperatures and heat waves since it's more representative 

of conditions in NYC. 

 

2005,2006,2008,2010,2011,2012 July average temperature

 

NYC....79.1

LGA....80.5

 

1980,1983,1988,1993,1994,1995 July average temperature

 

NYC...79.5

LGA...79.5

 

 

We seem to discuss this each year - the main issue is that all the news, radio and media outlets report the park as the center for representing weather for the entire NYC area, and its often cooler and skews the perspective of heat spells and summers in general.  A few recent examples are 2006 where the park had 8 90 (+) days meanwhile EWR, LGA and many others were near or greaer than 20.  In 2010 the park was almost 20 days behind other stations in 90 (+) days.  I agree we should use EWR for urban NJ, New Brunswick for urban C-NJ and LGA for urban  NYC.  Lately I have been seeing tv and radio reports make a point to include EWR/LGA when discussing heatwaves, etc.   

[forkyfork]

july 2009

june 2013

from http://www.weather2000.com/ASOS/NYC_ASOS.html

[SACRUS]

Further to the point some news stations claiming the longest and strongest heatwave in almost a decade.  I assume they mean the park and are talking about the heat stretch in 2002.  Meanwhile just this year many have had 7 straight days at 90 already, in 2012, 2011, 2010 most sites had more than a week of 90s. 

[user13]

Any update on the removal of airport weather stations due to the Sequester? Wasn't it scheduled for July or August?

[SACRUS]

july 2009

june 2013

from http://www.weather2000.com/ASOS/NYC_ASOS.html

 

Next time you go I'll buy you a weed wacker and chainsaw.  The mecca of weather records and observations for the NYC metro area.

[JBG]

I just wanted to start a thread documenting the summer cooling that we have seen at Central Park since the 90's. The easiest way to document this change is to make a comparison between NYC and LGA using July temperatures going back to the 60's. The Julys were selected for having above normal temperatures. The number of 90 degree days, monthly average temperature, and rainfall is included. The NYC cooling pattern looks to be a result of increased vegetation growth over the years. The recent wet Julys really show the contrast between LGA and NYC especially during July 2006. From the 60's to the 90's, NYC typically had more 90 degree days than LGA in July. Now LGA has more July 90 degree days and has higher average temperatures by a wider margin. Rainy July patterns in the past didn't

show this divergence that we see in recent years. The other question is whether the location of the LGA sensors were moved to a different spot at the airport at some point in the past to help contribute to this change?

.

I visited Belvedere castle on June 2, 2013. That is where temperatures for KNYC are recorded.  The area is highlyvegetated and on that day was quite cool, showing a high of 88, compared to the reality of the 90 degree day I experienced on the Salute to Israel Parade.

[bluewave]

Or just focus more on LGA for official NYC summer temperatures and heat waves since it's more representative 

of conditions in NYC. 

 

2005,2006,2008,2010,2011,2012 July average temperature

 

NYC....79.1

LGA....80.5

 

1980,1983,1988,1993,1994,1995 July average temperature

 

NYC...79.5

LGA...79.5

 

With a couple of  days to go this month, NYC is lagging LGA by a similar amount.

 

NYC....80.2

LGA....81.5

 

NYC would be running right along with LGA in recent years if the thermometer was placed correctly.

 

 

Warmest Julys at LGA

 

82.8.....2010

81.9.... 1999

81.5.....2013...so far

81.3.....1955

80.8.....1993...1966

80.7.....2006

80.6....1994

80.4.... 2012..2011

80.3...1952

80.0...2008

[uncle W]

Central Park could end up averaging 79.9...But the average was 81.7 between 6/23 and 7/24 give or take a day...this is why I like 30 day periods for max cold and warmth...the coolest start to August goes to 1964...I'd like to see a map of August from 7/31 to 8/20/1964...it has three record lows and four near miss record low days in the three week period...August 1962 to 1965 were quite cool in NYC...

 

[JBG]

Or just focus more on LGA for official NYC summer temperatures and heat waves since it's more representative 

of conditions in NYC. 

 

2005,2006,2008,2010,2011,2012 July average temperature

 

First, why not use all years in the 2005-12 period? I notice you exclude 1007 and 2009? Why, because July was cool in those years?

 

The main problem with KNYC is that it's no longer an urban station, at least for daytime purposes.  But it does reflect the overall area, sans the pavement. Is that bad? LGA is basically an ocean of pavement, as is KEWR.

[bluewave]

First, why not use all years in the 2005-12 period? I notice you exclude 1007 and 2009? Why, because July was cool in those years?

 

The main problem with KNYC is that it's no longer an urban station, at least for daytime purposes.  But it does reflect the overall area, sans the pavement. Is that bad? LGA is basically an ocean of pavement, as is KEWR.

 

The cooler years show a similar difference due to the overgrowth of vegetation too close to the sensor which

bias the summer temperatures too cool since the 1990's. 

 

July 2009

 

NYC....72.7

LGA....74.5

 

July  2007

 

NYC...75.0

LGA...77.8

[JBG]

The cooler years show a similar difference due to the overgrowth of vegetation too close to the sensor which

bias the summer temperatures too cool since the 1990's. 

 

July 2009

 

NYC....72.7

LGA....74.5

 

July  2007

 

NYC...75.0

LGA...77.8

Maybe it's that LGA is too warm?

 

True, KNYC doesn't reflect weather at Times Square or other intensely urban places, but it that representative of anything?

[ag3]

The cooler years show a similar difference due to the overgrowth of vegetation too close to the sensor which

bias the summer temperatures too cool since the 1990's. 

 

July 2009

 

NYC....72.7

LGA....74.5

 

July  2007

 

NYC...75.0

LGA...77.8

Didn't we already establish that the change came when NYC switched to ASOS?

[ag3]

Maybe it's that LGA is too warm?

True, KNYC doesn't reflect weather at Times Square or other intensely urban places, but it that representative of anything?

I moved to Astoria in 2009, and I can say LGA's temps are almost always exactly what my home thermometer read.

When I lived in NE Queens area (Bayside/Whitestone/Douglaston), I saw the differences. NE Queens was always colder during the day and especially the night time lows.

[JBG]

I moved to Astoria in 2009, and I can say LGA's temps are almost always exactly what my home thermometer read.

When I lived in NE Queens area (Bayside/Whitestone/Douglaston), I saw the differences. NE Queens was always colder during the day and especially the night time lows.

Sounds like vegetation effect to me.  NE Queens is rather leafy compared to Astoria or LGA area.

 

Then again, Astoria and LGA are directly adjacent to one another.

[ag3]

Sounds like vegetation effect to me. NE Queens is rather leafy compared to Astoria or LGA area.

Then again, Astoria and LGA are directly adjacent to one another.

We have shown stats that showed and proved that KNYC's #s have decreased at the same exact time the switch to ASOS occurred in the 90s.

[famartin]

Any update on the removal of airport weather stations due to the Sequester? Wasn't it scheduled for July or August?

This would have affected airport staff which augment ASOS (who, among other things, measure snowfall).  Snowfall at Central Park is measured by the zoo staff.  I don't know if they are compensated at all.

 

Currently a proposal is floating around to cut snowfall measurements down to once per day.  This would surely muck up the snowfall climo, but NWS doesn't have the money to pay for snow measurements 4-5 times a day at all ~250 first-order climate stations, which it might have to if the FAA does eliminate the weather station staff.  Right now it only pays for ~90 of those stations.

[JBG]

Excuse my ignorance but what is "ASOS"?

[Weathergun]

Excuse my ignorance but what is "ASOS"?

 

Automated Surface Observing System:

 

http://www.nws.noaa.gov/asos/index.html

 

Central Park and the airports are run by them.

[famartin]

Pictures etc here
http://en.wikipedia.org/wiki/Automated_airport_weather_station