December 2025 OBS and Discussion

[Dark Star]

15 minutes ago, North and West said:

I think it’s less on people and more on the cement/UHI. UHI is getting really noticeable; I’m often 15° or more difference versus the city on cold nights.


.

While I am witnessing the urbanization of suburbia (central Union County, NJ) I am still under the impression that the temperature increases are more due to the effects from the GulfStream/Labrador current.  It has been discussed here in the past.

[bluewave]

UHI was already well established in NYC as early as 1896. Notice the more than +10° low temperature difference between Central Park and rural areas in August 1895.

LGA and JFK UHI began to increase with the Queens urbanization and population growth expansion in the 1920s.

So this isn’t much of a change from the current 10°+ difference between NYC-LGA-JFK and surrounding areas when UHI episodes are more pronounced like during summer heatwaves and radiational cooling during the winter.
 

Data for August 9, 1896 through August 9, 1896
Click column heading to sort ascending, click again to sort descending.

NY	NY CITY CENTRAL PARK	WBAN	82
NJ	NEWARK LIBERTY INTL AP	WBAN	76
NY	WORLD TRADE CENTER	WBAN	75
NJ	PATERSON	COOP	75
NY	BRONX	COOP	75
NJ	PLAINFIELD	COOP	73
NJ	ELIZABETH	COOP	73
NY	PORT JERVIS	COOP	72
NY	SETAUKET STRONG	COOP	72
CT	MIDDLETOWN 4 W	COOP	72
NY	WEST POINT	COOP	71
CT	BRIDGEPORT	COOP	71
NY	BRENTWOOD	COOP	70
CT	COLCHESTER 2 W	COOP	70
CT	NORWALK	COOP	69
CT	WATERBURY ANACONDA	COOP	69
CT	NEW LONDON	COOP	69
NJ	CHARLOTTEBURG RESERVOIR	COOP	67

 

Data for August 10, 1896 through August 10, 1896
Click column heading to sort ascending, click again to sort descending.

NY	NY CITY CENTRAL PARK	WBAN	80
NJ	NEWARK LIBERTY INTL AP	WBAN	78
NY	WORLD TRADE CENTER	WBAN	77
NY	BRONX	COOP	77
CT	BRIDGEPORT	COOP	76
NJ	PATERSON	COOP	75
NY	WEST POINT	COOP	75
NY	SETAUKET STRONG	COOP	75
NJ	PLAINFIELD	COOP	74
NJ	ELIZABETH	COOP	74
CT	NORWALK	COOP	74
CT	WATERBURY ANACONDA	COOP	74
CT	NEW LONDON	COOP	73
CT	COLCHESTER 2 W	COOP	73
NY	BRENTWOOD	COOP	72
CT	MIDDLETOWN 4 W	COOP	72
NY	PORT JERVIS	COOP	71
NJ	CHARLOTTEBURG RESERVOIR	COOP	69

 

Data for August 11, 1896 through August 11, 1896
Click column heading to sort ascending, click again to sort descending.

NY	NY CITY CENTRAL PARK	WBAN	81
NJ	NEWARK LIBERTY INTL AP	WBAN	78
NY	BRONX	COOP	78
NY	WORLD TRADE CENTER	WBAN	76
CT	NEW LONDON	COOP	75
NJ	PATERSON	COOP	74
NJ	PLAINFIELD	COOP	73
NJ	ELIZABETH	COOP	73
CT	BRIDGEPORT	COOP	73
NY	SETAUKET STRONG	COOP	73
CT	WATERBURY ANACONDA	COOP	72
NY	PORT JERVIS	COOP	71
NY	WEST POINT	COOP	71
CT	MIDDLETOWN 4 W	COOP	71
CT	COLCHESTER 2 W	COOP	71
NY	BRENTWOOD	COOP	70
CT	NORWALK	COOP	69
NJ	CHARLOTTEBURG RESERVOIR	COOP	67

 

[the_other_guy]

38 minutes ago, bluewave said:

The NYC UHI intensity hasn’t changed much since the 1980s on clear and calm nights when we get radiational cooling in the surrounding areas. 

Bullshit. I was born and raised in Queens. My parents are now wall to wall AC from May thru Sept. Something that never happened before. The place just doesnt cool off at night anymore

[bluewave]

10 minutes ago, the_other_guy said:

Bullshit. I was born and raised in Queens. My parents are now wall to wall AC from May thru Sept. Something that never happened before. The place just doesnt cool off at night anymore

This is due to the overall climate warming since the 1970s and not an expansion of UHI. Even cooler surrounding areas are wall to wall AC usage now from May to September when they weren’t in the past. The warming in rural, suburban, and urban areas has been proportional. 

[NorthShoreWx]

2 hours ago, bluewave said:

https://news.ucar.edu/14009/snowfall-measurement-flaky-history

 

 

But when we turn to snowstorms in the Northeast, or elsewhere in the U.S., there is an additional factor at work when comparing modern numbers with historical ones. Quite simply, our measuring techniques have changed, and we are not necessarily comparing apples to apples. In fact, the apparent trend toward bigger snowfalls is at least partially the result of new—and more accurate—ways of measuring snowfall totals. Climate studies carefully select a subset of stations with consistent snow records, or avoid the snowfall variable altogether.

 

Earlier in our weather history, the standard practice was to record snowfall amounts less frequently, such as every 12 or 24 hours, or even to take just one measurement of depth on the ground at the end of the storm.

You might think that one or two measurements per day should add up to pretty much the same as measurements taken every 6 hours during the storm. It’s a logical assumption, but you would be mistaken. Snow on the ground gets compacted as additional snow falls. Therefore, multiple measurements during a storm typically result in a higher total than if snowfall is derived from just one or two measurements per day.

That can make quite a significant difference. It turns out that it’s not uncommon for the snow on the ground at the end of a storm to be 15 to 20 percent less than the total that would be derived from multiple snowboard measurements.  As the cooperative climate observer for Boulder, Colorado, I examined the 15 biggest snowfalls of the last two decades, all measured at the NOAA campus in Boulder. The sum of the snowboard measurements averaged 17 percent greater than the maximum depth on the ground at the end of the storm. For a 20-inch snowfall, that would be a boost of 3.4 inches—enough to dethrone many close rivals on the top-10 snowstorm list that were not necessarily lesser storms!

Another common practice at the cooperative observing stations prior to 1950 did not involve measuring snow at all, but instead took the liquid derived from the snow and applied a 10:1 ratio (every inch of liquid equals ten inches of snow). This is no longer the official practice and has become increasingly less common since 1950. But it too introduces a potential low bias in historic snowfalls because in most parts of the country (and in the recent blizzard in the Northeast) one inch of liquid produces more than 10 inches of snow.

This means that many of the storms from the 1980s or earlier would probably appear in the record as bigger storms if the observers had used the currently accepted methodology. Now, for those of you northeasterners with aching backs from shoveling, I am not saying that your recent storm wasn’t big in places like Boston, Portland, or Long Island. But I am saying that some of the past greats—the February Blizzard of 1978, the Knickerbocker storm of January 1922, and the great Blizzard of March 1888—are probably underestimated.

So keep in mind when viewing those lists of snowy greats: the older ones are not directly comparable with those in recent decades. It’s not as bad as comparing apples to oranges, but it may be like comparing apples to crabapples.

I've always agreed with all of this.  I just don't see it as settling the main question 

[lee59]

I'm not sure how much it has affected the UHI but the city skyline has changed a lot in the past 20 or so years. Many more skyscrapers, Western Brooklyn and Queens are like a continuation of Manhattan. So I would think this would have  at least some affect on the UHI

 

 

[sussexcountyobs]

Snow continues here. Maybe 2" on unpaved surfaces. 1" on paved surfaces.  Road covered again after plow came by an hour ago. Will go shovel driveway in a bit. 32

[MJO812]

Christmas miracle