December 2024

[bluewave]

21 minutes ago, EWR757 said:

It seems the way we measure snowfall these days isn't ideal, either.   It's overinflated compared to previous generations measurements, no?

Snowfall is already difficult to measure.   Using a snowboard, wind, measuring every six hours.  If an observer does this by the book the results are likely significantly inflated compared to a maximum daily snow depth.  

I think it would be good to revisit how we all measure snowfall.   There is so much subjectivity and inflation I'm not sure the numbers mean than much. 

 

I remember living in the Midwest with a day of lake effect snow.   It may have snowed 30" for the event in a day, but the snowdepth at any given time never exceeds 16".  Silliness. 

This is why we should probably think about adjusting the snowfall measurements higher prior to 1990 since they measured less frequently. So snowfall during the older era was underestimated compared to today. While it doesn’t take away from the 2010s, the older era storms would be heavier if measured the same way.

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

Many pre-1990 numbers would be higher using current methods

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.

[SACRUS]

 

Records:

Highs:

EWR:  71 (2015)
NYC: 72 (2015)
LGA: 72 (2015)
JFK: 69 (2015)


Lows: 

EWR: 3 (1983)
NYC: 6 (1983)
LGA: 4 (1983)
JFK: 5 (1983)

 

Historical:

 

1851: The Library of Congress caught fire. About 35,000 of the Library’s 55,000 volumes were destroyed.

1872 - Extreme cold gripped the Upper Midwest on Christmas Eve. Downtown Chicago reported an all-time record low of 23 degrees below zero, which stood until January 1982, and Minneapolis MN reached 38 below. The afternoon high at Minneapolis was 17 degrees below zero. (David Ludlum)

1963: At 0326 CDT on December 24th, 1963, a new all-time low for Memphis occurred with a reading of -13°F. The record still stands today.

 

1968: The crew of Apollo 8 took this photo, later dubbed “Earthrise,” on December 24th, 1968. During a broadcast that night, pilot Jim Lovell said: “The vast loneliness is awe-inspiring, and it makes you realize just what you have back there on Earth.”

1983 - The barometric pressure reached 31.42 inches at Miles City, MT, to establish a record for the U.S. It was the coldest Christmas Eve of modern record. More than 125 cities reported record low temperatures for the date, and all-time record lows for December were reported at seventeen cities, including Chicago with a low of 25 degrees below zero, and Havre MT with a reading of 50 below zero. (The National Weather Summary) (Storm Data)

1987 - A four day seige of heavy rain began in the south central U.S. Flooding claimed four lives and caused millions of dollars property damage. Western Tennessee was drenched with up to fourteen inches of rain in two days. Total rainfall exceeded twelve inches around Memphis TN, and the heavy rain and subsequent flooding added insult to injury to victims of the West Memphis tornado on the 14th of the month. Little Rock AR experienced their wettest December day of record with 5.01 inches of rain. West Little Rock reported 10.20 inches of rain in 24 hours. (The National Weather Summary) (Storm Data)

1988 - Early morning thunderstorms developing along a cold front spawned a powerful tornado at Franklin, TN, which killed one person, injured seven others, and caused eight million dollars damage. Another in a series of winter storms in the western U.S. produced 20 inches of snow at Blue Canyon CA in 24 hours. Bishop CA received 14 inches of snow in just six hours, and Redding CA, which averages three inches of snow per year, was blanketed with ten inches. (The National Weather Summary) (Storm Data)

1989 - Fifty-seven cities in the south central and eastern U.S. reported record low temperatures for the date, including Elkins, WV, with a reading of 22 degrees below zero. Key West FL equalled their record for December with a morning low of 44 degrees. The high of just 45 degrees at Miami FL was an all-time record for that location. It smashed their previous record for the date by twenty degrees. (The National Weather Summary) (Storm Data)

 

2004: An extremely rare snowstorm impacts southeastern Texas on this day. Corpus Christi International Airport officially measured 4.4 inches from this event. This was their second white Christmas ever recorded in Corpus Christi. The other white Christmas occurred in 1918 when 0.1 inches was reported.

[SACRUS]

 

NYC 1966

DEC 24 : 6.7 inches of snow fall on Christmas Eve - an additional half inch would fall on Christmas day to bring the the total over 7 inches,

 

[SACRUS]

[BoulderWX]

Picked up another half inch and snowing heavily. Have about 30 minutes left here in morris county. What a great way to start Christmas Eve with everything freshly whitened. 

[SACRUS]

23 hours ago, SACRUS said:

 

Cold spell

Dec 21:

NYC: 33 / 19 (-12)
EWR:  33 / 20 (-10)

Dec 22:

NYC: 21 / 13 (-20)
EWR: 23 / 13 (-18)

 

Dec 23:

NYC:  31 / 13 (-15)
EWR: 29 / 11 (-16)

 

[SACRUS]

 

Once we move past today's Christmas White, this is all wet >1 inch of rain Dec 25 - Jan 1

 

[nycwinter]

a white christmas very rare for nyc.

[Ace Mahomes]

Probably have a good inch here in Bergen county. Helps that everything is so cold the snow accumulated immediately 

[BoulderWX]

10 minutes ago, SACRUS said:

 

Once we move past today's Christmas White, this is all wet >1 inch of rain Dec 25 - Jan 1

 

Not great but I’ve seen flakes four of the last five days and will most likely have a white Christmas. Been cold much of the month and leading up to Christmas. December’s a win in my book. 

[the_other_guy]

absolutely is a win white Christmas for everybody flakes falling. Been cold all week. Can’t ask for more of a storybook than that.

[Allsnow]

White Christmas is a lock now. Unbelievable 

[bluewave]

The timing worked out very well this year for the coldest and snowiest part of the month close to Christmas before we warm back to the 50s to close out the year. 
 

[ebwx]

I was driving north from Wegmans on RT9 earlier and went from no snow to moderate within minutes.  Good times !

[Brian5671]

11 minutes ago, Allsnow said:

White Christmas is a lock now. Unbelievable 

Some will melt with temps in the upper 30's later guess it depends on whether we get sun or not...

[MJO812]

2 minutes ago, Brian5671 said:

Some will melt with temps in the upper 30's later guess it depends on whether we get sun or not...

That's why you have to make sure to put it in piles lol

[MJO812]

15 minutes ago, Allsnow said:

White Christmas is a lock now. Unbelievable 

We haven't had a December like this in years.

[weathermedic]

Snowing moderate to heavy at work in Jamaica Queens and sticking to all non treated surfaces as expected. Solid coating.

[Brian5671]

2 minutes ago, MJO812 said:

That's why you have to make sure to put it in piles lol

I used to do that as a kid in the 80's.  Snow was so rare you had to save whatever you got.

[Voyager]

2 minutes ago, MJO812 said:

That's why you have to make sure to put it in piles lol

Piles don't count. You have to steal all of your neighbors' snow and scatter it evenly across your own property.

[EastonSN+]

All three ensemble suites show a trough in the East Coast. Eps looks great. Gefs takes longer to get to a better look and has a much broader trough. G e p s looks good as well more in the middle however closer to the eps.

[MJO812]

1 minute ago, EastonSN+ said:

All three ensemble suites show a trough in the East Coast. Eps looks great. Gefs takes longer to get to a better look and has a much broader trough. G e p s looks good as well more in the middle however closer to the eps.

A storm signal around the 4th

[GaWx]

24 minutes ago, bluewave said:

The timing worked out very well this year for the coldest and snowiest part of the month close to Christmas before we warm back to the 50s to close out the year. 
 

 Chris, it appears NYC will get close to the 3” mark for snow in Dec that you follow during La Niña. 

[bluewave]

11 minutes ago, GaWx said:

 Chris, it appears NYC will get close to the 3” mark for snow in Dec that you follow during La Niña. 

The actual cutoff value is closer to 4” like Newark since they measure later in NYC after the snow has had time to melt or settle since the airports measure more frequently. The official NYC values have been too low compared to the airports since the 1990s. Many times the measurement at the park occurs hours after the snow has stopped yielding a lower value than at the airports that measure when the snow stops.

The December La Nina cutoff for above average seasonal snowfall at Newark is closer to 4”. It’s probably a little higher than the 3” at NYC since they measure more frequently than NYC before the snow has a chance to melt or settle. So the 3” measurements are actually closer to 4” in NYC if they measured at the end of the snow instead of waiting up to 6 hours. The only time that a lower December snowfall total worked out at Newark last 30 years was the 16-17 La Nina. The reason this works out for our area is due to La Ninas being frontloaded by nature. So the above average La Niña snowfall winters have a snowy start.

Newark December La Nina snowfall and seasonal totals

2024….2.5”……?

2022….0.1”…..2.7”

2021…..0.1”….17.9”

2020…11.9”….45.7”

2017….7.7”…..39.4”

2016….3.4”….30.0”

2011…..0……..8.8”

2010….24.5”….68.2”

2008….8.3”…..27.1”

2007…..3.9”….14.6”

2005….11.0”….37.9”

2000….14.9”….39.3”

1999……T……..18.4”

1998……1.2”…..12.8”

1995……12.8”….78.4”

[GaWx]

9 minutes ago, bluewave said:

The actual cutoff value is closer to 4” like Newark since they measure later in NYC after the snow has had time to melt or settle since the airports measure more frequently. The official NYC values have been too low compared to the airports since the 1990s. Many times the measurement at the park occurs hours after the snow has stopped yielding a lower value than at the airports that measure when the snow stops.

The December La Nina cutoff for above average seasonal snowfall at Newark is closer to 4”. It’s probably a little higher than the 3” at NYC since they measure more frequently than NYC before the snow has a chance to melt or settle. So the 3” measurements are actually closer to 4” in NYC if they measured at the end of the snow instead of waiting up to 6 hours. The only time that a lower December snowfall total worked out at Newark last 30 years was the 16-17 La Nina. The reason this works out for our area is due to La Ninas being frontloaded by nature. So the above average La Niña snowfall winters have a snowy start.

Newark December La Nina snowfall and seasonal totals

2024….2.5”……?

2022….0.1”…..2.7”

2021…..0.1”….17.9”

2020…11.9”….45.7”

2017….7.7”…..39.4”

2016….3.4”….30.0”

2011…..0……..8.8”

2010….24.5”….68.2”

2008….8.3”…..27.1”

2007…..3.9”….14.6”

2005….11.0”….37.9”

2000….14.9”….39.3”

1999……T……..18.4”

1998……1.2”…..12.8”

1995……12.8”….78.4”

 So, are you saying Newark needs another 1.5” from this morning’s snow? I see that it had snow and only 1/2 mile visibility at 8AM. That sounds pretty significant if it had continued for awhile.

[EastonSN+]

29 minutes ago, bluewave said:

The actual cutoff value is closer to 4” like Newark since they measure later in NYC after the snow has had time to melt or settle since the airports measure more frequently. The official NYC values have been too low compared to the airports since the 1990s. Many times the measurement at the park occurs hours after the snow has stopped yielding a lower value than at the airports that measure when the snow stops.

The December La Nina cutoff for above average seasonal snowfall at Newark is closer to 4”. It’s probably a little higher than the 3” at NYC since they measure more frequently than NYC before the snow has a chance to melt or settle. So the 3” measurements are actually closer to 4” in NYC if they measured at the end of the snow instead of waiting up to 6 hours. The only time that a lower December snowfall total worked out at Newark last 30 years was the 16-17 La Nina. The reason this works out for our area is due to La Ninas being frontloaded by nature. So the above average La Niña snowfall winters have a snowy start.

Newark December La Nina snowfall and seasonal totals

2024….2.5”……?

2022….0.1”…..2.7”

2021…..0.1”….17.9”

2020…11.9”….45.7”

2017….7.7”…..39.4”

2016….3.4”….30.0”

2011…..0……..8.8”

2010….24.5”….68.2”

2008….8.3”…..27.1”

2007…..3.9”….14.6”

2005….11.0”….37.9”

2000….14.9”….39.3”

1999……T……..18.4”

1998……1.2”…..12.8”

1995……12.8”….78.4”

Thanks for this. Out of curiosity why did 16 17 have a wall to wall winter in a La Nina. We had the thunder snow event in February that year and a major snowstorm in March. This also happened to a much greater extent in 95 96 and 2010 2011 (I know some think winter ended after January however we had two more snow events in February and March that year). Are there any signs to look out for that would indicate a winter like 16 and 17 in advance. Forky did mention earlier a weakening La Nina perhaps that's what happened in 1617 as well.

Finally in the middle of Atlantic forum they are tracking the PDO and has stated that is rapidly rising and perhaps to go positive perhaps that happened in 1617 as well.

[doncat]

Very close to an inch here with 0.07" equivalent on si....started snowing around 7:45 so not bad for a little over an hour.

[wxman]

1" even.  Snow done.  Nice!  Temp 24.

[EastonSN+]

The end of the gefs run. Taking a step back from a trough in the West that blocking looks really good. 

Looks like the reason for the difference between the EPs and a gefs out west is the fact that the mjo is extremely weak in phase 8 on the gefs however is moderately strong on the eps.

[Allsnow]

Buckle up haha