• Member Statistics

    16,116
    Total Members
    7,904
    Most Online
    Irish
    Newest Member
    Irish
    Joined
Rtd208

November 2020 General Discussions & Observations Thread

Recommended Posts

5 hours ago, jfklganyc said:

The city got rid of a lot of the native trees on the street (according to my cousin who works in the Parks Dept) Because they were susceptible to the Asian Long Horned Beetle.

But let’s face it, with the warm overnights, the city (not so much surrounding area yet) is in a different climate zone then it was 30 years ago. That is a huge reason for leaves hanging on in the concrete jungle

why cant they just kill off the beetles?

 

Share this post


Link to post
Share on other sites

Think the problem is the larvae chew out the trees from the inside, so they are hard to reach.

I don't think the adults do much eating, they focus on reproduction, so killing them requires a species specific virus or a very selective contact poison. Those are hard to come by.

 

  • Thanks 1

Share this post


Link to post
Share on other sites

New York City is concluding its warmest November on record. The temperature soared into the 60s today as a storm continued to push northward to the west of the region. With a high temperature of 63°, Central Park pushed its monthly mean temperature to 52.9°. The previous record was 52.8°, which was set in 2015. Records go back to 1869.

High Temperatures and rainfall amounts through 7 pm for select sites were:

Allentown: 61°; 2.72" (old record: 1.05", 2016)
Atlantic City: 65°; 1.43"
Boston: 59°; 0.40"
Bridgeport: 63°; 0.93"
Islip: 63°; 0.83"
New York City: 63°; 0.96"
Newark: 65°; 1.08"
Philadelphia: 67°; 0.98"
Poughkeepsie: 66°; 0.94"

December will start off mild before a period of cooler than normal to near normal temperatures commences. This cooler period could still give way to warmer readings at some point during the second week of December following a fairly sharp cold shot, but there is considerable uncertainty about the timing of this change. The development of a AO-/PNA+ pattern has shifted the outlook toward colder temperatures during the first half of December (consistent with statistical guidance). Exceptional cold is unlikely. The duration of the AO-/PNA+ pattern could delay any warmup until near mid-month.

An extended duration much warmer than normal regime will begin to develop in parts of western Canada starting during the first half of this week. Wednesday and Thursday could see record high temperatures in that region.

Statistical guidance based on the ENSO state and teleconnections would typically favor a colder regime for the first half of December. Both historic experience following exceptionally warm November cases and the latest weekly and monthly guidance suggest that a warmer than normal December remains the base case even if the first half of the month winds up colder than normal. Almost 90% of cases with a November mean temperature of 51.5° or above in Central Park went on to record a warmer than normal December and just over three-quarters of such cases saw December register a monthly mean temperature of 40.0° or above.  

The ENSO Region 1+2 anomaly was -1.0°C and the Region 3.4 anomaly was -1.0°C for the week centered around November 18. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.87°C and the ENSO Region 3.4 anomaly has averaged -1.40°C. La Niña conditions will likely prevail at least through the winter.

The SOI was +28.18.

Today, the preliminary Arctic Oscillation (AO) figure was -0.115.

On November 29 the MJO was in Phase 4 at an amplitude of 0.860 (RMM). The November 28-adjusted amplitude was 0.888.

Based on the latest guidance, no significant stratospheric warming event is likely through the middle of the second week of December. Some warming above 2 mb is likely toward the latter part of the first week of December on account of Wave 1 activity.  

Since 1950, there have been five cases where a La Niña developed during June-July-August or afterward following an El Niño winter. 4/5 (80%) of those cases saw a predominant EPO+/AO+ winter pattern. The most recent such case was 2016-17. 10/11 (91%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO. A predominant EPO+/AO+ pattern is very likely for winter 2020-21. It is likely that the Middle Atlantic and southern New England areas will see a warmer than normal winter with below normal snowfall.

Since 1970, there were 9 winters that saw the AO and EPO average +0.25 or above. Mean snowfall for Boston, Harrisburg, New York City, Philadelphia, and Washington, DC averaged 50% of the most recent 30-season mean. The largest snowfall deficits relative to the most recent 30-season mean figure were located in the Philadelphia to New York City corridor. In addition, 33% of cases saw less than 10" seasonal snowfall in New York City and 44% saw less than 10" seasonal snowfall in Philadelphia.

Finally, on November 30, 1842 an early-season snowstorm blanketed parts of the East Coast. The heaviest snows were focused on portions on Middle Atlantic region, with perhaps the heaviest snows falling in Virginia, Maryland and Pennsylvania. Parts of that area received more than a foot of snow.

 

  • Thanks 1

Share this post


Link to post
Share on other sites

It only took NYC 5 years to beat 2015 for warmest November. It took 14 years for 2015 to surpass 2001. And 2001 over 20 years to go ahead of 1979. 

Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Nov
Click column heading to sort ascending, click again to sort descending.
Rank
Year
Mean Avg Temperature 
Missing Count
1 2020 53.0 0
2 2015 52.8 0
3 2001 52.7 0
4 1979 52.5 0
5 1948 52.4 0
6 1975 52.3 0
7 2011 51.9 0
- 2006 51.9 0
- 1994 51.9 0
- 1931 51.9 0
8 1902 51.4 0
9 2009 51.1 0
10 1999 50.8 0
  • Thanks 1
  • Sad 1

Share this post


Link to post
Share on other sites
2 hours ago, bluewave said:

It only took NYC 5 years to beat 2015 for warmest November. It took 14 years for 2015 to surpass 2001. And 2001 over 20 years to go ahead of 1979. 

Time Series Summary for NY CITY CENTRAL PARK, NY - Month of Nov
Click column heading to sort ascending, click again to sort descending.
Rank
Year
Mean Avg Temperature 
Missing Count
1 2020 53.0 0
2 2015 52.8 0
3 2001 52.7 0
4 1979 52.5 0
5 1948 52.4 0
6 1975 52.3 0
7 2011 51.9 0
- 2006 51.9 0
- 1994 51.9 0
- 1931 51.9 0
8 1902 51.4 0
9 2009 51.1 0
10 1999 50.8 0

Sad, BW. A century from now the Smithsonian will likely have a special section for sleds. As always ....

Share this post


Link to post
Share on other sites

2015 definitely felt like a turning point.

Ever since then cold air has been hard to come by and winters have mostly been very warm with a few notable exceptions due to extreme blocking.

And with warming continuing to accelerate I feel we're going to see a major drop in the annual snowfall averages this decade. 

Share this post


Link to post
Share on other sites
1 hour ago, SnoSki14 said:

2015 definitely felt like a turning point.

Ever since then cold air has been hard to come by and winters have mostly been very warm with a few notable exceptions due to extreme blocking.

And with warming continuing to accelerate I feel we're going to see a major drop in the annual snowfall averages this decade. 

Agreed. It is all lining up against prolonged cold.

New normal is close to 3 degrees above normal.

AN is 5 plus degrees...Not through a few days of extreme warmth, but a persistent above normal that wont dissipate.

Snowstorms require luck now. Prolonged snow on ground is non existent.

We will see if this is a few year trend or not, but I have a feeling you are right

Share this post


Link to post
Share on other sites

I dropped into the forum to check that in fact NOV 2020 was warmest on record at NYC. I have a research thread on another weather forum (net-weather in the UK) outlining my research into climate records for Toronto (1840-2020) and more recently with a lot of assistance from Don Sutherland, added in comparative data for New York City. That part is all on page 2 of this thread (all Toronto stuff on page 1) ... 

https://www.netweather.tv/forum/topic/93113-toronto-180-a-north-american-data-base-of-180-years/#comments

I have compared rankings of all months that overlap since 1869 and you'll find that in general there is close agreement. This past November didn't quite make it to top of the list for Toronto, 1975 held on and 2011, 2016 and 1931 were not passed either. 

As part of this research I have applied urban heat island filters to the temperature records of both sets of data. NYC is in an even larger city of course but urban heat islands don't grow much stronger after a city reaches a critical size, they grow in areal extent instead. So I've applied the same decade by decade changes to both data sets with the assumption that New York City had a small urban heat island at the start of its records, Toronto only began to acquire one after 1881. So although I've changed the temperature data sets by similar amounts per decade, I assume NYC has a larger urban heat island by 0.3 to 0.5 C (0.5 to 0.9 F) deg. That is an average of all weather conditions and of course the urban effect is much bigger than that in calm, clear weather. 

The total adjustment for the Toronto data was 1.1 C (2.0 F) deg applied in full to the years since 1980, with 0.1 reductions in the filter each decade before that, until one reaches "no urbanization" before 1881 (there may have been a small amount). Applied to NYC that means 1869 to 1880 would be a step down also but there could have been further steps down in any data before 1869 in stages so the NYC total urban heat island is presumed to be around 1.5 C (2.7 F) averaged over all data. This applies mostly to overnight temperatures and this is reflected in the count of new record high max and min temps since 1970 (have done the same study at both sites, the counts are similar, around 15% more than random expectation for record high maxima, and 120% more for record high minima.) At Toronto, 218 days have a new record high minimum since 1970, only 108 have a new record high maximum. About 10 have a new record low minimum and 25 a new record low maximum again showing the diurnal bias of the u.h.i. effect. 

You'll find in this link tables of rankings for raw temperature data and adjusted. It does give the more ancient data some chance to make an upward move in the rankings but seldom do the "way back" months push more than five to ten ranks ahead and usually not into the top ten. (Years in the middle decades get smaller boosts, and the boosts ended in 1980, assuming almost steady-state u.h.i. since then). 

There was a remarkably hot July in 1868 at Toronto, unfortunately that's the year before the NYC data begin, maybe some other source would show this, but one or two very hot summer months at Toronto were surprisingly cool at NYC, for example July 1916 and 1921 both top ten months at Toronto, rather average to cool at NYC. Many other cases though have more similar outcomes at both locations. There's a circulation type with a narrow ridge over the western Great Lakes and an offshore trough in the Atlantic that can result in that differential. Even so, just about all the record highs at each location are either the same dates, or within 1-2 days, or do no worse than fall into top five, so generally similar results. I think you have to get into the Midwest before you start seeing a whole different set of record highs and lows, certainly by the time you reach the central plains that would be true.

I regularly update these tables and will probably put the same thread into some part of American Weather (not sure where is best suited) when I finish the project of creating an excel file with all data available. That is very close to completion (I am entering or proofing existing entries for 2019 today and 2020 tomorrow) but it would make sense to wait for 2020 to end then have this year complete as well. 

Eventually I will publish similar precip tables for NYC as I have done for Toronto. Once again Don S has been very helpful and I have all the raw data available, going through it to establish daily extremes and other useful info such as dry spells. The Toronto climate is more similar to NYC in temperature than precip, a dry month in each region may be closer to average or even a bit wetter than average that far afield. Snowfall does not correlate very well either, east coast storms miss Toronto on many occasions and Toronto snowstorms are often Apps runners or low-trajectory Colorado lows that warm up NYC. But some storms overlap. 

I am expecting a bit of a wild ride this winter, as many are saying, generally on the milder side of normal, but not a constant blowtorch situation and a few much colder intervals likely, mid to late January would be the most likely time. 

Share this post


Link to post
Share on other sites

I think you guys would find this interesting.  TWC posted a color coded map showing where snowy Novembers led to snowy winters, or not-snowy winters or no correlation at all.  Around the Great Lakes it was a positive correlation, for the east coast it was a negative correlation and for the middle of the country there was no correlation.

 

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

  • Recently Browsing   0 members

    No registered users viewing this page.