September 2021

[donsutherland1]

New York City's Central Park is on track to record a low temperature of 70° or above today. The mean last date such a temperature has increased 4 days from September 10 (1951-80) to September 14 (1991-20). The interval from the first and last dates has also widened 9 days to 104 days during that time. Most of that widening has occurred during the most recent 30-year period (104 days vs. 96 days for 1981-2010). Overall, September has been warming to the extent that it is now more an extension of summer than gateway into autumn.

[SnoSki14]

1 hour ago, bluewave said:

This is such a warm pattern, that even a late September cold front won’t have much cold air behind it. 
 

 

The acceleration in warming over just the last few years has been astounding and terrifying.

And the funny thing is that we're probably one of the coolest spot in the country relatively speaking outside parts of the Pacific NW. 

[wdrag]

No thread yet on a 3+" event for a portion of the subforum and spotty SVR.  Right now, I think it's marginal  but if we happen to get a meso low on the cold front Thursday night over NJ, then i think we'll have some non-routine heavier rains (3") and spotty damaging wind events.

[MJO812]

Happy Autumn 

[forkyfork]

sept so far at ewr: 73.8

august 1967: 73.4

[nycwinter]

2 hours ago, bluewave said:

This is such a warm pattern, that even a late September cold front won’t have much cold air behind it. 
 

 

normal high in nyc for the  last day in september i think is 73 it is not suppose to be cold dude..

[nycwinter]

3 hours ago, Rjay said:

How so?

the asphalt at the airport makes the temps hotter then they would be anywhere else.. the offilcal temp should not be taken at the airport but somewhere else in the city..

[uncle W]

my pool is still open...a nice three day warmth spell would be nice before it closes Oct 10th...

1967 was cool in Sept...much cooler than this year...

IPS-1BD83742-5475-4643-81C9-ACA5CC93FE4D.pdf (noaa.gov)

[FPizz]

20 minutes ago, nycwinter said:

the asphalt at the airport makes the temps hotter then they would be anywhere else.. the offilcal temp should not be taken at the airport but somewhere else in the city..

It is all asphalt practically.  

[donsutherland1]

Newark has reached 80 degrees for the 109th day this year.

[psv88]

52 minutes ago, nycwinter said:

the asphalt at the airport makes the temps hotter then they would be anywhere else.. the offilcal temp should not be taken at the airport but somewhere else in the city..

You realize most of the metro area is also asphalt right? When people walk on a sidewalk, etc, they are over asphalt. So it is more representative than a lush garden in the middle of manhattan

[dieselbug]

48 minutes ago, nycwinter said:

the asphalt at the airport makes the temps hotter then they would be anywhere else.. the offilcal temp should not be taken at the airport but somewhere else in the city..

Most weather sensors in big cities are at the major airports. Based on your reply, all temperatures taken from airports are invalid because they will be "too warm"??

As many here pointed out, the location of the sensor at KEWR is sandwiched on a strip of land with a runway on one side and a canal on the other side. Perfect location? No, but it could be worse!

If the "official" Newark temperature was taken from downtown Newark (more asphalt), the air temperature in my opinion, could be even warmer than it's location at the airport. 

[Rjay]

I give up

[bluewave]

Continuation of our new subtropical climate theme. The dew point at JFK reached 70° again today. This was the 64th day so far this year. All the top years for 70° or higher dew points have occurred since 2016.

https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=161&network=NY_ASOS&zstation=JFK&var=max_dwpf&dir=aoa&thres=70&month=all&year=2021&dpi=100&_fmt=js

#1…..89 days….2018

#2….77 days…..2019

#3….68 days…..2016

#4….64 days…..2021…2020
 

 

[Brian5671]

78/73 here

[forkyfork]

6 minutes ago, bluewave said:

Continuation of our new subtropical climate theme. The dew point at JFK reached 70° again today. This was the 64th day so far this year. All the highest number of days in a year have occurred since 2016.

https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=161&network=NY_ASOS&zstation=JFK&var=max_dwpf&dir=aoa&thres=70&month=all&year=2021&dpi=100&_fmt=js

#1…..89 days….2018

#2….77 days…..2019

#3….68 days…..2016

#4….64 days…..2021…2020
 

 

the super nino reset our climate

[bluewave]

1 hour ago, forkyfork said:

the super nino reset our climate

Yeah, December 2015 going +13 was the big reset month. Each El Niño since 2002-2003 has added new changes to our climate. You can look back and see new patterns of extremes following the 2002-2003, 2004-2005, 2009-2010, and 2015-2016 events. So each global temperature jump creates a new type of baseline for us.

[binbisso]

7 hours ago, bluewave said:

This is such a warm pattern, that even a late September cold front won’t have much cold air behind it. 
 

 

  true but conversely a 594dm  Ridge over the northeast in mid September Should have much warmer temperatures than in the mid to upper seventies for most of the region

[Jeff Grann]

1 hour ago, bluewave said:

Continuation of our new subtropical climate theme. The dew point at JFK reached 70° again today. This was the 64th day so far this year. All the top years for 70° or higher dew points have occurred since 2016.

https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=161&network=NY_ASOS&zstation=JFK&var=max_dwpf&dir=aoa&thres=70&month=all&year=2021&dpi=100&_fmt=js

#1…..89 days….2018

#2….77 days…..2019

#3….68 days…..2016

#4….64 days…..2021…2020
 

 

Subtropical? LOL. Let me know when Palm trees can survive a NYC Winter. Subtropical is not defined as Summer dews. It is a year round climate . 

[bluewave]

16 minutes ago, Jeff Grann said:

Subtropical? LOL. Let me know when Palm trees can survive a NYC Winter. Subtropical is not defined as Summer dews. It is a year round climate . 

We just shifted to a humid subtropical climate with the new 1991-2020 climate normals.

 

[rclab]

2 hours ago, bluewave said:

Continuation of our new subtropical climate theme. The dew point at JFK reached 70° again today. This was the 64th day so far this year. All the top years for 70° or higher dew points have occurred since 2016.

https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&q=161&network=NY_ASOS&zstation=JFK&var=max_dwpf&dir=aoa&thres=70&month=all&year=2021&dpi=100&_fmt=js

#1…..89 days….2018

#2….77 days…..2019

#3….68 days…..2016

#4….64 days…..2021…2020
 

 

 

13 minutes ago, Jeff Grann said:

Subtropical? LOL. Let me know when Palm trees can survive a NYC Winter. Subtropical is not defined as Summer dews. It is a year round climate . 

 Good afternoon JG. Your post reaction is understandable, however there are nuances to the term. Palm trees may be a physical manifestation of tropical as are dews. We are experiencing sustained heightened dews in a calendar time and geographic locations that gives pause. BW, as many other fine posters in our sub forums neither hypes or sensationalizes. Data and demonstration of such is their deep throat. As always ….

[bluewave]

56 minutes ago, binbisso said:

  true but conversely a 594dm  Ridge over the northeast in mid September Should have much warmer temperatures than in the mid to upper seventies for most of the region

This has been our 2nd warmest mid-September on record.

 

Time Series Summary for ISLIP-LI MACARTHUR AP, NY
Click column heading to sort ascending, click again to sort descending.

Rank	Ending Date	Mean Avg Temperature Sep 12 to Sep 21	Missing Count
1	2005-09-21	74.7	0
2	2021-09-21	72.0	0
3	2017-09-21	71.6	0
-	1998-09-21	71.6	0
4	2018-09-21	71.5	0

Time Series Summary for NEWARK LIBERTY INTL AP, NJ
Click column heading to sort ascending, click again to sort descending.

Rank	Ending Date	Mean Avg Temperature Sep 12 to Sep 21	Missing Count
1	2005-09-21	77.9	0
2	2021-09-21	75.2	0
3	2017-09-21	74.1	0
-	1957-09-21	74.1	0
4	1998-09-21	73.9	0
5	2018-09-21	73.3	0

 

Time Series Summary for JFK INTERNATIONAL AIRPORT, NY
Click column heading to sort ascending, click again to sort descending.

Rank	Ending Date	Mean Avg Temperature Sep 12 to Sep 21	Missing Count
1	2005-09-21	75.9	0
2	2021-09-21	73.4	0
3	1971-09-21	73.3	0
4	2017-09-21	73.0	0
5	2018-09-21	72.7	0

[doncat]

Flood watch extended...

[Rtd208]

[LongBeachSurfFreak]

1 hour ago, Jeff Grann said:

Subtropical? LOL. Let me know when Palm trees can survive a NYC Winter. Subtropical is not defined as Summer dews. It is a year round climate . 

There are actually several Palm species that can survive our winters. The most notable is the Windmill Palm. 
It’s the coldest lows that make the biggest difference. An average winter pre 1980s had a lowest temp averaging around 5. Recently it’s been more like 15.

[jm1220]

26 minutes ago, Rtd208 said:

The SE flow will make this worse in places vulnerable to upslope on those winds. Pretty deep moist flow will be riding up those mountains and squeezing out heavy rain. Central PA especially in for a drenching along with probably the Poconos/Catskills. 

[bluewave]

37 minutes ago, LongBeachSurfFreak said:

There are actually several Palm species that can survive our winters. The most notable is the Windmill Palm. 
It’s the coldest lows that make the biggest difference. An average winter pre 1980s had a lowest temp averaging around 5. Recently it’s been more like 15.

Yeah, I have been seeing more Windmill Palms on Long Island. The key seems to be wrapping them in the winter. 
 

 

[forkyfork]

what's wrong with oaks and maples

[uncle W]

NYC average minimums...

1950-59...6.7...

1960-69...4.8...

1970-79...4.7...

1980-89...3.5...

1990-99...7.1...

2000-09...9.0...

2010-19...6.6...

last two years had a min of 14...

[donsutherland1]

Today was variably cloudy and unseasonably warm. The temperature rose into the upper 70s and lower 80s across much of the region. In addition, Central Park was poised to record its 50th 70° or above minimum temperature of the year. Even as New York City has had a mature urban footprint, the number of such days has increased in recent decades. The average figures for select 30 year periods are: 1971-00 was 33.7 days; 1981-10: 34.7 days; and, 1991-20: 39.0 days. During 1869-1999, Central Park registered 40 or more such days once every 5.5 years. Since 2000, it has seen 40 or more days every 1.6 years. The change in return time for 50 or more such days is even more dramatic. 1869-1999: Once every 26.2 years; 2000-21: Once every 3.1 years (would be once every 2.8 years if today's low temperature remains at or above 70°).

The potential exists for a moderate to perhaps significant rainfall from tonight through Friday. A widespread 0.50"-1.50" rainfall with locally higher amounts is possible. Areas to the north and west of Newark and New York City could see 1"-3" amounts with locally higher figures. Flash flooding is possible. Parts of the region could also experience some severe weather, especially tomorrow afternoon into early Friday.

The MJO has recently been locked in Phase 3 at a high amplitude, frequently in excess of 1.500. Only 2006 and 2009 saw the MJO in Phase 3 at an amplitude of 1.500 or above for 2 or more days during September 10-20. Both years saw September end with a cold shot that continued into the first days of October. Both days saw Central Park's temperature fall to 49° on September 30. A fairly sharp rebound in temperatures followed. October wound up wetter than normal with 7.07" rainfall in 2006 and 5.58" of rainfall in 2009. Normal rainfall (1991-2020) is 4.38".

Despite the guidance of a few days ago and a likely cold shot to end the month, 2021 is still on course to become the 6th out of the last 7 years during which September has had a mean temperature of 70° or above in New York City. Considering that the close of September is still more than 10 days out, the guidance can still reverse. Prior to 2000, New York City saw such warmth on average once every five years. In short, September has become more an extension of summer than a gateway to autumn in the New York City area.

Fall 2021 will likely be wetter to much wetter than normal in the northern Middle Atlantic region. Since 1869, there have been 9 August cases where New York City picked up 20.00" or more rainfall during the summer. Two thirds of those cases (and 4/5 of those with summer mean temperatures of 73.0° or above) had 17.00" or more fall precipitation in New York City. 2011 is probably the closest match in terms of precipitation and a nearly identical summer mean temperature. Mean fall precipitation for those 9 cases was 14.86". The median was 17.35". The 1991-2020 normal value is 12.27".

The ENSO Region 1+2 anomaly was +0.2°C and the Region 3.4 anomaly was -0.4°C for the week centered around September 15. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.03°C and the ENSO Region 3.4 anomaly has averaged -0.45°C. Neutral ENSO conditions will likely prevail through September. Afterward, La Niña conditions could begin to develop.

The SOI was +0.12 today.

The preliminary Arctic Oscillation (AO) figure was +0.735 today.

On September 20 the MJO was in Phase 4 at an amplitude of 1.527 (RMM). The September 19-adjusted amplitude was 1.347 (RMM).

Based on sensitivity analysis applied to the latest guidance, there is an implied 85% probability that New York City will have a warmer than normal September (1991-2020 normal). September will likely finish with a mean temperature near 70.6° (1.4° above normal).