September 2020 wx discussion

[uncle W]

20 minutes ago, donsutherland1 said:

Tomorrow will be partly to mostly cloudy. Temperatures will likely still rise into the lower 80s in many parts of the region. Overall, the first half of September will likely wind up somewhat warmer than normal. The probability of the arrival of an autumn-like air mass near or just after mid-month has increased.

Following the historic heat in the Southwest, very cold air has plunged into the Rockies. Already, yesterday Casper recorded its earliest measurable snowfall on record. Numerous cities set record low maximum temperatures today. Select examples include:

Casper: 33° (old record: 46°, 1941) ***earliest high temperature below 40°; prior record September 13, 1970: 39°***
Cheyenne: 32° (old record: 36°, 1929)
Lander, WY: 34° (old record: 49°, 1962) ***earliest high temperature below 40°; prior record: September 11, 1903: 37°***

In addition, at 8 pm EDT, Denver was receiving light snow. Snow accumulations are likely tonight. Numerous record low temperatures will be established.

The ENSO Region 1+2 anomaly was -1.6°C and the Region 3.4 anomaly was -0.9°C for the week centered around September 2. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.08°C and the ENSO Region 3.4 anomaly has averaged -0.72°C. La Niña conditions are now developing.

The SOI was -2.61.

Today, the preliminary Arctic Oscillation (AO) figure was +1.270.

On September 7, the MJO was in Phase 3 at an amplitude of 0.751 (RMM). The September 6-adjusted amplitude was 0.723.

Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September.

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. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO.   

Based on sensitivity analysis applied to the latest guidance, there is an implied 63% probability that New York City will have a warmer than normal September. September will likely finish with a mean temperature near 69.5°.

 

thr AO is at its highest point in months...that scares me a little...The ao is forecast to go negative by most members that make up the forecast...an ao roller coaster ride during the winter would not be a bad thing...

[uncle W]

 

today in 1934 a tropical storm grazed the city and dumping 5" of rain on it...1934 was a very interesting year...one of the greatest periods for variable weather on record...record cold...alltime lowest temperature in Feb...record heat...alltime June hottest temperature...tropical storm with deluge in September...and blizzard in Jan 1935...I think the period from March 1960 to Feb 1961 was better with multable blizzards and a hurricane...the period from Feb 2010 to January 2011 was great but did not have a hurricane...

the 1934 storm...

http://bklyn.newspapers.com/image/59877271/

http://bklyn.newspapers.com/image/59877280

http://bklyn.newspapers.com/image/59877286

http://ibtracs.unca.edu/index.php?name=v04r00-1934248N24286

[donsutherland1]

13 minutes ago, uncle W said:

thr AO is at its highest point in months...that scares me a little...The ao is forecast to go negative by most members that make up the forecast...an ao roller coaster ride during the winter would not be a bad thing...

I hope we get some blocking this winter. Otherwise, it could be a really depressing season.

[donsutherland1]

1 hour ago, bluewave said:

This is a great example of what high enough snowfall rates can do.

 

Select snowfall amounts for September 8:

Casper: 5.2” (old record: 0.2”, 1962)

...2-day total: 7.5” (with yesterday’s 2.3” the earliest measurable snowfall on record)

Cheyenne: 0.5”

Lander, WY: 2.7” (old record: 2.4”, 1962)

...2-day total: 4.7”

[SACRUS]

9/8

PHL: 87
LGA: 84
EWR: 84
TEB: 84
New Brnswck: 84
TTN: 84
NYC: 84
ISP: 83
JFK: 81
ACY: 83
BLM: 79

[LibertyBell]

On 9/5/2020 at 8:20 AM, donsutherland1 said:

Morning thoughts...

Today will be mostly sunny and cooler than yesterday. Temperatures will likely reach the upper 70s and lower 80s across the region. Likely high temperatures around the region include:

New York City (Central Park): 79°
Newark: 81°
Philadelphia: 81°

A deep trough will continue to move into the Northern Plains in coming days. However, the cold will likely remain west of the Appalachians through at least much of next week.

Extreme heat will again scorch the Southwest. Numerous cities will approach or set daily record temperatures with some September records approached or broken. Death Valley could see the temperature top out near or just above its monthly record of 123°.

 

121 was recorded in LA county....I wonder if this is the latest 120 recorded in the region?

 

[LibertyBell]

2 hours ago, donsutherland1 said:

I hope we get some blocking this winter. Otherwise, it could be a really depressing season.

cant be any worse than last winter lol

 

[PB-99]

Just had an Earthquake here peeps at 2 am.

 

[PB-99]

3.1

[Franklin0529]

Yup I'm over on hwy 36. My whole house shook

24 minutes ago, PB-99 said:

3.1

 

[SnoSki14]

6 hours ago, LibertyBell said:

cant be any worse than last winter lol

 

Outside of no snow at all I agree. 

[CIK62]

The next 8 days are averaging 74degs., or 4.5degs. AN.      Make it -0.5.

72*(89%RH) here at 6am, overcast.

System nearest US has lost its footprint.       The snake eyes are at:       19N 46W,   17N 30W.

Did not feel the eartquake.      I did feel a similar one 3.5, in the same general area while lying  on the beach shortly after the August 2003 Power Outage.

[dWave]

6 hours ago, PB-99 said:

Just had an Earthquake here peeps at 2 am.

 

Centered in Freehold NJ. 3.1. Reports it was felt from south NJ to SI, Brooklyn & Queens. 

 

[donsutherland1]

Morning thoughts...

Today will be partly to mostly cloudy. Showers could arrive in parts of the area late in the day or at night. Temperatures will likely reach the lower 80s across much of the region. Likely high temperatures around the region include:

New York City (Central Park): 81°
Newark: 82°
Philadelphia: 82°

Somewhat warmer than normal conditions will likely prevail through much of the week. Cooler air could arrive late in the week.

September 9 has the lowest figure for record daily precipitation in Central Park. The record is just 0.86", which was recorded in 1903. Records go back to 1869.

 

[MJO812]

47 minutes ago, dWave said:

Centered in Freehold NJ. 3.1. Reports it was felt from south NJ to SI, Brooklyn & Queens. 

 

I remember  we had one here in NYC in 2011. A week later Irene hit.

[SACRUS]

73/71 cloudy , earthquake 3.1 a couple of miles down the road.  Dew points are back the next two days with showers and rain more plentiful Thursday.  Not sure we can reach forecasted highs in the low 80s but we will see if any pokes of sun, 850s are >16c.  Brief cool down Friday and Saturday before more humid and warm flow returns Sunday (8/13) and Monday (9/14).

Tue 9/16 - Fri 9/19 looks more onshore and near or below normal before more ridging returns later in the month could end on a much warmer note.

[SACRUS]

27 minutes ago, MJO812 said:

I remember  we had one here in NYC in 2011. A week later Irene hit.

That was centered in VA and was a 5.3.  Felt different.  This was more intense loud boom then the shaking.  

 

https://earthquaketrack.com/p/united-states/new-jersey/biggest

 

[SACRUS]

This looks off to me. Parts of NJ / NYC north and west may get 1 - 3 inches tomorrow.

 

 

[doncat]

25 minutes ago, SACRUS said:

That was centered in VA and was a 5.3.  Felt different.  This was more intense loud boom then the shaking.  

 

https://earthquaketrack.com/p/united-states/new-jersey/biggest

 

You felt it last night? 

[bluewave]

11 hours ago, LibertyBell said:

cant be any worse than last winter lol

 

The bar is set pretty low. This was the first time that NYC had two consecutive met winters (DJF) under 5”. 

 

Time Series Summary for NY CITY CENTRAL PARK, NY - Dec through Feb
Click column heading to sort ascending, click again to sort descending.

Rank	Season	Total Snowfall	Missing Count
1	1997-1998	0.5	0
2	1918-1919	1.1	0
3	1972-1973	2.6	0
4	1931-1932	2.7	0
5	1991-1992	3.2	0
6	2001-2002	3.5	0
7	2018-2019	3.7	0
8	2011-2012	4.5	0
9	2019-2020	4.8	0
10	1989-1990	5.0	0

[lee59]

1 hour ago, bluewave said:

The bar is set pretty low. This was the first time that NYC had two consecutive met winters (DJF) under 5”. 

 

Time Series Summary for NY CITY CENTRAL PARK, NY - Dec through Feb
Click column heading to sort ascending, click again to sort descending.

Rank	Season	Total Snowfall	Missing Count
1	1997-1998	0.5	0
2	1918-1919	1.1	0
3	1972-1973	2.6	0
4	1931-1932	2.7	0
5	1991-1992	3.2	0
6	2001-2002	3.5	0
7	2018-2019	3.7	0
8	2011-2012	4.5	0
9	2019-2020	4.8	0
10	1989-1990	5.0	0

What is also interesting about the last 2 seasons is last season ended up with the 4.8 inches meaning no snow in November or March. 2018-19 ended up with over 20 inches with big totals in November and March.

[Stormlover74]

2 minutes ago, lee59 said:

What is also interesting about the last 2 seasons is last season ended up with the 4.8 inches meaning no snow in November or March. 2018-19 ended up with over 20 inches with big totals in November and March.

Yeah last winter was more in line with 01-02 and 11-12

[bluewave]

22 minutes ago, lee59 said:

What is also interesting about the last 2 seasons is last season ended up with the 4.8 inches meaning no snow in November or March. 2018-19 ended up with over 20 inches with big totals in November and March.

South Shore coastal sections missed out on the heaviest of the March snows in 2019. So they had two consecutive well below normal snowfall seasons. But they also did much better than the NYC area from 2013 to 2018.

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

Ending Date	Total Snowfall Oct 1 to Apr 30	Missing Count
2020-04-30	6.8	1
2019-04-30	12.8	0
2018-04-30	65.9	0
2017-04-30	39.3	0
2016-04-30	41.4	0
2015-04-30	63.7	0
2014-04-30	63.7	0
2013-04-30	46.9	0

 

Time Series Summary for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending.

Ending Date	Total Snowfall Oct 1 to Apr 30	Missing Count
2020-04-30	4.8	1
2019-04-30	20.5	0
2018-04-30	40.9	0
2017-04-30	30.2	0
2016-04-30	32.8	0
2015-04-30	50.3	0
2014-04-30	57.4	0
2013-04-30	26.1	0

[uncle W]

2 hours ago, bluewave said:

The bar is set pretty low. This was the first time that NYC had two consecutive met winters (DJF) under 5”. 

 

Time Series Summary for NY CITY CENTRAL PARK, NY - Dec through Feb
Click column heading to sort ascending, click again to sort descending.

Rank	Season	Total Snowfall	Missing Count
1	1997-1998	0.5	0
2	1918-1919	1.1	0
3	1972-1973	2.6	0
4	1931-1932	2.7	0
5	1991-1992	3.2	0
6	2001-2002	3.5	0
7	2018-2019	3.7	0
8	2011-2012	4.5	0
9	2019-2020	4.8	0
10	1989-1990	5.0	0

some of these years had snow before December...1931, 2018, 2011 and 1989...

[bluewave]

1 hour ago, uncle W said:

some of these years had snow before December...1931, 2018, 2011 and 1989...

With the exception of the super El Niño in 15-16 and March 18, the anomalous NEPAC Ridge has told the story of the winter. 13-14 and 14-15 were cold and snowy as the ridge set up over NW Canada. 16-17 and 17-18 were warm and snowy as the ridge location pulled back to the Aleutians. The last 2 winters were warm and nearly snowless as the ridge locked in just north of Hawaii. It’s no coincidence that my favorite snowstorms since 12-13 were in January 16 and March 18 as we finally got a -NAO/-AO pattern. 

 

[forkyfork]

record pwats over 2.25" being forecast tomorrow without a tropical system nearby. impressive

[bluewave]

21 hours ago, forkyfork said:

record pwats over 2.25" being forecast tomorrow without a tropical system nearby. impressive

 

Record moisture instead of heat to go with the near record WAR for September.

 

 

 

[lee59]

4 hours ago, bluewave said:

South Shore coastal sections missed out on the heaviest of the March snows in 2019. So they had two consecutive well below normal snowfall seasons. But they also did much better than the NYC area from 2013 to 2018.

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

Ending Date	Total Snowfall Oct 1 to Apr 30	Missing Count
2020-04-30	6.8	1
2019-04-30	12.8	0
2018-04-30	65.9	0
2017-04-30	39.3	0
2016-04-30	41.4	0
2015-04-30	63.7	0
2014-04-30	63.7	0
2013-04-30	46.9	0

 

Time Series Summary for NY CITY CENTRAL PARK, NY
Click column heading to sort ascending, click again to sort descending.

Ending Date	Total Snowfall Oct 1 to Apr 30	Missing Count
2020-04-30	4.8	1
2019-04-30	20.5	0
2018-04-30	40.9	0
2017-04-30	30.2	0
2016-04-30	32.8	0
2015-04-30	50.3	0
2014-04-30	57.4	0
2013-04-30	26.1	0

Looking at the previous 6 years before the last 2, we were overdue for what we had the last 2 years.

[Cygnus X-1]

10 hours ago, dWave said:

Centered in Freehold NJ. 3.1. Reports it was felt from south NJ to SI, Brooklyn & Queens. 

 

I work practically across the street from ISP; I was sitting in my car on break at the time, and it felt like someone shook my car very lightly by hand. I even looked in my mirror, lol. I thought to myself, "Did I just feel an earthquake.....? Naaaaa".

SOB, I come here and see this. Not lying. 

[donsutherland1]

Tomorrow will be mostly cloudy and very humid. Showers and heavy thunderstorms are likely. Overall, much of the region will likely pick up 0.50"-1.50" rain with some locally higher amounts.

Overall, the first half of September will likely wind up somewhat warmer than normal. An autumn-like air mass will likely arrive late this week. Another cool air mass could arrive next week.

Beyond that, some of the guidance is hinting at a possible dramatic and sharp decline in the PNA. Such a pattern, should it develop, would favor a return to warmer and perhaps much warmer than normal conditions late in the month.

Numerous record low temperatures were established overnight in the Rockies and parts of the Southwest. Select low temperatures included:

Albuquerque: 39° (old record: 43°, 1915)
Amarillo: 37° (old record: 44°, 1941)
Casper: 25° (old record: 29°, 1962)
Colorado Springs: 30° (tied record set in 1941)
El Paso: 53° (old record: 55°, 1882 and 2004)
Denver: 30° (old record: 31°, 1962)
Lander, WY: 23° (old record: 26°, 1903 and 1962)

Snowfall totals through September 8 included:

Burris (11 WSW), WY: 17.0"
Casper: 7.5"
Cheyenne: 1.1"
Denver: 1.0"
Lander: 4.7"

At Denver, yesterday's 1.0" snow followed a four-day heat wave. The temperature on September 7 reached 93°. That was Denver's highest temperature one day before the city received measurable snowfall. The previous record was 92° on September 12, 1993.

At the Rapid City National Weather Service Office in East Rapid City, September 5 saw the temperature reach 102°. Just two days later on September 7, 1.0" snow was measured.

The air mass responsible for the record cold could send the temperature below 70° tonight in Phoenix. Temperatures below 70° on September 10 or earlier have become very uncommon occurrences. The last time the temperature was in the 60s on or before September 10 was August 28, 2008 when the mercury fell to 64°. The number of occurrences by recent decade are below:

1970s: 9 days
1980s: 6 days
1990s: 3 days
2000s: 1 day
2010s: None

The ENSO Region 1+2 anomaly was -1.6°C and the Region 3.4 anomaly was -0.9°C for the week centered around September 2. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.08°C and the ENSO Region 3.4 anomaly has averaged -0.72°C. La Niña conditions are now developing.

The SOI was -6.00.

Today, the preliminary Arctic Oscillation (AO) figure was +1.381.

On September 8, the MJO was in Phase 3 at an amplitude of 0.605 (RMM). The September 7-adjusted amplitude was 0.750.

Since 1990, there have been 11 La Niña events, 6 of which followed an El Niño winter. 10/11 (91%) case saw warmer than normal September. All 6 following an El Niño winter were warmer than normal. September mean temperatures for New York City for those cases were: 11 cases: 69.9°; Subset of 6 cases: 70.8°; Entire 1990-2019 period: 69.0°. The September mean temperature for all La Niña and neutral-cool cases following an El Niño winter (1950-2019: n=13) was 69.9°. Overall, the evolution of ENSO, along with the observed ongoing monthly warming (1.6°/decade in NYC and 1.5°/decade in the Northeast Region during September 1990-2019), favors a warmer than normal September.

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. 9/10 (90%) of the La Niña winters that followed an El Niño winter featured a predominantly positive EPO.   

Based on sensitivity analysis applied to the latest guidance, there is an implied 60% probability that New York City will have a warmer than normal September. September will likely finish with a mean temperature near 69.5°.