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September 2020 wx discussion

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25 minutes ago, donsutherland1 said:

Denver reached 32 degrees earlier today. It’s now had its first freeze.

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

 

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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°.

 

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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...

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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

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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.

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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”

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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?

 

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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.

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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. 

 

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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.

 

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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.

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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.

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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

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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.

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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

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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

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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...

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