donsutherland1

The coming weekend will be unseasonably chilly. Even Central Park could see the temperature drop below 50° this weekend for the first time in September since September 24, 2013 when the temperature fell to 47°. Tomorrow morning's low temperatures will likely be near the following values: Albany: 36° Allentown: 41° Boston: 48° Bridgeport: 49° Harrisburg: 47° Hartford: 42° Islip: 48° New York City: 50° Newark: 49° Philadelphia: 50° Poughkeepsie: 40° Providence: 46° White Plains: 44° Generally below normal readings could persist until near the middle of next week. Afterward, temperatures will moderate. There is an increasing possibility that September could wind up on the cool side of normal, which would be an uncommon event in recent cases preceding La Niña winters. Such an outcome is not assured. The highest rainfall from Hurricane Sally was 29.99" at Orange Beach, AL. 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 September 9. 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 -0.75°C. La Niña conditions have developed and will likely prevail through the remainder of autumn. The SOI was +17.89. Today, the preliminary Arctic Oscillation (AO) figure was +0.407. On September 17, the MJO was in Phase 4 at an amplitude of 1.592 (RMM). The September 16-adjusted amplitude was 1.624. 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°. 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 49% probability that New York City will have a warmer than normal September. September will likely finish with a mean temperature near 68.1°. Finally, on September 17, Arctic sea ice extent (JAXA) was 3.735 million square kilometers. It is likely that the summer minimum figure has been reached. That figure was 3.555 million square kilometers (JAXA), which was the second lowest minimum extent on record. 2020 is the second consecutive year with a minimum extent figure below 4.000 million square kilometers and the third such year on record.

It still varies quite a bit.

Here is another paper: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2010JD015065

Morning thoughts... A strong cold front is moving across the area. Clouds will gradually give way to partly sunny skies. Temperatures will rise mainly into the upper 60s to around 70° across the region. Likely high temperatures around the region include: New York City (Central Park): 69° Newark: 70° Philadelphia: 70° This weekend will see the coolest readings so far this season.

On JAXA, Arctic sea ice extent rose to 3.735 million square kilometers. The 2020 minimum figure was 3.555 million square kilometers. That figure will very likely be the final minimum extent for 2020.

Here’s one paper that shows increasing water vapor: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016JD024917 I’m not sure if NASA makes the underlying data for its cloud fraction maps public.

Today saw temperatures top out in the middle and upper 70s. However, this warmth will be short-lived. The coldest air mass so far this season will begin to overspread the region tomorrow. The coming weekend will be unseasonably chilly. Even Central Park could see the temperature drop below 50° for the first time in September since September 24, 2013 when the temperature fell to 47°. Generally below normal readings could persist into at least the last week of September. There is an increasing possibility that September could wind up on the cool side of normal, which would be an uncommon event in recent cases preceding La Niña winters. Elsewhere, Phoenix reached 109° today, which tied the daily record set in 1962. Today was also the 120th time this year that Phoenix reached 100° or above. 2020 is just the 7th year on record with 120 or more 100° readings. The last such year was 2018 with 128 days. The 30-year moving average is now 110.5 days. The 30-year moving average in 2010 was 109.6 days. Records go back to August 1895. 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 September 9. 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 -0.75°C. La Niña conditions have developed and will likely prevail through the remainder of autumn. The SOI was +17.89. Today, the preliminary Arctic Oscillation (AO) figure was +0.292. On September 16, the MJO was in Phase 4 at an amplitude of 1.620 (RMM). The September 15-adjusted amplitude was 1.428. 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°. 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 48% probability that New York City will have a warmer than normal September. September will likely finish with a mean temperature near 68.1°. Finally,on September 16, Arctic sea ice extent (JAXA) was 3.630 million square kilometers. To date, the summer minimum figure is 3.555 million square kilometers (JAXA). Based on 2010-2019 data, the highest 25% bound was 3.742 million square kilometers. The lowest 25% bound was 3.581 million square kilometers. The lowest 10% bound is 3.465 million square kilometers. 2020 is the second consecutive year with a minimum extent figure below 4.000 million square kilometers and the third such year on record. 2020 also has, by far, the second lowest extent on record. In contrast, according to NSIDC historical data, the 1920 minimum extent was approximately 8.826 million square kilometers and the 1970 minimum extent was 8.757 million square kilometers.

Here’s the attribution report on the Siberian heat: https://www.worldweatherattribution.org/wp-content/uploads/WWA-Prolonged-heat-Siberia-2020.pdf

There was additional rainfall. However, it seems that unlike a few years ago, WPC no longer provides precipitation amounts for ongoing events.

I agree. The NHC is very clear what a tropical cyclone is: " A warm-core non-frontal synoptic-scale cyclone, originating over tropical or subtropical waters, with organized deep convection and a closed surface wind circulation about a well-defined center." This is a very active season on account of developing La Nina conditions, wet conditions in Africa, and abnormally warm Atlantic waters. Prior to the season, NOAA, Colorado State, and Penn State forecasters all called near-record to possible record tropical activity.

Morning thoughts... Clouds have overspread much of the region from southeastern New York State southward. However, there remain breaks in the clouds back in a large part of Pennsylvania. As a result, today will be variably cloudy. It will also be warmer than yesterday. Temperatures will likely reach the middle and upper 70s across the region. Likely high temperatures around the region include: New York City (Central Park): 76° Newark: 78° Philadelphia: 77° An even colder air mass than the the most recent cold shot will likely begin overspreading the region tomorrow. The coming weekend will see the coolest readings so far this season. Farther south, the heavy rains from Sally are now moving out of the greater Atlanta area after dropping 3.57" rain from yesterday into early this morning. Sally's rains have moved into Greenville and will later be advancing into Charlotte and Fayetteville.

It is. This year’s record low ice in the central Arctic region, as part of a long-term trend of declining ice, is an example.

This is another significant paper. It confirms exactly what one would expect from the prior research showing a slowing and more wavy jet stream. It provides a unifying explanation for such events as last summer’s historic heat in Europe and Alaska, this year’s heat in Siberia, the record summer in parts of the Southwest, not to mention slowing forward motion of some recent hurricanes.

Temperatures rose into the lower and middle 70s today. Tomorrow will likely be several degrees warmer. Parts of the Southwest experienced record-tying and record-breaking heat. High temperatures included: Needles, CA: 112° (old record: 111°, 1924 and 2000) Phoenix: 109° (tied record set in 1928) Yuma, AZ: 111° (tied record set in 1922 and 2013) More record heat covered parts of Europe today. High temperatures in France included: Belin Beliet: 93° Chateauvillain: 98° Chablis: 94° Cogolin: 93° Durban-Corbières: 95° Montignac: 93° An even cooler air mass than the most recent one could arrive late in the week. Generally below normal readings could persist into at least the last week of September. There is an increasing possibility that September could wind up on the cool side of normal, which would be an uncommon event in recent cases preceding La Niña winters. 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 September 9. 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 -0.75°C. La Niña conditions have developed and will likely prevail through the remainder of autumn. The SOI was +14.09. Today, the preliminary Arctic Oscillation (AO) figure was -0.096. On September 15, the MJO was in Phase 4 at an amplitude of 1.428 (RMM). The September 14-adjusted amplitude was 1.033. 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°. 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 48% probability that New York City will have a warmer than normal September. September will likely finish with a mean temperature near 68.3°. Finally,on September 15, Arctic sea ice extent (JAXA) was 3.606 million square kilometers. To date, the summer minimum figure is 3.555 million square kilometers (JAXA). Based on 2010-2019 data, the highest 25% bound was 3.742 million square kilometers. The lowest 25% bound was 3.581 million square kilometers. The lowest 10% bound is 3.465 million square kilometers. 2020 is the second consecutive year with a minimum extent figure below 4.000 million square kilometers and the third such year on record. 2020 also has, by far, the second lowest extent on record. In contrast, according to NSIDC historical data, the 1920 minimum extent was approximately 8.826 million square kilometers and the 1970 minimum extent was 8.757 million square kilometers.

My allergies flared up, too. I suspect it's the ragweed more than anything else.

The last time the temperature fell into the 40s this early in the season at BOS was September 15, 2014 when the temperature fell to 48°. The last time the temperature fell into the 40s even earlier was September 10, 2003 when the temperature dropped to 49°.

Morning thoughts... Today will be sunny and somewhat milder. Temperatures will likely reach the lower 70s across the region. Likely high temperatures around the region include: New York City (Central Park): 71° Newark: 73° Philadelphia: 73° Tomorrow will be milder, but an even colder air mass than the most recent cold shot could arrive late in the week. Hurricane Sally made landfall near Gulf Shores, AL with maximum sustained winds of 105 mph. So far, Sally has brought 24.80" rain to Escambia, FL and 24.81" to Pensacola Naval Air Station. The ASOS at Pensacola Region Airport was knocked out yesterday evening. A storm report stated, "Landscape and architectural debris found lining the streets of downtown Mobile, AL."

Thanks for sharing this powerful quote. Once the smoke has passed, we’ll see more typical sunsets. The kind of sunset we witnessed today is commonplace in countries such as Indonesia and China. There’s just an incredible amount of pollution that produces such sunsets. At least that was the case when I was in both countries.

Today was the coolest day so far this month. After another cool start, tomorrow will be somewhat milder. Across the Atlantic Ocean, more monthly record high temperatures tumble in parts of Europe, including Belgium, France, and the Netherlands. Météo-France described the record-breaking September heat that occurred north of the Seine River as follows, "Monthly records have been beaten, even pulverized." Monthly record high temperatures included: Antwerp, Belgium: 94° Beauvechain, Belgium: 94° Brussels: 94° Charleroi, Belgium: 96° (national September record) Florennes, Belgium: 91° Geilenkirchen, Germany: 95° Gilze-Rijen, Netherlands: 95° (national September record) Kleine Brugel, Belgium: 94° Lille, France: 95° Luxembourg: 93° Maastricht, Netherlands: 94° Melun, France: 94° Paris-Le Bourget: 95° Pontoise, France: 95° St. Quentin, France: 94° An even cooler air mass could arrive late in the week. Generally below normal readings could persist into at least the last week of September. There is an increasing possibility that September could wind up on the cool side of normal, which would be an uncommon event in recent cases preceding La Niña winters. The most recent subseasonal guidance is in strong consensus that a generally cool regime could last through the first week of October. The latest EPS weeklies forecast an end to the cool anomalies near the end of September. 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 September 9. 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 -0.75°C. La Niña conditions have developed and will likely prevail through the remainder of autumn. The SOI was +7.67. Today, the preliminary Arctic Oscillation (AO) figure was -0.576. On September 14, the MJO was in Phase 3 at an amplitude of 1.030 (RMM). The September 13-adjusted amplitude was 0.743. 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°. 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 50% probability that New York City will have a warmer than normal September. September will likely finish with a mean temperature near 68.5°. Finally,on September 14, Arctic sea ice extent (JAXA) was 3.582 million square kilometers. To date, the summer minimum figure is 3.555 million square kilometers (JAXA). Based on 2010-2019 data, the highest 25% bound was 3.742 million square kilometers. The lowest 25% bound was 3.581 million square kilometers. The lowest 10% bound is 3.465 million square kilometers. 2020 is the second consecutive year with a minimum extent figure below 4.000 million square kilometers and the third such year on record. 2020 also has, by far, the second lowest extent on record.

Smoky sun this evening.

Thanks. It is a most unusual time.

No. The record is 41, which was set way back in 1913. Ironically, Mobile, AL received its record rainfall for September 15th in 1913 and that record could fall today on account of Sally.

Boston got down to 49 degrees this morning. The last time it was that chilly was June 2 when the temperature also fell to 49.

Morning thoughts... This morning saw some of the coolest readings so far this season. Low temperatures included: Allentown: 44° Boston: 49° Bridgeport: 50° Islip: 53° New York City: 54° Newark: 51° Philadelphia: 52° Poughkeepsie: 43° White Plains: 45° Today will be sunny but brisk. Temperatures will likely reach the upper 60s in much of the region to perhaps lower 70s in a few areas. Likely high temperatures around the region include: New York City (Central Park): 68° Newark: 70° Philadelphia: 70° Much of the week will feel like early autumn. An even colder air mass could arrive late in the week.

Two photos of this morning’s smoky sunrise.