donsutherland1

Snow, without question.

Central Park has switched to light snow.

Thanks Jerry. I hope all is well with you and also that the snowfall amounts are underdone.

Tomorrow will be very mild in the Middle Atlantic and southern New England region. Temperatures should top out in the upper 50s in southern New England and lower 60s in much of the Middle Atlantic region. This unseasonable warmth will be short-lived.　 As the front slowly moves eastward, a wave could develop along the front bringing parts of the region a light snowfall late Tuesday into Wednesday morning. New York City, Newark, and Philadelphia could be in line for perhaps an inch or two of slushy snow, especially on grassy surfaces. Outside the cities, a general 2"-4" with locally higher amounts appears possible. Lesser amounts remain possible should the arrival of the cold air be somewhat delayed. The ENSO Region 1+2 anomaly was +0.1°C and the Region 3.4 anomaly was +0.3°C for the week centered around December 4. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.23°C and the ENSO Region 3.4 anomaly has averaged +0.67°C. These recent conditions are consistent with a weak El Niño. Nevertheless, a neutral ENSO remains the base case for Winter 2019-20 and the recent cooling in Region 3.4 suggests that the base case remains viable. The SOI was -4.72 today. Today, the preliminary Arctic Oscillation (AO) figure was +0.922. In the long-range, there is disagreement among the guidance. The GEFS is colder than the EPS. The latest week 2 and 3 forecasts for the CFSv2 have moved dramatically away from the severe cold that prior runs had shown. The progression of the MJO over the next 10 days and the evolution of the AO could provide insight. No significant stratospheric warming event appears likely through December 18. Wave 2 activity is forecast to remain suppressed and the stratosphere is forecast to remain cold past mid-month on the EPS. According to NCEP, the correlation of 16-day 10 mb GFS temperature forecasts is near 0.25 (much worse than flipping a coin). 5 mb forecasts have an even lower correlation. When it comes to New York City's 4" or greater snowstorms the PNA is more important than the AO during the first half of December. Since 1950, December 1-15 has seen 10 storms bring 4.0" or more snow to New York City. 50% occurred with an AO- or AO+. However, 80% occurred when the PNA was positive. All 6" or greater snowstorms during this timeframe occurred when the PNA was positive. The December 1-3 storm occurred with a negative PNA and Central Park received 1.6" snow. During the second half of December, larger snowstorms have occurred with a negative PNA.

Following a mild start to the work week, a cold front will move across the region on Tuesday with additional periods of rain. Ahead of the front, much of the Middle Atlantic and southern New England region could see temperatures top out in the upper 50s and even at or above 60° tomorrow and/or Tuesday. The unseasonable warmth will be short-lived. As the front slowly moves eastward, a wave could develop along the front bringing parts of the region a light snowfall late Tuesday into Wednesday morning. New York City, Newark, and Philadelphia could be in line for perhaps an inch or two of slushy snow, especially on grassy surfaces. Outside the cities, a general 2"-4" with locally higher amounts appears possible. The ENSO Region 1+2 anomaly was +0.4°C and the Region 3.4 anomaly was +0.4°C for the week centered around November 27. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.43°C and the ENSO Region 3.4 anomaly has averaged +0.62°C. These recent conditions are consistent with a weak El Niño. Nevertheless, a neutral ENSO remains the base case for Winter 2019-20. The SOI was +4.83 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.725. In the long-range, there is considerable disagreement among the guidance. The GEFS is colder than the EPS. The CFSv2 favors much colder than normal conditions during weeks 2 and 3 with widespread two-week anomalies of 5° or more below normal. The forecast teleconnections argue for a less cold outcome, though the kind of warmth shown at the extended range of the EPS is not yet a high probability outcome. The progression of the MJO over the next 10 days and the evolution of the AO could provide insight. No significant stratospheric warming event appears likely through December 17. Wave 2 activity is forecast to remain suppressed and the stratosphere is forecast to remain cold through mid-month on the EPS. According to NCEP, the correlation of 16-day 10 mb GFS temperature forecasts is near 0.25 (much worse than flipping a coin). 5 mb forecasts have an even lower correlation. On December 7, the MJO was in Phase 2 at an amplitude of 0.925 (RMM). The December 6-adjusted amplitude was 0.859. When it comes to New York City's 4" or greater snowstorms the PNA is more important than the AO during the first half of December. Since 1950, December 1-15 has seen 10 storms bring 4.0" or more snow to New York City. 50% occurred with an AO- or AO+. However, 80% occurred when the PNA was positive. All 6" or greater snowstorms during this timeframe occurred when the PNA was positive. The December 1-3 storm occurred with a negative PNA and Central Park received 1.6" snow. During the second half of December, larger snowstorms have occurred with a negative PNA.

Utqiagvik is easily on course for its warmest year on record. It is all but improbable that the record will fall. Further, that city will likely finish with its first annual mean temperature of 20.0 degrees or above.

Following yesterday's mild readings, today saw readings remain well below normal across the region. The ENSO Region 1+2 anomaly was +0.4°C and the Region 3.4 anomaly was +0.4°C for the week centered around November 27. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.43°C and the ENSO Region 3.4 anomaly has averaged +0.62°C. These recent conditions are consistent with a weak El Niño. Nevertheless, a neutral ENSO remains the base case for Winter 2019-20. The SOI was +7.16 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.496. No significant stratospheric warming appears likely through December 16. Wave 2 activity is forecast to remain suppressed and the stratosphere is forecast to remain cold through mid-month on the EPS. According to NCEP, the correlation of 16-day 10 mb GFS temperature forecasts is near 0.25 (much worse than flipping a coin). 5 mb forecasts have an even lower correlation. On December 6, the MJO was in Phase 2 at an amplitude of 0.854 (RMM). The December 5-adjusted amplitude was 0.631. The first week of December saw readings average more than 4° below normal across the northern Mid-Atlantic and southern New England regions. A more variable pattern is now poised to develop. There is a chance that the coming week could see one or more days with much above normal readings topping out in the 50s and perhaps even near 60° in the northern Mid-Atlantic region. Nevertheless, cold shots will continue to occur on a periodic basis. By December 15, the anomaly will likely be 1°-2° below normal. The third week of the month could turn colder and possibly for a more sustained period of time, especially if the EPO goes negative. When it comes to New York City's 4" or greater snowstorms the PNA is more important than the AO during the first half of December. Since 1950, December 1-15 has seen 10 storms bring 4.0" or more snow to New York City. 50% occurred with an AO- or AO+. However, 80% occurred when the PNA was positive. All 6" or greater snowstorms during this timeframe occurred when the PNA was positive. The December 1-3 storm occurred with a negative PNA and Central Park received 1.6" snow. During the second half of December, larger snowstorms have occurred with a negative PNA.

Despite bright sunshine and a cloudless sky during the mid- and late-afternoon, the temperature in New York City reached a maximum reading of 38°. The snow from earlier in the week had almost completely disappeared from the landscape. At the New York Botanical Garden, the annual train show was underway. At the show were replicas of present and past New York City-area landmarks constructed out of wood and other natural materials. Four photos (three from inside the show for a flavor).

It’s a strong Arctic front. Hopefully, the record will fall.

The week 2-3 forecast on the CFSv2 (-3.5 degree C average anomaly) could be overdone. It’s an outlier relative to the other guidance.

Back on October 30, Social Media contained a forecast for an exceptionally cold pattern to lock in. https://www.americanwx.com/bb/topic/52511-autumn-2019-banter-thread/?do=findComment&comment=5338034 While there is always high uncertainty in the extended range, the probability of extreme patterns locking in for weeks at a time is relatively low (not zero, but low). Some examples include the exceptionally cold February of 2015 and the historically warm December of 2015. In general, one needs strong evidence to make such forecasts. At the time, the forecast state of the teleconnections argued against the outcome. Here's the forecast and the actual outcome: 11/16-30 temperatures for two select sites: NYC: 43.0° (2.3° below normal); ORD: Actual: 38.3° (0.6° above normal).

Ahead of another push of colder air, the temperature reached 50° in Central Park. Over the next 7-10 days, temperatures will exhibit wide variability. The ENSO Region 1+2 anomaly was +0.4°C and the Region 3.4 anomaly was +0.4°C for the week centered around November 27. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.43°C and the ENSO Region 3.4 anomaly has averaged +0.62°C. These recent conditions are consistent with a weak El Niño. Nevertheless, a neutral ENSO remains the base case for Winter 2019-20. The SOI was +4.00 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.967. No significant stratospheric warming appears likely through December 15. Wave 2 activity is forecast to remain suppressed and the stratosphere is forecast to remain cold through mid-month on the EPS. According to NCEP, the correlation of 16-day 10 mb GFS temperature forecasts is near 0.25 (much worse than flipping a coin). 5 mb forecasts have an even lower correlation. On December 5, the MJO was in Phase 2 at an amplitude of 0.630 (RMM). The December 4-adjusted amplitude was 0.485. After a generally cold first week of December, warmer conditions will likely return. There is a chance that the second week of December could see one or more days with much above normal readings topping out in the 50s and perhaps even near 60° in the northern Mid-Atlantic region. Nevertheless, cold shots will continue to occur on a periodic basis. Moreover, the third week of the month could turn colder and possibly for a more sustained period of time, especially if the EPO goes negative. Despite the periodic cold shots and possible longer-duration period of cold, no snowstorms appear likely through at least the next 7-14 days in much of the region. Lake effect regions, upstate New York, and northern New England could see additional accumulations. The possibility could also exist for rain to end as a period of snow or flurries as storms depart and colder air returns. When it comes to New York City's 4" or greater snowstorms the PNA is more important than the AO during the first half of December. Since 1950, December 1-15 has seen 10 storms bring 4.0" or more snow to New York City. 50% occurred with an AO- or AO+. However, 80% occurred when the PNA was positive. All 6" or greater snowstorms during this timeframe occurred when the PNA was positive. The December 1-3 storm occurred with a negative PNA and Central Park received 1.6" snow. During the second half of December, larger snowstorms have occurred with a negative PNA.

He may have misspoke. Fortunately, the 1.6” figure is listed in the climate record.

From the ECMWF's Copernicus Program: Globally, November 2019 was one of the three warmest Novembers on record, differing only marginally from November 2015 and 2016. Most land areas saw above average temperatures, with the exception of much of the eastern USA and Canada and a central Asian region extending from Siberia to the Iranian coast. Europe saw an autumn (September-November) temperature 1.1°C above the 1981-2010 average, a value that since at least 1979 has been exceeded only in 2006, 2015 and 2018. https://climate.copernicus.eu/surface-air-temperature-november-2019

Despite partly sunny skies, readings remained below normal across the Middle Atlantic and southern New England regions today. A brisk breeze added to the chill. The ENSO Region 1+2 anomaly was +0.4°C and the Region 3.4 anomaly was +0.4°C for the week centered around November 27. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.43°C and the ENSO Region 3.4 anomaly has averaged +0.62°C. These recent conditions are consistent with a weak El Niño. Nevertheless, a neutral ENSO remains the base case for Winter 2019-20. The SOI was -8.15 today. Today, the preliminary Arctic Oscillation (AO) figure was +2.366. Daily MJO data has continued to be unavailable. Model initializations can provide a general idea of the MJO's progression and amplitude. After a generally cold first week of December, warmer conditions will likely return. There is a chance that the second week of December could see one or more days with much above normal readings topping out in the 50s and perhaps even near 60° in the northern Mid-Atlantic region. Nevertheless, cold shots will continue to occur on a periodic basis. Moreover, the third week of the month could turn colder and possibly for a more sustained period of time, especially if the EPO goes negative. Despite the periodic cold shots and possible longer-duration period of cold, no snowstorms appear likely through at least the next 7-14 days in much of the region. Lake effect regions, upstate New York, and northern New England could see additional accumulations. When it comes to New York City's 4" or greater snowstorms the PNA is more important than the AO during the first half of December. Since 1950, December 1-15 has seen 10 storms bring 4.0" or more snow to New York City. 50% occurred with an AO- or AO+. However, 80% occurred when the PNA was positive. All 6" or greater snowstorms during this timeframe occurred when the PNA was positive. The December 1-3 storm occurred with a negative PNA and Central Park received 1.6" snow. During the second half of December, larger snowstorms have occurred with a negative PNA.

Under cloudy skies readings remained in the upper 30s and lower 40s across much of the Mid-Atlantic region. The ENSO Region 1+2 anomaly was +0.4°C and the Region 3.4 anomaly was +0.4°C for the week centered around November 27. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.43°C and the ENSO Region 3.4 anomaly has averaged +0.62°C. These recent conditions are consistent with a weak El Niño. Nevertheless, a neutral ENSO remains the base case for Winter 2019-20. The SOI was -3.95 today. Today, the preliminary Arctic Oscillation (AO) figure was +2.722. Stratospheric temperatures remain below normal at both 10 mb and 30 mb in the Arctic region. No significant warming event is likely through at least December 13. Daily MJO data has continued to be unavailable. Model initializations can provide a general idea of the MJO's progression and amplitude. After a generally cold first week of December, warmer conditions will likely return. There is a chance that the second week of December could see one or more days with much above normal readings topping out in the 50s and perhaps even near 60° in the northern Mid-Atlantic region. However, the third week of the month could turn colder. There has been growing consensus toward a return of colder air on the guidance. It remains uncertain whether the cold will be transient or sustained for a period of time. Should the AO stay mainly positive or strongly positive, such cold shots would have an increased likelihood of proving relatively short-lived. When it comes to New York City's 4" or greater snowstorms the PNA is more important than the AO during the first half of December. Since 1950, December 1-15 has seen 10 storms bring 4.0" or more snow to New York City. 50% occurred with an AO- or AO+. However, 80% occurred when the PNA was positive. All 6" or greater snowstorms during this timeframe occurred when the PNA was positive. The December 1-3 storm occurred with a negative PNA and Central Park received 1.6" snow. During the second half of December, larger snowstorms have occurred with a negative PNA.

I saw that the figure was reduced from the 7.1” (preliminary data summary) to 5.9”. The storm was really impressive around the Albany area.

The daily climate report issued at 5:08 pm lists 1.6" for the December total snowfall.

Overall, my forecast for the recent storm was a bad one. The worst outcomes were in the southern and western edge of the snowfall (Allentown and Philadelphia). Later and farther east development of the upper-level low contributed to this outcome. The historic tendency related to the PNA held true for the greater New York City area with 4" or more snowfalls during the first half of December being uncommon when the PNA is negative, as was the case this time around. Snowfall estimates and verification: Albany: 12"-18"; Total snowfall: 20.1" Allentown: 4"-8"; Total snowfall: Trace Binghamton: 8"-16"; Total Snowfall: 10.7" (within range) Boston: 5"-10"; Total Snowfall: 7.1" (within range) Bridgeport: 2"-4" (high uncertainty); Total snowfall: 2.8" (within range) Hartford: 6"-12"; Total snowfall: 16.4" Islip: 1"-3"; Total snowfall: 1.9" (within range) New York City: 3"-6"; Total snowfall: 1.6" Newark: 3"-6"; Total snowfall: 2.4" Philadelphia: 3"-6" (high uncertainty); Total snowfall: Trace Providence: 4"-8"; Total Snowfall: 5.5" (within range) Worcester: 8"-16"; Total snowfall: 17.0" In the wake of yesterday's snowfall, brilliant sunshine accompanied by a cold breeze prevailed. Overnight and tomorrow, a weak disturbance could touch off a few snow flurries and snow showers. The ENSO Region 1+2 anomaly was +0.4°C and the Region 3.4 anomaly was +0.4°C for the week centered around November 27. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.43°C and the ENSO Region 3.4 anomaly has averaged +0.62°C. These recent conditions are consistent with a weak El Niño. Nevertheless, a neutral ENSO remains the base case for Winter 2019-20. The SOI was +9.08 today. Today, the preliminary Arctic Oscillation (AO) figure was +3.059. That is the highest figure since March 29, 2019 when the AO was +3.149. Daily MJO data has continued to be unavailable. Model initializations can provide a general idea of the MJO's progression and amplitude. After a generally cold first week of December, warmer conditions will likely return. There is a chance that the second week of December could see one or more days with much above normal readings topping out in the 50s and perhaps even near 60° in the northern Mid-Atlantic region. However, the third week of the month could turn colder. There has been growing consensus toward a return of colder air on the guidance. When it comes to New York City's 4" or greater snowstorms the PNA is more important than the AO during the first half of December. Since 1950, December 1-15 has seen 10 storms bring 4.0" or more snow to New York City. 50% occurred with an AO- or AO+. However, 80% occurred when the PNA was positive. All 6" or greater snowstorms during this timeframe occurred when the PNA was positive. The December 1-3 storm occurred with a negative PNA and Central Park received 1.3" snow. During the second half of December, larger snowstorms have occurred with a negative PNA.

The New York Botanical Garden following the early December snowfall:

December (4.1° below normal in NYC) and January (0.9° below normal in NYC) were colder than normal in the region. February was exceptionally warm (Central Park set a monthly mean temperature record of 42.0° which surpassed the 41.6° average set just a year earlier).

No. I believe there will be transient cold shots and perhaps one or more opportunities for snowfall. Whether the closing week of the month turns colder remains to be seen.

Heaviest snow of the evening in Larchmont near the Long Island Sound.

East Grenville had 25.2” as of the last PNS.

A storm continues to bring some snow to the region this evening. Storm total accumulations include: Albany: 17.3"; Binghamton: 10.6"; Bridgeport: 0.7"; East Glenville, NY: 25.2"; Hartford: 5.5"; Highland Lakes, NJ: 10.5"; Islip: 0.2"; New York City: 1.0"; and, Newark: 1.4". The ENSO Region 1+2 anomaly was +0.4°C and the Region 3.4 anomaly was +0.4°C for the week centered around November 27. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.43°C and the ENSO Region 3.4 anomaly has averaged +0.62°C. These recent conditions are consistent with a weak El Niño. Nevertheless, a neutral ENSO remains the base case for Winter 2019-20. The SOI was +6.80 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.749. The preliminary PNA value was -0.108. Daily MJO data was unavailable. Outgoing long-wave radiation is currently unavailable according to Australia's Bureau of Meteorology (BOM). The BOM is working on the issue. After a generally cold first week of December, warmer conditions will likely return. There is a chance that the second week of December could see one or more days with much above normal readings topping out in the 50s and perhaps even near 60° in the northern Mid-Atlantic region. Overall, December will likely finish somewhat warmer than normal to warmer than normal across the region. When it comes to New York City's 4" or greater snowstorms the PNA is more important than the AO during the first half of December. Since 1950, December 1-15 has seen 10 storms bring 4.0" or more snow to New York City. 50% occurred with an AO- or AO+. However, 80% occurred when the PNA was positive. All 6" or greater snowstorms during this timeframe occurred when the PNA was positive. During the second half of December, larger snowstorms have occurred with a negative PNA.