donsutherland1

A milder pattern will commence this weekend. Overall, the final 10 days of December will likely have above normal temperatures, with perhaps a few somewhat cooler days. Whether or not there will be any snow in parts of the region during that time remains to be seen. Colder air could return during the first week of January. The progression of the MJO in concert with the teleconnections could be crucial in determining whether most of North America's cold air stays bottled up north of the Canada-U.S. border beyond the first week of January or comes south and eastward into the region just after the start of 2020. In the southern Hemisphere, Australia's historic December heat wave, which saw the nationwide maximum temperature average 41.9°C (107.4°F) on Wednesday crested with a national December record high temperature of 49.9°C (121.8°F) at Nullarbor earlier today. The previous December record, which was set on December 24, 1972 was 49.5°C (121.1°F) at Birdsville Police Station. At Marble Bar, the minimum temperature was 34.5°C (94.1°F). That was the second highest minimum temperature ever recorded anywhere in Australia during December. A cold front has now pushed north and east through southern Australia, breaking the extreme heat that had been baking the country since early this week. In addition, parts of central and eastern Europe experienced record warmth earlier today. At Linz, Austria, the temperature reached 63°, which surpassed the previous December record high temperature of 60°. The ENSO Region 1+2 anomaly was +0.5°C and the Region 3.4 anomaly was +0.5°C for the week centered around December 4. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.05°C and the ENSO Region 3.4 anomaly has averaged +0.53°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 -8.46 today. Today, the preliminary Arctic Oscillation (AO) figure was -1.051. No significant stratospheric warming event appears likely through December 29, but some warming above 3 mb could develop near the end of the forecast period. Moderate Wave 2 activity could occur after December 20, likely leading to some upper stratospheric warming. Overall, most of the stratosphere is forecast to remain cold into the closing days of December on the EPS. On December 19, the MJO was in Phase 4 at an amplitude of 0.546 (RMM). The December 18-adjusted amplitude was 0.615. Based on sensitivity analysis applied to the latest guidance, there is an implied near 50% probability that December will wind up colder than normal in New York City.

Australia's Bureau of Meteorology reported regarding yesterday: Based on preliminary analysis, yesterday, Australia recorded its hottest day on record. The nationally-averaged maximum daytime temp was 41.9 °C exceeding the record set on Tuesday, 40.9 ºC. 40.9°C is 105.6°F. 41.9°C is 107.4°F. The highest temperature anywhere in Australia yesterday was 47.7°C (117.9° F) at Birdsville Airport. The national December record is 49.5°C (121.1°F), which was set on December 24, 1972 at Birdsville Police Station. Australia's hottest temperature on record is 50.7°C (123.3°F), which was set on January 2, 1960 at Oodnadatta Airport.

Despite ample sunshine, most of the region saw its coldest December temperatures since December 31, 2017. Select low temperatures included: Boston: 15° (lowest since March 7); Bridgeport: 17° (lowest since March 8); Islip: 17° (lowest since December 8); New York City: 16° (lowest since February 2); Newark: 16° (lowest since March 7); and, Philadelphia: 19° (lowest since March 7). Beginning this weekend, a milder pattern will commence. Overall, the final 10 days of December will likely have above normal temperatures, with perhaps a few somewhat cooler days. Colder air could return during the first week of January. However, some of the guidance has shifted away from that idea. The progression of the MJO in concert with the teleconnections could be crucial in determining whether most of North America's cold air stays bottled up north of the Canada-U.S. border beyond the first week of January or comes south and eastward into the region just after the start of 2020. The ENSO Region 1+2 anomaly was +0.5°C and the Region 3.4 anomaly was +0.5°C for the week centered around December 4. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.05°C and the ENSO Region 3.4 anomaly has averaged +0.53°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 -6.90 today. Today, the preliminary Arctic Oscillation (AO) figure was -1.408. No significant stratospheric warming event appears likely through December 28, but some warming above 3 mb could develop near the end of the forecast period. Moderate Wave 2 activity could occur after December 20, likely leading to some upper stratospheric warming. Overall, most of the stratosphere is forecast to remain cold into the closing days of December on the EPS. On December 18, the MJO was in Phase 4 at an amplitude of 0.621 (RMM). The December 17-adjusted amplitude was 0.769. Based on sensitivity analysis applied to the latest guidance, there is an implied 54% probability that December will wind up colder than normal in New York City. That probability has fallen sharply in recent days, as the guidance has made large adjustments to the warmer side for the final seven days of December.

Central Park was also reporting light snow despite no radar returns.

An Arctic front moved across the region this afternoon triggering snow showers and even snow squalls that coated the ground in places. Following the frontal passage, parts of the region will likely experience their lowest temperatures so far this season. New York City will likely see the temperature fall into the middle or upper teens tomorrow morning with a high temperature only in the middle and perhaps upper 20s. The ENSO Region 1+2 anomaly was +0.5°C and the Region 3.4 anomaly was +0.5°C for the week centered around December 4. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.05°C and the ENSO Region 3.4 anomaly has averaged +0.53°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 -7.94 today. Today, the preliminary Arctic Oscillation (AO) figure was -1.376. No significant stratospheric warming event appears likely through December 27, but some warming above 3 mb could develop near the end of the forecast period. Moderate Wave 2 activity could occur after December 20, likely leading to some upper stratospheric warming. Overall, most of the stratosphere is forecast to remain cold into the middle of the fourth week of December on the EPS. On December 17, the MJO was in Phase 3 at an amplitude of 0.770 (RMM). The December 16-adjusted amplitude was 0.850. For the December 20-27 period overall, the temperature in such cities as Washington, Philadelphia, and New York will likely average above normal despite the cold start to the period. There is a chance that colder air could return near the end of December or the beginning of January. Based on sensitivity analysis applied to the latest guidance, there is an implied 56% probability that December will wind up colder than normal in New York City.

Some photos of the ice this morning:

It's a difficult situation. Externalities e.g., the cost of carbon emissions and their consequences, aren't captured in the pricing mechanism of fossil fuels. That's part of the reason at least some economists favor a carbon tax. In addition, certain governments have little or no meaningful commitment to addressing the great challenge of climate change (or even recognition of the science). Yet, the time left to avoid making what amounts to an almost irrevocable commitment via emissions to temperature increases above 2.0 degrees C or 1.5 degrees C is shrinking.

Thanks for this information. The 12/13-16 data has now been pulled and replaced by "M." Given the temperatures at Sitka, I suspect based on what you found and the lower temperatures there than a few days ago, the sensor was, in fact, malfunctioning.

I don't think such a model is practical given the risks that such power could be abused given human nature as it is. However, the issue of ignorant leaders or those who put narrow interests (e.g., Russia and oil) ahead of even serious global challenges are a real problem.

I believe I was quoting Vice Regent. We agree about living in a more sustainable way. The former almost certainly won't be broadly supported. The latter could and should be.

A widespread 0.10"-0.25" freezing rain event affected areas just to the north and west of New York City earlier today. Parts of eastern Pennsylvania, northwestern New Jersey, New York State, and Connecticut picked up 0.30" or more freezing rain. Some freezing rain totals included: Allentown: 0.29"; Bridgeport: 0.39"; Center Valley, PA: 0.50"; Highland Lakes, NJ: 0.30"; Islip: 0.19"; Monroe, NY: 0.44"; Stockholm (1 WNW), NJ: 0.40"; and, Westhampton: 0.19". In the wake of the departing ice storm, a short but sharp shot of cold will push into the region tomorrow, possibly accompanied by snow showers and even a snow squall. Tomorrow night, parts of the region could experience the lowest temperatures so far this season. New York City will likely see the temperature fall into the middle or upper teens Thursday morning with a high temperature only in the middle 20s. The ENSO Region 1+2 anomaly was +0.5°C and the Region 3.4 anomaly was +0.5°C for the week centered around December 4. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.05°C and the ENSO Region 3.4 anomaly has averaged +0.53°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 -13.44 today. Today, the preliminary Arctic Oscillation (AO) figure was -1.370. No significant stratospheric warming event appears likely through December 26, but some warming above 2 mb could develop near the end of the forecast period. Moderate Wave 2 activity could occur after December 20, likely leading to some upper stratosphere warming. Overall, most of the stratosphere is forecast to remain cold into the middle of the fourth week of December on the EPS. On December 16, the MJO was in Phase 3 at an amplitude of 0.849 (RMM). The December 15-adjusted amplitude was 1.127. For the December 20-27 period overall, the temperature in such cities as Washington, Philadelphia, and New York could average somewhat above normal despite the cold start to the period. There is a chance that colder air could return near the end of December. The potential for a full-fledged Arctic outbreak could be available during the first week in January if some of the guidance has correctly forecast the pattern evolution heading into January. Based on sensitivity analysis applied to the latest guidance, there is an implied 62% probability that December will wind up colder than normal in New York City.

Five photos from today’s ice storm: Larchmont, NY New Rochelle, NY Bronx, NY Bronx, NY Bronx, NY

It's not far from Van Cortlandt Park. From there northward into Yonkers, there was quite a bit of ice. Farther south and east, the ice was much less.

Bronx, NY: 32° with freezing rain

Your location shows as Bolton Landing. Probably 1"-3" snow with 2"-4" in the Albany area. White Plains less than one inch and then sleet/freezing rain (probably 0.10"-0.20" freezing rain).

Sleet is currently falling in Larchmont, NY.

Variability will likely continue to define to weather into the closing week of December. As a result, much of the region could see perhaps additional snowfall through December 26, along with periodic intrusions of cold air. A short but sharp shot of cold will follow the system that will impact the region tonight into tomorrow with snow, sleet, freezing rain and rain. Parts of the region could experience the lowest temperatures so far this season. New York City will likely see the temperature fall below 20° with one day where the high temperature remains in the middle or upper 20s. Another window of opportunity snowfall could be available during the December 21-23 timeframe. During that time, the Arctic Oscillation (AO) is forecast to be negative. However, some of the latest guidance now shows a weakly positive NAO in combination with a negative PNA. As a result, the synoptic pattern looks less promising than it did a few days ago. Since 1950, 33% of storms that brought 4" or more snow during December 16-31 to just one city from among Philadelphia, New York City, or Boston had an AO- and 19% had an AO-/NAO-. However, from among the storms that brought 4" or more snow to at least two of those cities, 77% occurred with an AO- and 54% occurred with an AO-/NAO-. For the December 20-27 period overall, the temperature in such cities as Washington, Philadelphia, and New York could average somewhat above normal despite the cold start to the period. The ENSO Region 1+2 anomaly was +0.5°C and the Region 3.4 anomaly was +0.5°C for the week centered around December 4. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.05°C and the ENSO Region 3.4 anomaly has averaged +0.53°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 -15.00 today. Today, the preliminary Arctic Oscillation (AO) figure was -0.986. No significant stratospheric warming event appears likely through December 25. Wave 2 activity is forecast to remain relatively weak. Overall, the stratosphere is forecast to remain cold into the middle of the fourth week of December on the EPS. On December 15, the MJO was in Phase 3 at an amplitude of 1.130 (RMM). The December 14-adjusted amplitude was 1.292. Differences for the closing days of December between the EPS and GEFS are narrowing. Consistent with the colder idea having prevailed more often than not since late autumn, the EPS has begun to move toward a colder solution for the end of December. When it comes to New York City's 4" or greater snowstorms during the second half of December, the AO is highly important. Since 1950, December 16-31 has seen 15 storms bring 4.0" or more snow to New York City. 73% occurred with an AO-. Further, 80% of the 6" or greater snowstorms during this timeframe occurred when the AO was negative. Even as the PNA and NAO had a lesser impact on the 4" or greater snowstorms, an NAO- was present in 70% of the 6" or greater snowstorms during that timeframe and a PNA+ was also present during 70% of the 6" or greater snowstorms. Based on sensitivity analysis applied to the latest guidance, there is an implied 63% probability that December will wind up colder than normal in New York City.

The high temperatures at Yakutat, Alaska for the past three days and for today (preliminary value) were: December 13: 56° (old record: 49°, 2017) December 14: 58° (old record: 49°, 2017) December 15: 61° (old record: 48°, 2005) December 16: 57° (old record: 50°, 2005) All four days exceeded the previous December record high temperature of 52°, which had been set on December 8, 1960. The 61° temperature yesterday broke the meteorological winter record of 58°, which was set on January 19, 1930 and tied on December 14, 2019 and was also above the November monthly record of 59°, which was set on November 1, 1947. Prior to yesterday, the latest 60° temperature on record occurred on October 13, 1969 when the temperature reached 60°. Daily records go back to May 1, 1917.

It's beginning to feel a lot like... spring?

According to the GISS dataset, November 2019 ranked as the second warmest November on record with a +1.02°C anomaly. Only 2015 with a +1.06°C anomaly was warmer. As a result, 2019 has a year-to-date anomaly of +0.97°C, which is the second warmest at this point in time. 2019 is extremely likely to wind up as the second warmest year on record on that dataset. To wind up cooler than 2017 (+0.92°C annual anomaly), which currently ranks as the second warmest year on record, December would need a temperature anomaly of +0.37°C. The last month with a temperature anomaly of +0.37°C or less was January 2008, which had a temperature anomaly of +0.30°C. The last time December was at least as cool occurred in 2000 when the monthly anomaly was +0.28°C. The coolest anomaly so far this year is +0.86°C, which occurred in May.

Yes. It's possible. It will be interesting to see how things evolve this afternoon and evening.

Winter Forecast Update... Over the past 6 weeks, the ENSO Region 3.4 anomaly had averaged +0.53°C. Gradual cooling of that region is forecast for the remainder of the winter. As a result, the base case idea of a neutral-warm ENSO remains on track. At the same time, the cool anomaly in ENSO Region 1+2 has largely disappeared (-0.05°C average anomaly over the past 6 weeks). Persistent warmth in this region could have an adverse impact on seasonal snowfall in parts of the eastern United States. The NAO had been positive for 100% of the first 15 days of December before falling to -0.069 on December 16. The core assumption of a predominantly positive NAO remains on track. During the December 1-15 period, the Arctic Oscillation (AO) averaged +1.584 with a peak figure of +3.059on December 3. Nevertheless, a portion of the northern Middle Atlantic and southern New England regions had colder than normal temperatures on average. Since 1950, there were 13 prior cases where the AO averaged +1.000 or above during the first fifteen days of December. Such outcomes have typically been followed by somewhat less than normal snowfall in parts of the Great Lakes Region, Middle Atlantic States, and southern New England. These figures are modestly below those in the winter idea posted at the beginning of this thread. However, the differences are sufficiently small to suggest that the overall idea remains on track. What could lead to higher snowfall amounts: 1. Prolonged deep blocking (AO of -1.000 or below) 2. The MJO's persistently being in Phases 7, 8, 1 and 2 at a high amplitude 3. The ENSO Region 3.4 anomaly falling to somewhat negative values as the winter progresses 4. A mainly negative NAO What could lead to lower snowfall amounts: 1. A persistently positive AO coupled with a strongly negative SOI 2. The MJO's persistently being in Phases 4, 5, and 6 at a high amplitude 3. Dramatic warming in ENSO Region 1+2

The latest guidance suggests the potential for significant freezing rain not too far north and west of New York City. Based on the latest guidance, it is likely that an area stretching from West Milford, NJ across White Plains and to Danbury could pick up 0.10" to 0.25" freezing rain with the potential for more, especially in northwestern New Jersey. Some of the local media outlets (radio forecasts I heard coming into work this morning) are downplaying the freezing rain risk (the specific mention concerned not more than a few hundredths of an inch). However, those outlets may be using dated guidance and/or relying on the much warmer GFS to reach a conclusion that understates risk of icing. The 3 km NAM, 12 km NAM, and RGEM are very aggressive, both with amounts and the southern extent of the freezing rain.

I don't think one can be certain about how much of the needed CO2 can be absorbed. IMO, until the risks are better understood, society should probably avoid such approaches unless absolutely necessary.

Such a geoengineering approach, not withstanding other risks that may or may not be known, would only capture a fraction of the annual CO2 emissions per year (around one-eighth). That assumes one could produce enough iron sulfate for maximum effect. https://www.theguardian.com/environment/2012/jul/18/iron-sea-carbon