donsutherland1

As of 3:05 pm, Richmond had picked up 1.29" rain today. That broke the daily rainfall record of 0.85", which was set in 1964.

The biggest rainfall in several months and possibly within the past year for parts of the region is now poised to affect the New York City area. Areas of moderate rain were advancing to the north and west of the region with moderate rain recently falling at Allentown. Farther south, rain has been falling heavily in Washington, DC and Baltimore for the past 1-2 hours. As of 1:39 pm, Washington, DC had picked up 1.09" rain. The daily record there is 1.38", which was set in 2002.

The heaviest precipitation in several months appears likely for parts of the region tomorrow into Thursday. A general 1.00"-2.00" rainfall now appears likely. Some areas, especially on Long Island, will likely see even higher amounts. The last time New York City received 1.00" or more rain in a day was August 22 when 1.01" fell. The last time New York City picked up 1.50" rain in a day was July 22 when 1.66" fell. The last time New York City received 2.00" or more rain in a day was August 11, 2018 when 2.90" fell. Following the storm, cooler weather will give way to another round of warmer than normal temperatures. The last week of October will likely start mild but end with a cool shot. The cool conditions could linger into the first few days of November, but overall the cool shot will likely be transient in nature, not the start of a long-duration cold pattern. The ENSO Region 1+2 anomaly was -1.0°C and the Region 3.4 anomaly was +0.4°C for the week centered around October 9. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.88°C and the ENSO Region 3.4 anomaly has averaged +0.12°C. The strong cooling that took place in Region 1+2 during September indicates that the prospects for a neutral-cool ENSO during the winter have increased. A neutral ENSO is currently the base case for Winter 2019-20. The SOI was -13.60 today. Today, the preliminary Arctic Oscillation (AO) figure was +0.044. Since 1950, there have been five prior cases when the AO averaged -0.500 or below in both July and August: 1950, 1958, 1960, 1968, and 2015. The average temperature for September through November in New York City was 58.9° (59.6° adjusted). All cases featured a warmer than normal fall. The potential for autumn 2019 to rank among the 30 warmest cases on record has increased in recent weeks. For New York City, that would translate into a September-November mean temperature of at least 58.8°. In August, the AO averaged -0.722 and in September the AO rose to +0.306. The possible transition to predominantly positive values from September into October has been a relatively uncommon occurrence. Since 1950, only 1963 and 2011 saw a transition of an August value of -0.500 or below to positive values in September and a positive average in October. Both cases featured a warmer than normal November in the Middle Atlantic and southern New England areas. On October 14, the MJO was in Phase 1 at an amplitude of 1.285 (RMM). The October 13-adjusted amplitude was 1.333. In the two prior cases when the MJO moved into Phase 1 in late September or early October and then remained in Phase 1 for 12 or more consecutive days as occurred this year, the average decline in the 14-day average temperature for the 2-3 weeks that followed the MJO's moving out of Phase 1 was gradual. The current long-duration Phase 1 episode suggests that the second half of October could be warmer than normal. For New York City, an October mean temperature of 58.5°-59.5° (1.6° to 2.6° above normal) would be implied by those earlier long-duration Phase 1 cases. Based on the sensitivity analysis, the estimated October mean temperature is currently near 59.5°. Based on sensitivity analysis applied to the latest guidance, the implied probability of New York City having a warmer than normal October is approximately 78%. Finally, Arctic sea ice extent on JAXA was 4.943 million square kilometers on October 14. That was the latest sub-5 million square kilometer extent on record. The previous latest date was October 13.

Usually, that's the case.

Not in this case. The closer low is forecast to rapidly deepen. In most cases, the offshore low is dominant and/or deepening, pulling the moisture offshore.

One is dealing with dual centers. On the 0z ECMWF, between hours 48 and 51, a developing second center crosses western/central Long Island while another center is offshore. The second center rapidly intensifies and reaches just under 980 mb over Rhode Island and continues north-northeastward into eastern New Hampshire by 60 hours. The offshore center passes southeast of Nantucket and then into the Gulf of Maine from 54 hours to 60 hours. JFK has received 39.07" precipitation, which is 4.89" above normal for this time of year.

The recent dry spell has led to New York City's precipitation having fallen below normal on a year-to-date basis. In addition, the implied probability of New York City's seeing 50" or more precipitation this year has decreased to 45%. However, there is strong model consensus that the region will likely experience its biggest rainstorm in several months as a strong nor'easter moves across western Long Island into New England. Widespread 1"-2" rainfall amounts with local amounts in excess of 3" appears likely tomorrow into Thursday. Below is a summary of the precipitation status for select cities:

Much of the region experienced bright sunshine and readings in the 70s today. The heaviest precipitation in several months appears likely for parts of the region Wednesday into Thursday. For New York City, 84% of the EPS members show 1.00" or more precipitation; 71% show 1.50" or more precipitation; and, 41% show 2.00" or more. Therefore, a general 1.00"-2.00" rainfall now appears likely. Some areas, especially on Long Island, will likely see even higher amounts. The last time New York City received 1.00" or more rain in a day was August 22 when 1.01" fell. The last time New York City picked up 1.50" rain in a day was July 22 when 1.66" fell. The last time New York City received 2.00" or more rain in a day was August 11, 2018 when 2.90" fell. Following the storm, cooler weather will give way to another round of warmer than normal temperatures. The last week of October will likely start mild but end with a cool shot. The cool conditions could linger into the first days of November, but overall the cool shot will likely be transient in nature, not the start of a long-duration cold pattern. The ENSO Region 1+2 anomaly was -1.0°C and the Region 3.4 anomaly was +0.4°C for the week centered around October 9. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.88°C and the ENSO Region 3.4 anomaly has averaged +0.12°C. The strong cooling that took place in Region 1+2 during September indicates that the prospects for a neutral-cool ENSO during the winter have increased. A neutral ENSO is currently the base case for Winter 2019-20. The SOI was -5.74 today. Today, the preliminary Arctic Oscillation (AO) figure was +0.654. Since 1950, there have been five prior cases when the AO averaged -0.500 or below in both July and August: 1950, 1958, 1960, 1968, and 2015. The average temperature for September through November in New York City was 58.9° (59.6° adjusted). All cases featured a warmer than normal fall. The potential for autumn 2019 to rank among the 30 warmest cases on record has increased in recent weeks. For New York City, that would translate into a September-November mean temperature of at least 58.8°. In August, the AO averaged -0.722 and in September the AO rose to +0.306. The possible transition to predominantly positive values from September into October has been a relatively uncommon occurrence. Since 1950, only 1963 and 2011 saw a transition of an August value of -0.500 or below to positive values in September and a positive average in October. Both cases featured a warmer than normal November in the Middle Atlantic and southern New England areas. On October 13, the MJO was in Phase 8 at an amplitude of 1.334 (RMM). The October 12-adjusted amplitude was 1.225. In the two prior cases when the MJO moved into Phase 1 in late September or early October and then remained in Phase 1 for 12 or more consecutive days as occurred this year, the average decline in the 14-day average temperature for the 2-3 weeks that followed the MJO's moving out of Phase 1 was gradual. The current long-duration Phase 1 episode suggests that the second half of October could be warmer than normal. For New York City, an October mean temperature of 58.5°-59.5° (1.6° to 2.6° above normal) would be implied by those earlier long-duration Phase 1 cases. Based on the sensitivity analysis, the estimated October mean temperature is currently 59.2°. Based on sensitivity analysis applied to the latest guidance, the implied probability of New York City having a warmer than normal October is approximately 74%. Finally, on account of very slow ice growth, Arctic sea ice extent for October 13 was a daily record low figure of 4.881 million square kilometers. There is a chance that today's figure will be the latest ever figure under 5 million square kilometers.

Under crystal clear skies and brilliant sunshine, the temperature soared into the lower 70s today. Even as the calendar has advanced deeper into autumn, the day had almost a late September feel to it. The Monarch migration remained well underway.

On JAXA, Arctic sea ice extent was 4,880,849 square kilometers on October 13. That figure is now below the 2012 extent for the same date. In 2012, Arctic sea ice extent was 4,911,701 square kilometers.

Unseasonably mild weather will prevail into midweek. Afterward, a short period of cooler weather will be followed by another warmer pattern for the southern New England areas. This cooler weather will likely coincide with a mid-week system that could bring much of the region 0.50"-1.50" rain with locally higher amounts. The last time New York City received 1.00" or more rain in a day was August 22 when 1.01" fell. The last time New York City picked up 1.50" rain in a day was July 22 when 1.66" fell. After August 22, New York City has picked up just 2.26" rain in total. The last week of October will likely start mild but end with a cool shot. The cool shot will likely be transient in nature. The ENSO Region 1+2 anomaly was -0.6°C and the Region 3.4 anomaly was +0.5°C for the week centered around October 2. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.78°C and the ENSO Region 3.4 anomaly has averaged +0.02°C. The strong cooling that took place in Region 1+2 during September indicates that the prospects for a neutral-cool ENSO during the winter have increased. Since 1991 when weekly ENSO region data was available, five years have seen September record two or more weeks with -1.0°C or cooler weekly anomalies in Region 1+2: 1996, 1999, 2007, 2010, and 2017. 4/5 (80%) of those cases went on to feature warm December-February temperature anomalies in the Middle Atlantic and southern New England regions. Those cases include La Niña winters. However, the larger pool of neutral-cool ENSO winters, many of which predate the weekly ENSO regional data, have often featured frequent Atlantic blocking. For now, there is a mixed winter signal. The SOI was +8.12 today. Today, the preliminary Arctic Oscillation (AO) figure was +0.957. Since 1950, there have been five prior cases when the AO averaged -0.500 or below in both July and August: 1950, 1958, 1960, 1968, and 2015. The average temperature for September through November in New York City was 58.9° (59.6° adjusted). All cases featured a warmer than normal fall. The potential for autumn 2019 to rank among the 30 warmest cases on record has increased in recent weeks. For New York City, that would translate into a September-November mean temperature of at least 58.8°. In August, the AO averaged -0.722 and in September the AO rose to +0.306. The possible transition to predominantly positive values from September into October has been a relatively uncommon occurrence. Since 1950, only 1963 and 2011 saw a transition of an August value of -0.500 or below to positive values in September and a positive average in October. Both cases featured a warmer than normal November in the Middle Atlantic and southern New England areas. On October 12, the MJO was in Phase 8 at an amplitude of 1.226 (RMM). The October 11-adjusted amplitude was 1.143. In the two prior cases when the MJO moved into Phase 1 in late September or early October and then remained in Phase 1 for 12 or more consecutive days as occurred this year, the average decline in the 14-day average temperature for the 2-3 weeks that followed the MJO's moving out of Phase 1 was gradual. The current long-duration Phase 1 episode suggests that the second half of October could be warmer than normal. For New York City, an October mean temperature of 58.5°-59.5° (1.6° to 2.6° above normal) would be implied by those earlier long-duration Phase 1 cases. The first week of November and possibly beyond could be warmer than normal overall. Based on sensitivity analysis applied to the latest guidance, the implied probability of New York City having a warmer than normal October is approximately 78%.

October 29, 1971 when the temperature hit 80.

2005-06. 40.0”

It is typically a signal of a warmer winter. Since 1980, the following has occurred in New York City when both October and November were warmer than normal: Succeeding winter: Colder than normal: 3/13 (23%) cases Near normal: 1/13 (8%) cases Warmer than normal: 9/13 (69%) cases Breakdown of months: December: Colder than normal: 4/13 (31%) months Warmer than normal: 9/13 (69%) months January: Colder than normal: 2/13 (15%) months Warmer than normal: 11/13 (85%) months February: Colder than normal: 2/13 (15%) months Warmer than normal: 11/13 (85%) months December-February: Colder than normal months: 8/39 (21%) months Warmer than normal months: 31/39 (79%) months The snowfall signal was mixed. Mean: 24.2" Median: 24.9" Lowest: 3.5", 2001-02 Highest: 61.9", 2010-11 <10": 2/13 (15%) cases < 20": 5/13 (38%) cases 20" or more: 8/13 (62%) cases 30" or more: 5/13 (31%) cases 40" or more: 2/13 (15%) cases

Unseasonably mild weather will prevail through Columbus Day. Afterward, a short period of cooler weather will be followed by another warmer pattern for the southern New England areas. This cooler weather will likely coincide with a mid-week system that could bring much of the region 0.50"-1.00" rain with locally higher amounts. The last week of October will likely be mild, but a cool shot could occur at some point. The GFS remains most aggressive. The cool shot will likely be transient. The ENSO Region 1+2 anomaly was -0.6°C and the Region 3.4 anomaly was +0.5°C for the week centered around October 2. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.78°C and the ENSO Region 3.4 anomaly has averaged +0.02°C. The strong cooling that took place in Region 1+2 during September indicates that the prospects for a neutral-cool ENSO during the winter have increased. Since 1991 when weekly ENSO region data was available, five years have seen September record two or more weeks with -1.0°C or cooler weekly anomalies in Region 1+2: 1996, 1999, 2007, 2010, and 2017. 4/5 (80%) of those cases went on to feature warm December-February temperature anomalies in the Middle Atlantic and southern New England regions. Those cases include La Niña winters. However, the larger pool of neutral-cool ENSO winters, many of which predate the weekly ENSO regional data, have often featured frequent Atlantic blocking. For now, there is a mixed winter signal. The SOI was +4.45 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.305. Since 1950, there have been five prior cases when the AO averaged -0.500 or below in both July and August: 1950, 1958, 1960, 1968, and 2015. The average temperature for September through November in New York City was 58.9° (59.6° adjusted). All cases featured a warmer than normal fall. The potential for autumn 2019 to rank among the 30 warmest cases on record has increased in recent weeks. For New York City, that would translate into a September-November mean temperature of at least 58.8°. On October 11, the MJO was in Phase 8 at an amplitude of 1.144 (RMM). The October 10-adjusted amplitude was 1.277. In the two prior cases when the MJO moved into Phase 1 in late September or early October and then remained in Phase 1 for 12 or more consecutive days as occurred this year, the average decline in the 14-day average temperature for the 2-3 weeks that followed the MJO's moving out of Phase 1 was gradual. The current long-duration Phase 1 episode suggests that the second half of October could be warmer than normal. For New York City, an October mean temperature of 58.5°-59.5° (1.6° to 2.6° above normal) would be implied by those earlier long-duration Phase 1 cases. In August, the AO averaged -0.722 and in September the AO rose to +0.306. The possible transition to predominantly positive values from September into October has been a relatively uncommon occurrence. Since 1950, only 1963 and 2011 saw a transition of an August value of -0.500 or below to positive values in September and a positive average in October. Both cases featured a warmer than normal November in the Middle Atlantic and southern New England areas. Based on the latest extended guidance, the first week of November and possibly beyond could be warmer than normal overall. Based on sensitivity analysis applied to the latest guidance, the implied probability of New York City having a warmer than normal October is approximately 74%.

Both Central Park and LGA reached 78° on November 3. JFK reached 75°. Newark had a high temperature of 79°. So, 1990 came close, but just missed.

Clouds parted and it was a partly to mostly sunny afternoon at the New York Botanical Garden. Temperatures rose into the middle 60s. Four photos:

The slow recovery is certainly disconcerting. Unfortunately, there's still a lot of room for discovery when it comes to ice-related dynamics. FWIW, below is the difference between 2019 and 2012 in Arctic Sea Ice Extent for the past 7 days (2019 - 2012): 10/4 607,225 square kilometers 10/5 527,475 square kilometers 10/6 459,846 square kilometers 10/7 426,436 square kilometers 10/8 336,167 square kilometers 10/9 231,673 square kilometers 10/10 182,153 square kilometers 2019's slow ice growth relative to the faster recovery following 2012's record low figure may yet lead to 2019 falling below 2012's extent, especially as the Arctic was notably colder at this time in 2012 than it is today.

Yesterday, 7.1" snow fell in Bismarck. That easily surpassed the previous daily record for October 10 of 2.3" from 1959. Today, an additional 6.1" fell, surpassing the daily record of 1.6" from 1909. The 13.2" total is the earliest snowfall of at least a foot on record for Bismarck. The previous record was October 28-29, 1991 when 15.9" snow fell. In addition, 5 of the 6 12" or greater snowstorms (including the current storm) that occurred on or before November 30 took place after 1980. Record low temperatures were also set in parts of the West. Records included: Colorado Springs: 9° (old record: 14°, 1946); Denver: 9° (old record: 22°, 1946); Laramie, WY: 3° (old record: 9°, 1977); and, Pocatello, ID: 14° (old record: 19°, 2003). After mid-month, a warmer pattern will likely develop and then, following perhaps a transient shot of cold, could still lock in throughout the Middle Atlantic and southern New England areas. The last week of October will likely be unseasonably mild. The ENSO Region 1+2 anomaly was -0.6°C and the Region 3.4 anomaly was +0.5°C for the week centered around October 2. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.78°C and the ENSO Region 3.4 anomaly has averaged +0.02°C. The strong cooling that took place in Region 1+2 during September indicates that the prospects for a neutral-cool ENSO during the winter have increased. Since 1991 when weekly ENSO region data was available, five years have seen September record two or more weeks with -1.0°C or cooler weekly anomalies in Region 1+2: 1996, 1999, 2007, 2010, and 2017. 4/5 (80%) of those cases went on to feature warm December-February temperature anomalies in the Middle Atlantic and southern New England regions. Those cases include La Niña winters. However, the larger pool of neutral-cool ENSO winters, many of which predate the weekly ENSO regional data, have often featured frequent Atlantic blocking. For now, there is a mixed winter signal. The SOI was -4.32 today. Today, the preliminary Arctic Oscillation (AO) figure was +0.535. Since 1950, there have been five prior cases when the AO averaged -0.500 or below in both July and August: 1950, 1958, 1960, 1968, and 2015. The average temperature for September through November in New York City was 58.9° (59.6° adjusted). All cases featured a warmer than normal fall. The potential for autumn 2019 to rank among the 30 warmest cases on record has increased in recent weeks. For New York City, that would translate into a September-November mean temperature of at least 58.8°. On October 10, the MJO was in Phase 8 at an amplitude of 1.281 (RMM). The October 9-adjusted amplitude was 1.200. In the two prior cases when the MJO moved into Phase 1 in late September or early October and then remained in Phase 1 for 12 or more consecutive days as occurred this year, the average decline in the 14-day average temperature for the 2-3 weeks that followed the MJO's moving out of Phase 1 was gradual. The current long-duration Phase 1 episode suggests that the second half of October could be warmer than normal. For New York City, an October mean temperature of 58.5°-59.5° (1.6° to 2.6° above normal) would be implied by those earlier long-duration Phase 1 cases. Based on sensitivity analysis applied to the latest guidance, the implied probability of New York City having a warmer than normal October is approximately 70%. 　

While that's probably not the most likely scenario, it is a possibility sometime after mid-October if things turn out a little warmer than currently shown on the guidance. November would be less likely, as such readings are relatively rare.

Yesterday, 7.1" snow fell in Bismarck. That easily surpassed the previous daily record for October 10 of 2.3" from 1959. In addition, it was the earliest daily snowfall of 6" or more on record. The prior record was established on October 23, 1991.

The following was posted on Twitter: https://twitter.com/BigJoeBastardi/status/1182331950318718978 While technically true, that is not a good use of the CFSv2. Several points are in order: First, the CFSv2 monthly forecasts are not typically skillful until 5-7 days out. Second, within 6 days, the CFSv2 had highlighted the potential for cold anomalies in the northern Rockies and Northern Plains. October 1-8, 2019 Temperature Anomalies: Third, if one applied the logic used to dismiss the CFSv2, which is not always accurate, it would be tantamount to judging the ECMWF's failure to forecast a significant storm from 5-days out when its forecasts from 72 hours and less were accurate. In general, there can be benefit to waiting for additional data before reaching conclusions. Model verification scores closer to events bear that out. Setting artificial cut-offs that deprive one of later data generally increases one's forecasting error.

On account of the nor'easter's taking a track farther offshore than modeled, much of the region enjoyed a partly to mostly sunny day with readings in the upper 60s and lower 70s. Eastern New England and eastern Long Island experienced cloudy and windy conditions with at least some rain. Heavy rain affected Nantucket. Meanwhile, a strong taste of winter prevailed in the Northern Plains. Snow was falling across the Dakotas. Blizzard conditions were likely in a portion of North Dakota. Record cold also affected parts of the northwestern United States. Record low temperatures included: Cut Bank, MT: -3° (old record: 3°, 2009); Great Falls, MT: 0° (old record: 4°, 2009); Olympia, WA: 26° (old record: 27°, 1972); Pocatello, ID: 16° (old record: 18°, 1985); Quillayute, WA: 28° (old record: 31°, 1983 and 2008); Seattle: 34° (tied record set in 1946); and, Yakima, WA: 21° (old record: 24°, 2009). Farther east, this air mass will likely result in only a transient shot of cold. After mid-month, a warmer pattern will likely develop and then could lock in throughout the Middle Atlantic and southern New England areas. The last week of October will likely be unseasonably mild. The ENSO Region 1+2 anomaly was -0.6°C and the Region 3.4 anomaly was +0.5°C for the week centered around October 2. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.78°C and the ENSO Region 3.4 anomaly has averaged +0.02°C. The strong cooling that took place in Region 1+2 during September indicates that the prospects for a neutral-cool ENSO during the winter have increased. Since 1991 when weekly ENSO region data was available, five years have seen September record two or more weeks with -1.0°C or cooler weekly anomalies in Region 1+2: 1996, 1999, 2007, 2010, and 2017. 4/5 (80%) of those cases went on to feature warm December-February temperature anomalies in the Middle Atlantic and southern New England regions. Those cases include La Niña winters. However, the larger pool of neutral-cool ENSO winters, many of which predate the weekly ENSO regional data, have often featured frequent Atlantic blocking. For now, there is a mixed winter signal. The SOI was -9.35 today. Today, the preliminary Arctic Oscillation (AO) figure was +0.612. During the July 1-August 31 period, the AO was negative on 56/62 (90%) days. Since September 1, the AO has been positive on 29/40 (73%) days. Since 1950, there have been five prior cases when the AO averaged -0.500 or below in both July and August: 1950, 1958, 1960, 1968, and 2015. The average temperature for September through November in New York City was 58.9° (59.6° adjusted). All cases featured a warmer than normal fall. The potential for autumn 2019 to rank among the 30 warmest cases on record has increased in recent weeks. For New York City, that would translate into a September-November mean temperature of at least 58.8°. The latest EPS weeklies show a return to warm anomalies in the East after mid-October, likely following a brief cool shot, as does the extended range of the EPS. The unseasonable warmth could roll into the start of November. On October 9, the MJO was in Phase 8 at an amplitude of 1.203 (RMM). The October 8-adjusted amplitude was 1.313. In the two prior cases when the MJO moved into Phase 1 in late September or early October and then remained in Phase 1 for 12 or more consecutive days as occurred this year, the average decline in the 14-day average temperature for the 2-3 weeks that followed the MJO's moving out of Phase 1 was gradual. The current long-duration Phase 1 episode suggests that the second half of October could be warmer than normal. For New York City, an October mean temperature of 58.5°-59.5° (1.6° to 2.6° above normal) would be implied by those earlier long-duration Phase 1 cases. Based on sensitivity analysis applied to the latest guidance, the implied probability of New York City having a warmer than normal October is approximately 62%.

Through 1 pm, Nantucket had received 1.64". That surpassed the October 10 daily precipitation record of 1.15", which was set in 1971. So far, New York City eastward across most of Long Island has been dry. Nevertheless, rain is now backing westward across the Twin Forks.

At this point in time, ice was growing very quickly in 2012. Unless the rate of ice growth accelerates, 2019 could fall below 2012 within the next 5-7 days.