donsutherland1

I was referring to today. That was yesterday’s 12z run. Both today’s 0z and 12z runs dropped the storm.

While the GFS is largely on its own with this idea, it should be noted that during winter 1972-73, Columbia, SC picked up 16.0" snow on February 9-10. That winter, just 2.8" snow fell in New York City and only a trace was recorded in Philadelphia.

On GISS, January 2020 was the warmest January on record globally. The temperature anomaly was +1.18°C, which was narrowly above the previous record of +1.17°C from 2016.

Temperatures were falling through the 20s this evening in the northern Middle Atlantic region. The minimum temperature tomorrow morning could fall into the teens in New York City and Philadelphia. Readings in the lower teens and perhaps single digits are likely outside both cities. But then winter's latest effort to take hold will fail again. Warmer air will quickly return. It is likely that the second half of February will be warmer than normal overall. During that time, cold shots will likely be of a short duration. Consistent with the pattern and supported by most of the guidance, no significant snowfalls (6" or more) are likely in the major Middle Atlantic cities through at least the first three weeks of February. There is a greater but still fairly low probability for Boston to see such a snowstorm. Winter 2019-2020 became the 19th winter on record that saw New York City receive less than 6" seasonal snowfall through February 14. Mean total snowfall for the 18 prior cases was 12.5" vs. the historic mean figure of 28.8". In addition, 39% of such winters wound up with less than 10" seasonal snowfall vs. 6% of winters in the historic record. 89% of such winters wound up with less than 20" seasonal snowfall vs. 31% of winters in the historic record. Just 11% of such winters wound up with 30" or more seasonal snowfall vs. 41% of winters in the historic record. The ENSO Region 1+2 anomaly was +0.8°C and the Region 3.4 anomaly was +0.2°C for the week centered around February 5. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.22°C and the ENSO Region 3.4 anomaly has averaged +0.48°C. The remainder of winter 2019-2020 will likely feature neutral-warm to weak El Niño conditions. The SOI was -17.05 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.686. No significant stratospheric warming is likely through February 22, but the upper stratosphere above 3 mb will likely be warm. Wave 2 activity will remain relatively suppressed. Overall, most of the stratosphere is forecast to remain cold on the EPS into the third week of February. On February 13, the MJO was in Phase 6 at an amplitude of 1.234 (RMM). The February 12-adjusted amplitude was 1.122. Based on sensitivity analysis applied to the latest guidance, there is an implied 89% probability that New York City will have a warmer than normal February and an implied 55% probability that February 2020 will be among the 10 warmest such months on record. Finally, a sizable majority (>80%) of years during which the AO has been, on average, strongly positive during the first 15 days of February were followed by a warmer than normal March. The preliminary February 1-12 AO average is +2.926. Recent rapid warming in ENSO Region 1+2 has also typically preceded a warmer than normal March and spring in the Middle Atlantic region.

A very warm winter has had a higher frequency of warm summers in Philadelphia. Based on data from winters 1873-74 to the 2018-19, the historic summer average temperature was 74.9°. Warm summers were as follows: Above the historic mean: 45% 1° or more above the historic mean: 25% 2° or more above the historic mean: 12% In the 19 cases where the December-February mean temperature was 38.0° or above (2019-20 was averaging 39.6° through 2/13), the mean summer temperature was 76.1°. Warm summers were as follows: Above the historic mean: 79% (1.8X the historic frequency) 1° or more above the historic mean: 53% (2.1X the historic frequency) 2° or more above the historic mean: 32% (2.6X the historic mean and more frequent than the historic figure for 1° or more above the historic mean) All said, if the above data is representative, summer 2020 will likely be warmer and possibly much warmer than normal. The evolution of ENSO will have an important impact.

Winter 2019-2020 is just the 7th winter on record that has seen Philadelphia receive less than 2" seasonal snowfall through February 14. Mean total snowfall for the 6 prior cases was 3.8" vs. the historic mean figure of 22.6". In addition, 100% of such winters wound up with less than 10" seasonal snowfall vs. 16% of winters in the historic record. The snowiest case from those prior winters was 1931-32 with 8.0" seasonal snowfall. Below is a chart that illustrates mean and +/- 3 sigma cumulative snowfall amounts based on the 0.3" that has fallen to date for those six cases. The 3 sigma upper limit based on those 6 cases is 11.3". Statistically, there would be a 1-in-741 chance that this value would be reached or exceeded. *-The - sigma value has been constrained to that it cannot fall below the 0.3" seasonal snowfall to date. That value would imply no measurable snowfall for the remainder of winter 2019-2020.

An insightful video (h/t Mark Boslough):

It should be noted that since winter 1869-70, there is only 1 case where seasonal snowfall through February was less than 10" and March had an 8" or greater snowfall in New York City: 1956. Seasonal snowfall through February 1956 was 8.2". The February 1956 AO average was -2.029. The second lowest figure was 10.8" in 1981 (February AO: -0.331).

The temperature fell to 16 degrees on December 19.

The President's Day snowstorm was the highlight of a remarkably cold winter. Almost the entire CONUS was colder to much colder than normal.

At 7 pm EST, the temperature was 10° in Chicago, 19° in Detroit, 33° in Pittsburgh, 43° in New York City,and 47° in Philadelphia. The cold that has now moved into the Great Lakes region will be pushing into the region overnight. As a result, readings will be much below normal tomorrow and on Saturday. The lowest temperatures on Saturday morning could fall into the teens in New York City and Philadelphia. Readings in the lower teens and perhaps single digits are likely outside both cities. But then winter's latest effort to take hold will fail again. Warmer air will quickly return. It is likely that the second half of February will be warmer than normal overall. During that time, cold shots will likely be of a short duration. Consistent with the pattern and supported by most of the guidance, no significant snowfalls (6" or more) are likely in the major Middle Atlantic cities through at least the first three weeks of February. There is a greater but still fairly low probability for Boston to see such a snowstorm. On this date in 2014, Philadelphia received a daily record 10.4" snowfall. This winter, the city is mired in a deepening snow drought. Winter 2019-2020 is just the 7th winter on record that saw Philadelphia receive less than 2" seasonal snowfall through February 13. Mean total snowfall for the 6 prior cases was 3.8" vs. the historic mean figure of 22.6". In addition, 100% of such winters wound up with less than 10" seasonal snowfall vs. 16% of winters in the historic record. The snowiest case from those prior winters was 1931-32 with 8.0" seasonal snowfall. The ENSO Region 1+2 anomaly was +0.8°C and the Region 3.4 anomaly was +0.2°C for the week centered around February 5. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.22°C and the ENSO Region 3.4 anomaly has averaged +0.48°C. The remainder of winter 2019-2020 will likely feature neutral-warm to weak El Niño conditions. The SOI was -12.49 today. Today, the preliminary Arctic Oscillation (AO) figure was +1.860. No significant stratospheric warming is likely through February 21, but the upper stratosphere above 3 mb will likely be warm. Wave 2 activity will remain relatively suppressed. Overall, most of the stratosphere is forecast to remain cold on the EPS into the third week of February. On February 12, the MJO was in Phase 6 at an amplitude of 1.121 (RMM). The February 11-adjusted amplitude was 1.211. Based on sensitivity analysis applied to the latest guidance, there is an implied 84% probability that New York City will have a warmer than normal February and an implied 50% probability that February 2020 will be among the 10 warmest such months on record. Finally, a sizable majority (>80%) of years during which the AO has been, on average, strongly positive during the first 15 days of February were followed by a warmer than normal March. The preliminary February 1-12 AO average is +2.926. Recent rapid warming in ENSO Region 1+2 has also typically preceded a warmer than normal March and spring in the Middle Atlantic region.

Philadelphia had measurable snowfall in January 1979 (first was 1/5 when 1.2" fell). The February days with measurable snowfall were as follows: 2/7 7.6" 2/12 4.8" 2/14 0.4" 2/15 0.3" 2/16 0.2" 2/18 0.4" 2/19 13.9"

The NOAA also reported that January 2020 was the warmest January on record globally. https://www.ncdc.noaa.gov/sotc/global/202001

On February 9, 2020, a record temperature of 20.75 degrees C (69.35 degrees F) was recorded on Antarctica's Seymour Island. https://www.theguardian.com/world/2020/feb/13/antarctic-temperature-rises-above-20c-first-time-record

Winter 2019-2020 became the 7th winter on record that saw Philadelphia receive less than 2" seasonal snowfall through February 12. Mean total snowfall for the 6 prior cases was 3.8" vs. the historic mean figure of 22.6". In addition, 100% of such winters wound up with less than 10" seasonal snowfall vs. 16% of winters in the historic record. The snowiest case from those prior winters was 1931-32 with 8.0" seasonal snowfall. Winter 2019-2020 is also only the 3rd winter on record to receive less than 1" seasonal snowfall through February 12. The others were 1972-73 (0.0") and 1997-98 (0.7").

Tomorrow will very likely see temperatures top out in the 50s in much of the Middle Atlantic region. However, a brief shot of modified Arctic air will move into the region for Friday and Saturday. The lowest temperatures could fall into the teens in New York City and lower teens and perhaps single digits outside the City. Afterward, warmer air will quickly return. It is likely that the February 15-21 period will be warmer than normal overall. Any cold shots would likely be of a short duration. The general above normal temperature regime could persist afterward. Consistent with the pattern and supported by most of the guidance, no significant snowfalls (6" or more) are likely in the major Middle Atlantic cities through at least the first three weeks of February. There is a greater but still fairly low probability for Boston to see such a snowstorm. The ENSO Region 1+2 anomaly was +0.8°C and the Region 3.4 anomaly was +0.2°C for the week centered around February 5. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.22°C and the ENSO Region 3.4 anomaly has averaged +0.48°C. The remainder of winter 2019-2020 will likely feature neutral-warm to weak El Niño conditions. The SOI was -9.03 today. Today, the preliminary Arctic Oscillation (AO) figure was +3.286. No significant stratospheric warming is likely through February 20, but the upper stratosphere above 5 mb will likely warm toward mid-February. Wave 2 activity will remain relatively suppressed. Overall, most of the stratosphere is forecast to remain cold on the EPS into the third week of February. On February 11, the MJO was in Phase 5 at an amplitude of 1.204 (RMM). The February 10-adjusted amplitude was 1.540. Based on sensitivity analysis applied to the latest guidance, there is an implied 86% probability that New York City will have a warmer than normal February and an implied 56% probability that February 2020 will be among the 10 warmest such months on record. Finally, a sizable majority (>80%) of years during which the AO has been, on average, strongly positive during the first 15 days of February were followed by a warmer than normal March. The preliminary February 1-12 AO average is +2.926. Recent rapid warming in ENSO Region 1+2 has also typically preceded a warmer than normal March and spring in the Middle Atlantic region.

I hope we don't get buried in pollen.

Good news: Climate scientist Brian Brettschneider's Twitter account has been restored to full functionality.

The ridging across Europe teleconnects to troughs in the Middle East and Northern Africa during the winter.

I don’t know. The factors responsible for the seasonal AO state remain uncertain. The recent extreme North Atlantic storms have played a recent role.

3.8” at JFK. MPO hasn’t measured snow since 1988-89. Up to then, its lowest seasonal snowfall was 22.1” during winter 1954-55.

Recent paper on the 2018-19 SSW event: https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/wea.3643

Another warmer than normal day and more signs of spring. The coming cold shot will be short-lived and warmer than normal conditions should quickly return. Photo courtesy of my brother in Mamaroneck, NY from a short time ago:

Morning thoughts... While attention has been fixed on the record-setting AO+ regime that saw the AO reach a preliminary all-time record of +6.342, another development that has occurred in the eastern Pacific has increased the probability of a warmer than normal March. That development also suggests that any snowfall in the Middle Atlantic region after February could be limited. ENSO Region 1+2 has warmed dramatically over the past two weeks. During the week centered around January 22, the ENSO Region 1+2 anomaly was -0.2°C and for January 2020 it was -0.04°C. During the most recent period (week centered around February 5), that anomaly had risen to +0.8°C. Both the 2/12/2020 0z EPS and GEFS suggest that the AO will return to extremely positive values near or above +4.000 around February 20. In addtion, based on the outcomes following the 1989 and 1990 super AO+ regimes in February and assuming a secondary peak at extremely positive values (+4.000 or above) around February 20 +/- a few days, March will likely begin with a noted absence of blocking in the AO+ region. The evolution of the February AO+ regime would argue that the AO would likely remain positive for much of March. During the 1981-2019 period, there were seven cases where the February ENSO Region 1+2 anomaly increased by +0.5° over the January average: 1989, 1991, 2002, 2006, 2008, 2011, and 2012. Five (71%) of those cases had an AO+ to end February and start March: 1989, 2002, 2008, 2011, and 2012. The March composite 500 mb and temperature anomalies for those five cases are below: Mean March-April snowfall for New York City for those five cases was 0.7" (skewed by 2.5" in March-April, 1989) and 0.5" in Philadelphia (skewed by 2.4" in March-April 1989).

Israel’s biggest snowfalls usually occur with an AO+.