donsutherland1

That was the monthly total. The biggest storm was 6.0”.

The 0z ECMWF showed a blockbuster snowfall from eastern Pennsylvania into New England (again). This time, the storm was kicked a few days into the future and was centered around March 14th. In response, 240-hour snow maps are already popping up like mushrooms after a summer thunderstorm on Social Media. Some reminders: 1. Much can change between now and then as the models work through the synoptic details. Almost certainly, there will be some significant changes. 2. Ensemble support is currently modest albeit with a few members showing a major storm (one shows a borderline historic storm). 3. Model consensus does not currently exist and run-to-run continuity has not been established. 4. Historic experience argues for extra caution. Since 1884-85, there were 19 previous winters that saw less than 10" of snow through February in New York City and Philadelphia. None saw a 10" snowstorm in either city during March. Just one saw March come out with 10" or more total snowfall in New York City. Select Data for those Winters: New York City: Mean March Snowfall: 3.5" Median March Snowfall: 2.5" Highest March Snowfall: 17.1", 1890 Philadelphia: Mean March Snowfall: 2.3" Median March Snowfall: 2.1" Highest March Snowfall: 5.8", 1890 and 1932 History is not a guarantee and the sample size is modest. It does provide some insight that asserts the importance of being cautious about jumping prematurely on extended range solutions, especially in a winter that has seen one failure after another in the snowfall department. In addition, the modeled evolution for the March 10-12 timeframe--the ECMWF's most recent try at a big snowstorm--illustrates the need for caution. For several 0z runs, the operational ECMWF had 10" or more snow in both New York City and Philadelphia (peaking at 10" in Philadelphia and 24" in New York City). Run-to-run continuity was very poor with the 12z runs shattering the dreams built from the 0z cycle. The overwhelming share of EPS members were always below 4". That potential event now appears poised to be a mostly rain event. Now, a single run of the ECMWF--again at the seemingly notorious 0z cycle--shows a massive snowstorm for both cities a few days later. Given the four points above, one should wait until there is strong support, model consensus, and good run-to-run continuity. Will this time be different? Perhaps. But a lot more data will be needed. Any firm call at this time is simple speculation in the near-absence of sufficient data. It is a largely-uninformed guess, though Twitter and other Social Media platforms have nothing that distinguishes between an informed assessment and a wild guess. In most cases, such gambles fail, as relying on near random chance to ride to the rescue of a speculative guess in the absence of underlying support is typically futile.

First one.

Not all snow. For the City, some mixing. The National Blend of Models, which peaked at barely over an inch now shows 0.1" for the City (for Central Park, that likely means a trace).

Morning thoughts… Snow will end and the clouds will yield to sunshine. High temperatures will reach the middle and upper 40s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 45° Newark: 47° Philadelphia: 49° Somewhat cooler than normal to near seasonable readings will likely prevail through the remainder of the week. Normals: New York City: 30-Year: 46.9°; 15-Year: 47.4° Newark: 30-Year: 48.0°; 15-Year: 48.6° Philadelphia: 30-Year: 49.6°; 15-Year: 49.9°

A clipper system will bring some light rain changing to snow to parts of the region, especially from northern New Jersey southward. Snowfall amounts will 1"-2". Central Park will likely see around 0.5". Little or no accumulation is possible north of New York City. Amounts could still be somewhat higher or lower in the City given how close it will be to the heaviest precipitation. Following the clipper, it will become somewhat cooler tomorrow ahead of the development of a colder regime that will very likely commence later this week. At present, no severe March cold appears likely. However, the March 13-20 timeframe could be the month's coldest week with temperatures averaging 4°- 7° below normal for the week. The colder regime will gradually fade afterward, but could through the closing week of March. Potential storminess around the March 11-12 timeframe will need to be monitored. There is the potential for at least some snowfall in New York City, Newark, and Philadelphia. Considerable uncertainty persists, but the picture should become clearer near or just after midweek. Historic experience with very low snowfall totals through February argues that a very snowy March or big snowstorm during March or April are unlikely. Despite attractive 500 mb patterns, the base case is that at least through March 10th, snowfall will likely be below normal from Philadelphia to New York City. For further historical perspective, there were 16 winters that had less than 8" of snowfall through February in New York City. Just two (13%) had a 6" or greater snowstorm during March or April: 1889-1890: 6.0" on March 19th and 1991-1992: 6.2" on March 19th. Historical perspective argues for caution when the operational models are popping big snowstorms into and out of existence like quantum particles in the extended range. The ENSO Region 1+2 anomaly was +0.4°C and the Region 3.4 anomaly was -0.3°C for the week centered around February 22. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.25°C and the ENSO Region 3.4 anomaly has averaged -0.50°C. La Niña conditions fading and they should evolve to neutral conditions during late winter or early spring. The SOI was +0.53 today. The preliminary Arctic Oscillation (AO) was -2.340 today. On March 4 the MJO was in Phase 7 at an amplitude of 3.111 (RMM). The March 3-adjusted amplitude was 2.219 (RMM).

That would be great if the needed 0.7" falls.

The latest ECMWF weeklies are not as cold for March 13-20 as they were last week. 3/2: 3/6:

The 3/5 0z ECMWF had it. Hopefully, the more wrapped up ensemble members will prove to be correct. There's still plenty of time left.

The last time it occurred at Central Park was way back in 1967.

No. NYC has never gone below zero in March since regular recordkeeping began in 1869. The March record of 3° was set on March 5, 1872.

Yes. It should be over before sunrise. JFK: 3/18-19: 3.2”; 3/22: 3.7” LGA: 3/18-19: 6.6”; 3/22: 3.6” NYC: 3/18-19: 6.2”; 3/22: 3.2”

It's going to be a close call for the City. I think the high-resolution models will tell the story, especially the 18z and 0z runs. My initial thoughts are that that accumulating snow would grave the City. Measurable amounts in Central Park will be a close call, as it is plausible that JFK, Brooklyn, Queens, and Staten Island see some accumulations while the Park falls just short.

Morning thoughts… Today will be partly sunny and mild. High temperatures will reach the lower and middle 50s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 52° Newark: 54° Philadelphia: 55° It will become somewhat cooler tomorrow. Normals: New York City: 30-Year: 46.6°; 15-Year: 47.1° Newark: 30-Year: 47.7°; 15-Year: 48.3° Philadelphia: 30-Year: 49.3°; 15-Year: 49.6°

3/6 0z EPS Members: Notes: 1. The operational ECMWF did not go wild at 0z for the first time in 3 0z runs 2. A focus on ensembles over the operational guidance is useful as uncertainty remains considerable 3. In the next 24-72 hours, the picture should be much clearer Below is an illustration of what things should look like when the ensembles lock in on a potential event. This chart is from the late February event that saw 1.8" fall at Central Park.

Milder weather returned today. Temperatures surged into the 50s across the region and approached 60° in southeastern Pennsylvania. Tomorrow will be another mild day A colder regime will develop starting later this week. At present, no severe March cold appears likely. However, the March 13-20 timeframe could be the month's coldest week with temperatures averaging 5°- 8° below normal for the week. The colder regime will gradually fade afterward, but could last into or even through the closing week of March. The operational ECMWF has been oscillating wildly on a run-to-run basis in terms of snowfall for the northern Mid-Atlantic region for the March 10-12 period: March 3 12z: New York City: 1"; Philadelphia: 0" March 4 0z: New York City: 12"; Philadelphia: 10" March 4 12z: New York City: 0"; Philadelphia: 0" March 5 0z: New York City: 24"; Philadelphia: 10" March 5 12z: New York City: 4"; Philadelphia: 1" These heart-stopping swings signal a volatile period with high potential that could either bring great joy to the snow-starved region or massive heartbreak. Extreme solutions should be discounted without strong and sustained support. Instead, until run-to-run continuity improves, one should focus on developments on the ensembles, especially as historic experience has not been kind. Historic experience with very low snowfall totals through February argues that a very snowy March or big snowstorm during March or April are unlikely. Despite attractive 500 mb patterns, the base case is that at least through March 10th, snowfall will likely be below normal from Philadelphia to New York City. For further historical perspective, there were 16 winters that had less than 8" of snowfall through February in New York City. Just two (13%) had a 6" or greater snowstorm during March or April: 1889-1890: 6.0" on March 19th and 1991-1992: 6.2" on March 19th. Historical perspective argues for caution when the operational models are popping big snowstorms into and out of existence like quantum particles in the extended range. The ENSO Region 1+2 anomaly was +0.4°C and the Region 3.4 anomaly was -0.3°C for the week centered around February 22. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.25°C and the ENSO Region 3.4 anomaly has averaged -0.50°C. La Niña conditions fading and they should evolve to neutral conditions during late winter or early spring. The SOI was -4.55 today. The preliminary Arctic Oscillation (AO) was -1.640 today. On March 3 the MJO was in Phase 7 at an amplitude of 2.208 (RMM). The March 2-adjusted amplitude was 1.841 (RMM).

In terms of the extreme forecast made for NYC to average 5° below normal for March 1-April 15, the needed anomaly for the remainder of the period has increased to 6.0° below normal.

Morning thoughts… Today will be partly sunny and noticeably milder. High temperatures will reach the lower and middle 50s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 53° Newark: 55° Philadelphia: 59° The mild weather will continue tomorrow. Normals: New York City: 30-Year: 46.4°; 15-Year: 46.8° Newark: 30-Year: 47.4°; 15-Year: 48.0° Philadelphia: 30-Year: 49.0°; 15-Year: 49.2°

EPS Snowfall amounts for New York City and last four runs of the operational ECMWF for New York City and Philadelphia:

In the wake of the storm that brought heavy rain and coastal flooding to the region overnight into today, milder weather will follow tomorrow and continue into early next week. Afterward, it will turn more seasonable for a time. A colder regime will develop during the second week of the March. At present, no severe March cold appears likely. However, the March 13-20 timeframe could be the month's coldest week with temperatures averaging 5°- 8° below normal for the week. The colder regime will gradually fade afterward, but could last into or even through the closing week of March. Historic experience with very low snowfall totals through February argues that a very snowy March or big snowstorm during March or April are unlikely. Despite attractive 500 mb patterns, the base case is that at least through March 10th, snowfall will likely be below normal from Philadelphia to New York City. For further historical perspective, there were 16 winters that had less than 8" of snowfall through February in New York City. Just two (13%) had a 6" or greater snowstorm during March or April: 1889-1890: 6.0" on March 19th and 1991-1992: 6.2" on March 19th. Historical perspective argues for caution when the operational models are popping big snowstorms into and out of existence like quantum particles in the extended range. The ENSO Region 1+2 anomaly was +0.4°C and the Region 3.4 anomaly was -0.3°C for the week centered around February 22. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +0.25°C and the ENSO Region 3.4 anomaly has averaged -0.50°C. La Niña conditions fading and they should evolve to neutral conditions during late winter or early spring. The SOI was +0.19 today. The preliminary Arctic Oscillation (AO) was +0.186 today. On March 2 the MJO was in Phase 7 at an amplitude of 1.836 (RMM). The March 1-adjusted amplitude was 1.389 (RMM).

Yes. This year’s figure is 1.7”.

1.6”.

No. NYC is now at 2.2”. The record is 2.8” during 1972-73.

Morning thoughts… Rain will end and clouds could break late in the day. High temperatures will reach the middle and upper 40s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 47° Newark: 49° Philadelphia: 51° It will turn milder on tomorrow. Normals: New York City: 30-Year: 46.1°; 15-Year: 46.5° Newark: 30-Year: 47.1°; 15-Year: 47.7° Philadelphia: 30-Year: 48.7°; 15-Year: 48.9°

EPS ensembles for the March 10-12 period: