donsutherland1

Morning thoughts... At 8:05 am, pockets of snow, sleet, and freezing rain were moving north and eastward in central and southern Pennsylvania. That precipitation/will move into the region later this morning or early this afternoon. Today will be cloudy with periods of light snow, sleet, freezing rain, and rain developing. Minor accumulations are possible in New York City and Philadelphia (generally 1” or less). North and west of New York City, from the Hudson Valley into southern New England, 1”-3” snow is possible. East of a line running from Philadelphia to New York City, including Long Island, generally 0.5” or less of snow is likely. Temperatures will likely top out in the middle and upper 30s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 37° Newark: 38° Philadelphia: 39° Precipitation will end tomorrow morning.

Tomorrow into Wednesday morning, a weak system will come eastward bringing snow, sleet, freezing rain and rain to parts of the region. Snowfall amounts will be fairly light. Initial snowfall estimates include: Allentown: 2" or less Boston: 1"-3" Hartford: 1"-3" Islip: 0.5" or less New York City: 2" or less Newark: 1" or less Philadelphia: 1" or less Worcester: 2"-4" A few days later during January 28-29, another storm will impact parts of the East Coast. That storm will likely exit off the Southeast coast bringing some accumulating snow to parts of the Southeast and lower Middle Atlantic region, including the Richmond and Washington, DC areas. It now appears that the storm could develop too far offshore to produce an appreciable snowfall. AO-/PNA- patterns typically do not produce significant or major snowstorms for the Middle Atlantic or southern New England regions in late January or early February. During the January 20-February 7, 1950-2020 period, there have been 5 storms that brought 4" or more snow to at least two of the following cities--Boston, New York City, or Philadelphia--during an AO-/PNA- pattern. None of those storms brought 6" or more snow to two or more of those cities. Therefore, until the potential events are within 72 hours or less and the guidance suggests otherwise, the base case is against a widespread significant or major snowfall. Overall, the final week of January will feature generally below normal readings. The coldest air mass so far this season could bring the temperature below 20° in Central Park on one or two days late this week. The ensembles suggest that the PNA could briefly go positive near the end of the month and start of February. That could allow for the potential of a snow event during the February 1-2 period before milder air returns during the first week of February. Some of the guidance suggests that a period of much warmer than normal temperatures could develop for a time once the warmer air moves in. The ENSO Region 1+2 anomaly was -0.8°C and the Region 3.4 anomaly was -1.1°C for the week centered around January 20. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.85°C and the ENSO Region 3.4 anomaly has averaged -1.07°C. La Niña conditions will likely prevail at least through meteorological winter. The SOI was +10.13 today. Today, the preliminary Arctic Oscillation (AO) figure was -3.380. On January 24 the MJO was in Phase 6 at an amplitude of 1.900 (RMM). The January 23-adjusted amplitude was 1.766. Following a significant stratospheric warming event, the stratosphere is now cooling. The cooling will likely accelerate during the second half of January. As is typical for vortex-splitting events, the major piece of the polar vortex migrated to Eurasia. The end result has been an absence of severe cold in much of North America. The significant December 16-17 snowstorm during what has been a blocky December suggests that seasonal snowfall prospects have increased especially from north of Philadelphia into southern New England. At New York City, there is a high probability based on historic cases that an additional 20" or more snow will accumulate after December. Were blocking to disappear, snowfall prospects would diminish. Based on sensitivity analysis applied to the latest guidance, there is an implied 99% probability that New York City will have a warmer than normal January. January will likely finish with a mean temperature near 35.0°.

Probably midweek if the guidance remains as is.

The idea of a possible snow event during the February 1-2 period has some merit. First, there is a clustering of ensemble members around that timeframe. Second, that timeframe will coincide with a rise in the PNA to briefly positive levels allowing for a temporarily more favorable pattern. Having said that, it's too soon to lock in such an event, even as the probability is higher than climatology. It's also too soon to speculate as to potential impacts.

Morning thoughts... Today will be partly sunny and somewhat warmer than yesterday. Clouds will increase as the day progresses. Temperatures will likely top out in the middle and upper 30s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 36° Newark: 37° Philadelphia: 39° Tomorrow and tomorrow night, a weakening system will bring a light snowfall to parts of the region. An area running from Philadelphia to New York City remains in line for 1”-3” snow. Lesser amounts are likely to the east. A second larger storm will pass too far to the south and east to do more than graze much of the region. It increasingly appears that this storm will intensify too far off shore to bring a significant snowfall to the Middle Atlantic region.

Tomorrow will be dry and continued cold. On Tuesday into Tuesday night, a weakening system will come eastward bringing a swath of 1"-3" snowfall in an area running from Philadelphia to New York City and north and west of those areas. Areas just to the east of New York City could see little accumulation. A few days later during January 28-29, another storm will impact parts of the East Coast. That storm will likely exit off the Southeast coast bringing accumulating snow to parts of the Southeast and lower Middle Atlantic region. The heaviest snows could be focused on the Richmond to Washington, DC areas and eastward. That area could pick up light or moderate snowfall. As the storm rapidly intensifies offshore, it could still bring a period of heavy wind-swept snow to parts of eastern Virginia, Maryland's Eastern Shore, and extreme southeastern New Jersey. AO-/PNA- patterns typically do not produce significant or major snowstorms for the Middle Atlantic or southern New England regions in late January or early February. During the January 20-February 7, 1950-2020 period, there have been 5 storms that brought 4" or more snow to at least two of the following cities--Boston, New York City, or Philadelphia--during an AO-/PNA- pattern. None of those storms brought 6" or more snow to two or more of those cities. Therefore, until the potential events are within 72 hours or less and the guidance suggests otherwise, the base case is against a widespread significant or major snowfall. Overall, the final week of January will feature generally below normal readings. Milder temperatures will likely return during the first week of February. Some of the guidance suggests that a period of much warmer than normal temperatures could develop for a time. The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -1.2°C for the week centered around January 13. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.73°C and the ENSO Region 3.4 anomaly has averaged -1.08°C. La Niña conditions will likely prevail at least through meteorological winter. The SOI was +5.66 today. Today, the preliminary Arctic Oscillation (AO) figure was -2.462. On January 23 the MJO was in Phase 6 at an amplitude of 1.765 (RMM). The January 22-adjusted amplitude was 1.489. Following a significant stratospheric warming event, the stratosphere is now cooling. The cooling will likely accelerate during the second half of January. As is typical for vortex-splitting events, the major piece of the polar vortex migrated to Eurasia. The end result has been an absence of severe cold in much of North America. The significant December 16-17 snowstorm during what has been a blocky December suggests that seasonal snowfall prospects have increased especially from north of Philadelphia into southern New England. At New York City, there is a high probability based on historic cases that an additional 20" or more snow will accumulate after December. Were blocking to disappear, snowfall prospects would diminish. Based on sensitivity analysis applied to the latest guidance, there is an implied 99% probability that New York City will have a warmer than normal January. January will likely finish with a mean temperature near 35.3°.

Morning thoughts... Today will be partly sunny and cold. Temperatures will likely top out in the lower 30s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 32° Newark: 34° Philadelphia: 34° On Tuesday and Tuesday night, a weakening system will bring a light snowfall to parts of the region. An area running from Philadelphia to New York City appear to be in line for 1”-3” snow. Lesser amounts are likely to the east. Later this week, a second larger storm will pass too far to the south and east to do more than graze much of the region. That storm’s heaviest snow will likely occur in eastern Virginia, Maryland’s Eastern Shore, and extreme southeastern New Jersey.

Tomorrow will be another fair and cold day. Afterward, parts of the East could see one or two snowfall possibilities during the upcoming week. During January 25-27, a system coming eastward could bring a swath of 1"-3" snows from Philadelphia to New York City with a few locally higher amounts. The higher amounts would likely be confined to the west of both cities. Areas just to the east of New York City could see little accumulation. A few days later during January 28-29, another storm will impact parts of the East Coast. That storm will likely exit off the Southeast coast bringing accumulating snow to parts of the Southeast and lower Middle Atlantic region. The heaviest snows could be focused on the Richmond to Washington, DC areas and eastward. That area could pick up a moderate snowfall. As the storm rapidly intensifies offshore, it could bring a period of heavy wind-swept snow to parts of eastern Virginia, Maryland's Eastern Shore, and extreme southeastern New Jersey. AO-/PNA- patterns typically do not produce significant or major snowstorms for the Middle Atlantic or southern New England regions in late January or early February. During the January 20-February 7, 1950-2020 period, there have been 5 storms that brought 4" or more snow to at least two of the following cities--Boston, New York City, or Philadelphia--during an AO-/PNA- pattern. None of those storms brought 6" or more snow to two or more of those cities. Therefore, until the potential events are within 72 hours or less and the guidance suggests otherwise, the base case is against a widespread significant or major snowfall. Overall, the final week of January will feature generally below normal readings. Milder temperatures will likely return during the first week of February. Some of the guidance suggests that a period of much warmer than normal temperatures could develop. The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -1.2°C for the week centered around January 13. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.73°C and the ENSO Region 3.4 anomaly has averaged -1.08°C. La Niña conditions will likely prevail at least through meteorological winter. The SOI was +4.86 today. Today, the preliminary Arctic Oscillation (AO) figure was -2.075. On January 22 the MJO was in Phase 6 at an amplitude of 1.489 (RMM). The January 21-adjusted amplitude was 1.073. Following a significant stratospheric warming event, the stratosphere is now cooling. The cooling will likely accelerate during the second half of January. As is typical for vortex-splitting events, the major piece of the polar vortex migrated to Eurasia. The end result has been an absence of severe cold in much of North America. The significant December 16-17 snowstorm during what has been a blocky December suggests that seasonal snowfall prospects have increased especially from north of Philadelphia into southern New England. At New York City, there is a high probability based on historic cases that an additional 20" or more snow will accumulate after December. Were blocking to disappear, snowfall prospects would diminish. Based on sensitivity analysis applied to the latest guidance, there is an implied 99% probability that New York City will have a warmer than normal January. January will likely finish with a mean temperature near 35.5°.

The position and strength of the block.

It’s definitely having an impact. At the regional scale, not all of its impacts are evident.

The exceptionally warm SSTs may have played a role in influencing the position of the block.

Morning thoughts... Today will be partly sunny and cold. Temperatures will likely top out in the lower 30s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 33° Newark: 34° Philadelphia: 35° Tomorrow will be fair and continued cold.

Colder air drilled into the region with a few snow flurries and snow showers. A much colder air mass will cover the region during the weekend. Parts of the region could struggle to reach freezing tomorrow and again on Sunday. The closing week of January will likely be colder than normal across the region. Milder weather will likely return during the first week of February. Some of the guidance suggests that temperatures could surge to much above normal levels for a time. Meanwhile in northern Canada, Nunavut experienced another day with near record and record high temperatures. High temperatures included: Coral Harbour: 22° (old record: 20°, 1963) Iqaluit: 33° Kimmirut: 36° (old record: 14°, 2003) Kinngait: 29° (old record: 17°, 1980) Kugaaruk: 19° (old record: 6°, 1995) Naujaat: 25° (old record: 3°, 1995) Pangnirtung: 32° (old record: 20°, 2000) Qikiqtarjuaq: 15° (missed record from 2013 by 0.2°C) The abnormal warmth will likely continue in Nunavut through tomorrow. As Arctic blocking persists, next week could feature two opportunities for snowfall. The earlier event (January 25-27 timeframe) will likely focus its heaviest snows on the Philadelphia to New York City area. The latter event (January 28-29 timeframe) will likely focus its heaviest snows in an area running from Richmond to Washington, DC. A widespread significant snowfall (6" or above) still appears relatively unlikely, especially for the first event. A light or moderate snowfall (2"-4" or 3"-6") remains more likely. However, some of the guidance suggests that the second storm could rapidly intensify, so there is a greater degree of uncertainty for that event in terms of amounts. AO-/PNA- patterns typically do not produce significant or major snowstorms for the Middle Atlantic or southern New England regions in late January or early February. During the January 20-February 7, 1950-2020 period, there have been 5 storms that brought 4" or more snow to at least two of the following cities--Boston, New York City, or Philadelphia--during an AO-/PNA- pattern. None of those storms brought 6" or more snow to two or more of those cities. Therefore, until the potential events are within 72 hours or less and the guidance suggests otherwise, the base case is against a widespread significant or major snowfall. The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -1.2°C for the week centered around January 13. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.73°C and the ENSO Region 3.4 anomaly has averaged -1.08°C. La Niña conditions will likely prevail at least through meteorological winter. The SOI was +1.14 today. Today, the preliminary Arctic Oscillation (AO) figure was -2.238. On January 21 the MJO was in Phase 6 at an amplitude of 1.071 (RMM). The January 20-adjusted amplitude was 0.684. Following a significant stratospheric warming event, the stratosphere is now cooling. The cooling will likely accelerate during the second half of January. As is typical for vortex-splitting events, the major piece of the polar vortex migrated to Eurasia. The end result has been an absence of severe cold in much of North America. The significant December 16-17 snowstorm during what has been a blocky December suggests that seasonal snowfall prospects have increased especially from north of Philadelphia into southern New England. At New York City, there is a high probability based on historic cases that an additional 20" or more snow will accumulate after December. Were blocking to disappear, snowfall prospects would diminish. Based on sensitivity analysis applied to the latest guidance, there is an implied 95% probability that New York City will have a warmer than normal January. January will likely finish with a mean temperature near 35.2°.

Some of the guidance has suggested the potential for a moderate to significant snowfall (4" or more snow) in and around Richmond next week. An AO-/PNA- pattern is a favorable pattern for snow events in Richmond. Since 1950, there have been 24 days on which 2" or more snow fell during the January 20-February 10, 1950-2020 period in Richmond. Based on the AO/PNA states, the breakdown was as follows: AO-/PNA-: 25% AO-/PNA+: 46% AO+/PNA-: 4% AO+/PNA+: 17% AO-: 71% AO+: 29% PNA-: 29% PNA+: 71% Below is a bubble chart showing the distribution of such days, with bubble size based on the amount of snowfall. The AO and PNA are forecast to be negative through the remainder of January. Richmond's largest snowstorms during the above January 20-February 10, 1950-2020 timeframe were: 6.4", February 7, 1979 (AO: -1.696; PNA: -1.080) 5.6", January 22-23, 1954 (AO: -0.082; PNA: -0.747) 5.3", February 2, 1972 (AO: -1.896; PNA: -1.097) In addition, a storm brought 3.0" on January 20, 2000 during an AO-/PNA- state. A much larger snowstorm occurred shortly thereafter. The three largest AO-/PNA- storms also brought accumulating snowfall to to Washington, DC: January 22-23, 1954: 6.4" February 2, 1972: 3.4" February 7, 1979: 5.6" Only one of those storms brought more than 1.0" snow as far north as New York City: the February 7, 1979 storm, which brought 5.0" to Central Park.

0.2” at both JFK and LGA.

I suspect that the second storm could be even more suppressed, if anything. If so, it is possible that it would bring little or nothing to the New York City or Newark areas.

Morning thoughts... At 7:45 am, a line of snow showers, with some embedded pockets of moderate to heavy snow, stretched from central Vermont down to western Massachusetts. That area of snow was pushing eastward. The potential existed for Boston to pick up a small accumulation later this morning or early this afternoon. That area of snow was associated with a strong push of colder air. The frontal passage will likely be dry in the New York City and Philadelphia areas. As a result, under partly sunny skies, readings will likely top out in the lower and middle 40s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 45° Newark: 47° Philadelphia: 47° Tomorrow will be fair and much colder. The temperature will struggle just to reach freezing in parts of the region.

Temperatures again rose into the lower 40s across much of the region today. The remainder of the week will be fair and seasonably cold. A much colder air mass will arrive for the weekend. Parts of the region could struggle to reach freezing on Saturday and Sunday. Meanwhile, Nunavut experienced another day with near record and record high temperatures. High temperatures included: Eureka: -4° (just missed its daily record from 1985 by 0.2°C) Grise Fiord: 16° (old record: 9°, 1985) Iqaluit: 32° Kimmirut: 35° (old record: 23°, 2003) Pangnirtung: 30° (old record: 24°, 2007) Qikiqtarjuaq: 13° (old record: 12°, 2013) Resolute: 9° The abnormal warmth will likely continue in Nunavut through Saturday. As Arctic blocking persists, next week could feature two opportunities for snowfall. The earlier event (January 25-27 timeframe) will likely focus its heaviest snows on the Philadelphia to New York City area. The latter event (January 28-29 timeframe) will likely focus its heaviest snows on the Washington, DC to Philadelphia area. A widespread significant snowfall (6" or above) still appears relatively unlikely. A light or moderate snowfall (2"-4" or 3"-6") remains more likely. However, some of the guidance suggests that the second storm could rapidly intensify, so there is a greater degree of uncertainty for that event in terms of amounts. AO-/PNA- patterns typically do not produce significant or major snowstorms for the Middle Atlantic or southern New England regions in late January or early February. During the January 20-February 7, 1950-2020 period, there have been 5 storms that brought 4" or more snow to at least two of the following cities--Boston, New York City, or Philadelphia--during an AO-/PNA- pattern. None of those storms brought 6" or more snow to two or more of those cities. Therefore, until the potential events are within 72 hours or less and the guidance suggests otherwise, the base case is against a widespread significant or major snowfall. Afterward, the evolution of the AO will determine whether potential for measurable snow events will continue into February. The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -1.2°C for the week centered around January 13. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.73°C and the ENSO Region 3.4 anomaly has averaged -1.08°C. La Niña conditions will likely prevail at least through meteorological winter. The SOI was -1.27 today. That is the first negative value since November 23, 2020 when the SOI was -7.83. Today, the preliminary Arctic Oscillation (AO) figure was -2.510. On January 20 the MJO was in Phase 6 at an amplitude of 0.682 (RMM). The January 19-adjusted amplitude was 0.424. Following a significant stratospheric warming event, the stratosphere is now cooling. The cooling will likely accelerate during the second half of January. As is typical for vortex-splitting events, the major piece of the polar vortex migrated to Eurasia. The end result has been an absence of severe cold in much of North America. The significant December 16-17 snowstorm during what has been a blocky December suggests that seasonal snowfall prospects have increased especially from north of Philadelphia into southern New England. At New York City, there is a high probability based on historic cases that an additional 20" or more snow will accumulate after December. Were blocking to disappear, snowfall prospects would diminish. Based on sensitivity analysis applied to the latest guidance, there is an implied 91% probability that New York City will have a warmer than normal January. January will likely finish with a mean temperature near 35.0°.

Morning thoughts... An area of clouds may move across parts of the region this morning, but the afternoon should be mostly sunny throughout the region. Temperatures will likely reach the lower to perhaps middle 40s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 42° Newark: 44° Philadelphia: 45° A strong cold front could bring another period of light snow or flurries on Friday.

A weak disturbance brought a round of light snow and snow showers across the region today. Snowfall amounts included: Allentown: Trace Bridgeport: Trace Islip: 0.2" New York City: Trace Newark: 0.3" Philadelphia: Trace The remainder of the week will be fair and seasonably cold. A much colder air mass will arrive for the weekend. Parts of the region could struggle to reach freezing on Saturday and Sunday. As Arctic blocking persists, next week could feature one or perhaps two more opportunities for snowfall, with the greatest risk focused on the January 25-28 timeframe. However, a widespread significant snowfall (6" or above) still appears relatively unlikely. A light or moderate snowfall is more likely. AO-/PNA- patterns typically do not produce significant or major snowstorms for the Middle Atlantic or southern New England regions in late January or early February. During the January 20-February 7, 1950-2020 period, there have been 5 storms that brought 4" or more snow to at least two of the following cities--Boston, New York City, or Philadelphia--during an AO-/PNA- pattern. None of those storms brought 6" or more snow to two or more of those cities. Therefore, until the potential events are within 72 hours or less and the guidance suggests otherwise, the base case is against a widespread significant or major snowfall. Afterward, the evolution of the AO will determine whether potential for measurable snow events will continue into February. The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -1.2°C for the week centered around January 13. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.73°C and the ENSO Region 3.4 anomaly has averaged -1.08°C. La Niña conditions will likely prevail at least through meteorological winter. The SOI was +4.86 today. Today, the preliminary Arctic Oscillation (AO) figure was -2.124. On January 19 the MJO was in Phase 5 at an amplitude of 0.425 (RMM). The January 18-adjusted amplitude was 0.638. Following a significant stratospheric warming event, the stratosphere is now cooling. The cooling will likely accelerate during the second half of January. As is typical for vortex-splitting events, the major piece of the polar vortex migrated to Eurasia. The end result has been an absence of severe cold in much of North America. The significant December 16-17 snowstorm during what has been a blocky December suggests that seasonal snowfall prospects have increased especially from north of Philadelphia into southern New England. At New York City, there is a high probability based on historic cases that an additional 20" or more snow will accumulate after December. Were blocking to disappear, snowfall prospects would diminish. Based on sensitivity analysis applied to the latest guidance, there is an implied 90% probability that New York City will have a warmer than normal January. January will likely finish with a mean temperature near 35.0°.

Three photos from this morning’s light snow: At 9:46, the sun is shining and the snow is rapidly disappearing.

Falling snow is always beautiful. Even light amounts are special.

Certainly, with a warming climate, moisture content has increased.

Morning thoughts... Following this morning’s light snow and flurries, it will become partly sunny. Temperatures will likely reach the lower 40s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 41° Newark: 43° Philadelphia: 43° A strong cold front could bring another period of light snow or flurries on Friday.

A quick video of this morning’s light snow: