donsutherland1

The NAO stays positive.

Tomorrow will be briefly milder. Many areas will see the thermometer rise into the lower 40s. However, the warmth will be short-lived. A strong cold shot will bring much colder weather for Wednesday. Parts of the Northeast have the potential to experience their coldest temperatures of the winter. Afterward, the cold will likely begin ease, but the risk of a potentially significant storm in parts of the East could increase. A pattern change toward persistent milder conditions could begin to evolve during the first week of February. The extended range of the EPS already shows the start of a warming trend in the closing days of January, so the timing remains somewhat uncertain. Such large-scale pattern changes have sometimes been preceded by or coincided with storms. The PNA is positive and is likely to remain positive through at least January 27th. A positive PNA is associated with more frequent snowfalls in the Middle Atlantic region. However, big snowfalls typically occur when the AO is negative, especially in such cities as Washington and Philadelphia. Some individual ensemble members hint at the AO's going negative for a time in the closing days of the month. The ENSO Region 1+2 anomaly was -0.5°C and the Region 3.4 anomaly was -0.8°C for the week centered around January 19. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.05°C and the ENSO Region 3.4 anomaly has averaged -0.98°C. La Niña conditions will likely persist through meteorological winter. The SOI was +13.15 today. The preliminary Arctic Oscillation (AO) was +0.947. On January 21 the MJO was in Phase 7 at an amplitude of 0.888 (RMM). The January 20-adjusted amplitude was 0.757 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied near 100% probability that New York City will have a colder than normal January (1991-2020 normal). January will likely finish with a mean temperature near 30.4° (3.3° below normal).

Morning thoughts… It will be partly sunny and cool today. High temperatures will likely reach the lower and middle 30s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 33° Newark: 34° Philadelphia: 36° Normals: New York City: 30-Year: 39.2°; 15-Year: 39.7° Newark: 30-Year: 39.7°; 15-Year: 40.4° Philadelphia: 30-Year: 41.0°; 15-Year: 41.5° Tomorrow will be briefly milder before another very cold air mass overspreads the region.

Mamaroneck, NY:

It’s pretty much there, except statistically.

Not exactly the 2016 event, but still nice. https://youtu.be/Bq7UYqO939U

A generally cold but dry week lies ahead. A strong cold shot is likely around midweek. Parts of the Northeast have the potential to experience their coldest temperatures of the winter. Afterward, the cold will likely begin ease. A pattern change toward persistent milder conditions could begin to evolve during the first week of February. The extended range of the EPS already shows the start of a warming trend in the closing days of January, so the timing remains somewhat uncertain. Such large-scale pattern changes have sometimes been preceded by or coincided with storms. The PNA is positive and is likely to remain positive through at least January 27th. A positive PNA is associated with more frequent snowfalls in the Middle Atlantic region. However, big snowfalls typically occur when the AO is negative, especially in such cities as Washington and Philadelphia. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around January 12. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.20°C and the ENSO Region 3.4 anomaly has averaged -1.03°C. La Niña conditions will likely persist through meteorological winter. The SOI was +11.17 today. The preliminary Arctic Oscillation (AO) was +1.406. On January 21 the MJO was in Phase 7 at an amplitude of 0.734 (RMM). The January 20-adjusted amplitude was 0.664 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 99% probability that New York City will have a colder than normal January (1991-2020 normal). January will likely finish with a mean temperature near 30.4° (3.3° below normal).

Morning thoughts… It will be variably cloudy and somewhat milder today. High temperatures will likely reach the middle 30s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 35° Newark: 36° Philadelphia: 37° Normals: New York City: 30-Year: 39.2°; 15-Year: 39.7° Newark: 30-Year: 39.7°; 15-Year: 40.4° Philadelphia: 30-Year: 41.0°; 15-Year: 41.5° A generally cold and dry week lies ahead. A strong cold shot is likely at midweek. Meanwhile, 30-year normal temperatures have now begun to increase at New York City, Newark, and Philadelphia.

A quiet weekend will conclude with another fair but cool day tomorrow. Next week will feature a continuation of the generally colder than normal temperatures. A strong cold shot is likely around midweek. Afterward, the cold will likely begin ease. A pattern change toward persistent milder conditions could begin to evolve during the first week of February. The extended range of the EPS already shows the start of a warming trend in the closing days of January, so the timing remains somewhat uncertain. Such large-scale pattern changes have sometimes been preceded by or coincided with storms. The PNA is positive and is likely to remain positive through at least January 27th. A positive PNA is associated with more frequent snowfalls in the Middle Atlantic region. However, big snowfalls typically occur when the AO is negative. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around January 12. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.20°C and the ENSO Region 3.4 anomaly has averaged -1.03°C. La Niña conditions will likely persist through meteorological winter. The SOI was +11.26 today. The preliminary Arctic Oscillation (AO) was +1.549. On January 20 the MJO was in Phase 6 at an amplitude of 0.665 (RMM). The January 19-adjusted amplitude was 0.402 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 99% probability that New York City will have a colder than normal January (1991-2020 normal). January will likely finish with a mean temperature near 30.4° (3.3° below normal).

A cold and dry weekend lies ahead. Overnight and tomorrow, a storm will move offshore well to the south and east of the region. No precipitation is likely. Next week will feature a continuation of generally colder than normal temperatures. A strong cold shot is likely around midweek. Afterward, the cold will likely ease. A pattern change toward persistent milder conditions could begin to evolve during the first week of February. The extended range of the EPS already shows the start of a warming trend in the closing days of January, so the timing remains somewhat uncertain. Moreover, the currently forecast drop in the AO, should it verify, provides additional uncertainty. The PNA is positive and is likely to remain positive through at least January 27th. A positive PNA is associated with more frequent snowfalls in the Middle Atlantic region. However, big snowfalls typically occur when the AO is negative. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around January 12. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.20°C and the ENSO Region 3.4 anomaly has averaged -1.03°C. La Niña conditions will likely persist through meteorological winter. The SOI was +6.46 today. The preliminary Arctic Oscillation (AO) was +1.135. On January 19 the MJO was in Phase 6 at an amplitude of 0.399 (RMM). The January 18-adjusted amplitude was 0.365 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 97% probability that New York City will have a colder than normal January (1991-2020 normal). January will likely finish with a mean temperature near 30.5° (3.2° below normal).

Morning thoughts… It will be variably cloudy and very cold today. High temperatures will likely reach the lower and middle 20s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 22° Newark: 24° Philadelphia: 27° Normals: New York City: 30-Year: 39.1°; 15-Year: 39.7° Newark: 30-Year: 39.6°; 15-Year: 40.4° Philadelphia: 30-Year: 40.9°; 15-Year: 41.5° The weekend will be cold and dry.

In the wake of an Arctic cold front, much colder air is pouring into the region. This air mass will cover the region tomorrow through the weekend. The weekend will be mainly dry as a storm moves offshore well to the south and east of the region. A pattern change toward persistent milder conditions could begin to evolve during the first week of February. The extended range of the EPS already shows the start of a warming trend in the closing days of January, so the timing remains somewhat uncertain. The PNA is positive and is likely to remain positive through at least January 27th. A positive PNA is associated with more frequent snowfalls in the Middle Atlantic region. However, big snowfalls typically occur when the AO is negative. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around January 12. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.20°C and the ENSO Region 3.4 anomaly has averaged -1.03°C. La Niña conditions will likely persist through meteorological winter. The SOI was +7.92 today. The preliminary Arctic Oscillation (AO) was +0.486. On January 18 the MJO was in Phase 7 at an amplitude of 0.364 (RMM). The January 17-adjusted amplitude was 0.429 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 96% probability that New York City will have a colder than normal January (1991-2020 normal). January will likely finish with a mean temperature near 30.5° (3.2° below normal).

Snow is starting to mix with the rain in Larchmont, NY.

Morning thoughts… Rain will end as a period of snow or flurries. 1” of snow is likely in Philadelphia, Newark, and New York City with local amounts as high as 3”. The temperature will fall throughout the day. High temperatures will likely reach the upper 30s and lower 40s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 39° Newark: 37° Philadelphia: 40° Normals: New York City: 30-Year: 39.1°; 15-Year: 39.7° Newark: 30-Year: 39.6°; 15-Year: 40.4° Philadelphia: 30-Year: 40.9°; 15-Year: 41.5° Tomorrow through the weekend will be cold and dry.

An advancing cold front will bring rain changing to snow overnight into midday tomorrow. A general 1"-3" snowfall is likely in Philadelphia, Newark, New York City and nearby areas. Lighter amounts are likely north and west of those cities. Much colder air will follow for the weekend. The weekend will be mainly dry as a storm moves offshore well to the south and east of the region. Generally colder than normal conditions will persist through midweek next week. A pattern change toward persistent milder conditions could begin to evolve during the first week of February. At present, the CFSv2 is somewhat faster than the EPS weeklies in bringing about that transition. The PNA is positive and is likely to remain positive through at least January 27th. A positive PNA is associated with more frequent snowfalls in the Middle Atlantic region. However, big snowfalls typically occur when the AO is negative. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around January 12. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.20°C and the ENSO Region 3.4 anomaly has averaged -1.03°C. La Niña conditions will likely persist through meteorological winter. The SOI was +5.75 today. The preliminary Arctic Oscillation (AO) was +0.161. On January 17 the MJO was in Phase 8 at an amplitude of 0.430 (RMM). The January 16-adjusted amplitude was 0.658 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 97% probability that New York City will have a colder than normal January (1991-2020 normal). January will likely finish with a mean temperature near 30.4° (3.3° below normal).

Arctic refers to the source region of the air mass. The Arctic has warmed quite rapidly over the past few decades, so the magnitude of cold is generally less expansive and less intense that it was then. There remain exceptions, though.

It is. Still, we'll get another look at the 0z HREF ahead of the event.

HREF for late tonight into tomorrow:

Morning thoughts… It will be variably cloudy and mild today. High temperatures will likely middle and upper 40s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 45° Newark: 46° Philadelphia: 49° Normals: New York City: 30-Year: 39.1°; 15-Year: 39.8° Newark: 30-Year: 39.6°; 15-Year: 40.4° Philadelphia: 30-Year: 40.9°; 15-Year: 41.5° There will be a period of accumulating snow late tonight through tomorrow morning. A general 1”-3” is likely across most of the region, including New York City, Newark, and Philadelphia.

Milder air will return early tomorrow ahead of an approaching cold front. That front will likely bring some rain and snow showers to the region. There is a chance that the precipitation ends as a period of accumulating snow in parts of the region. The potential exists for a 1"-3" accumulation in parts of the region. Much colder air will follow for the weekend. Some of the guidance hints at the development of another storm that could impact parts of the East Coast, but there remains considerable uncertainty. The PNA is positive and is likely to remain positive through at least January 27th. A positive PNA is associated with more frequent snowfalls in the Middle Atlantic region. However, big snowfalls typically occur when the AO is negative. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around January 12. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.20°C and the ENSO Region 3.4 anomaly has averaged -1.03°C. La Niña conditions will likely persist through meteorological winter. The SOI was -2.63 today. The preliminary Arctic Oscillation (AO) was +0.507. On January 16 the MJO was in Phase 8 at an amplitude of 0.662 (RMM). The January 15-adjusted amplitude was 0.927 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 92% probability that New York City will have a colder than normal January (1991-2020 normal). January will likely finish with a mean temperature near 30.6° (3.1° below normal).

Morning thoughts… It will be mostly sunny, breezy, and cold today. High temperatures will likely middle and upper 30s in most of the region. Likely high temperatures around the region include: New York City (Central Park): 34° Newark: 36° Philadelphia: 39° Normals: New York City: 30-Year: 39.1°; 15-Year: 39.8° Newark: 30-Year: 39.6°; 15-Year: 40.5° Philadelphia: 30-Year: 40.9°; 15-Year: 41.6° Tomorrow will be milder ahead of the next cold front. There could be a period of snow or flurries early Thursday.

Most of the cold on the 30-day map is from January.

If the pattern change unfolds as shown on the latest EPS, there could be opportunities until mid-February. A faster transition would reduce the window of opportunity.

First week of February:

The powerful storm that raked coastal areas with winds gusts in excess of 60 mph and brought heavy rain to the region after some snow to some areas is now moving away. Daily precipitation amounts included: Bridgeport: 0.86" (old record: 0.77", 1994) Islip: 1.48" (old record: 0.70", 1994) New York City-JFK: 0.92" New York City-LGA: 1.06" New York City-NYC: 1.15" Newark: 1.30" Tomorrow will be blustery and colder before milder air returns early on Thursday ahead of an approaching cold front. That front will likely bring some rain and snow showers to the region. There is a chance that the precipitation ends as a period of accumulating snow in parts of the region. Much colder air will follow for the weekend. Some of the guidance hints at the development of another storm that could impact parts of the East Coast, but uncertainty is high. The PNA is positive and is likely to remain positive through at least January 27th. A positive PNA is associated with more frequent snowfalls in the Middle Atlantic region. However, big snowfalls typically occur when the AO is negative. The ENSO Region 1+2 anomaly was -0.4°C and the Region 3.4 anomaly was -0.8°C for the week centered around January 12. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -1.20°C and the ENSO Region 3.4 anomaly has averaged -1.03°C. La Niña conditions will likely persist through meteorological winter. The SOI was -8.76 today. The preliminary Arctic Oscillation (AO) was +1.540. On January 15 the MJO was in Phase 7 at an amplitude of 0.928 (RMM). The January 14-adjusted amplitude was 1.309 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 91% probability that New York City will have a colder than normal January (1991-2020 normal). January will likely finish with a mean temperature near 30.7° (3.0° below normal).