donsutherland1

Tomorrow will be partly sunny and milder with highs reaching the middle 60s. However, a fresh shot of cool air will move into the region late in the day or at night. Following the frontal passage, parts of the region could experience their coolest temperatures so far this fall. Dry conditions will likely prevail through the remainder of the week. In the 18 past years where Central Park saw at least two 80° or above highs and Newark saw at least two 84° or above highs during the first week of October, the temperature returned to 70° or above on at least one day during the second half of October in 17 (94.4%) of those cases. For all other cases, 84.1% saw at least one such high temperature during the second half of October. Therefore, the sharp cool spell very likely won't mean that New York City has seen its last 70° or above high temperature. The ENSO Region 1+2 anomaly was -0.1°C and the Region 3.4 anomaly was -0.3°C for the week centered around October 8. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.12°C and the ENSO Region 3.4 anomaly has averaged -0.42°C. La Niña conditions will likely continue through mid-winter. The SOI was -3.48 today. The preliminary Arctic Oscillation (AO) was -0.487 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 66% probability that New York City will have a warmer than normal October (1991-2020 normal). October will likely finish with a mean temperature near 58.9° (1.0° above normal). Supplemental Information: The projected mean would be 2.0° above the 1981-2010 normal monthly value.

Three-day rainfall totals for the New York City area:

Probably less than that in most places, but a few areas could still see another 0.25". Favored areas for the heavier amounts are on Long Island.

The nor'easter that brought heavy rainfall to the coastal plain is now poised to pull away. Some additional showers, periods of rain, and drizzle are likely overnight. Following the nor'easter, tomorrow will be mostly cloudy and mild. Clouds could break from west to east during the afternoon. Temperatures will top out in the lower 60s in many parts of the region. Wednesday will be partly sunny and milder with highs reaching the middle 60s. However, a fresh shot of cool air will move into the region late Wednesday or Wednesday night. Following the frontal passage, parts of the region could experience their coolest temperatures so far this fall. Dry conditions will likely prevail through the remainder of the week. In the 18 past years where Central Park saw at least two 80° or above highs and Newark saw at least two 84° or above highs during the first week of October, the temperature returned to 70° or above on at least one day during the second half of October in 17 (94.4%) of those cases. For all other cases, 84.1% saw at least one such high temperature during the second half of October. Therefore, the sharp cool spell very likely won't mean that New York City has seen its last 70° or above high temperature. The ENSO Region 1+2 anomaly was -0.1°C and the Region 3.4 anomaly was -0.3°C for the week centered around October 8. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.12°C and the ENSO Region 3.4 anomaly has averaged -0.42°C. La Niña conditions will likely continue through mid-winter. The SOI was +7.15 today. The preliminary Arctic Oscillation (AO) was -0.345 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 63% probability that New York City will have a warmer than normal October (1991-2020 normal). October will likely finish with a mean temperature near 58.8° (0.9° above normal). Supplemental Information: The projected mean would be 1.9° above the 1981-2010 normal monthly value.

Select rainfall amounts through 6 pm: Daily Record for October 13: Poughkeepsie: 1.89" (old record: 1.25", 2005)

Two photos from Day 2 of the Nor'easter:

One doesn't need to include 2013-2014 to get some sustained periods of high latitude blocking, particularly in the EPO domain. If, and it remains conditional, 2013 falls apart in its ability to predict the fall pattern evolution, it's tough to argue that it should be retained. None of the cases, including the emerging 2021-2022 case, is perfect. But their ability to retain predictive value heading toward winter matters. For now, there is no strong evidence for a "blow torch" winter in the Northeast or Great Lakes Region. Snowfall looks better than in recent winters e.g., I posted an initial guess of 15"-25" for NYC in the NYC forum (Boston looks even better, though not a blockbuster).

Through 9 am, rainfall amounts have been pretty much in line with expectations for the ongoing event.

I agree. That it misses on some other key variables i.e., IOD, QBO, etc., leads me to rank it lower, excluding the SSTs. It's still in the larger mix. I'll re-examine the SSTAs later this month. The October outcome could provide a powerful clue. The 2013 500 mb outcome diverges from the last monthly ECMWF forecast for October. If the ECMWF forecast is reasonably accurate, that will indicate that the 2013 scenario is off track. And if the "Blob" continues to dissipate, that would be a further signal.

It's too soon to tell. Last winter's miss was unusually large. One can probably use a +/- 1°C range to consider reasonable possibilities.

To date, among the emerging cases that could provide insight into Winter 2025-2026 temperatures is 2021 (ENSO, RONI, QBO, IOD, and PDO). Consistent with the lack of statistical relationship between ACE and winter temperatures/snowfall, ACE isn't considered. Solar flux is also a mismatch (suggesting perhaps a milder version of 2021-2022), but for now this is an emerging case. The evolution of the North Pacific SSTAs and continuing evolution of ENSO will be important factors. Here's the fall 2025 outlook using 2021: Fall 2025 (through October 10): Winter 2025-2026 using 2021-2022: ECMWF DJF Forecast:

Just in time for Thanksgiving Day. Have a great Thanksgiving Day, tomorrow.

Two photos from late this afternoon from the Long Island Sound:

A nor'easter will continue to bring periods of rain and strong winds to the region into early Tuesday. A general 1"-3" rainfall is likely across the region with locally higher amounts. The wind will gust to 40 mph in New York City and its nearby suburbs, and 60 mph along portions of the Jersey Shore and eastern Long Island. Coastal flooding and beach erosion are likely. Following the nor'easter, a fresh shot of cool air will move into the region during the middle of next week. Some parts of the region could experience their coolest temperatures so far this fall. Dry conditions will likely prevail through the remainder of the week. In the 18 past years where Central Park saw at least two 80° or above highs and Newark saw at least two 84° or above highs during the first week of October, the temperature returned to 70° or above on at least one day during the second half of October in 17 (94.4%) of those cases. For all other cases, 84.1% saw at least one such high temperature during the second half of October. Therefore, the sharp cool spell very likely won't mean that New York City has seen its last 70° or above high temperature. The ENSO Region 1+2 anomaly was -0.1°C and the Region 3.4 anomaly was -0.5°C for the week centered around October 1. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.15°C and the ENSO Region 3.4 anomaly has averaged -0.43°C. La Niña conditions will likely continue through mid-winter. The SOI was +8.31 today. The preliminary Arctic Oscillation (AO) was -0.008 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 61% probability that New York City will have a warmer than normal October (1991-2020 normal). October will likely finish with a mean temperature near 58.8° (0.9° above normal). Supplemental Information: The projected mean would be 1.9° above the 1981-2010 normal monthly value.

While the New York City area waits as the nor'easter's rain spreads north and westward into the region, Phoenix has been having an incredibly wet day. It has seen hourly rainfall as high as 0.63" and has picked up 1.83" so far, today. Today is the fourth wettest October day on record there. The two-day figure of 2.53" is the second highest two-day amount on record. October records go back to 1895.

Hopefully, the flooding won't be so bad that it would affect the unraised homes.

Through October 10th, 2025 has the 3rd warmest start to October globally on the ERA-5 dataset. The five warmest October 1-10 periods are: 1. 15.72°C, 2023 2. 15.59°C, 2024 3. 15.45°C, 2025 4. 15.38°, 2015 5. 15.30°C, 2020 With the warm global forecast (generally 0.8°C-1.0°C) on the ECMWF weeklies, there is a growing chance that 2025 could join 2023 and 2024 as the only years with an October mean temperature of 15.00°C or above.

Steadier periods of rain will arrive tomorrow as a developing coastal nor'easter begins to affect the region. The wind will also pick up as the day wears on. Highs should reach the lower 60s tomorrow. The nor'easter will bring periods of rain and strong winds to the region into Tuesday. A general 1"-3" rainfall is likely across the region with locally higher amounts. The wind will gust to 40 mph in New York City and its nearby suburbs, and 60 mph along portions of the Jersey Shore and eastern Long Island. Coastal flooding and beach erosion are likely. Following the nor'easter, a fresh shot of cool air will move into the region during the middle of next week. Dry conditions will likely prevail through the remainder of the week. In the 18 past years where Central Park saw at least two 80° or above highs and Newark saw at least two 84° or above highs during the first week of October, the temperature returned to 70° or above on at least one day during the second half of October in 17 (94.4%) of those cases. For all other cases, 84.1% saw at least one such high temperature during the second half of October. Therefore, the sharp cool spell very likely won't mean that New York City has seen its last 70° or above high temperature. The ENSO Region 1+2 anomaly was -0.1°C and the Region 3.4 anomaly was -0.5°C for the week centered around October 1. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.15°C and the ENSO Region 3.4 anomaly has averaged -0.43°C. La Niña conditions will likely continue through mid-winter. The SOI was +10.31 today. The preliminary Arctic Oscillation (AO) was +0.286 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 62% probability that New York City will have a warmer than normal October (1991-2020 normal). October will likely finish with a mean temperature near 58.9° (1.0° above normal). Supplemental Information: The projected mean would be 2.0° above the 1981-2010 normal monthly value.

All of the major reporting sites around New York City have seen less than 40" of rain since September 1, 2024. The 1"-3" for NYC/nearby suburbs and 2"-4" on Long Island/Jersey Shore should help, but drier conditions will likely resume following the nor'easter.

NWS forecast for most significant coastal flood impacts expected for Long Island:

Temperatures started out the day in the 30s and 40s across the region. The coldest spots saw readings drop into the upper 20s. Lows included: Albany: 31° Atlantic City: 40° Binghamton: 31° Boston: 41° Bridgeport: 40° Danbury: 31° Hartford: 29° Islip: 40° Montgomery: 26° (old record: 27°, 2000) New Haven: 39° New York City-Central Park: 46° New York City-JFK Airport: 43° New York City-LaGuardia Airport: 48° Newark: 41° Philadelphia: 45° Poughkeepsie: 28° Sussex: 29° Trenton: 39° Westhampton: 31° White Plains: 42° Temperatures will moderate during the weekend, but rain will arrive on Sunday. Highs should reach the middle and upper 60s tomorrow and lower and middle 60s on Sunday. A strong nor'easter will bring periods of rain and strong winds to parts of the region. Uncertainty as to amounts and locations of the heaviest rainfall has increased on the guidance, as a complex phasing situation is involved. For now, it still appears that a general 1"-3" rainfall is likely across New York City and its nearby suburbs, along with winds that will gust past 40 mph. Long Island could see 2"-4" of rain. Winds in this region could gust to 60 mph. There is the potential for lesser rainfall amounts along the Jersey Shore, but that is not yet certain. More revisions may be necessary after the overnight model cycles. A period of near normal to somewhat below normal temperatures and dry conditions will likely follow the nor-easter. In the 18 past years where Central Park saw at least two 80° or above highs and Newark saw at least two 84° or above highs during the first week of October, the temperature returned to 70° or above on at least one day during the second half of October in 17 (94.4%) of those cases. For all other cases, 84.1% saw at least one such high temperature during the second half of October. Therefore, the sharp cool spell very likely won't mean that New York City has seen its last 70° or above high temperature. The ENSO Region 1+2 anomaly was -0.1°C and the Region 3.4 anomaly was -0.5°C for the week centered around October 1. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.15°C and the ENSO Region 3.4 anomaly has averaged -0.43°C. La Niña conditions will likely continue through mid-winter. The SOI was +18.82 today. The preliminary Arctic Oscillation (AO) was +1.044 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 61% probability that New York City will have a warmer than normal October (1991-2020 normal). October will likely finish with a mean temperature near 58.9° (1.0° above normal). Supplemental Information: The projected mean would be 2.0° above the 1981-2010 normal monthly value.

NYC had a trace of snow on October 10, 1979. The snow fell but didn't accumulate.

Yes it was.

Looking at the dry start to October, the guidance had been showing what would be a fairly uncommon event. Perhaps, in retrospect, if rainfall amounts wind up becoming greatly reduced, the lesson is that until one is in the near range (< 3 days out), one should be skeptical of statistical outlier events, even when there is strong model support. The model support was based on the idea of a complex phasing situation, which, itself, is difficult for models to handle in the medium-range and beyond. A scenario concerning slower developing system that grazes the coastal plain (Long Island and eastern New England should still do well) is becoming more probable. We'll see what the later model runs show. For Central Park, here are the maximum one- and two-day rainfall events following a completely dry first week of October, as was the case this year. What still seems more certain is that the development of a drier pattern consistent with the development of an NAO-/AO- following the nor-easter remains on track.

They're known for their hype. From last winter, here was one of their hyped long-range forecasts: https://www.americanwx.com/bb/topic/60046-2024-2025-la-nina/?do=findComment&comment=7582201