donsutherland1

Revisiting the above post now that some time has passed. The general idea about being cautious about outlier model runs that lack support holds. Today's 12z run of the GFS: The National Blend of Models shows NYC's temperatures falling through the 50s during the showers/rain. That's somewhat warmer than previously shown on the guidance, but 40s remains a possibility. The outlier notion of an accumulating snowstorm is not plausible.

And for context: Low skill for much of the CONUS.

Many record lows will fall, especially in the South.

A quick note: Denver finally surpassed its monthly record that was set in 2006 this year. On November 2, the mercury topped out at 83° in Denver.

A few showers are possible overnight as a warm front moves across the region. The weekend will be unseasonably mild with tomorrow being the warmest day. Highs Tomorrow will likely reach the lower and perhaps middle 60s. Newark could again approach or reach 70°. A strong cold front will then bring this season's coldest temperatures so far early next week. It could trigger some showers or a thunderstorm Sunday evening or Sunday night. Afterward, lows would fall well into the 30s in New York City while highs struggle to reach the middle and upper 40s during the height of the early-season chill. The ENSO Region 1+2 anomaly was +0.1°C and the Region 3.4 anomaly was -0.6°C for the week centered around October 29. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.05°C and the ENSO Region 3.4 anomaly has averaged -0.52°C. La Niña conditions will likely continue through mid-winter. The SOI was +29.26 today. The preliminary Arctic Oscillation (AO) was -0.721 today. Based on sensitivity analysis applied to the latest guidance, there is an implied 55% probability that New York City will have a cooler than normal November (1991-2020 normal). November will likely finish with a mean temperature near 47.5° (0.5° below normal). Supplemental Information: The projected mean would be 0.2° below the 1981-2010 normal monthly value.

Bridgeport, Islip, and White Plains all experienced their first freeze of the season. Today's Low Temperature and First Freeze Data: Bridgeport: 32°; Last Year: November 13; Normal: November 4 Islip: 32°; Last Year: November 10; Normal: October 28 White Plains: 32°; Last Year: November 13; Normal October 28

Tomorrow will be fair with temperatures topping out in the middle and upper 50s. The weekend will be unseasonably mild with Saturday being the warmest day. Highs on Saturday will likely reach the lower and perhaps middle 60s. Newark could again approach or reach 70°. A strong cold front will then bring this season's coldest temperatures so far early next week. Lows would fall well into the 30s in New York City while highs struggle to reach the middle and upper 40s. The ENSO Region 1+2 anomaly was +0.1°C and the Region 3.4 anomaly was -0.6°C for the week centered around October 29. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.05°C and the ENSO Region 3.4 anomaly has averaged -0.52°C. La Niña conditions will likely continue through mid-winter. The SOI was +27.67 today. The preliminary Arctic Oscillation (AO) was -0.510 today.

GaWx, Thanks. It looks like I messed up my pre-1980 values on the spreadsheet. By any chance, do you have a link to the monthly Region 1+2 anomalies. I can't find it on the moved ENSO page.

While those weren’t La Niña winters, I expanded the very limited dataset to include all years with rapid warming of ENSO Region 3.4 from a cool December figure. The response in January and February was the same with or without those two cases.

Were the La Niña to collapse prematurely, that would herald the likelihood of warmth in parts of the East in both January and February. Perhaps the best proxy for rapid collapses are cases where the ENSO R3.4 anomaly was -0.50° or below during December and >-0.50° during January. There were only four cases since 1950 that met that criteria: Winters 1951-52, 1952-53, 1974-75, and 2001-02. I don't expect this winter to meet such criteria. If so, the coming winter would wind up quite a bit warmer than what I'm currently thinking and also what the latest ECMWF suggested.

As of 4 pm, the high temperature in New York City had reached 66°. That was a full 2 standard deviations above the NBM forecast from 11z, a remarkable bust. Newark was even warmer with a high of 70°. However, this warmth will be short-lived, as a cold front is now crossing the region. In doing so, it could trigger some widely scattered showers. Most areas will remain dry. The first half of tonight will be very windy. Winds will likely gust past 50 mph for several hours. Afterward, winds will slowly diminish. Highs will then fall back to the lower and middle 50s tomorrow and middle and upper 50s on Friday. The weekend will be mild with Saturday being the warmest day. Highs on Saturday will likely reach the lower and perhaps middle 60s. Newark could again approach or reach 70°. A strong cold front will then bring this season's coldest temperatures so far early next week. Lows would fall well into the 30s in New York City while highs struggle to reach the middle and upper 40s. The ENSO Region 1+2 anomaly was +0.1°C and the Region 3.4 anomaly was -0.6°C for the week centered around October 29. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.05°C and the ENSO Region 3.4 anomaly has averaged -0.52°C. La Niña conditions will likely continue through mid-winter. The SOI was +26.97 today. The preliminary Arctic Oscillation (AO) was +0.140 today.

Tomorrow will be a mild day with highs reaching the lower 60s. A weak cold front could touch off a few scattered showers. It will turn increasingly windy following the frontal passage. Winds will likely gust past 50 mph for several hours. Highs will then fall back to the lower and middle 50s Thursday and Friday before milder conditions return for the weekend. Afterward, there is the potential for a short but sharp cold shot, possibly preceded by a chilly rain. Lows would fall well into the 30s in New York City while highs struggle to reach the middle and upper 40s. The ENSO Region 1+2 anomaly was +0.1°C and the Region 3.4 anomaly was -0.6°C for the week centered around October 29. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.05°C and the ENSO Region 3.4 anomaly has averaged -0.52°C. La Niña conditions will likely continue through mid-winter. The SOI was +17.81 today. The preliminary Arctic Oscillation (AO) was +1.343 today.

Nothing is cast in stone right now. Here are overall December cases: For recent La Niña events (1980-2025), December snowfall of 6" or above is more conducive to a snowy winter. Frequency of 30" or more for January-April: December < 4": 16.7% December 4" or above: 25.0% December 6" or above: 28.6% December 8" or above: 40.0%

I think he was referring to Eric's analogs. I might be wrong, though.

Yes. Fast start, then typically a collapse of winter. That may be the baseline for this coming winter where things get off to a good start and then winter ends prematurely.

In other words, things seem to be moving toward a vintage fast start to winter as is often, though not always, the case during La Niña winters.

Yes, but sharp cold shots are still possible. Below normal months can also occur.

A few showers are possible tonight. Tomorrow and Wednesday will be mild days. Highs will reach the upper 50s and lower 60s. A weak cold front could cross the region Wednesday, perhaps touching off a few scattered showers. It will turn increasingly windy following the frontal passage. Highs will then fall back to the lower and middle 50s before milder conditions return for a time next weekend. Afterward, there is the potential for a short but sharp cold shot, possibly preceded by a chilly rain. The ENSO Region 1+2 anomaly was +0.1°C and the Region 3.4 anomaly was -0.6°C for the week centered around October 29. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.05°C and the ENSO Region 3.4 anomaly has averaged -0.52°C. La Niña conditions will likely continue through mid-winter. The SOI was +18.96 today. The preliminary Arctic Oscillation (AO) was +1.583 today.

The short and sharp shot of cold looks good. Probably mid (maybe low) 30s for lows in the City, well into the 20s outside (teens in the coldest spots).

Aside from the 11/2 12z run of the GFS, the GFS is not showing an early season snowstorm in the New York City area. Outlier events typically do not verify when they lack support. So far, there is very little support on either the EPS or GEFS for the kind of snowstorm one run of the GFS showed yesterday. In general, one should wait for support to develop and run-to-run continuity to develop before embracing outlier events. The probability of the kind of event for New York City and its immediate suburbs shown yesterday remains low. More likely is a cold rain event with highs in the 40s with perhaps some flakes mixed in, though the mixing remains uncertain at this time. A better chance of snow exists for parts of the Poconos, Catskills, Adirondacks, and central/northern New England, which would include parts of Dutchess and Orange Counties.

Highs will reach the upper 50s and lower 60s through Wednesday. A weak cold front could cross the region after midweek, perhaps touching off a few scattered showers. Highs will then fall back to the lower and middle 50s before milder conditions return for a time next weekend. Afterward, there is the potential for a short but sharp cold shot, possibly preceded by a chilly rain. The ENSO Region 1+2 anomaly was +0.3°C and the Region 3.4 anomaly was -0.6°C for the week centered around October 22. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.07°C and the ENSO Region 3.4 anomaly has averaged -0.48°C. La Niña conditions will likely continue through mid-winter. The SOI was +18.96 today. The preliminary Arctic Oscillation (AO) was +1.073 today.

Here are the statistics for Central Park (1869-70 through 2024-25):

I agree with your post. IMO, those maps should not be published on any credible site. Such wild swings and extremes on a run-to-run basis are not too surprising. That's why NCEP blends multiple cycles.

I agree. It should also be noted that very few ensemble members show a measurable snow threat for NYC or its immediate suburbs. Yes, it's going to be unseasonably cool. But the threat to NYC and its immediate suburbs appears to be a cold rain with highs in the 40s. If a few wet flakes mixed in, it would be an early "win," but that isn't the base case. Tempting as it might be to take the GFS verbatim or amplify what is a cool synoptic situation into a wintry one (not supported right now), one should resist those temptations, starved for snow as many of us are. If things converge toward a colder, wintry outcome in the short-range, that would be different. The most likely outcome appears to be an accumulating snow threat that is confined to the Catskills, Adirondacks, and parts of Upstate New York and New England.

Highs will reach the middle and upper 50s in much of the region tomorrow. It will then turn slightly milder with highs in the upper 50s and lower 60s through the middle of next week. A weak cold front could cross the region after midweek, perhaps touching off a few scattered showers. Highs will then fall back to the lower and middle 50s. In the long-range, the guidance suggests that an AO+/NAO+ regime could develop during the first week of the month. As has often happened with the loss of strong blocking, a milder regime could develop shortly afterward. The ENSO Region 1+2 anomaly was +0.3°C and the Region 3.4 anomaly was -0.6°C for the week centered around October 22. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.07°C and the ENSO Region 3.4 anomaly has averaged -0.48°C. La Niña conditions will likely continue through mid-winter. The SOI was +5.79 today. The preliminary Arctic Oscillation (AO) was -0.149 today. The NAO was -1.008.