donsutherland1

Good luck with the snow. I hope it meets or exceeds your expectations.

The last time in Philadelphia was 2009-2010.

Kuchera maps are different from 10:1 maps.

From the KU books: The trough went negative and the storm wound up tracking inland relative to NYC.

Yesterday was -4.873.

Today is New York City's 7th consecutive day with a low < 20°. The last streak as long or longer than 7 days was during December 27, 2017-January 8, 2018 (13 days).

Below is the NWS forecast for parts of North Carolina and South Carolina. Since 1950, eight storms brought 4" or more snow to Wilmington, NC. Just one of those storms brought measurable snowfall to New York City.

So far, one.

Yes. I've fixed the typo.

A fresh surge of Arctic air is moving into the region. Tonight and tomorrow night will likely see the temperature bottom out at their lowest levels this winter. Single digits are likely in Central Park. The last winter with more than one single-digit day was Winter 2022-23 when there were three such days. Highs will be mainly in the upper teens and lower 20s through Saturday. The last winter with more than one high in the teens was Winter 2018-19 when there were two such days. Temperatures should begin to moderate on Sunday into early next week and could briefly rise to or above freezing. Nevertheless, readings are likely to remain below normal into at least the start of next week. Some light snow or flurries remain possible on Sunday if a developing storm passes close enough to the coast. This outcome is not assured. Eastern Long Island into southeastern New England would have the greatest chance of seeing an accumulating snowfall. Overall, January 20th-February 3rd will likely be the coldest and perhaps snowiest two-week period this winter. The forecast WPO-/EPO-/AO-/PNA+ pattern is typically the coldest pattern in January and among the coldest during the first half of February. A persistently positive PNA will have above climatological risk of moderate or significant snowfalls. For perspective, the coldest two-week period this winter prior to January 20th was January 3-16, 2026 and January 4-17, 2026 with a mean temperature of 30.3°. The snowiest two-week period was December 14-27, 2025 when 7.2" of snow fell. Already, snowfall since January 20th has surpassed that figure. The ENSO Region 1+2 anomaly was -0.3°C and the Region 3.4 anomaly was -0.7°C for the week centered around January 14. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.48°C and the ENSO Region 3.4 anomaly has averaged -0.68°C. La Niña conditions will likely continue into at least late winter. The SOI was +6.84 yesterday. The preliminary Arctic Oscillation (AO) was -4.195 today. Based on sensitivity analysis applied to the latest guidance, there is an implied near 100% probability that New York City will have a cooler than normal January (1991-2020 normal). January will likely finish with a mean temperature near 30.2° (3.5° below normal). Supplemental Information: The projected mean would be 2.4° below the 1981-2010 normal monthly value.

I suspect that there's a programming issue of some kind. Last winter, there were a number of cases where the NBM showed measurable snow even when QPF was 0.00". I raised the issue and was told it would be addressed in the next version (v. 5.0). I suspect that issue is skewing the numbers. For the upcoming system, the 19z NBM showed 0.02" QPF for Philadelphia. Its snowfall forecast was 4.9" (4.3" if 24-hour snowfall is used). That's a wholly unrealistic snowfall estimate.

I don't know. Normally, one doesn't see such a pattern. More may have been involved.

Don't forget X and YouTube, as well.

Based on the preliminary data, the January PNA has averaged +0.172. That average is poised to increase further over the next two days. Given the PNA forecasts, it is virtually certain that a regime change to PNA+ occurred following the long-duration PNA- as had occurred in all 10 previous cases following the end of winter PNA- regimes of 25 days or longer. This outcome runs counter to some of the bold claims made on social media. It also illustrates anew why social media influencers, who are often unaware of historical outcomes, among other things, are typically not a good source of forecasting information. In contrast, numerous people here had correctly suggested the risk of a switch from December's PNA- to a PNA+ in January.

That was from the 1z NBM (QPF: 0.11"); the 13z cycle had 0.04" QPF for Philadelphia. Moreover, it seems that Mount Holly is using v4.3, which is the operational version. V.5.0 is currently in testing, but isn't widely accessible and is not incorporated into the widely used probabilistic tools. V5.0 is supposed to have more realistic snow-liquid ratios, but it won't become operational until spring. During prior upgrades, there was a test site where one could access the output. This time around, the test site isn't being utilized, which undermines early operational examination of the newer version.