donsutherland1

Highest snowfall so far: 6.0", Highland, VA. 0.4" at Wilmington, DE.

there is a coating of snow in Atlantic City:

Philadelphia and New York City will see their streaks end. It will be close in Atlantic City, which would set a new record of 716 days if it fails to measure 1" today.

Select snowfall amounts from the Washington-Baltimore Area: Baltimore: 1.4" Sterling (Dulles Airport): 1.8" Washington, DC: 1.8"

Periods of snow brought light accumulations to the Washington, DC area today. Light snow and flurries have also been falling in the Philadelphia and Wilmington, DE areas. Dulles Airport saw its record 673-day streak without an inch of daily snowfall come to an end. A similar fate awaits record-breaking streaks in Baltimore, New York City, Philadelphia, and likely Atlantic City. The storm bringing periods of snow to the Middle Atlantic region will likely bring a general 1"-3" snowfall to New York City and Boston tonight into early Wednesday. Philadelphia and areas north and west of New York City and Newark could see 2"-4" of snow with some locally higher amounts. In addition, the snow could change to some light rain or freezing rain, especially in areas from New York City south and east. A fresh shot of cold air will overspread the region following the storm. A stronger shot of cold will arrive late in the week or during the weekend following another storm. The low temperature could fall into the teens in New York City during the middle of the week for the first time this season and should fall into the teens during the weekend, which will likely see this winter's coldest readings so far. Beyond that, a noticeable warming trend that could send temperatures well into the 40s across the region and even into the 50s in parts of the region will likely commence. This warm period will very likely assure that January winds up as a warmer than normal month and Winter 2023-24 winds up as a warmer than normal winter in the New York City and Philadelphia areas. The ENSO Region 1+2 anomaly was +0.9°C and the Region 3.4 anomaly was +1.9°C for the week centered around January 10. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +1.18°C and the ENSO Region 3.4 anomaly has averaged +1.95°C. A basinwide El Niño event is ongoing. The ongoing El Niño event has recently peaked. The SOI was +33.74 today. That is the highest SOI figure since April 8, 2023 when the SOI reached +33.74. The preliminary Arctic Oscillation (AO) was -2.459 today. Strong blocking in the final week of November, as occurred this year, has often been followed by frequent blocking in December and January. On January 13 the MJO was in Phase 4 at an amplitude of 1.515 (RMM). The January 12-adjusted amplitude was 1.365 (RMM). Based on sensitivity analysis applied to the latest guidance, there is an implied 72% probability that New York City will have a warmer than normal January (1991-2020 normal). January will likely finish with a mean temperature near 35.1° (1.4° above normal).

Early snowfall amounts from the Mid-Atlantic Region: Baltimore: 0.5" Sterling, VA: 0.9" Washington, DC: 0.7" The highest figure so far is 2.8" at Bayard, WV. Light snow and flurries were continuing to fall in Philadelphia and Wilmington, DE. Reading had seen its first flurries. Richmond had flipped to a period of moderate snow prior to the changeover to light rain, which has now occurred.

Richmond (the Airport) has flipped to light snow.

For those looking beyond the warmup following next weekend's cold shot, here's how February looked for ENSO cases where the tri-monthly ENSO Region 3.4 anomaly reached +1.5°C or above: Those are mean temperatures and there was substantial variability year-to-year. The key insight is that there should be a return of colder weather for at least a time.

I’m thinking around 6”, but ratios should be high and the snow fluffy. Maybe the highest elevations will see 8”.

The 12z HREF 24 hour snowfall for the period ending 1/17 0z:

It has been an impressively warm start to winter and the first half of January. The magnitude of the warmth makes it likely that winter 2023-24 will go in the books as yet another warmer than normal winter.

Weekly outcomes: Overall, the period wound up even warmer than had been suggested on the guidance. It was also very wet as highlighted by the guidance.

Light snow commenced in Baltimore just before 8:30. The snow will be marching slowly northward, reaching Philadelphia between 4 pm and 7 pm, Newark and New York City between 6 pm and 9 pm, and Bridgeport between 8 pm and 10 pm. It is possible that Central Park's streak without 1" daily snowfall could continue today, but the streak should be brought to an end by the storm with a general 1"-3" falling across the New York City Metro Area. Latest EPS and NBE numbers: The snow is coming.

Things remain on track for a general 1"-3" snowfall tomorrow night and Tuesday. There is now a good consensus among the guidance. The coming snowfall will likely to end record streaks with less than 1" daily snowfall at Atlantic City, Baltimore, New York City (Central Park), Philadelphia, and Sterling. Snowfall ratios in New York City and nearby areas will generally be in the 9:1 to perhaps 12:1 range unlike with the January 6-7 storm where ratios were barely above 1:1 in the New York City area. EPS and NBE Data: WPC Probability of 24-Hour Snowfall of 1" or More: WPC Probability of 24-Hour Snowfall of 2" or More: Overall, the storm should only have minor impacts even as it will be the biggest snowfall in nearly two years in New York City and Philadelphia. WPC's Winter Storm Severity Index:

Buffalo saw the temperature fall below 20° today for the first time this season. The previous latest first occurrence of teens was January 3, 2016 and January 3, 2022. The Buffalo area, especially the Southtowns, was experiencing heavy lake effect snow. Nothing like that is occurring in the northern Middle Atlantic Region. Nevertheless, in the wake of this afternoon's snow flurries and snow showers, a significant push of cold air is underway. This cold air mass will set the stage for a snow event across the region. A storm will likely bring a general 1"-3" snowfall to Philadelphia, New York City, and Boston on Tuesday into Wednesday. Some uncertainty persists. However, consistent with historic climatology, a significant snowfall (general 6" or above snowfall) is not likely in the northern Mid-Atlantic region. Additional cold air will arrive following the storm and then late in the week following another storm. The low temperature could fall into the teens in New York City during the middle or end of the week for the first time this season. Friday or Saturday could afford another opportunity for snowfall. Beyond that, a noticeable warming trend that could send temperatures well into the 40s across the region and even into the 50s in parts of the region will likely commence. The ENSO Region 1+2 anomaly was +1.0°C and the Region 3.4 anomaly was +1.9°C for the week centered around January 3. For the past six weeks, the ENSO Region 1+2 anomaly has averaged +1.38°C and the ENSO Region 3.4 anomaly has averaged +1.97°C. A basinwide El Niño event is ongoing. The SOI was +26.53 today. The preliminary Arctic Oscillation (AO) was -2.459 today. Strong blocking in the final week of November, as occurred this year, has often been followed by frequent blocking in December and January. On January 12 the MJO was in Phase 3 at an amplitude of 1.365 (RMM). The January 11-adjusted amplitude was 1.127 (RMM). 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 January (1991-2020 normal). January will likely finish with a mean temperature near 34.8° (1.1° above normal).

Buffalo saw the temperature fall below 20° for the first time this winter. That was the latest first teens on record. The old record was set on January 3, 2016 and tied on January 3, 2022. Buffalo's record 322-day streak with temperatures at or above 20° also came to an end.

There was a brief snow shower in the White Plains area. Some dustings occurred in Armonk.

Flurries in Larchmont.

Both models had upgrades.

In terms of verification scores, the Canadian model consistently ranks third. Recently, it has ranked second.

The potential is better, at least from this far out. There's a risk that it could wind up becoming a January 30-31, 1987-type event if the trough exits a bit faster than currently modeled. Were that to happen, eastern New England would be favored and New York City and southward could miss out on most of the snow. Long Island could still get brushed. During that event, Boston picked up 3.9" of snow, NYC had no measurable snow, and Philadelphia saw 0.4". There is a significant difference from 1987, as colder air should be available this time around. January 30-31, 1987 500 mb anomalies: EPS 500 mb anomalies: 168 hours

It will be tough to keep the streak doing through this week. Even if Tuesday's event falls apart, there's another shot Saturday.

Weekly numbers: The most "winterlike" week so far this season lies ahead.

Today will be the 700th consecutive day on which New York City's Central Park has seen less than 1" daily snowfall. A system could end the streak on Tuesday.

A general 1" to perhaps 3" snowfall still appears likely for Philadelphia to Boston. There is a possibility that somewhat more snow could fall in and around the Boston area. There remains some uncertainty, but the guidance has been converging on a solution. WPC Maps: Latest EPS and NBE Data: