December 2025 OBS and Discussion

[MJO812]

8 minutes ago, EastonSN+ said:

Little Christmas miracle on the EURO. 1 to 3 inches, however, in any event not warm.

Gfs also 

[Jersey_Snowhole]

59 minutes ago, EastonSN+ said:

Little Christmas miracle on the EURO. 1 to 3 inches, however, in any event not warm.

GFS back to it long range fantasy storms. Something to monitor 

Euro as well 

[SACRUS]

 

Snow is about 4 - 6 hours out.

[donsutherland1]

Snow will overspread the region tonight and continue into tomorrow. It should taper off to flurries during the middle or latter part of the morning in New York City and early afternoon on Long Island. The New York City area will see a general 3"-5" snowfall with some locally higher amounts.

Final estimates:
Allentown: 2"-4"
Atlantic City: 3"-5"
Baltimore: 3"-5"
Bridgeport: 2"-4"
Islip: 3"-6"
New York City: 3"-5"
Newark: 3"-5"
Philadelphia: 3"-6"
Poughkeepsie: 1"-3"
Washington, DC: 2"-4"

In the wake of the system, tomorrow and Monday will be blustery and cold days. High temperatures will likely wind up below freezing.

The WPO has reached severely negative levels. That will likely contribute to the December 10-20 period being colder than normal overall. Moderation is possible late in the period as the WPO begins to rise.

The probability that December 2025 will have a maximum monthly temperature below 60° is increasing. The last time that happened was in 2019 when the monthly high was 58°. If 2025 has a monthly high below 60°, that would be only the fifth such occurrence since 2000 (2003, 2004, 2005, and 2019 are the cases since 2000).

The ENSO Region 1+2 anomaly was -0.2°C and the Region 3.4 anomaly was -0.5°C for the week centered around December 3. For the past six weeks, the ENSO Region 1+2 anomaly has averaged -0.27°C and the ENSO Region 3.4 anomaly has averaged -0.65°C. La Niña conditions will likely continue through at least mid-winter.

The SOI was +4.62 today. 

The preliminary Arctic Oscillation (AO) was +1.254 today. 

Based on sensitivity analysis applied to the latest guidance, there is an implied near 91% probability that New York City will have a cooler than normal December (1991-2020 normal). December will likely finish with a mean temperature near 34.7° (4.4° below normal). 

Supplemental Information: The projected mean would be 2.7° below the 1981-2010 normal monthly value. 

 

[Roger Smith]

Lowest maxima for Sunday and Monday for NYC

DEC 14 _ 21 (1902), 22 (1888), 23 (2010), 24 (2005), 26 (1903,1904), 27 (1898), 28 (1933)

DEC 15 _ 20 (1874,1914), 22 (1917), 25 (1871), 26 (1903), 27 (1919, 1962, 2010), 28 (1904, 1905, 1916, 2017)

Lowest minima for Monday

DEC 15 ___ 8 (1874), 9 (1883), 10 (1914, 1917), 13 (1900, 1902), 14 (1910, 1943, 1962), 15 (1904, 1921) __ 18 (1980, 2005) coldest recent years

Heaviest snowfalls 13-14 (2d totals include all > 1.0")

1917 _9.5" (8.0+1.5)

1902 _6.1" (6.0" 13th, 0.1" 14th)

1915 _6.0" (5.0+1.0)

2003 _5.8" (all on 14th)

1889 _5.5" (all on 14th) 

2013 _5.0" (all on 14th)

1942 _4.1" (all on 13th)

1922, 1945 _3.2" (all on 14th)

1904 _2.8" (on 13th, followed 4.2" on 12th for 7.0" total)

1951 _2.5" (all on 14th) +0.8" 15th = 3.3" total

1933 _2.2" (2.0+0.2)

1995 _1.7" (all on 14th)

1892 _1.5" (all on 13th), 1893 and 1907 _1.5" (all on 14th)

1981 _1.4" (all on 14th)

1923, 2017 _1.2" (all on 14th) _ 2017 added 1.2" 15th for 2.4" total.

1909 _1.0" (all on 13th)