Roger Smith

Even so, mild Jan 1890 had zero snowfall and Jan 1933 (Tr) is t-2nd lowest with 2008 and 2023. Jan 1934 is 5th lowest at 0.1" (it was between epic cold Dec 1933 and Feb 1934). So it probably always needed cold air nearby to snow at NYC. 68 of 156 Decembers have had less snow than 2024 at 2.8" so far. The 69th lowest Jan snowfall is 4.7" and for Feb it is 5.4", mar 2.5", Apr trace, so those would be "persistence" forecasts of winter snow, adding to a total of 15.4" (69th lowest winter total is 24.5" in 1976-77, 15.4" would rank 37th lowest and close to 15.3" in 1912-13 and 15.5" in 1970-71).

Feb 1981 was 15th warmest (of 156) at NYC and 13th warmest (of same 156 and 14th of 184 total, 1842 was lone addition not in NYC data) at Toronto, records were set in second half as first half was transitional from the cold January (ranked 19th coldest NYC and 18th coldest Toronto, even better cold ranks if urban heat island correction applied). For comparison, Jan 1994 ranked 17th NYC and t4th at Toronto. I believe there was also a potent cold shot in early Jan 2010 to Florida, followed by a mild spell mid-Jan and the epic storminess from Jan 30 to late Feb (best for mid-Atl).

Probably coastal mixing Dec 31-Jan 1 4-7" snow inland ... I like Jan 13-14 for a big coastal event. A clipper to near-coast scenario in between (Jan 7-8?) Large energy peak in theory for Jan 13-14, as long as resultant storm stays off coast it could be a blizzard scenario. (if it picks up too much warm air over TN-WV it could also become an inland snowstorm and coastal mixer). First faint signs of this one at 384h on GFS. Energy cycle is 8-10 days so I won't expect to see great progs for Jan 13-14 before Jan 4-5 and it will likely show as being for Jan 11-12 for a while then get slowed down as models pick up stronger forcing.

Be optimistic for NYE-NYD potential and watch Jan 13-15 for "big one" as there is a very large energy peak around Jan 14. One medium event possibly in between. I believe there is 20-30 per cent more forcing potential than models are capable of picking up on 5-15 days ahead.

I will go on with contests in 2025, let's keep one annual contest thread ... I will always post on 25th of preceding month any news about additional contests (summer max, snowfall) and scoring will be same format. Readers who might prefer to discuss in general terms can post ideas without being entered in contest, I will only score forecasts in format of departures from 1991-2020 averages at ______ DCA _ NYC _ BOS __ ORD _ ATL _ IAH ___ DEN _ PHX _ SEA ... deadlines will be 06z of 1st of each month, and late penalties 1% per half day to 18z 4th, then 1% an hour. (7% + hrs, expiry 8th 15z) Contest will continue regardless of participation rates even if it turns into a smaller group, as we strive for the elusive new record of 810/900. A history of this contest (2013-2024) is posted in Dec 2023 contest and will migrate to Dec 2024 at end of contest year. Don't forget, no contest threads in 2025, all months will be contained and scored in this one thread. Good luck everyone, and welcome to any new participants. (scroll thru Dec 2024 contest to get an idea of what we do).

In 1981, the warmest Dec was 1891 It is now 11th warmest! 1982 began the parade of warmer Dec averages. Data in C deg and a comparison of Toronto averages and ranks (basically same story, 1923 was warmest, and is now t-6th; it's 13th for NYC) ... the older cases fare a bit better if we assume a gradually increasing urban heat island stabilizing at 2F (1.1 C) deg after 1980. ... 2015 was also warmer in Britain (by 1.6 C) than any other Dec. (9.7 C vs 8.1 in 1934). It would have been the second warmest Nov in the CET series! (It would also have been 15th warmest Nov at NYC, t42nd at Toronto). Rank _ Year _Avg __Tor rank_ avg (C) ___01 __ 2015 __ 10.44 ____ 01 ___ 5.2 ___02 __ 2023 ___7.00 ____ 02 ___ 3.6 ___03 __ 2001 ____6.72 ___ 03 ___ 3.2 ___04t__ 1984 ___ 6.56 ___ 11 ____ 1.7 ___04t__ 2021 ___ 6.56 ___ 05 ___ 2.5 ___06 __ 2006 __ 6.44 ___ 04 ___ 2.9 ___07 __ 2011 ___ 6.28 ___ 10 ___ 2.0 ___08 __ 1998 ___ 6.22 __t06 ___ 2.3 ___09 __ 1982 ___ 6.00 _ t06 ___ 2.3 ___10 __ 1990 ___ 5.89 __ 34 ___ 0.7 ___ 11 __ 1891 ___ 5.72 __ t28 ___ 0.8 ___ 12 __ 1994 ___ 5.67 __ 12 ___ 1.6 ___ 13 __ 1923 ___ 5.56 __ t06 ___ 2.3 ___ 14 __ 2012 ___ 5.28 __ 09 ___ 2.1 ___ 15t __1953 ___ 5.17 __ t20 ___ 1.1 ___ 15t __1996 ___ 5.17 __ t15 ___ 1.2 ___ 17 __ 1979 ___ 5.06 __ 41 ___ 0.3 ___ 18 __ 1931 ___ 5.00 __t28 ___ 0.8 ___ 19 __ 1956 ___ 4.94 __ 44 ___ 0.1 ___ 20 __ 1971 ___ 4.89 __t28 ___ 0.8 ___ 21t __ 1965 ___ 4.72 __t13 ___ 1.3 ___ 21t __ 2014 ___ 4.72 __t26 ___ 0.9 ___ 23 __ 1957 ___ 4.56 __t15 ___ 1.2 ___ 24 __ 2018 ___ 4.50 __t26 ___ 0.9 ___25t __1889 ___ 4.44 __t15 ___ 1.2 ___25t __1999 ___ 4.44 __t22 ___ 1.0 ___ 27 __ 1991 ___ 4.22 __ 55 ___ -0.5 ___ 28 __ 1987 ___ 4.17 __t15 ___ 1.2 ___29t __ 1881 ___ 4.11 __t22 ___ 1.0 ___29t __ 1911 ___ 4.11 __t20 ___ 1.1 ___29t __ 1918 ___ 4.11 __t50 ___-0.4 ___29t __ 1949 ___ 4.11 __t42 ___ 0.2 ___29t __ 1974 ___ 4.11 __t13 ___ 1.3 ___34t __ 1912 ___ 4.06 __t38 ___ 0.4 ___34t __ 1928 ___ 4.06 __t36 ___0.5 ___36 __ 2020 ___ 4.00 __t28 ___ 0.8 ___37 __ 1932 ___ 3.94 __t60 ___-0.9 ___38t __1973 ___ 3.89 __t82 ___-1.9 ___38t __1986 ___ 3.89 __t38 ___ 0.4 ___40t __1905 ___ 3.83 __t50 ___ -0.4 ___40t __1978 ___ 3.83 __t60 ___-0.9_ Also in top 50, recent 2013 and 2022 (t46); 2004 (t49)

I wonder how well the 1947 storm was predicted? I was active in forecasting in 1970s and generally I recall standards were almost equal to present day (if that's a good thing), but in 1947 they were going by hand-drawn prog maps and no NWP, satellite or radar. If somebody can get hold of a newspaper forecast for that storm it would be interesting. (the blizzard of 1888 had a reasonably good forecast for NYC issued from DC, problem being, it never arrived, as the storm destroyed telegraph lines that would have placed a snowstorm warning in the newspaper a few hours before it began ... in 1888 the forecast in the newspaper was basically tonight and tomorrow, sometimes an outlook for next day also. I looked this up a few years ago, DC forecaster knew it was going to change from rain to snow at midnite but nobody in NYC got that warning so people (may have) had no idea what was coming. At forecast time snow had already begun in DC). I recall a 16" snowstorm in Toronto in Jan 1966 that was well predicted, and also a 17" fall west of Toronto in Feb 1965 that we knew was going to occur. But by then satellite imagery was available and very rudimentary models were being tested. I don't think the Chicago Blizzard of Jan 1967 was any big surprise either, we knew in Toronto it was going to go rain-sleet-snow and temp would drop 30F from our record setter on Jan 25th (61F). I was following weather as a high school student then, and as a home wx-stn observer during those tremendous weather events (winter 1963-64 was a bit of a dud but all the others to about 1971-72 were good ones). I observed at various locations to about 1980. Off topic but I have 24" snow pack and 8" of it fell yesterday. It is mild but we're above rain-snow line (barely, Columbia valley has only patchy snow and bare ground in places, at 1500' below my elevation of 3300').

Sunday's max of 21F at NYC is tied third coldest for the date (Dec 22) 1871 and 1888 also had 21F, records that lasted to 1921 with 20F. That record was broken in 1989 (18F). ... tied 6th coldest were 1924 and 1955 (22F). Lowest minima for Dec 23 are -1 F 1883 6 F 1989 8 F 1872, 2022 9 F 1959,60 10F 1945 11F 1943 (will edit in how NYC did this year relative to that group)

I was interested in this too so I looked it up ... only five years had an earlier sub-20F reading after 1905 hit 20F on Nov 14 and 1967 on Nov 15 (and 16). You could say only seven years if you counted those two, no other years hit 20F and no colder before 2018 joined the slowly expanding list. 1880 joined the club on the same date as 2018 but with lower (and still record) readings so that would add one more beating 2018 if the colder reading counts. These years below 20F in order of earliest dates are 1933 _ 17F on Nov 16, 19F on Nov 17 1924 _ 19F on Nov 17 (tied by 1933) 1936 _ 18F on Nov 18, 1924 another 19F (1936 repeated 18F on 19th; Nov 20th has never been below record of 21F set in 1873) 1879 _ 16F on Nov 21, this was the earliest before 1924 despite the much less developed urban heat island 1987 _ 18F on Nov 21, first year to join sub-20F group not to set a daily record when doing so. 1880 _ 13F on Nov 22, prevented 2018 from setting a record with its 17F (also 1987 had 19F) 1880 _ 14F on Nov 23 also prevented 2018 from setting a record with 15F (also 1888 had 19F) From Nov 24 to 30, the following years joined the sub-20F list: Nov 24_ no new members, 1880 hit 14F again Nov 25_ 1938 became 9th year (19F) Nov 26_ 1932 joined, 19F was not a record as 16F in 1880 later tied by 1938. Nov 27_ 1903 and 1917 (tied 19F) joined, their record was broken by 12F in 1932. Nov 28_ 1871 (16F), 1890 (19F), 1901 (19F), 1930 (15F) eventual record low, were years 13 to 16 joining sub-20 list. Nov 29_ 1875 (14F) after 1871,72 at 15F, 1891 at 17F, 1929 and 1930 at 18F, 1955 (15F) (five of seven new to list for total of 21 so far) Nov 30_ 1875 (5F) is Nov record low, 1871 another 15F and 1872t91 (14F), new were 1887 (14F), 1958 (18F) and 1976 (17F) making it 24 years sub-20F by end of November. ... 1929 had 12F and 1936 17F (were already in list). Not only was 2018 a standout, 2017 and 2019 set early marks of 24F (11th 2017 tied 9th 1976 as second coldest so early), and 23F (13th 2019 was colder at that date than any previous year except for 23F on Nov 6, 1879).

It's quite a productive low at present, seeing 1-2" an hour in past few hours (n of Spokane at border). Perhaps models will pick up some new data as the low tracks towards n plains states.

At this point, GFS is essentially a dry transition to very cold, but other models give some support for 1-3" snowfalls Friday night into Saturday morning. The potential for 3-6" is weak but could be revived by any stronger phasing. For now I would predict 0.5 to 2.0 inches to limit error potential. (BTV could get a locally heavy lake effect snowfall too).

Decent snow potential for IA-WI around Dec 30-31, colder pattern to follow, and Jan 12-14 is a good estimate of when there could be a major winter storm in all of the midwest.

If this thing slows down, temps won't be a problem anyway, frigid air will be in place but so far it looks like 1-3" widespread (Fri-Sat, 15-20 F) and 3-6" in down east maine, to 6-12" in NB and parts of NS, PEI.

Looking at all data, NYC has seen a few cold Dec with little or no snow. In the colder half of all data, these Dec had 2.0" or less snowfall: Rank _ DEC _ Avg T _ Snow 77 _ 1900 _ 36.3 _0.1" 72t_ 1954 _ 35.9 _0.1" 72t_ 1988 _ 35.9 _0.3" 67t_ 1885 _ 35.7 _Tr 67t_ 1901 _ 35.7 _2.0" 67t_ 1977 _ 35.7 _0.4" 65 _ 1937 _ 35.4 _0.7" 63 _ 1983 _ 35.2 _1.6" 61 _ 1925 _ 34.8 _ 0.9" 59t_ 1888 _ 34.7 _ Tr 57t_ 1898 _ 34.6 _1.5" 51t_ 1906 _ 34.2 _0.3" 51t_ 1985 _ 34.2 _0.9" 48t_ 1924 _ 34.0 _0.9" 46t_ 1875 _ 33.9 _1.0" 38t_ 1934 _ 33.4 _1.0" 37 _ 1943 _ 33.0 _Tr 17 _ 1882 _ 30.6 _ 0.0" 03 _ 1989_ 25.9 _ 1.4" (note Dec 1875 was very cold first half and very mild second half)

There seems to be a lot of consensus for a snowstorm in NB, n Maine, and eastern Quebec, starting to need retrogression to shift capture closer to s NE or LI. It will definitely be quite cold for a couple of days, lake squalls and a coating of snow in NNW flow but for a big snowfall the current signal is down east. The energy peak for Dec 30-31 is starting to look like a cutter and a snowstorm for parts of the Midwest. I would keep Jan 12-14 open for consideration as timing for a really big east coast storm.

Will go Dec 30-31 for big event, pattern will need to shift for it to be wintry so if it does not shift, event will be a surge of record warm followed by strong winds. Possible inland to GL snowstorm. If pattern shifts, winter storm for coast also. Big energy peak then anyway. We'll see what it has to work with.

Table of forecasts for snowfall winter 2024-2025 ... listed in order of total snowfall predicted ... FORECASTER ______________ DCA _NYC _BOS __ ORD _DTW _BUF ___ DEN _SEA _BTV ___ TOTAL Roger Smith ________________13.5_ 32.0_ 47.0 ___ 50.6_ 52.2_ 130.0 ___ 89.0_ 1.5_109.3 ___ 525.1 wxdude64 _________________ 18.8_ 36.2_ 44.3 ___ 37.8_ 41.3_ 122.9 ___ 71.2_ 7.4 _102.7 ___ 482.6 Tom ________________________26.2_ 38.1_ 42.4 ___ 37.6_ 42.3_ 102.6 ___ 57.7_ 6.4__83.4 ___ 436.7 ___ Normal 1991-2020 _____13.7_ 29.8_ 49.2 ___38.4 _45.0__95.4 ___ 49.0_ 6.3__87.5 ___ 414.3 BKViking ___________________12.0_ 27.0_ 44.0 ___ 30.0_ 28.0__ 98.0 ___ 55.0_14.0_ 100.0 ___ 408.0 RodneyS ____________________5.8_ 22.0_ 38.5 ___ 42.5_ 45.0__ 99.0 ___ 58.0_ 9.5__85.0 ___ 405.5 ___ Consensus ____________14.8_ 23.6_ 34.8 __ 35.0_ 36.7 _ 104.2 __ 57.4 _ 5.8 _ 91.7 ___ 404.0 RJay _______________________ 4.0_ 12.0 _ 50.0 ___ 29.0_ 35.0_ 100.0 ___ 60.0_ 6.0_ 100.0 ___ 396.0 Scotty Lightning ___________20.0_ 25.0_ 30.0___ 35.0_ 30.0_ 106.0 ___ 45.0 _ 3.0_ 100.0 ___ 394.0 wxallannj __________________25.0_ 30.0_ 34.0 ___32.0_ 35.0__ 94.0 ___ 40.0_ 4.0__ 88.0 ___ 382.0 Don Sutherland1 ___________ 8.0_ 16.5_ 35.0 ___ 40.0_ 45.0__ 95.0 ___ 55.0_ 8.0__ 75.0 ___ 377.5 hudsonvalley21 ____________17.0_ 21.0_ 28.0 ___ 26.0_ 24.0_ 102.0 ___ 51.0 _ 4.0__ 84.0 ___ 357.0 so_whats_happening ______13.0_ 19.0_ 35.0 ___ 29.0_ 31.0__ 98.0 ___ 39.0 _ 3.0__ 81.0 ___ 348.0 ___________________________ Persistence (2023-2024) ___ 8.0__ 7.5__ 9.8 ___ 22.2_ 23.5__ 71.3 ___ 44.6_ 0.3__ 60.8 ___ 248.0 _________________________ To date _____ (Jan 25) ______ 8.6 __ 5.8 __12.5 ___ 9.9 _14.1 __ 48.7 ___ 37.0 __0.0 __27.9 ____164.5 (contest incl all seasonal snow) 1991-2020 normals from NWS website, DEN is Stapleton (since new airport did not exist all years of period) Consensus does not incl 1991-2020 or Persistence (last winter's contest finals). It is average of eleven forecasts.

TRW 70% likely 22z to 23z in NYC metro, 23z to 00z sw CT and LI. Expect first T reports from cNJ 21z to 22z. Slight bow echo on cold front near PA-NJ border now. Gusts to 45 possible and 35 likely. Could be minor svr wx risk by 01-03z in e NE, gusts to 60 kts (all gust references earlier in kts)

Given how conventional weather models are designed and operate, how is "AI" any different? A conventional weather model is an objective prediction not based on any human input (after humans give model latest data), so I can't really see how "AI" is anything different? What does an AI weather model do that a conventional weather model (in use since 1970s) does not do? (and if they aren't as good, what's the point of them, what can in future allow them to outdo the ones we use now?) And what prevents operators of those models from incorporating same advances? Why would one not do so? I guess I am a bit skeptical about the real nature of "AI" and I suspect it is just jargon for "different technique" since we already have weather models that are objectively derived simulations of a future state of the atmosphere, what can AI possibly be other than that same thing?

Table of forecasts for December 2024 FORECASTER ___________________ DCA _ NYC _ BOS __ ORD _ ATL _ IAH ___ DEN _ PHX _ SEA RJay _____________________________+1.5 _ +1.5 _ +1.5 ___ +1.5 _ +1.0 _ +2.0 __ +4.0 _ +4.0 _ +4.0 Scotty Lightning _________________ +1.0 _ +1.0 _ +0.5 __ +0.5 _ +1.0 _ +1.5 __ +0.5 _ +1.0 _ +0.5 StormchaserChuck _______________+0.8 _ +0.8 _+0.4 ___+1.1 _ +2.0 _ +2.0 __+4.5 _ +3.8 _+0.9 hudsonvalley21 __________________ +0.6 _ +0.5 _ +0.2 __+0.2 _ +0.7 _ +1.0 __+0.2 _ +0.9 _ +0.1 ___ Normal _______________________ 0.0 __ 0.0 __ 0.0 ___ 0.0 __ 0.0 __ 0.0 ___ 0.0 __ 0.0 __ 0.0 Don Sutherland1 __________________ 0.0 _ -0.5 _ -0.3 ___ +1.2 _ +0.2 _ +1.7 ___+3.6 _ +3.6 _ +4.4 BKViking _________________________ -0.5 _ -0.7 _ -2.0 ___+0.2 _ +0.5 _ +2.2 ___+4.0 _+4.0 _+3.2 ___ Consensus __________________ -0.6 _ -0.6 _ -0.8 ___+0.2 _+0.4 _ +1.4 __ +1.9 _ +2.4 _+1.0 wxallannj ________________________ -0.7 _ -1.0 _ -1.2 ____ -0.6 _ +1.4 _ +1.8 ___ +2.1 _ +1.8 _ +2.4 so_whats_happening ____________ -0.8 _ -0.6 _ -1.0 ___ +1.0 _ +0.8 _ +1.2 ___ +1.6 _ +2.2 _ +0.8 wxdude64 _______________________ -1.1 __-1.5 __-0.7 ___ -0.4 _ -0.3 _ +0.6 ___ +0.6 _ +1.4 _ -0.4 Tom ______________________________-1.2 _ -1.5 _ -1.5 ____ -1.1 __ -0.8 _ +0.5 ___ +1.7 _ +1.9 _ +2.1 Roger Smith ______________________-2.2 _ -2.4 _ -1.5 ___ -3.0 __ 0.0 _ +1.5 ___ +1.5 _ +3.5 _ -0.2 RodneyS _________________________ -3.7 _ -3.2 _-3.2 ___ -2.5 _ -3.6 _ -1.5 ____ +2.9 _ +2.6 _ +1.1 ___________________________ Persistence (Nov 2024) _________ +5.3 _ +3.4 _+4.2 ___+4.9 _+5.4 _+7.3 ____-1.2 _ -1.0 _ -0.5 highest and lowest forecasts are color coded ... Normal is lower than all forecasts for DEN and PHX

I would expect a few fast-moving squalls of hail and then snow after frontal passage Thursday, temps peaking at 45F before front passes, and a fast drop to 30F by evening. Winds gusting to 45 mph. A milder spell Sunday to midweek with a peak temp near 60F then a week or so close to mid-Dec normals in 40s. Signs of a colder reload near end of GFS 12z. Overall the month could hang on to a negative departure if there is in fact a later reload.

Four Seasons Contest __ Final Report Points for four seasons ... 10 for first (total 3 scores), 7 for second, 6 for third, etc, 1 point for all entrants with 2/3 or 3/3 ___________________________ Winter ___________ Spring __________Summer _________________ Autumn _______________ Annual FORECASTER _______TOTAL_Points __ TOTAL_Points _ TOTAL_Points _ S_ O _N __ TOTAL_Points _ Contest TOTAL wxallannj ______________ 1736 __10 ____ 2224 __10 ____1706 ___6t ____ 602 481 568_ 1651 __ 7 ______ 32 DonSutherland 1 ________1524 __ 7 ____ 2010 ___3 ____1694 ___ 4 _____588 495 648_ 1731 __10 _____ 24 Roger Smith _____________ 793 __ 1 _____2124 ___6 ____1954 __ 10 _____530 330 688_ 1548 __3 _____ 20 ___ Consensus __________1408 __3.3 ___2088 __5.5 ___1758 ___ 6.2 ___ 594 450 588_ 1632__4.8_____19.8 so_whats_happening ___1487 __ 5 _____1946____2 ____1706 ___ 6t ____ 516 425 585_ 1526 __ 2 ______ 15 RJay ___________________ 1391 __ 3 _____2142 ___7 ____1580 ___ 1 ______664 468 510_ 1642 __ 5 ______ 16 Tom ____________________1038 __ 1 _____ 2050 ___5 ___ 1682 ___ 3 _____ 556 437 650_ 1643 __ 6 ______ 15 hudsonvalley21 _________1450 __ 4 ____ 1918 ___ 1 ____ 1568 ___ 1 ______576 524 499_ 1599 __ 4 ______ 10 Scotty Lightning ________1184 __ 1 ______1900 ___1 ____ 1906 ___ 7 _____ 572 470 429_ 1471 ___ 1 ______ 10 RodneyS _______________ 1497 __ 6 _____1700 ___1 ____ 1550 ___ 1 _____ 488 540 494_ 1522 ___ 1 _______9 rainsucks _______________ 1111 ___ 1 _____2040 __ 4 ____1622 ___ 2 _____ 636 --- ---____ 636 __ 0 _______7 BKViking ________________ 1336 __ 2 ____1921 ___ 1 _____1130 ___ 1 _____ 558 428 --- ___ 986 __ 1 _______5 wxdude64 _______________1098 __ 1 ____ 1722 ___ 1 ____ 1412 ____1 _____ 442 296 437 _ 1175 __ 1 _______4 ___ Normal ______________ 1002 __ 1 ____ 1474 ___ 1 ____ 1470 ___ 1 _____ 526 294 296 _ 1116 __ 1 _______4 Stormchaser Chuck ______792 ___ 1 _____708 ___ 0 ____ 1484 ____ 1 _____--- 665 --- ___665 __ 0 ______2 Rhino16 __________________ 747 ___ 1 _____672 ____ 0 ____ 739 ___ 0 _____ --- --- --- _____--- __ 0 ______ 1 ***= = ====================== [[[]]] ====================== = =*** Persistence ______________ 972 ___ 1 ____ 1818 ___ 1 _____1592 ____ 1 _____ 706 602 490_1798 __10 _____ 13 ____________________________ GeorgeBm 590 in July only entry not qualified for contest points.

-2.2 _ -2.4 _ -1.5 __ -3.0 _ 0.0 _ +1.5 _ +1.5 _ +3.5 _ -0.2 13.5 _ 32.0 _ 47.0 __ 50.6 _52.2_130.0 _ 89.0_1.5 _ 109.3

Note to regulars and potential new entrants, Dec contest is approaching deadline in general forum.

As you know, 2023 was warmest year for NYC and it looks possible that 2024 will replace it unless DEC is cold (last year it was very mild). Allowing for a drop of 1.9 in NOV (now at 52.9 after 26 days), these are the differentials showing that 2024 has overtaken 2023 after June and will have a total differential of +7.2 deg. Therefore DEC will need to average 7.2 lower than last year's toasty 44.6 (2nd to 2015) to create a tie (a narrow range around 37.4 F will create a one-decimal tie). 36.8 appears to be a target value to prevent 2024 from overtaking 2023, and that average for DEC ranks 74th out of 155 and is below all but six averages for DEC since (and incl) 2000 (2002, 2005, 2009, 2010, 2017). 2023 ___43.5 _41.1 _44.6 _ 57.6 _62.7 _70.0 _79.0 _74.0 _69.4 _ 60.5 __46.7 __ 44.6 ___ 58.0 2024 ___37.0 _40.1 _48.1 _ 55.6 _65.0 _75.1 _79.6 _75.1 _68.8 __ 60.9 __ 51.0 __ ?? diff ____ -6.5 _-1.0 _+3.5 _-2.0 _+2.3 _+5.1 _+0.6 _+1.1 _-0.6 __ +0.4 __ +4.3 __ ?? DEC 2024 will need to average below 31 F to fall below tied 2nd warmest 2012, 2020. An extremely cold DEC could take 2024 out of the top ten because the ranks are quite densely populated starting with four years tied 4th warmest (1990,91,98, 2016) just behind the second place tie.