Roger Smith

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 ___ 413.6 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 ___ 404.5 ___ 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 _______ (Dec 17) ______ Tr ___ Tr ___ 0.3 ____ 3.1 _ 3.7 __ 15.1 ____ 23.3 __ 0.0 __ 8.4 ____ 53.7 (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 _ -0.5 _ -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.