Roger Smith

Weak arctic front is being wrapped into core as low enters Atlantic and a gradient fr S- to S+ conditions will develop in c/n NJ, NYC and w LI, expect 2-3" ISP and JFK, 3-5" LGA-NYC-EWR and 5-8" parts of n NJ and seNY, w CT.

Largest snowfalls at NYC for Jan 18, 19 and 20 For Jan 18, record daily snow was only 5.0" (1875); tied for lowest daily record in Jan. (6, 9 also 5.0" records) For Jan 19, record daily snow 9.0" 1936. (a total snow of 9.2" 18-19) For Jan 20, record daily snow 11.1" 1978. (a total snow of 13.6" 19-20) Other significant snowfalls: 9.9" Jan 19-20 1961 (4.4" + 5.5") 7.0" Jan 20 1925 6.0" Jan 19 1869 5.7" Jan 20 1937 4.0" Jan 19 1886 4.0" Jan 18-19, 2009 (2.2" + 1.8") Before NYC records began, a blizzard hit n.e. states on Jan 19, 1857, 18" was recorded by Caswell in Providence RI, and it was followed by extreme cold (-14 F on 21st and 22nd). Daytime readings stayed below zero F. Jan 1857 was coldest on record at Toronto (1840 to present) and Feb 1857 became very mild with severe ice jam flooding reported in Ontario, New York state and New England. Temps rose into 60s and some heavy rainfalls were reported; march went back to being very cold and the entire spring was cold.

The second of the three "threats" looks way suppressed and OTS, but the third one looks interesting. The first one is beginning to lock into a 3-6" event.

This is a scaled down version of historical big coastal storms followed by severe cold, so far no guidance raises the intensity to a major snowstorm (12"+) but 4 to 7 inches ain't too shabby. I wonder if there will be a last minute intensification trend on track already pretty solidly set? I will say 4.5" DCA, 6.0" IAD and BWI, jacks a bit north near 8" if no last ditch intensification, probably the flow is too flat to allow for it. That's good in a way, colder air won't be forced to retreat, it's a glider and a slider.

Is there any easy answer to the question, what is the difference between an "A.I." weather model and the regular models? At first glance, it would see that all weather models are "A.I."

Anomalies and projections ... _____________________ DCA _NYC _BOS __ ORD _ATL _IAH ___ DEN _PHX _SEA ___ (anom1-16) ______ -4.2 _-2.3 _ -1.1 ___ -3.8 _-4.9 _-4.1 ___ -4.2 _ +0.9 _-1.0 __ (p anom 1-31) ____ -5.0 _-3.5 _ -2.5 ___ -6.5 _-6.5 _-4.5 ___ -4.0 __ 0.0 _-2.5 Very cold intervals for all locations expected to dominate second half, PHX stays closer to normal and will be near +1.5 before seeing any negatives, IAH possibly too conservative if snow cover develops as it can create -25 anoms for several days, DEN is also going to recover to around -2 before dropping back, and SEA will have a very cold final week and drop a bit further below, despite possibly no snow cover in Puget Sound region (it has not snowed s of Anacortes WA so far in winter 24-25 at low elevations, lots above 1200' ... a little snow was reported in BLI and YVR in Dec, bare now). Snowfall contest updates are back in Dec contest thread, probably won't appear here until Feb (keep in mind, all 2025 contests will be in one huge thread going forward -- it's pinned and I will always be in around 25-26 to end of each month to indicate any additional contests).

A very dry first two weeks (0.10" at NYC). On pace to break record for driest Jan, top 25 are: _01 __ 0.58 __ 1981 _02 __ 0.66 __ 1970 _03 __ 0.77 __ 1955 _04 __ 0.94 __ 1876 _05 __ 0.96 __ 1896 _06 __ 1.00 __ 1985 _07 __ 1.10 __ 1969 _08 __ 1.28 __ 1916 _09 __ 1.39 __ 1967 _10 __ 1.54 __ 1956 _11 __ 1.65 __ 1954 _12 __ 1.66 __ 1901 _13 __ 1.68 __ 1992 _14 __ 1.70 __ 1957 _15 __ 1.72 __ 1980 _16 __ 1.78 __ 1933 _17 __ 1.86 __ 1946 t18 __ 1.87 __ 1928 t18 __ 1.87 __ 1984 t20 __ 1.88 __ 1872 t20 __ 1.88 __ 1961 t22 __ 1.93 __ 1963 t22 __ 1.93 __ 2002 t22 __ 1.93 __ 2020 _25 __ 2.01 __ 1894 __________ We'll see where 2025 finishes, if among these.

I've heard of the illuminati and now we have the eliminati, a group that may have a few more members by next week.

Severe cold to follow snow (or no snow) window.

Pattern looks like 3-6" Jan 12-13 followed by 2-3 days of severe cold Jan 14-16. It can still evolve into 5-10" if trof digs a bit better.

What's the max report so far? (I don't have time to read last 30 pages)

Any actual storm in time frame Jan 11-14 will be tapping on tidal energy peak as moon passes its northern declination max on Jan 12, and full moon is Jan 14. In my research, storm index values in eastern N America generally peak at 2-3x random expectation in this time window; another peak will occur Jan 26-29 with the opposite pair of events, southern max and new moon. The separation is longer each "syzygy" as declination cycle is 27.32 days (sidereal) and full moon period is 29.53 days (synodic). By June, new moon and northern max coincide. Research establishes that moon is not setting up steering patterns so it's a second-order energy peak entirely dependent on other factors setting up the scenario it works within, but if there's any sort of reasonable pattern, Jan 11-12 is likely to be a "big event." If this were a torch pattern, a northern max low would be expected to be a strong cutter bringing warmth and rainfall to n.e. states, if it were a near-average zonal flow it would likely be a mild day followed by strong W-NW winds. The models are clearly picking p the energy peak, depends on the degree of suppression as to where the deep low goes once passing 85W. In previous years, snowfall events around Jan 11-12: 7.8" Jan 10-11, 1954 5.7" Jan 11 1991 9.1" Jan 11-12, 2011 12.5" Jan 12-13, 1964 8.7" Jan 13 1939

Call (first and last) ... 7 to 12 in widespread in all areas, tapering to 4 in s VA. DCA _ 7.5" IAD _ 11.0" FDK _ 12.5" BWI _ 9.5" SBY _ 5.5" RIC _ 3.7"

Dr Ray, Dr Ray to the operating theater ... the patient refuses to die and we've promised the organs to another institute ... surgery is required ... Dr Ray ...

I waived late penalties to earlier Friday so if you want to get started at a very reasonable 5% penalty (by 18z Sat) you can jump in.