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Some top-notch AFD writing out in MPX. Not quite “bombogenesis, baby!” Thought. A quick note before we dive into the upcoming system: I understand that this event will attract a larger audience than a normal forecast discussion would receive. With that in mind, some may struggle to understand probabilities and the statistics side of this discussion, but I`ll do my best to use layman`s terms when possible. I want to put this Winter storm into into context for the wider audience. This system has maintained remarkable consistency in model and ensemble guidance going back several days. This itself is a rare feat for any system. This storm is a high floor, high ceiling event. What does that mean? There are high probabilities (75 to 90+ percent) that many locations in our forecast area will see a foot of snow by the time it ends Thursday night. This would be considered our "floor" or the lower limit of the potential outcomes. We`ll call this the "if everything goes wrong" scenario. The "ceiling" or upper limit of the potential outcomes or the "if everything goes right" scenario. The ceiling for the entire event is around 2 feet of snow. In hockey, every team wants to draft a prospect that has a high floor/high ceiling because if they only hit their floor, it`s still an impact player on the bottom 6 of your team. But, if they can hit the ceiling, you`re getting a superstar type player that doesn`t come around often. You know the type. Back to the Meteorology.

More interesting is the temperature range in the past week. For KBOS, -10˚ to 57˚ , a 67˚ range in a week which has only happened three times before at Logan. Getting into the top 3 would require 69˚ which is certainly not out of the question: 74˚, Feb 1943 (when Logan recorded its lowest temperatures). -14˚ on 2/15, and 60˚ on 2/21. 70˚, Apr 1976. 24˚ on the 12th, 94˚ on the 18th. 69˚, Feb, 2016, -9˚ to 60˚ (and 54˚ within two days!) 63˚, March 2007, 5˚ to 68˚ 62˚, Jan 2018, -2˚ to 61˚ Three of the top six within the last 7 years …

Ha. Meanwhile on 1/31 the GFS had BOS >0. 12˚ bust.

Just drove to Lake Placid. Car read 0 at CON, -9 at LEB, -18 over the greens (Midd Gap), -9 in Midd, -22 in LKP. Heat did fine in the car. Heat in the motel, not so great.

This year's January Thaw was 31 days long.

Logan has gone below -5˚ 10 days, and half of those were Dec 1942 to Feb 1943. Anything below -5 is a once-in-a-decade occurrence (1942-3, 1957, 1980, 2004, 2016).

Also finding morons: I mean, yes, unless you're talking about Kelvin.

HRRR likes cold. -3˚ at 48h. -25˚ during the day at KSLK, and by 48h at KBML. Wind chills -50.

Ah so 2016 all over again. -9 12Z on the 14th to +55 18Z on the 16th.

I dropped the data for KBOS into a Google Sheet and ran a conditional formatting to compute departures from normal (since 1890). Looks like there are only a few years where DJFM were all AN: 1947-1948 26.8 32.5 17 11.8 1960-1961 16.9 18.7 14.9 9 1992-1993 2.1 0.5 6.6 31.5 1993-1994 4.0 21.3 23.2 7.4 1995-1996 16.5 27.4 2.5 9.4 That's it. 2004-2005 was ever so close, all AN except for Dec, which was -0.4. Yea, 1992-1996 was a good stretch, although with the 1994-5 ratter below in between. As for all months BN, many more since the data is not uniform because the tail can't go past zero. 1900-1901 -6.8 -4.5 -4.2 -7.4 1907-1908 -0.6 -8.0 -3.7 -2.6 1908-1909 -4.1 -1.1 -10.7 -4.3 1914-1915 -3.5 -5.3 -7.9 -7.4 1923-1924 -4.6 -3.8 -5.1 0.0 1927-1928 -7.6 -7.2 -4.3 -0.9 1931-1932 -6.2 -11.1 -3.0 -1.6 1934-1935 -6.0 -11.5 -0.3 -5.3 1936-1937 -6.9 -10.3 -13.0 -5.5 1946-1947 -2.7 -8.4 -4.0 -6.5 1972-1973 -4.3 -8.8 -10.5 -7.1 1978-1979 -1.8 -1.9 -6.4 -7.4 1979-1980 -5.6 -12.0 -6.5 -3.8 1980-1981 -2.0 -0.5 -11.1 -6.9 1984-1985 -3.9 -5.4 -2.8 -3.7 1985-1986 -6.3 -11.6 -2.6 -4.8 1988-1989 -3.9 -10.9 -6.3 -4.2 1990-1991 -6.4 -0.7 -10.2 -4.0 1994-1995 -6.1 -8.0 -4.5 -7.0 2001-2002 -2.6 -4.5 -12.5 -6.0 2011-2012 -7.6 -5.6 -12.1 -6.8 Definite clustering. 5(ish) between 1923 and 1937, then one in the next 36 years, then 8 in 16 years, from 1979-1995, and then 2 in the last 27 years (although this year is shaping up to be one). Some of these data might be off by 0.1" since I changed the Jan and Feb data to input some missing values and that slightly changed the averages.

Not sure what kind of tree it was, but in 2016 where I lived there was a backyard peach tree. No crop that summer (anywhere in New England). But in 2017 there were so many peaches the branches were on the ground.

There's snow on the ground at KASH, which is only about 50 miles. It only seems like there's no snow anywhere because there really hasn't been any south of the border all year.

Strong 2016 feels here. Way AN early on, then no snow until Feb. Then the lowest temperature in 59 years in Boston to kill the peach crop, and the 54° two days later with rain to melt the snow. hooray?

ICON at 180h: -10 in Boston. Sure.

Looks like KBOS may have its warmest Jan low temp on record. Low temp this month sitting at 23, and does not look likely to go lower until right around Feb 1. Previous record is 22 (2002, 2 days that month) and before that 18 in 1932 and 15 in 1953.

Lock that in pls.

Yup, new house has a skylight and it's great for observing p-type. I could hear the pingers two rooms away!

There's a frame of the GFS which shows promise … 1039 high over Quebec, 16 in Boston and -30 in NNE, a strong storm brewing over the SE of the CONUS getting ready to slide off the coast … I don't know what happens next because its in February and it's 384h … but it's an idea! (It's probably good it doesn't go out a few more hours because it would slide up to BUF or something.)

It's been very snowy out there but also warm. December was a -4 month but January is running +8. Temps haven't been below 0 this month, although also not above 37 (and it hasn't been 40 since late November). Normal Jan range is -19 to +41. DLH is even warmer: +11 this month, no temperature below 1 (or above 35). Normal Jan range is -25 to +38.

no

This is a nice CAD storm, with the RA/SN line sitting right where the hills start near Winnipesaukee and not budging in the last hour (the 3k had it further north, even the recent RAP did). With the heaviest SN falling now, the areas with the cold surface air locked in (North Conway, etc) should do quite well. Meanwhile the areas with western exposure get zilch. Not a Mitch storm! But an overperformer for some.

Yeah it's January. Get those snows on stat. This is the kind of setup where south of the notch can hold cold air for a while. Hoping it does!

Congrats YMX / YQB on the NAM. IIRC YQB was getting some rain a few runs ago on some models so that's a slight improvement overall.

I mean if you ask a person on the street in California, they'd probably say it's an El Niño.

That retrograding low on the GFS spinning back from BDA towards the outer banks is just icing on the cake (and maybe a bit of icing in NNE).