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Focus below is the I-84 corridor inclusive of just w and n of NYC by just a few miles. May post an OBS thread for this at 530PM if it looks close enough to NYC to measure. For now probably not. Friday 4AM-2PM: Two bands of snow cross the area with 1/2-2" accumulations Poconos - nw NJ (high terrain there) and Trace to around 1 inch CT/MA. Slight chance of freezing rain mix but mostly snow. It will be slippery on untreated surfaces in ne PA/nw NJ Friday morning, and may be slippery in norther CT and MA, especially high terrain.

One additional note: I think the NAM which has hints on its 06z run will be helpful in trends, whether this was an aberrant 06z GFS northward cycle. The 06z GGEM says no way and we need that on board for an event.

Thursday Feb 4: 614AM topic update. Have dropped the wind event (45MPH+) and wind chill (-15 Poconos) and narrowed the date range. As many are witnessing, the modeling has been uncertain but always the ensembles have suggested a little bit of snow Sunday. Individual model operational cycles have tended to be nil (exception EC and V16 robust early on) until the 06z/4 GFS V15 and 16. The 06z GEFS has developed an 850MB LO just south of LI and increased qpf dramatically. (graphic added). Noting also other 00z/4 ensemble MINOR increases in QPF and NAEFS indications of rapidly developing low pressure as it passes southeast of our subforum Sunday night. Until the ensembles nix the event, am continuing the snow threat. The 00z/4 MEX MOS was only 14% chance of qpf Sunday, so it's difficult to be sure about an event Sunday. Ensembles suggestion and recent GFS northward trend (uncertain) in my mind require consideration of a general 1-4" snow event Sunday (may be melting on pavement on LI with marginal near freezing temps during any snow). I've kept the 9" max in there, just in case the coastal comes closer but 9" is highly unlikely. We do know it's going to be a vigorous event but its northwest proximity to our area is in doubt. Gusty north-northwest winds may follow Sunday night and it could be quite a bit colder Monday morning (near 14 NYC?) than statistical guidance suggests. No thread on the 9th-10th, if ever) until Super Bowl Sunday is better resolved. Added 06z GEFS 24 hr qpf, as well as a number of plumes for LGA , qpf, snow, 2m temps and 850 temp)

Forgetting about records--- and barring seeing a specific message on the discounting of 35... which I have no stake in, but I do have a stake in useful snow measuring. For sure, imperfect. There are different standards. once/day SD as per CoCoRAHS does not work for me as most useful, where some NWS offices use the clear the board every 6 hours technique which I think has useful application commercially. Attached p 63 of the CoCoRAHS snow guide. I had 27" of snow FALL, (right in the middle of the pack), but the SD I measured amid morning Tuesday in this part of Wantage NJ was 18". This 9" less than fell report is I think easily possible, due to crystal packing in gusty winds, as well as increasingly wet snow during the the 45+ hour storm evolution would result in packing. There may be some science regarding snow packing down with time? Just wanted to make sure the differences were noted between snowfall measuring processes and the large difference in SD vs what fell in 6 holy increments. Which is best? I argue differently for possible commercial snow clearing application and rate alerts etc. Nothing will get solved with this today.

On WPC snow amount probs for Long Island, which i like to use as a self check for expectations. This should provide greater understanding of some of the problems and is offered as helpful information for those who may use this guidance. --- I agree with you that this guidance looks pretty bad. I looked back at some individual members of the ensemble, and it wasn't a QPF problem, but a precip type issue. I think that a large part of this has to do with the resolution of the ensembles. The GEFS is only 1/4 degree and the ECMWF ensemble is 1/2 degree. These two sources are pretty predominant through the entire forecast period, and I'd assume they can't handle what are probably relatively sharp temperature gradients and/or are including nearby warmer SSTs in the grid boxes due to the geography of the area. The higher resolution Day 1 guidance did not suffer from this error, but don't make up a large percentage of the ensemble, so they tend to get lost in the calculations. Unfortunately, a short fuse fix is not really possible. To solve this problem, we'd need to use mainly high resolution guidance (at least for Day 1) and cut out the lower-resolution ensembles. This is a big change, and to get approval would be difficult. In addition, we'd have to do a fair amount of testing to see if the results would be acceptable. We have this problem with lake effect, too. We are starting to explore running smaller domains with different ensemble membership to improve the lake effect. We could try something similar for nor'easters.

Good evening will rewrite the thread headlines tomorrow morning, probably dropping the wind, wind chill and sub14 potential and maybe even snow. If we get down to 60hours and the ensembles are zero, near zero then this thread won't work. For now, while op models are not interested in any qpf here, 1/3 of the 12z GEFS ensembles have qpf snow. Much lower chance than a couple of days ago. The big change seems to be associated with the 5th short wave being stronger and further east, while the second has receded into the Great Lakes only on the 7th, with rising heights immediately following on the 8th.

AND...if no one believes now...please the 00z/3 GGEM move up 1 day. It's meager for now, compared to prior EC ops but a confused atmosphere, which means I dunno but think the opportunity is there...especially when you look at GEFS 06Z 2m temp anoms that show a window of opportunity here around late 7. Off line til probably 230. It is so beautiful here too... wow!

Wantage NJ (this part) 8a report 0.2" since midnight. snowing lightly at 8a. I don't consider as direct to the storm of 2/1-2 (indirect yes, direct not me).

There is plenty to digest and try to sort out for all of us. I am going to post something later today on a communique I've received regarding an inquiry with WPC about their probs for snow and ice on LI. (my over reliance for 2/1 and subsequent under prediction on my part-it's illuminating and now allows me to take the guidance for Li with more grains off salt). Sometimes I think throwing everything into a pot and blending is best, though some modeling is clearly better than others, especially when it comes to snow-ice vs rain.

They might allude too these in their heavy snow discussions... I just don't read those - no time. Yes, it would be cool to see those stats. If they have them, they might be fluid (sorry, didn't mean it that way, maybe should have said, snoid). In other words as sample sizes grow the stats change.

Sorry... you're way ahead of me on programming and I cannot help. You might want to write NWS EMC-NCEP. Someone there might be able to assist.

Good morning everyone, As noted above the EC has temporarily (hmmmm-do we remember about 4-5 days before this top 10r just past?) dropped the ball. GFS now closer. V16 not posting due to data flow problems with an unknown (to us, or at least me) return. As noted above the UK unreliable but on. What I think, and I'll attach as a placeholder for WPC, is that we're still on... with atmospherics needing to sort out the myriad of disturbances and bring us a little more consensus (or is the consensus too many short waves and a relatively flat but cold westerly flow?). One thing that's changed since the thread inception. Great Lakes 500MB troughing has put much more stock in the first disturbance carving into the northeast Friday, and holding back on the 7th-8th. That would probably negate sub 14F cold into NYC by the 9th, but not necessarily beyond as modeling persists with anomalous cold from the Great Lakes to the Northern Plains beyond Valentines Day. One of these disturbances coming through between now and the 19th 'should' become a substantial northeast wintry weather event and draw in a pretty decent cold shot. So, since the ensmbles and modeling are flipping and uncertain, I keep the thread alive as is, with doubts about wind and temps meeting thread options by the 9th but not a shut down yet, in my mind. Snow is definitely on the table (aside from current on going at this 6AM writing, and the 5th 1" potential for the I84 corridor for which I may eventually start an OBS thread I84?). I do think we'll see some sort of snow here in NYC 7th or 8th- but will be corrected by reality. Not every thread works out... this one may be that. Too much uncertainty as of now.

Am not adjusting anything in this thread headline til at least 630A Wednesday. EC seems a little robust, but we're getting down to D5-6 so it's got life. GFSv16 is right there with the EC. Keep at it... will review again Wednesday morning.

I didn't google but am sure it's related to water content and light passing through.

Looking back: This was on the thread at least back to the 25th, (not as a top 10 snowstorm). EPS was initially steadfast for 4 days, then around Thursday, all the models for some reason dropped the primary threat axis considerably far south, so much so that I was wondering if this would be a prolific advance EPS bust. Thereafter, modeling started edging north, I think around Friday. The results are attached. (personally i was way to conservative NYC eastward and the snow was dry enough with enough wind going to prevent a massive wet snow related power outage situation) . Moderate coastal flooding occurred for two successive high tide cycles Monday 2/1 and minor on Tuesday 2/2. Kuchera snowfall on the EC and GFSV16 (para) was helpful in focusing the potential for up to 30" amounts. The EPS was conservative when compared to Kuchera.

Catching up now: CoCoRAHS snow amounts etc. Meanwhile...interesting here in Wantage NJ. My snowfall through 930A was 27", but my SD ~18... and looks blue in the footsteps. Plenty of water content. At least 2-3" via attached. NOHRSC analyzed snowfall, CocoRAHS water equiv and CoCoRAHS snowfall follow.

Wantage NJ (this part): 940AM report 27" will get you an SD by 1130A. S- continues to accumulate. 30F. 10A/2 This is steady snow... not snow showers. The continued accumulation only increases roof and branch snow load.

Prelim CoCoRAHS to hold the fort til i get back at 11. Note the big qpf bullseye in NNJ... modeling had that. Also the big snows there. I give the Kuchera method some credit, even if some on our forums don't like it. It's helpful and was a cue for me in the Dec storm and again this one... allows me to be more confident on the higher end. GFS V16 and NAM did very well on this event, I thought. EC was very close as well.

fwiw... 3/4S- here in Wantage at 740A.

Good to know! Thanks... sort of suspected. I feel we sort of got lucky late yesterday that the wind blew the snow off the trees/wires and that it wasn't a 32-33F snow instead a 30F snow. So those are immediate considerations ahead. Hopefully all the snow melts slowly without multiple big rains in spring. Certainly going to keep the snow on the ground here NYC west and North for another two weeks, despite melting. Lets' see what happens V16 is north of the EC op... no lock. MOS has us in NYC down to 16 on morning of the 9th.

Clear snowboard every 6 hours only, or max snowfall in the midst of a 6 hr period if snow changes to rain-/sleet. .SD is the daily 7A report. CocoRAHS likes the 1 day max SD for their report. I see both ways, two different sets of users and I lean 6 hourly because of two factors. Many more commercial and traveling users for the 6 hourly that dictates work and travel requirements. that assist our daily commerce, whereas the 1/day is nice for climate but does not account for wind/melting settling. Not going into scenarios due to time constraints but I hope we can agree two sets of users. I'll get a snow depth up here after my 10A clearing of driveway. btw, am definitely over 25" since the 3AM report at least another half inch. I've seen some prelim qpf from CoCoRAHS..several reports 2.3-2.8" in NJ. Will post all at 10A.

I have my doubts as well, BUT!! I can''t be sure. I can tell you I'm confident of my 25... I will post a CoCoRAHS summary - two day at 10AM. That's what i would use as official. NWS filters data as best it can in the hurried mode of posting the snowfall data, while doing many other duties, including answering phones. I have NOT seen PHI post 32", so it's a little dissapointing that it is out there. Mendham, 30". We know 25-30 up in these parts... You want some pix? I went up and down my driveway with a snowblower 3x yesterday and will proceed again here at 8AM, but the road? Not yet plowed so i go nowhere.

While the I84 corridor I think is going to see areas of 1-4" new snow after 7A today through Wednesday morning in increasingly unstable lapse rates, I could see NYC picking up an inch or 2 of wet snow the next 24 hours as well (after 7AM today).

fwiw: I think another 1-4" between now and sunrise Wednesday in the increasingly unstable most lapse rates, periods of snow and flurries. Also Friday morning: A possible inch in the WAA ahead of the cold front.

615AM/2: no change. Added some WPC ~05z/2 graphics for the event on 1/7. Chance we'll be watching the Super Bowl either during a snow event (rain e LI?) or cleaning up from whatever occurs. Multiple ensembles have something but whether it's a coastal low (probable) or just a strong cold front is debatable. The snow amount range listed suffices, despite the the EC multiple cycles heavier. This give this opportunity a most probable start.