It was our weekly poker night (COVID home game is on line now - will start a thread on that if people are interested in the on-line site we use), so I missed all the bickering and will try to not engage since it's pointless. I will just say this though: I didn't start any of the arguing and I never post about my love for snow in these threads since some dislike that so I leave it out, in an attempt to not start arguments.
Anyway back to the storm. Tonight's 0Z models are all in and there is even a bit higher confidence in a major (major is 8-12" to me) winter storm for most of the Philly-NJ-NYC region (and most places from DC to Boston). We're still about 4 days out from the start of the storm, as depicted by every model now (they all start with some light snow by late Sunday afternoon to Sunday late evening (the spread on start/end times was about 18 hours, 12 hours ago and is now <6 hours, which indicates better consensus/confidence); the end times are Tues morning/afternoon on all of the models (it's a long duration storm, as modeled). And 3 of the 4 global models show widespread "historic" snowfall amounts (12-20" for me; one can debate the descriptor, so that's why I include the amounts) for most of CNJ/NNJ/NYC. With respect to the big picture model details...
- The Euro shows a major to historic snowstorm for all of CNJ/NNJ/NYC/EPA with 12-16" of snow for everyone N of 195/276 and 6-12" everywhere else in EPA/SNJ S of 195/276, except for about 3-6" for SE of Salem to Toms River. These lower amounts are due to mixing/change to sleet/rain at times.
- The Canadian shows a historic snowstorm for all of CNJ/NNJ/NYC/LI and Monmouth/Ocean with a range of 12-20", but with 20-26" for the eastern parts of Middlesex to Bergen and all of NYC/LI. The CMC has a general 8-12" for EPA and the rest of SNJ/Phillly (even down to Cape May. The CMC probably represents the ceiling with this storm and nobody is going to predict that as an outcome without every other model in line with it <1 day out.
- The GFS shows 12-16" for NENJ from Monmouth up to Bergen and for NYC/LI and 8-12" for the western 1/3 of CNJ/NNJ (Merceer-Hunterdon-Warren) and E-PA N of 276 and has 3-6" for SEPA and SNJ S of 276/195 (except much of Monmouth, as per above) and only a few inches for SENJ, again due to sleet/rain.
- Finally, the UK is now only showing a little less snowfall than the other models, as it's no longer further offshore (it had a fair amount less earlier today). It's showing 6-12" for everywhere in EPA/NJ N of 276/195 and for NYC/LI, including a decent area of 12-16" N of 80 in NNJ and the HV. South of 276/195 is about 3-6" with less towards the coast and far SNJ, due to mixing/changeover.
- One other thing to keep in mind: if this storm ends up being anything like modeled, there will be mesoscale deformation snowbands that setup which will put down an extra several inches of snow in some spots (these are normally SW to NE oriented and well inland of the surface low and are often about 20 miles wide by 50-75 miles long), but we won't know where they set up until the storm hits.
- With the primary surface low still off the US West Coast, the data inputs are still sparser than they'll be tomorrow afternoon, after the system comes ashore, so, in theory, we should have higher confidence forecasts starting tomorrow night, as the data inputs will be more complete and we'll be closer to the event. But that doesn't always happen that way. Figure I'll post snowfall maps starting tomorrow night (another reason not to is that they don't always remain for reasons I can't figure out, as I host them on imgur - those big red X's). The usual links below including to the free model output sites I usually use and which are pretty easy to use.
So, some will read all that and think I'm predicting an 8-12" or even 12-20" snowstorm for most of us. No, I'd never do that this far out, but confidence is pretty high in at least several inches of snow and is growing in getting at least 8", but a coastal hugger track bringing a fair amount of rain to the 95 corridor/coast is still on the table, as is a mostly suppressed storm to our south that might only given a few to several inches of snow primarily SE of 95 and towards the coast. A complete whiff is almost off the table (and will be if we still have a pretty good consensus tomorrow night), but a storm that's just weaker with less precip is also possible.
For some perspective, we're 4 days out and in the modern era of numerical weather prediction (last 20-25 years or so) we've had one horrible complete bust for everyone in this area (March 2001, which was off by 100+ miles) vs. what was forecasted right up until the storm start and one mostly bad bust for this area (Jan-2015, where the forecast for Philly and most of NJ was way way off, while eastern NJ/coastal NJ/NYC were off, but not nearly as badly. Those two and especially Jan-2015, which was recent, as some major advances have been made in modeling since 2001, will always make any forecasters reluctant to predict big snowstorms 4 days out let alone even 2-3 days out.
We've also had some other modest busts on some big storms, where some areas busted, but other areas didn't (like last month on 12/16) and we've also had some pretty good forecasts on big storms from a few days out (not always 4 days, though), including Jan-96, Dec-2000, Feb-2003, Dec-2003, Feb-2006, Feb-2010, Dec-2010, Jan-2011, Feb-2014, and Jan-2016, which were all 12" or more storms in NYC (and much of CNJ/NNJ). The point is, for forecasted big storms, most of them have been forecasted pretty decently (never perfectly) from a few to several days out, with a few major busts.
