Been talking about this one in the pattern thread for a few days and now that we're 4.5 days out from the event, which would start late Friday night or very early Saturday morning and go through Saturday afternoon, we're seeing the global models all showing a major winter storm, in general, with most of them (not all) also showing a significant to a major winter storm for our area (Philly-NJ-NYC), thought it was time for a thread. But, as usual, being this far out, uncertainty is quite high and other solutions (snow to rain or mostly out to sea that are much less snowy are still very possible.
Today's 6Z (1 am EST data inputs) and 12Z (7 am EST data inputs) GFS runs, the last two runs of the CMC (from 0Z last night and today's 12Z run) and today's 6Z Euro ensembles and today's 12Z GFS/CMC ensembles (ensemble forecasts are often the better way to go this far out before a storm, as they take into account variations in initial conditions, which the operational model runs do not) all are showing a major winter storm for our area (major for me is over 8" of snow), while the UK continues to be offshore with a snowstorm only for SE New England. Last night's 0Z Euro was very close to being a big snowstorm for us, but was just far enough offshore to only bring minor to moderate snowfall especially SE of 95 - it showed a major winter storm from NYC and NE of there and today's 12Z Euro will be out in an hour. Prior to last night's 0Z models, we were seeing occasional runs showing a major storm for us, but more runs showing an out to sea solution, but models and forecasts always get better as we get closer to an event, so today's runs take precedence over last night's.
With regard to the uncertainty, I think earthlight (one of the best meteorologists out there, who runs NY Metro Weather) on 33andrain put it perfectly: that the setup is explosive, but fragile, meaning so many things could still go "wrong" (for snow lovers, which includes mets and almost all weather board posters), i.e., the storm could go inland a bit and bring a snow to rain scenario or could stay too far offshore, giving us maybe a glancing blow or a complete miss, depending on some fairly small changes in the evolution of the setup.
For example, a small change in the angle of approach of the northern (jet) stream energy (still way offshore in the Pacific) entering Canada and then the CONUS can make large changes in the eventual phasing of the 2 systems (the other is a southern stream system ejecting from the SW US into the GOM, which then may "phase" with that northern energy and come up the coast) or the amplification of the trough as the final storm comes up the coast. So, most pros right now think it's a given we're going to have a big storm, but it's nowhere near a given that we're going to have a major snowstorm here. But for people who enjoy this hobby and like snow, it's going to be fascinating to track and see how it evolves. For the rest, it's always best to be prepared.
https://www.33andrain.com/topic/2046-weather-pattern-storm-threat-discussion-winter-21-22/page/390/
https://www.americanwx.com/bb/topic/56684-january-28-30th-possible-noreaster/page/11/
Today's 6Z (1 am EST data inputs) and 12Z (7 am EST data inputs) GFS runs, the last two runs of the CMC (from 0Z last night and today's 12Z run) and today's 6Z Euro ensembles and today's 12Z GFS/CMC ensembles (ensemble forecasts are often the better way to go this far out before a storm, as they take into account variations in initial conditions, which the operational model runs do not) all are showing a major winter storm for our area (major for me is over 8" of snow), while the UK continues to be offshore with a snowstorm only for SE New England. Last night's 0Z Euro was very close to being a big snowstorm for us, but was just far enough offshore to only bring minor to moderate snowfall especially SE of 95 - it showed a major winter storm from NYC and NE of there and today's 12Z Euro will be out in an hour. Prior to last night's 0Z models, we were seeing occasional runs showing a major storm for us, but more runs showing an out to sea solution, but models and forecasts always get better as we get closer to an event, so today's runs take precedence over last night's.
With regard to the uncertainty, I think earthlight (one of the best meteorologists out there, who runs NY Metro Weather) on 33andrain put it perfectly: that the setup is explosive, but fragile, meaning so many things could still go "wrong" (for snow lovers, which includes mets and almost all weather board posters), i.e., the storm could go inland a bit and bring a snow to rain scenario or could stay too far offshore, giving us maybe a glancing blow or a complete miss, depending on some fairly small changes in the evolution of the setup.
For example, a small change in the angle of approach of the northern (jet) stream energy (still way offshore in the Pacific) entering Canada and then the CONUS can make large changes in the eventual phasing of the 2 systems (the other is a southern stream system ejecting from the SW US into the GOM, which then may "phase" with that northern energy and come up the coast) or the amplification of the trough as the final storm comes up the coast. So, most pros right now think it's a given we're going to have a big storm, but it's nowhere near a given that we're going to have a major snowstorm here. But for people who enjoy this hobby and like snow, it's going to be fascinating to track and see how it evolves. For the rest, it's always best to be prepared.
https://www.33andrain.com/topic/2046-weather-pattern-storm-threat-discussion-winter-21-22/page/390/
https://www.americanwx.com/bb/topic/56684-january-28-30th-possible-noreaster/page/11/