Sunday Evening Blizzard Update

This Premium discussion a few hours ago has been freely released to keep you up to date on the latest happenings with the storm:

Let’s take a look at some of the latest model runs.  The 18z GFS shifted far east, as seen here.  That’s snowfall amounts in the region around 12-18 inches, which is still quite a storm but certainly not what the National Weather Service is calling for.  The 18z NAM also shifted east, as seen here, with the 0z NAM following the trend.  It shows 30+ inches in New Haven County, but also shows amounts around 24 inches in Fairfield County and amounts as low as 16-18 inches in Westchester County, even with ratios around 15:1.  This again shows just how extreme this snowfall gradient is, and why snow forecasts will hold such large accumulation ranges.  Even the NMM weather model here shows the potential for a bust with the heavy snow off to the east.  This is not a bust in terms of no storm, and the storm would still be quite dangerous, but it would not be a widespread 2-3 foot storm.  Instead, it would be a widespread foot/foot and a half to two feet snowstorm.  Still dangerous, still impressive, but not necessarily the complete record-setter some call for in the region.  Even the latest 18z  RGEM here does not have the entire region over 2 feet, but does show the potential for localized areas approaching 30 inches or so.  The idea behind this is that you are not guaranteed two feet of snow.  The National Weather Service Blizzard Warning forecasts of 20-30 inches are still in line with my thinking of 16-28 inches, and I think even those may be slightly revised down on some recent guidance, even though I do believe as well that localized amounts up to 30-36 inches may be possible in some of the heaviest banding.  It is just worth noting that what goes up must come down; where there is extreme lifting to support banding, there will also be another region with falling that is not as conducive to sustained heavy precipitation, and hence the wide range is possible accumulations.  This storm is serious, and this is in no way trying to call off the storm.  I’m just saying that confidence in widespread 2-3 foot amounts is not quite yet there, and some of the forecasts I am seeing could bust (primarily in Westchester County) if they come true.  If you’re in New Haven County, get ready.  You’re locked into the high-end of the forecast range.  Fairfield County and Westchester COULD be on the cusp, or they could be in the center of the strongest banding.  Until we see the proper indicators of lift right before the storm moves in and after it forms, it will be very hard for me to determine where might “bust,” but the potential is certainly there for someone to not hit, say, a foot and a half or 2 feet of snow.  That’s why the low-end of my forecast is still 16 inches, and that is why I continue to watch the latest data very closely.

Overall, however, the forecast remains the same for widespread 16-28+ inch accumulations, and given higher ratios of the storm does trend a little east, it seems likely that we hit this despite numerous different model scenarios.  Stay tuned for the latest, and there will be continuous discussions on the storm through the day tomorrow.

One response to “Sunday Evening Blizzard Update

  1. Hi Jacob – I am traveling to Boston later in the week as JSA is a sponsor of the Harvard Model UN Conference this year. Following your predictions closely. Stay warm!

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>