NOWCAST UPDATE #3: Mon-Wed Nor’Easter
CHANGES TO SOME DETAILS
Summary:
Timing:
Rain Changes to Snow: 10pm to 2am Tuesday
Stop : 4pm Tuesday to 12am Wednesday
Consistency- temps near freezing = heavy, wet snow
Wind gusts 25mph to 40mph Tuesday PM
Heavy Snow rates, 1 to 2” per hour in some areas
DRASTIC changes in snow accumulation over short distances
Downsloping event likely for parts of the region (Central Ulster)
Accumulation
– Eastern Catskills: 20 to 30 inches +
– Catskills & Upper Hudson Valley: 8 to 16 inches +
– Mid & Lower Hudson Valley: 6 to 12 inches
Central/Lower Ulster County: 2 to 7 inches
– Extreme Lower Hudson Valley: 2 to 7 inches
DISCUSSION
We waited until the last second to issue this adjusted snowfall map. The reason being that the data with this storm continues to change, even at this moment. We like to issue a snow map, and only change it when necessary. The last thing we want to do is change a snowfall forecast, and then have to back track.
WHAT CHANGED??
The low pressure system is now very likely to take a track MUCH further east. This will have several effects on what we see in the Hudson Valley.
1. The eastern track is all but surely going to pull the heaviest snow that we highlighted on Sunday… east of where we expected. Instead of the Catskills and western Hudson Valley getting the heaviest snow, it now appears that the eastern Hudson Valley, as well as Connecticut and Massachusetts will see the heaviest snow overnight tonight into Tuesday morning. East of the Hudson River, snowfall rates 1 to 2 inches per hour are possible.
2. The Low pressure is expected to loop into Massachusetts from the Atlantic Ocean. This could have severe impacts on snowfall for the Mid Hudson Valley, especially parts of Ulster County. The winds would shift out of the NNE, and this would result in significant downsloping from the Kingston area, down toward New Paltz & Wallkill (the exception being the Shawangunk Mountains). If this setup unfolds, those areas may mix with rain on and off through the storm. And snowfall accumulations could struggle to reach 6 inches there.
3. The bulk of the precipitation is further east than projected on Sunday. This means much less precipitation (snow) for the SW viewing area. Some guidance pulls the back edge of the snow into the mid Hudson Valley by morning on Tuesday. Eventually the snow band pivots over the Hudson Valley, but the question is how much snow is left over Orange and Sullivan counties when that happens. In the worst case scenario, locations closest to the NY/PA and NY/NJ borders could taper off completely for a time early on Tuesday.
This storm continues to throw surprises our way, and is very likely to have more “booms” and “busts” heading our way. Stay safe, as more updates are coming through the night and day on Tuesday.
-Bill
