Estimates are roughly the same after the latest model runs. To clarify about the conflicting reports you're seeing on TV (which you should probably turn off, 4 of the major stations are giving 4 wildly conflicting reports), first here's the rundown of the storm itself:
Current models have the storm tracking with the low 20 miles south of NYC as it passes through. GFS is edging towards partial wintry mixed precip early on Monday while the rest are all snow. As you go north and west you have a greater chance of all snow, south and east the greater chance of having it mix. Please note that if mixing occurs it will be after 7am on Monday morning so forecasted amounts before that will remain the same.
Here are the chances in % to make it easier:
NYC:
Northern 80-90% chance of all snow, 10-20% mixed
Southern 60-80% chance of all snow, 30% mixed
Long Island (including the boroughs)
Northern 70-90% chance of all snow, 10-30% mixed
Southern 60-80% chance of all snow, 30% mixed
Western 80-90% chance of all snow, 10-20% mixed
Eastern 50-70% chance of all snow, 30-50% mixed
The reason for this wide error is because of the still to-be-determined position of the storm. As we learned last week (a Nor'Easter that moved SW to NE), a 20-30 mile shift of the storm to the East was all that was needed to make it 60-80% miss NYC while 20 miles East in Nassau get 80-90% of the amount and Suffolk right on target.
This storm is a clipper, so it moves almost due West to East (5-15° tilt) so this time, if it shifts North or South then we'll get different amounts and by quite the difference as the mixing line is at the moment only 10-20 south of the southern short of LI. By tomorrow morning the models should be able to better predict the path, but again at this time predicting the storm's path down to the 10s of miles is impossible to tell, and unfortunately we need that to get the amounts.
Speaking of that first here's the liquid precip that is forecasted to drop which is independent of the type of precip falling:
6PM-10PM: trace (0.02-0.04")
10PM-1AM: 0.12-0.18"
1AM-7AM: 0.35-0.50"
7AM-2PM: 0.30-0.45"
2PM-6PM: 0.15-0.25"
6PM-9PM: trace
Now using that, here's both values you can get depending on if you see mixing precip or not:
Both:
6PM-10PM: 30% chance of passing flurries ahead of the storm <.50"
10PM-1AM: 60% chance of light snow showers 1-2"
1AM-7AM: 100% heavier snow showers 4-6"
All-snow event vs. mixing event
7AM-2PM: 100%
heavier snow showers with higher winds 3-5"
mix of snow and sleet, possible freezing rain with higher winds ~1" snow, rest sleet, ~.01" f.rain possible
2PM-6PM: 80%
snow showers with higher winds 1-2"
mix of snow and sleet with higher winds ~1" snow, rest sleet
6PM-9PM: 10% leftover flurries/light sleet
Totals: 9-13" if all snow (locally higher), down to 5-8" if it mixes. Partial mixing will be in between the two but closer to the later.
More to come tomorrow morning as the models come together more.
-Mike Merin
Current models have the storm tracking with the low 20 miles south of NYC as it passes through. GFS is edging towards partial wintry mixed precip early on Monday while the rest are all snow. As you go north and west you have a greater chance of all snow, south and east the greater chance of having it mix. Please note that if mixing occurs it will be after 7am on Monday morning so forecasted amounts before that will remain the same.
Here are the chances in % to make it easier:
NYC:
Northern 80-90% chance of all snow, 10-20% mixed
Southern 60-80% chance of all snow, 30% mixed
Long Island (including the boroughs)
Northern 70-90% chance of all snow, 10-30% mixed
Southern 60-80% chance of all snow, 30% mixed
Western 80-90% chance of all snow, 10-20% mixed
Eastern 50-70% chance of all snow, 30-50% mixed
The reason for this wide error is because of the still to-be-determined position of the storm. As we learned last week (a Nor'Easter that moved SW to NE), a 20-30 mile shift of the storm to the East was all that was needed to make it 60-80% miss NYC while 20 miles East in Nassau get 80-90% of the amount and Suffolk right on target.
This storm is a clipper, so it moves almost due West to East (5-15° tilt) so this time, if it shifts North or South then we'll get different amounts and by quite the difference as the mixing line is at the moment only 10-20 south of the southern short of LI. By tomorrow morning the models should be able to better predict the path, but again at this time predicting the storm's path down to the 10s of miles is impossible to tell, and unfortunately we need that to get the amounts.
Speaking of that first here's the liquid precip that is forecasted to drop which is independent of the type of precip falling:
6PM-10PM: trace (0.02-0.04")
10PM-1AM: 0.12-0.18"
1AM-7AM: 0.35-0.50"
7AM-2PM: 0.30-0.45"
2PM-6PM: 0.15-0.25"
6PM-9PM: trace
Now using that, here's both values you can get depending on if you see mixing precip or not:
Both:
6PM-10PM: 30% chance of passing flurries ahead of the storm <.50"
10PM-1AM: 60% chance of light snow showers 1-2"
1AM-7AM: 100% heavier snow showers 4-6"
All-snow event vs. mixing event
7AM-2PM: 100%
heavier snow showers with higher winds 3-5"
mix of snow and sleet, possible freezing rain with higher winds ~1" snow, rest sleet, ~.01" f.rain possible
2PM-6PM: 80%
snow showers with higher winds 1-2"
mix of snow and sleet with higher winds ~1" snow, rest sleet
6PM-9PM: 10% leftover flurries/light sleet
Totals: 9-13" if all snow (locally higher), down to 5-8" if it mixes. Partial mixing will be in between the two but closer to the later.
More to come tomorrow morning as the models come together more.
-Mike Merin