Now inside of 12 hours from this storm system, below is the finalized storm forecast:
Finalized Storm Timeline
- Snow begins Sunday, between 6pm and 10pm from southwest to northeast.
- Snow could fall heavy at times (1 to 2 inches per hour) between 2am and 10am Monday
- Snow will likely mix with sleet and freezing rain for a time during the morning, near and south of I-287.
- Snow tapers off between 3pm and 6pm Monday evening
Finalized Storm Impacts
- Very cold arctic air, temperatures in the mid teens to low 20s
- Winds out of the north / northeast at 10 to 15mph, could cause some blowing and drifting
- Heavy snowfall rate during the morning could greatly reduce visibilities
- Cold temperatures, snow will stick to ALL surfaces, roads likely snow covered and icy throughout storm
- Areas south of I-84 could see snow mix with sleet for a period of time Monday morning.
- Rockland & Westchester counties could see prolonged period of sleet and freezing rain.
- Snow likely to start during the Superbowl, could be more people on the roads than on a typical Sunday night. Plan accordingly, and take it slow.
- Monday Morning commute likely to be significantly impacted by this winter storm, expect delays and cancellations.
- Temperatures will plummet behind the system, making road treatment very difficult, and could cause icing issues for Tuesday AM commute.
Finalized Snow Accumulation
- Zones 1, 2, 5 & 6: 10 to 18 inches (locally higher snowfall amounts in zone 2) [shadow effect in zone 1 – see commentary below]
- Zones 3 & 4: 10 to 15 inches [shadow effect in zone 4 – see commentary below]
- Zone 7: 8 to 14 inches
- Zone 8: 6 to 12 inches (snow likely to mix with or change to sleet and freezing rain Mon. AM)
- Zone 9: 5 to 9 inches (snow likely to change to an extended period of sleet and freezing rain Mon. AM)
The details of this storm are coming together, and there will be some uncertainly with the snow/sleet/freezing rain line… but that is consistent with any winter storm.
Areas near and south of I-287 (zone 9, and southern part of zone 8), will likely have an extended period of sleet and freezing rain. This will serve to hold down snowfall accumulations a bit, and also create concern for ice accumulation. If the period of freezing rain is extended… we could see some power outages. It’s a situation that will need to be monitored thru the storm, but something to consider.
The bulk of the Hudson Valley (zones 3, 4 & 7) will see between 8 and 15 inches of snow. The uncertainty in this region being with regard to the snow/ice line. The computer data has bounced back and forth by 20 miles with the northern edge of the snow/ice line. We’re thinking that the line will remain south of I-84… but if it creeps further north (toward Poughkeepsie)… snowfall totals could be held down on the lower end of the range. If the snow/ice line stays closer to I-287… snowfall amounts over 12″ could become quite common. We won’t know for sure until the storm is underway, so like the ice potential in the lower Hudson Valley… this will be a “nowcasting” situation.
The big winners in this storm, will be the areas that are colder, and remain all snow. We expect the Catskills, Gunks and Hurley Highlands to be in this category… 10 to 18 inches of snow are possible there. The jackpot zone of this storm could be zone 2… where a combination of orographic lift and colder temperatures could really enhance the snowfall. Orographic lift occurs when moist air is being forced upward due to rise in elevation… which enhances precipitation. In the higher elevations of zone 2… someone could exceed 18″ of snow.
Another wildcard with this system is a shadowing effect, which is basically the opposite of orographic lift. The air sinks on the backside of higher elevations, and precipitation can be lessened in the shadow of the mountain. This could occur in parts of zone 1 and zone 4. Snowfall accumulations could be held down a touch in those areas, it’s something to watch.
Otherwise… there is considerable confidence in the storm forecast as described above. Here is the latest NAM computer model snowfall projection for the event. With slightly higher snowfall ratios expected (15 inches of snow to 1 inch liquid) than what this model shows (10 inches of snow to 1 inch liquid)… the NAM model supports our idea well, so confidence remains high.
We’re targeting a storm update for the half time of the Superbowl. As long as time allows, we hope to share our updated thoughts, and any ideas we might have at that time. But we don’t expect to make any changes to the forecast at that time, just update you on the situation. Have a great day… and enjoy the Superbowl!