Our first significant winter storm in 2 months is taking aim at the Hudson Valley, and it has the potential to cause major disruptions to weekend travel plans.
– 4pm to 8pm Saturday : Snow develops from west to east
– 8pm to 2am Saturday Night: Snow falls heavy at times (1 to 3 inches per hour)
– 2am to 8am Sunday: Snow mixes with sleet and freezing rain from I-84 corridor on south
– 8am to 12pm Sunday: Snow / wintry mix tapers from SW to NE
– Snowfall Rates 1 to 3 inches per hour, very low visibilities
– Snow covered and icy roads, very treacherous travel
– Thunder snow cannot be ruled out as deep convection pushes into the colder air.
– Icy roads where mix/changeover to sleet and freezing rain occurs
– Strong wind gusts Sunday Afternoon blow and drift snow, ground blizzard possible
– Catskills & Upper HV (Zone 1,2,5,6, & northern half of zones 3&4): 10 to 20 inches (all snow)
– Mid Hudson Valley (southern half of zones 3&4, Zone 7&8): 7 to 14 inches (w/ some sleet)
– Lower/Extreme Lower Hudson Valley (Zone 9): 3 to 8 inches (changeover to sleet & frz rain)
Cold arctic air is approaching from Canada on Saturday. At the same time, the southern branch of the jet stream will be collecting moisture and a low pressure system, and pushing it northeast, into the Ohio Valley. The warm moist air will overrun the invading arctic air, and a textbook overrunning snowstorm will develop across the northeast US.
The key to this entire forecast is the precise positioning of the arctic boundary, that this storm system will then travel along, and spread substantial amounts of moisture along its path. The trend in the last 24 hours, has been toward a colder solution… suppressing the arctic boundary slightly further south than suggested earlier. This is consistent with the ideas we’ve presented over the past few days, but we are finally seeing the models confirm the idea that the cold will be stubborn to lift out.
Strong upward motion will generate heavy snow bands to enter the Hudson Valley before midnight Saturday night. This heavy snow bands, coupled with air temperatures in the upper teens and low 20s will result in snowfall rates possibly 1 to 3 inches per hour, of a light fluffy powder.
The good news, is the latest guidance suggests that ice accretion will be less of a concern, if at all, for most of the Hudson Valley. The cold air should be deep enough, that even where mid level warmth turns the snow over to a wintry mix… that mix should be mostly in the form of sleet, and not freezing rain. Freezing rain is what coats the surface, and turns paved surfaces into skating rinks… as well as brings down trees and power lines. We’ll have to focus on the trends to see if this concern remains low.
What Are Our Concerns-
- – While our latest idea suggests this concern may be diminishing… a prolonged period of heavy freezing rain with high amounts of ice accrual that may damage trees and impact power is possible across our region, this area looks to potentially be well south of i84.
- – Rapidly dropping temps on the back side of this storm will lead to a flash freeze. Areas where snow melts, or rain falls, will quickly refreeze into a sheet of ice, causing very dangerous conditions. Even where all snow falls, salt may be thrown on the roads to melt the snow… and that could flash freeze Sunday afternoon and evening.
- – Precipitation rates during the storm may help to offset some of the warming in the atmosphere and lead to the mostly snow zone being slightly further south than modeled. This is part of what we’re seeing in latest guidance
- – Intense precipitation rates and stationary banding may lead to a band of overachieving snowfall accumulations.
- – We will likely see small corrections north or south in the track of the storm for the next 24 hours of modeling, this has large implications as any minor adjustment will cause corrections to where mix precipitation line sets up.
We will continue to track the latest guidance as we get closer to the storm. We anticipate releasing our “HVW Storm Forecast” around 11pm Friday night… with the “Final Storm Forecast” featuring any minor tweaks Saturday afternoon before things get underway. We continue to appreciate all your tremendous support! Thank you for being a part of the HVW community!