As we turn the calendar to December, we’ll kick off the 19/20 winter season with a bang. A 2 part storm system that has the potential to deliver well over a foot of snow to some parts of the viewing area. Because of the structure of this storm, it will start around noon on Sunday, and likely won’t end until after midnight Monday night. The complex structure of this storm will also mean some inevitable surprises. So here are the forecast details as we see them…
– 10am to 1pm : Snow begins from west to east
– 1pm to 5pm : Snow, mixes with sleet near I-84 corridor, changes to sleet south of I-84
– 5pm to 10pm : Snow mixing with sleet north of I-84, sleet near I-84, sleet/rain near I-287
– 10pm to 6am : Precip tapers… snow showers upper HV, light sleet Mid HV, light rain showers Lower HV
– 6am to 12pm Monday : Snow redevelops over HV, becomes steady to moderate at times
– 12pm to 12am Tuesday : Snow… gradually tapering near midnight
Impact: High Impact
– Long Duration Event, 24 to 36 hours possible
– Significant snowfall in northern HV, travel extremely hazardous
– Icing possible late Sunday Mid and Lower HV, treacherous travel likely
– First widespread school delays and cancellations likely
– Monday commutes likely very hazardous
– Catskills (Zone 1 & 2): 10″ to 20″
– Southern & Eastern Catskills (Zone 5 & 6): 8″ to 14″
– Mid and Upper HV (Zone 3, 4 & 7): 6″ to 12″
– Lower HV (Zone 8): 4″ to 9″
– Extreme Lower HV (Zone 9): 2″ to 6″
The precise details that we have highlighted over the past several days, continue to be major factors in the forecast. We’ll have additional discussions both here and on Facebook to try and clarify the significance of these uncertainties.
- Dynamic Cooling along Warm Advection precipitation band
- Precise location of Upper Level Low on Monday
We’re seeing some data just in the last hour, that suggests that precipitation falls heavily enough Sunday afternoon, that instead of the sleet we have anticipated advancing all the way up the HV… that snow falls for a longer period of time. To put it simply… in the battle between snow and sleet, it looks like snow may hold ground for longer than expected, especially north of I-84. If this happens, snow totals will be on the higher end of the ranges.
Also, with regard to the Upper Level Low… the snows on Monday are a product of the upper level energy moving by to our south. These features are NOTORIOUSLY DIFFICULT to forecast, because they produce areas of heavy snow… but those bands of heavy snow are rather narrow. So a shift by 50 to 100 miles can be the difference from 8″ of snow… and 2″ of snow. So no matter how precise we try to get… if this feature provides any surprises on Monday, it will either mean higher than forecasted… or lower than forecasted snowfall amounts.
Expect more commentary as often as possible through Sunday and into Monday. Thank you for all your continued support!