Final Storm Forecast : Sunday 12/1 – Monday 12/2

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…

Storm Timeline:
– 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

Snowfall Accumulations
– 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″

Additional Highlights:

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!

19 thoughts on “Final Storm Forecast : Sunday 12/1 – Monday 12/2

  1. I always rely on your forecast. You have the highest rate of success over any other outlet by far! Thank you for all of your nerdy information, (and not dumbing down) it satisfies the weather geek in me!

  2. On the map it says “Lower HV” just above and to the right of the 7, but the description of the snowfall amounts says “Lower HV (Zone 8)”. Shouldn’t “Lower HV” be in zone 8?

  3. Your forecasts are very much appreciated! I guess I am also a “foul weather friend”,as someone here as aptly termed it!Your team is the one I turn to when the weather gets rocky throughout the the seasons.We are very fortunate to have you here with us in the Hudson Valley!You are still the best!At the risk of sounding sappy,thanks for being here for me!(Sappy or not,it’s true!)

  4. It looks like in this version of the map, the divider between zone 3 and 7 is removed. Same with the divider between zones 5 and 6 and between 1 and 2.

    • That usually means that HVW is forecasting the same weather for the two connecting areas that have the divider removed. Blessings & Stay warm!

  5. I’m in wurtsboro. It has been sleeting since 9am no snow yet but there’s accumulation of ice already. This storm going to be interesting to say the least if sleet on the bottom

  6. Snow steadily falling here now-changed from freezing rain.Town of Newbugh plowers are out already in my neighborhood.Keep up the good work,guys!

  7. not much snow at all between saugerties and woodstock…. maybe an inch…or MAYBE 2 inches. almost nothing. and it looks like it has stopped snowing. i guess most of the snow will come on monday?

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