Preliminary Storm Forecast : Sun 12/1 – Mon 12/2

We are now officially in storm mode as we are within 24 hours of the beginning of this two phase storm system. Confidence is high with Sunday phase and medium with Sunday Night into Monday. Because confidence of the second phase is still moderate our prelim snow map remains the going forecast until the final is posted.
 
So what can go wrong with the forecast? If the secondary low forms further north the axis of heavier snow shifts further into the capital region.  If low forms further south we can expect high totals shifting into the mid and lower Hudson Valley. If colder air is deeper and first round over performs with more snow than sleet in some locations or vice versa.
 
Finally the notoriously impossible to forecast location of quasi stationary, mesoscale banding and pivot points of precipitation as coastal low moves NE. These bands combined with orographic enhancement in the Eastern Catskills will cause some localized heavier totals that may exceed 2’. These same uncertainties have caused the NWS to withhold warnings in their morning updates. We will monitor the hires short range data throughout the day and have final snow map late afternoon/eve.
 
Below we have also included snowfall forecasts from all three of the National Weather Service offices that serve our forecast region for your digesting in combination with our on-going forecast from yesterday.
 
Storm Timeline:
– 9am to 12pm Sunday : Snow/sleet begins from west to east
– 12pm to 5pm Sunday : Snow/mixes with sleet and freezing rain
– 5pm to 9pm Sunday : Wintry mix slowly tapers from west to east
– 9pm Sunday to 3am Monday : Cloudy, scattered snow/sleet/rain showers
– 12am to 6am Monday : Snow redevelops, falls moderate at times
– 6pm Monday to 12am Tuesday : Snow gradually tapers off
 
Precipitation Types– Snow, Sleet, Freezing Rain,Rain
 
Impacts– High Impact (Long Duration,High Snowfall Totals, Ranging conditions over short distances, Work/School day)
 
Travel-Difficult/Impassable
 
Snowfall Accumulations:
8-16″ (Zone 2,3,4&6) Mostly snow with sleet possible across southern parts of this zone Sunday afternoon and Night.

5″-10″ (Zone 1,5,7,N8) Snow… with sleet Accumulations likely. Possibly mixing with freezing rain, before changing back to all snow by sunrise Monday. Accumulations highest across northern parts of this zone where localized amount may exceed 10″.

2″-6″ (Zone 9 & S8) Snow to sleet, and freezing rain, and possibly rain. Highest accumulations Northern part of area. Change to all snow Monday morning.

Snow Consistency- Light and Dry to start, transitions to heavier and wet Sunday afternoon, especially where sleet mixes in, and begins to transition back to lighter and drier on Monday.
 
Additional Hazards- Blowing and Drifting across higher terrain. Sporadic power outages.
We will try to have additional discussions as the day progresses, but our previous discussion on this really has a good line on our current ideas.  We will have conversation and lesser discussion on Facebook today, and will have the Final Storm Forecast issued tonight.  Once again, this storm is 24 hours away from starting (as of this post)… and over 60 hours away from completion.  Have a great Saturday!

8 thoughts on “Preliminary Storm Forecast : Sun 12/1 – Mon 12/2

    • Christina, HVW is more detailed to specific areas (Zones) of the Hudson Valley, as opposed to “general” local forecasts, which aren’t really local forecasts when they report the “weather for the Hudson Valley”. There’s a big difference In weather patterns between the Catskills, eastern Putnam county and Rockland county, as an example. There is a lot of different elevations to consider, and being close to and at the same elevation as the Hudson river vs being 1000 feet higher in elevation can mean rain or sleet in one area and snow in another. Hope this answers your question.

  1. Thank you for the information. It’s been so unseasonably cold for so much of this autumn so I guess an early “winter” storm before winter begins is par for the course. I did manage to plant my tulip bulbs today, anticipation of a foot or more of snow falling up here in the Capital District.

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