-Spotty light wintry mix possible between 8am-10am across higher terrain.
-Rain from 11am Sunday- 2am Monday, change over occurs from higher elevations down, with most places ending as snow.
-Change over to snow possible in valley locations after sunset,with light accumulations possible, if change over occurs quicker accumulations may be higher.
-Earlier change over across higher terrain means 2-6 inches possible, especially across the Catskills
– Plummeting temps overnight into Monday morning may cause a flash freeze and slick travel
-Very cold temps in wake of the system
-Watching the Thur/Fri timeframe of next week for another storm potential
Let’s try to take a stab at tomorrows system, based on the most recent data, it still appears that the precipitation will start as rain for most locations. Most models do not support accumulating snowfall outside of the highest elevations of the Catskills where the rain is expected to change to snow the fastest. Colder air will eventually crash into the region overnight into Monday morning, but the bulk of the precipitation would have exited the region by this time. One wildcard continues to be something called “dynamic cooling” which in laymen’s terms is the ability for the air to cool itself due to the evaporation of snowflakes, so as snow falls into warmer air,it melts and some of it evaporates, this process steals heat from the atmosphere in return dropping the temperatures. The harder the precipitation, the more rapid the cooling that takes place, as scientific as it all sounds, most of you have seen this process at work. Anytime you have watched snow turn back into light rain as soon as the intensity decreases, and then back to snow as it intensifies, you have seen dynamic cooling in action. The reason why this is the wildcard is because this process could cause some areas to turn to snow sooner, and therefore bring accumulating snowfall to areas not forecasted to receive any. First image up in the NAM model set to show precipitation type, and amounts, you can clearly see this is an elevation only storm on this model with snow in the Catskills and rain in the valley locations.
The NAM model is not the only one showing an elevation snow event, below is the European model projected snowfall accumulations for the duration of the storm. Once again, all rain in the lower elevations and snow in the Catskills
The GFS model also has a similar snowfall output, so we basically have a model consensus on snowfall being limited to the higher elevations. Now we take a look at the possibility of a flash freeze overnight into Monday morning due to colder air that will rush in behind this departing storm. Below is a temperature forecast from the NAM model, showing that as soon as the precipitation exits the region, below freezing temps will rush in, causing any rain,snow, or slop to freeze up quickly overnight.
That only leaves us with who gets how much in terms of snowfall:
Zones 1,2,- These zone of the highest potability of snowfall with 2-6 inches possible
Zones 4,5,6 – These zones have a medium probability of snowfall in elevations above 1500 feet with 1-4 inches possible.
Zones 3,7,8,9 – These zone will likely see mostly rain, if the wildcard scenario comes to fruition or if colder air holds strong then snow is also possible in these zones as well.