********AS OF 9AM 2-12-20 THIS FORECAST REMAINS VALID, NO CHANGES*******
Let’s take a closer look at our next storm system, as I’m sure you’ve read in the previous updates we are once again looking at a storm track that is less than ideal for anyone looking for a pure snow event, this system will be very similar to our Sunday night storm. A good place to start the conversation is with a simulated radar projection from the 18z run of the NAM model. What we are seeing is classic warm air advection precipitation, a storm system moving to our west with its counterclockwise flow is pushing a warm front into our region, the warm air being forced up and over the colder air at the surface is all the lift the atmosphere needs to give us precipitation.
The same process that giveth snow, shall also taketh away, in what has been a weather pattern that has us feeling like Bill Murray in the movie Groundhog’s Day! The airmass in place is only marginally cold and it does not have a source of high pressure close by to help supply fresh cold air. With the storm tracking to our west the warmer air is uncontested in its mission to root out cold air and shatter the hopes of snow lovers once again. You can see this process quite well in the precipitation types on this sim radar, warm air floods in from the south, then up the valley as it spreads into every nook and topographical cranny from the lowest elevations first and slowly as the warm air fills it continues to chase the cold air, the only safe place is for the cold air to climb, it finds safety in the highest elevations of the Catskills. Even across the higher terrain subfreezing temps will only exist near the surface, at 5000 feet warm air will have already wiped any subfreezing air away from the altitude that determines our precipitation type which is why plain rain that freezes on cold surfaces is the best that even the highest peaks of the Catskills will achieve by the afternoon.
Below the radar, we have posted the surface temps for the same period as the radar, you can see the progression of the warmth and its impacted on the precipitation types across the region. We have some concerns with the potential for a prolonged period of freezing rain across the Catskills, but it appears to be limited to areas above 2000′ and climbing.
Below is the areas we have the potential to see a glazing of freezing rain, ignore the accumulation amounts as they are always overdone, focus only on the areas in pink as these areas may have icy roads to contend with on Thursday.
Starts-Southwest to Northeast between 10PM Wednesday and 1AM Thursday
Ends- West to East between 11am Thursday and 1PM Thursday
Purple Circle- 2″-5″ of snow with freezing rain across the highest terrain.
North of the Red Line- Moderate to Heavy snow at onset, duration 2-6 hours, shortest south and longer north and higher elevations. Coating to 3″ of snow, transitions to sleet and plain rain.
South of the Red Line- Moderate to Heavy snow and sleet at onset, duration 1-3 hours, shortest south and longer north and higher elevations. Trace to 1″ of snow and sleet, then plain rain.
South of the Green Line- Potentially a very short period of snow or sleet, transitions to rain, duration 1 hour or less with some areas seeing only rain for entire event.
******** Trends in todays guidance has been colder on the last three consecutive runs of the data, important to stay tuned for any changes*****