Best way to start the forecast update for Friday is with a simulated radar loop from about Midnight till about 6PM Friday, it tells a story of waves of low pressure moving along a boundary, most of them weak. These waves of energy keep an almost continuous stream of moisture across the region. Overnight some pockets of cold air allow for a continuation of freezing rain across the higher peaks of the Catskills. Warm air surging north ahead of the front eventually erodes all of the cold air and leaves the region under the influence of a soaking cold rain through the morning. At the same time you can see the colder air slowly pushing in from the west, and heavier precipitation moving up from the south. This heavier batch of precipitation is associated with a very deep area of low pressure that will track directly over our region (Not the track you ever want for snow). The passage of this low pressure may trigger not only a potentially record low air pressure, but an are of enhanced precipitation and even the potential embedded thunderstorms. As this low passes to our NW, it will wrap the cold front through the region and turn the rain over to snow, this change over will likely be limited to the higher elevations of the Catskills and some upslope snow across eastern Dutchess and Columbia Counties, some accumulations can’t be ruled out across parts of Sullivan and Ulster Counties as well, this will depend heavily on how quickly the change over can occur. Across the higher terrain of Delaware, Western Green and Western Ulster accumulations will range between 2-8″ as a longer snowfall duration will occur, be prepared for changing conditions across this part of the region. We will also see increasing winds tomorrow afternoon and evening as the low departs with gusts between 20-40MPH possible.
Lets take a deeper look at the potential for a record low pressure across the region, below is a model image for tomorrow afternoon and an image showing the all time record low pressure by location.
As you can see a deepening 968MB low pressure traveling NW across our region is a very uncommon occurrence and may be low enough to set some local low pressure records especially across the NW parts of the region as records are much lower to our south and east due to the track of Hurricane Irene in 2011.
Finally a look at the convective potential of this deepening low pressure as it tracks across the region Friday afternoon. As you can see, it will be quite interesting as the low passes through, deep convection with heavy rain and even some thunder to the north and east of the low as cold air rushes in and changes rain to heavy snow across the eastern Catskills. Keep and eye to your barometer and maybe preemptively take an advil as this low pressure advances towards the region.