As reported yesterday, we have been looking at the latest models to see the chances of a snowstorm for the interior northeast this upcoming weekend (28th/29th). The chances have been increasing incrementally with each successive model run. However, modeling keeps changing the positioning and timing of the cold air dynamics expected to push into the area. This could severely limit any snow possibilities below 2500 feet in New England. Despite this, there are still a large realm of possibilities over 7 days out. Lets examine some of the more likely possibilities.
Inland Runner – This possibility seems to be the more valid of the ones we are looking at. This essentially means that the low develops much closer to the coastline, and gets caught by the upper level trough. This allows it to tuck into the coast and move north from the coastline of New Jersey. This keeps the warm core closer to the coastlines and keeps everything rain for the major cities. There could be some stronger wind profiles, however, the low would have to essentially remain over the water a bit longer to build up high winds. Nevertheless, wind gusts up to 35-40 mph may not be far-fetched in this setup. Snow chances would remain into the mountains of Vermont, New Hampshire, New York, and some slight chances in the hills of Massachusetts and extreme northwest Connecticut.
Offshore Low – This scenario places the center of the low just offshore from the major cities. This does allow a bit of colder air to work its way into the system, however, not enough to push any snow chances farther south and east than the Hudson valley of New York. There may be slight intrusions into the hills of western Massachusetts, however, mixing would be limited as the core of warmer air in the mid levels would still be allowed to progress north and west. This would change any frozen precipitation to liquid fairly quickly. Any intrusion at lower levels could make it a bit slick for a few hours, but would quickly be won over by the retreat of colder air to the north and then to the northeast. Wind profiles would be a bit stronger, given the position of the low and longevity over water, reducing land friction on wind production. This solution is being painted right now by the ECMWF (Euro) and the CMC (Canadian Model). Slight variations are occurring, and a full storm phase is still not in view on these models.
Phasing Monster – This would place the storm farther south and push the core of warm air farther offshore. This situations causes pressures to drop centrally, and allow dynamic cooling to take effect, causing colder temperatures to work their way in at the lower and mid levels as far south and east as Hartford, CT. Te lack of solid cold air damming, which would effective lock the colder air in place as the storm develops, would severely limit any snowfall production in the areas closer to the big cities of the northeast. However, a large snowstorm would result for areas just west of the Hudson Valley. Totals between 6 to 8 inches would be highly possible in those areas, but would quickly fall as you move south and east. Areas to the southeast could still see some mixing snow, however, will not accumulate. This is the least likely of the 3 aforementioned scenarios. As of this time, all major models are not showing a full phase to the storm, but could progress in this direction as we move closer to the event.