The past weekend storm once again, produce less snowfall many areas. Exception here in is Central and Southern NJ, where the inverted trough unexpectedly setup there. I will do some post-mordem on it this week. But another winter storm is already on it’s way for tonight. The snowfall forecast is after the end of this discussion.

A low pressure that is producing snow and ice over Central Plains and the Tennessee Valley, will stay south of the area through early this evening. Then as an upper-level low over the Canadian Martimes to lifts out, this storm will head more northeast towards the area tonight. The question here, is how much room will this storm have to come northward? Enough confluence from the upper-level low could lead to sharp cut-off of snowfall totals in the Tri-State area. Models are also indicate that 500mb shortwave energy for this system will tend to weaken a bit as moves into the Ohio Valley and Mid-Atlantic. However, there is fairly strong 700-8500mb southwesterly jet associated with this system. This could help enhance warm-air advection on top very cold airmass, currently in place. There some models on amount of lift and moisture that will be able to make to parts of Tri-State area. Also snow to rain ratios will be higher with very cold airmass aloft. The snow growth region ins 10C-20C layer. Ratios could be as high 25 to 1, especially if more lift and moisture is realized.

This is not a very powerful or explosive Nor’easter type storm. The southern stream system that will tapping to more Gulf of Mexico moisture then many of our systems have this season. However, it will be a fast-moving system, with not enough of blocking in the Atlantic. Snow will move in from southwest later this evening and last through early tomorrow morning. Snow will have difficult time making far north into the Hudson Valley and CT. While snow be steadier and heavier the farther south, especially over Central and Southern NJ. Snow should mid to late morning for all areas and skies should clear in the afternoon.

Morning update. My confidence level is moderate here. I’m looking more frontogenesis and vertical velocities here than qpf. Particularly on the NAM, RGEM, and GFS. Bust potential here is mainly with be mesoscale bands, especially with the inverted trough, producing more snow in some areas and cause more subsidence on other areas  The CCB could be weaker and further east reducing totals further northeast over CT or the east of end of Long Island. Or if the inverted trough and CCB are both weaker and further east. Then many of these totals will be too high.

A polar shortwave at 500mb and clipper low at the surface will dive south towards the Northern Mid-Atlantic coast this weekend. Then close off at 500mb and rapidly intensifisy as it heads offshore. The snowfall forecast below is my guess how much snow will fall in general. How this forecast is not easy, as there several areas of lift on models on focusing of banding. Some of these band can produce heavier snowfall in some areas. While time same creating subsidence for other areas. So snowfall may seem to be as uniform as portrayed here. As storm explodes offshore, the pressure gradient with tighten and high winds become an issue. There is potential for damaging wind gusts over 60mph. Saturday night and Sunday morning. Stay tuned for more details and updates on this storm, as necessary tonight and tomorrow.