Major Nor'easter Imminent!

Synopsis:

Today will be mostly cloudy with seasonal temperatures across the region as we await the arrival of our next storm system. Snow will start across the region very late tonight and continue through tomorrow afternoon, mixing with sleet and freezing rain at times. Amounts are still uncertain, but we shouldn't expect more than a couple inches of slop in the the State College area with more off to the north and east. Then next couple days will be more mild with sunny skies. It appears out next storm system will come Sunday night into Monday in the form of freezing rain and plain rain.

Short-Term:

With the Euro leading the way, the models have come to agreement on the birth of a powerful Nor'easter. Based on the current HPC analysis, there are two low pressure systems: one over the upper Plains, and one centered over the deep-south. These two systems are forecasted to merge around 15Z Friday morning just off the coast of NJ and bomb out. The merged system is expected to bomb and bottom out around 980mb Friday night into Saturday morning over Cape Cod. According to recent model runs, this classic and powerful Nor'easter is expected to produce upwards of 3" of QPF (30" of snow with 10:1 ratio) in the Boston metro area, with liquid totals decreasing to the north,west, and south. The only exception is in western CT and extreme eastern NY, where short-range models have trended towards ~3" of QPF due to a couple local, heavy snow bands. More recent runs have showed the system moving out to sea earlier than before, but have also showed it stalling out just off the coast of MA before departing. The storm will be occluding at this point, but any stalling off the MA coast would result in additional QPF for Boston, most likely on the order of 0.5".

Most Pennsylvanians won't have to worry about any major snow from the merged system. The only accumulations we will see here will be from the northern low before it merges with the southern low. This will result in QPF totals less than 0.5" for central and western PA, with eastern PA receiving upwards of 1" (5" snow for C & W PA, 10" snow for E PA).

Long-Term:

After the storm passes, expect lake-effect clouds and scattered snow showers through the weekend. Recent GFS and Euro show a strong low pressure system developing over the Plains and moving NE into Canada. This system won't impact us nearly as much as the Nor'easter will tomorrow. Expect rain showers across the commonwealth from this system on Monday with clearing skies and seasonal conditions afterwards.