Winter's last stand

Moderate to heavy rain will continue to affect the area tonight as low pressure shifts into the Gulf of Maine. Colder air will filter in behind the storm, possibly changing rain to snow into Wednesday morning across higher elevations. No accumulation is expected.

Skies will clear in the late afternoon Wednesday as the upper low pulls away. Gusty northwest winds can be expected as high pressure builds into the Mid Atlantic region, tightening the pressure gradient. This high will shift offshore south of the region on Thursday, maintaining sunny skies and allowing winds to back to the west. Temperatures should rebound into the upper 50's to near 60, which is about 10 degrees above the normal.

A huge change will come Thursday night into Friday however. A polar vortex will be plunging south into Quebec on Thursday, with a strong cold front slicing through New England Thursday Night. This front will mark a very tight temperature gradient, with the 850mb 0C isotherm draped across Cape Cod, while the -20C isotherm advances into northern Maine! This type of airmass is one we have not seen for a while. In fact, many places in the region have 40 to 50 day streaks of above normal temperatures! High temperatures on Friday will be stuck in the low to mid 30's, while lows Friday night tumble into the teens.

The cold air is not the end of the story. A shortwave will be moving through the central plains and swing into the Mid Atlantic region by Friday morning. This system will never intensify much, as it's flattened by the vortex to the north. However, it will be enough to transport precipitation into Southern New England Friday morning, while temperatures are cold enough to support snow. A few inches of slushy accumulation is entirely possible for areas north of the Mass Pike.

The next storm on the radar will come early next week. Shortwave energy swinging through the central plains next weekend will support intensifying low pressure in the Mid Atlantic by Monday night. This storm will likely be a rain-producer however as cold air retreats northward.

Moving forward toward Easter Weekend, a strong Pacific Jet will nose onshore in the west, amplifying a trough west of the Rockies, and downstream ridging over the Plains by the middle of the next week. This ridging will shift into the east by Easter Weekend, marking a return to above normal temperatures.