BOX is a bit more bullish than I would expect this far out"
Wednesday...
It appears increasingly likely that interior southern New
England could see its first widespread accumulating snow of the
season. Ensemble model guidance (GFS, EC and GEM) probability of
24 hour 3+ inches of snowfall is now up to at least 40-50% for
Wednesday into Wednesday night across interior MA and CT. Given
how progressive the system is, initial thinking is 3-6 inches of
snow across interior MA and CT, and perhaps an inch or two
along the Boston- Providence corridor. Areas along the coast
probably see mostly if not all rain.
That said, there remains considerable uncertainty on the
placement of the rain/snow line and timing of the heaviest
precipitation as the deterministic guidance differs amongst each
other and with the ensemble guidance. The GFS deterministic run
takes the center of low pressure well inside the 70W/40N
benchmark while the EC is considerably colder. With 925mb temps
starting out at -4 to -6C Wednesday morning, it should be cold
enough to start out as all or mostly snow except for the
immediate coast Wednesday morning. Then the question becomes
whether the cold air has any staying power as the main
precipitation shield moves in. The EC and GEM deterministic
guidance are colder than the GFS. But again, would put more
weight on the ensemble guidance than deterministic guidance. And
the former actually shows more consistency as discussed above.
Still plenty of time to fine tune the specifics.