12z Update on impending Winter Storm...

After one last review of 12z data, this will be Mike and I's final snowmap (2nd map overall). Only real significant change was to tweak the latter range. Upgraded the initial area of 12+ from locally higher (dashed hollow) to widespread (filled in) across eastern New England and issued a new locally higher area just downwind from this area that extends back to northeast suburbs of Philadelphia. In here, still expect amounts to be in the 8-12" range with highest amounts (10-12) on the eastern periphery (roughly from I-95 eastward). However, good chance some areas will see higher than 12" so hence area of locally higher that was inserted (dashed hollow). Outside of that, 1st map still looks in good shape, so no need to make any wholesale changes. I think the highest amounts end up falling in the Worcester Hills area of Northeast CT/Northwest RI/Central MA extending up into interior Maine. Localized amounts here may end up reaching 20".

...LTE

The Rare I-95 Snowstorm

It has seemed that in the most recent couple winters that it's been like pulling teeth to get a decent coastal storm into the I-95 corridor to dump a good heavy snowfall. Well take heart I-95ers... this ones for you.



With the 6-12 zone we expect lolipops of 15" in isolated spots possible and once into new England, some totals in the 12-18 range could show up in our dashed 12-18 zone. Remember our dashed zone still considers a general 6-12 but with the chance a bit more than the isolated spot gets a total in the 12-18 range. (This method worked out beautifully for the last coastal storm that killed NNE). We feel attm that has a better chance of happening further north.

Issues, track of course, that's going to setup the heavy snow axis and how far back the edge goes. We don't see mixing to be an issue for virtually anyone at this juncture, even if the storm ends up coming even further in the west. There is liable to be a tight gradient, perhaps not as tight as DT or the NAM would suggest but it will be a tight one. One significant thing i see at the moment is our current precip shield is way up into southern/southeast PA. Whether that's hitting the ground yet in some spots i'm not sure, but the precip is situated considerably further north than what the NAM, GFS, or ECMWF initialized. Couple that with the HPC notes about the GFS/NAM 500mb initialization and have to keep an open mind about the low being closer to the coast. Will reevaluate after 12z runs most likely.

Our models of choice right now is the GFS/ECMWF. the NAM just looks too tight and a bit east with precip IMO.

Big things i'll be watching for in the next couple model runs:
-Advisory-level snow penetrating west thru the PA I-81 corridor.
-A broader deform precip shield to the north and west.

...MAG