Significant Late Season Snowstorm Likely

News of a potential snow storm has begun to spread this afternoon. The time frame would be Tuesday evening through Wednesday evening. As this period is anywhere from 84-100 hours away, lets state what we know so far.

Upper Level Set Up

Remarkably good agreement from the 3 major global ensemble models (in a winter where there has been minimal compatibility amongst the models). Strong upper level wave will develop downstream of a building western US ridge. The trough in the East will dig deep (black circle), becoming negatively tilted thanks to some weak ridging in the Northern Atlantic (purple circle).

A strong and rapidly intensifying surface low will develop somewhere near the 40/70 benchmark just south of Cape Cod. Strong vorticity advection and favorable positioning will allow this storm to bomb out, dropping several millibars in pressure level over a short period.

So lets jump to the facts at this point as I need to leave shortly to host trivia!

What We Know

- A strong storm will develop close to New England on Tuesday night.
- Exact track uncertain but good agreement on a pass close enough to New England for a significant impact.
-Plenty of cold air in place so precipitation will be all snow.
- Rapid intensification may create blizzard conditions, especially for Cape Cod and southeastern Massachusetts.
-Likely a sharp snow total gradient, with highest totals to the south.
- Extreme drop in pressure will create impressive winds. Sustained winds of 30-40 mph with higher gusts in Boston. 40-55 mph winds likely on Cape Cod and southeastern MA.
- As always, the exact track is key. Such a strong, wrapped up storm will have more narrow band of heavy precipitation. The closer or further the storm tracks to us, the chances of higher snow totals increases or decreases.
- There is some silver lining here. After the storm departs, we can expect a nice warm up for next weekend. Temps on Friday and Saturday will be near 60, eating up any snow that falls.

Lots of details to iron out. Stay tuned!