In case you’ve missed it, there’s a big amount of snow heading our way. The National Weather Service is warning of a “crippling and potentially historic blizzard” will hit the city with snow totals predicted to be 20-30 inches or more in some areas. The last time a storm of this magnitude struck, passengers were stranded for hours on an N train stuck in Brooklyn and an A left near Howard Beach. Since then, the MTA has been very proactive in managing subway service and its storm response.

As now, it’s not clear how Monday is going to unfold. As of just before midnight, the MTA’s website offers up only this tidbit regarding tomorrow’s New York City Transit service:

NYC Transit personnel are in place to clear platforms and stairs of snow. De-icers and snow-throwers have been strategically deployed to focus on outdoor areas and open cuts that are the most susceptible to high snow accumulations. The MTA is planning to operate normal bus service tomorrow morning, but depending on road conditions, service may be curtailed as the day progresses. All local buses, including articulated buses, will have chains or snow tires installed by tomorrow’s PM rush hour. Paratransit customers may experience additional travel and wait times.

Gov. Cuomo meanwhile has sounded a more urgent alarm. While asking commuters to stay home if possible, the governor has said “the public transit network including…MTA Subways and Buses may be closed ahead of the evening commute.” The language is rather stilted, and it’s not totally clear what Cuomo means. My guess is that he’s referring to a Plan 4 response to the storm.

In all likelihood, then, as the snow begins to fall around 1 p.m. tomorrow afternoon, the MTA will look to curtail service. Trains will be stored on underground express tracks, and all express service is likely to run local. At-grade subway lines — such as the A through the Rockaways and the N down the Sea Beach Line — are likely to be curtailed while the trains that don’t run 24 hours — the M and the B — will stop early. Now, that’s not official, but that’s been the general approach to major snowstorms.

For the MTA, this week’s storm is shaping up to be a big test. They’ve had successful storms over the past few years, but we haven’t seen something of this magnitude in over four years. Since then, the subways weathered Irene and emerged limping out of Sandy. We’ll see how this week’s storm goes, but ultimately, the same advice applies: Don’t travel if you don’t have to.

I’ll update the site with any weather-related service advisories as they are announced. For now, we’re all just waiting for snow and waiting for service changes.