Boom - winter storm warnings (pink) and blizzard warnings (orange) now up for I-95 counties and coastal counties in NJ/LI, respectively, as well as winter weather advisories (blue). And snowfall amounts up again as per maps. Strap in folks.
A couple of points for anyone interested, which were in my email updates but hadn't posted here yet (as far as I recall).
Snow Will Accumulate: First, with temps generally in the mid/upper 20s during daylight hours, the snow, which will start after midnight towards Philly and after about 3 am towards NYC, will immediately accumulate on all untreated surfaces, making walking and driving treacherous, even on major highways, once the snowfall rate exceeds the melting rate from salt/traffic (which it will, if we get the forecasted amounts) – and the worst of it will likely be from 4 am to 10 am, right around the morning rush hour, so be careful out there and consider putting a snow emergency kit in your car.
Shovel by Evening: Second, while the snow will be high ratio/low density fluffy stuff and should be easy to shovel, any snow that gets mixed with salt from road treatments and ends up at the bottom of your driveway from a plow will have melting going on in that pile during the afternoon tomorrow. Then, when the bottom drops out of the temperature tomorrow night (low of 5-10F) that mix will freeze solid and won't melt until at least Monday. So shovel before 6-7 pm if at all possible.
Uncertainty Still: This is still an extraordinarily complex synoptic setup and while the models have converged somewhat on the solutions upon which this forecast is made, there’s still decent variability in them and uncertainty in how this will play out, i.e, only a few inches of snow is still a potential outcome for I-95, for example (no snow is close to a 0% probability), while up to a foot of snow is also still possible for the I-95 corridor. And similar variabilities exist for other locations. Some of us remember Jan-15 very well when our 18-30” of snow for most of NJ, forecasted right up until the start of the storm, ended up being 3-9” from W to E.
1/25/00 Analog: Also, if this does verify, remember the Jan 25, 2000 “surprise” snowstorm, where little to no snow was forecast up until the night before and most of the area got 8-14”? I do, painfully, as I left for Ireland the night before and didn’t even know it snowed back home until the next night! Well, that storm is the #1 analog to this storm and was called out by many mets when the models were showing not much snow for this one 2 days ago. Several pros highlighted how this could happen, meteorologically, if the northern jet stream energy moved faster than was being modeled, as well as in a more S/SW direction instead of SE (as per my comments Monday evening), such that the leading southern jet stream energy would have to respond to that “action” with an equal and opposite reaction (yes Newton’s 3rd Law still applies) by heading more N or even NNW after formation off of FL, rather than moving more NE out to sea. That’s what’s being modeled by all the models now. DT/WxRisk did a wonderful podcast showing how this might happen - link below.
Coastal Flooding: A coastal flood advisory is up for the NJ Shore for minor flooding Thursday morning; despite the recent lunar high tide, the storm is likely to be far enough away and not sticking around long enough to have a major impact. However, one unusual effect will be that there will be areas of stagnant salt water that will freeze solid, given temps below 20F for the next few days and salt water freezes around 27-28F. Could be locally treacherous.
Record Cold: It's coming for the next 3 days for many locations - will post on this later - worth its own post, if not its own thread, really.
https://www.wxrisk.com/the-wxrisk-com-snowstorm-page/
http://www.raymondcmartinjr.com/weather/2000/25-Jan-00.html