*Significant late season snowstorm moves into the region later today through Wednesday*
Good morning. Our winter storm is currently organizing itself and will move into the region starting later today. The main event will not be until tomorrow however. Some snow and mixed precipitation will break out in areas to the south today, but I do not expect much in terms of impacts for most areas. The main area of concern is from around daybreak tomorrow through the evening.
The good news is the bulk of this storm happens during the daylight hours tomorrow. That doesn't mean there will not be imparts but the March sun will help keep the roads more resilient for the metro areas. This makes the snowfall forecast tricky as the grassy areas will do much better. Regardless, you need to expect impacts tomorrow from this as it will snow hard at times. Below is my updated impact map...
Now there are forecasts out there that are much more aggressive with amounts of 8 to 14 inches projected. I am being cautious here due to the late season nature of this storm. From experience, I tend to go more conservative this time of year. Regardless, I do still expect localized amounts over a foot with this storm.
Now to the projections. My model of choice is the regional Canadian for this storm as it has been the most consistent so far.
In the image above you see the evolution of this storm starting form this afternoon and ending tomorrow evening. Notice how the initial wave of precipitation is mostly rain/mixed today. Then by tomorrow morning a new coastal low takes over and pulls in the cold air causing heavy snow to breakout. This snow will last all day and cause the accumulations to pile up. As I mentioned, there will be impacts.
So the bottom line is a major late season storm is moving in. Tomorrow will not be ideal for travel as we get to the late morning hours.
Next update 7pm tonight.
Hey Willy, very interesting point about the RGEM -- I gather that RGEM is roughly the Canadian equivalent of our intermediate-scale NAM model. And yea, the NAM is a real flip-flopper on this storm; just this morning, the 6 am run was showing 6 to 8 inches in Essex and Hudson, the noon run goes back to 12+. The RGEM has been more of steady-Eddie at around 8 to 9 inches.
ReplyDeleteBut who knows, it's always a balance between responsiveness to new data and understanding the underlying longer-run trends and processes. NAM seems to be over-responding to updates, but is the RGEM under-responding? Every model is ultimately only as good as the understanding of what the underlying physical processes are and how they work on various levels, along with the accuracy and amount of current information inputted. The problem with this storm, I gather, is that there haven't really been too many like it in the past. A 4th Noreaster in late March, as Spring begins? Not much past experience to go by. So IMHO, it's not all that surprising that for this one, we are seeing a LOT of divergence between models and between model-runs every 6 or 12 hours, even in the final day before the storm.
You forecasters, who the public expects an answer from as to how much snow we are going to get and where and when are we getting it -- you good people are really in the hot seat on this one! You yourself seem to be playing it a little bit safe here, by in effect saying on your map, 6 to 12 anywhere between Salem, Toms River, Alpine and High Point. But that's not a bad idea, as this storm is still in the mystery zone! Jim G
Mid-day model runs -- still confusing. The Canadian global model CMC and the regional HRDPS have bumped up, now showing 12+, from 7-8 in their morning runs. BUT, the RGEM has backed off an inch or two.
ReplyDeleteThe sea level pressure charts are also head-scratchers for a rookie like me. It almost looks as if 3 different low pressure waves are involved in this event -- or is the second newly-formed low making an S turn off the Del Mar and Cape May? Or is it the original inland low that's doing that?
Curiouser and curiouser! cried Alice . . . (and Jim G)