Thursday, January 27, 2022

Expected track of historic nor'easter shifts west and puts the MRV in play for some moderate snow late Saturday

Seems like a good time to do a two-a-day update on our historic nor'easter so lets go for it. This is an incredible looking storm, certainly rivaling anything I've blogged about and seems poised to earn itself a chapter in some future book about 21st century New England winter storms. Indeed, it looks that good, but it's also a dangerous storm with high winds, very limited visibility and cold temperatures so be careful out there. In Vermont, many folks have thrown up the white flag and given up on this storm against my advice. Well, put those flags away because there's a little room in this tent for us as well. The track of this storm has shifted west and hopefully continues to do so. There's still some critical disagreement but we've pulled this storm to within 100 miles of the Cape and it is a beast, perhaps as strong as 970 mb as it lurks just offshore. The actual strength and the actual track, every mb and every few miles really matters so ironing out all of those last details remains of import. 

Now that we have some better agreement on the phasing and have pulled the storm closer to the coast, I can discuss why we are pretty well positioned to get a nice 5-10 from the event which is a big improvement verses earlier expectations. I am leaning heavily on experience but I also have the support of some trusted model data. Often times with these "bombs", snowfall will be fairly consolidated around the low pressure center initially but will ultimately explode westward when the rapid intensification has concluded. In many instances the westward retrogression of the moisture of the moisture is underpredicted by the models though they have certainly gotten better in recent years. It might seem like a struggle for the snow to work its way into the MRV on Saturday but ultimately it will and if the current track of the storm holds or better yet, moves farther west, snow should fall at a decent rate Saturday evening and night. It remains unlikely we hit a home run, but a well-struck 5-10 inch double would be my current expectation. I might add that this is a very cold snow and would be of a very low density except for the howling north winds blowing upwards of 50 mph at the summit. Snow will exit quickly and likely be gone by Sunday morning and the strong winds should also subside as the day progresses. 

I didn't get to the longer range earlier and I know there has been some legitimate concern over that. We've got a chilly start to the upcoming week with more sub-zero temperatures but the cold is expected to subside and ultimately give way to some sort of thaw around the time frame of Thursday. We may see some overrunning snow or mixed precipitation on Wednesday before what appears to be 24-36 hours of above freezing temperatures beginning Wednesday night or Thursday and lasting into early Friday. The concern involves the nature of this period of warmth and not necessarily the warmth itself and whether or not its associated with a well organized Great Lakes cutter capable of bringing wind and heavy rain into northern Vermont. There have been indications of this and hints that the situation might be better than worst case with a less amplified pattern, less rain and less warmth. As of now though, it appears to be a challenge to make it through Thursday without some rain and 40-plus temps, 

Cold weather will return for the weekend and the pattern looks somewhat wintry thereafter. Winter, by no means appears finished after the early part of this week.

1 comment:

Ryan said...

chances that rain falls as snow at high elevations ? i have a stowe trip feb 3-5 :(