Storm system bringing wind, rain and even snow to the Northeast

AccuWeather

AccuWeather's Geoff Cornish breaks down the details of the forecast for the latest storm to soak the Northeast on Oct. 30.

Transcript

00:00Well, in the forecast feed this evening, we want to take a look at the northeast storm system. It's

00:08going to bring a variety of impacts. We're going to reveal our thought process here as we look at

00:14the computer models, kind of pulling back the curtain, looking at a few different factors. So

00:18one, we've got strong wind. That's going to lead to some coastal flooding. We'll take a look at

00:23even a little bit of flood concerns inside the Chesapeake Bay with some very high water along

00:28the mouth of the Potomac, for example. We'll take a look at some soaking rain and also, could there

00:33be a little bit of snow in the highest elevations? The short answer is yes. We'll give you a little

00:37bit of context before we get too excited for those of you in the middle elevations. We're not going

00:42to see flakes below 2,000 feet, but we might see some light accumulations by the end of the week

00:48and the very, very end of Friday in the high ground. Now, we want to take a look at some of

00:52these headlines here. And overall, again, some of the stronger impacts of this storm will begin to

00:59ramp up later this Thursday night and into Friday morning in the higher ground of the interior where

01:06we begin to see that cold air. But the teeth of the storm for most of us, looking at late Wednesday

01:11night through Thursday night for the rainfall. Coastal flooding will be a big concern. We're going

01:16to have some tough travel weather out there. I-95 will be messy for the second half of Thursday.

01:22Thursday evening's commute is going to be kind of a mess. And we'll see a gradual changeover of rain

01:27to snow above 2,500 feet. So a little bit of perspective on this big picture. We are looking at,

01:34we're going to look initially at the 500 millibars, about 20,000 feet up into the sky.

01:40What we're dealing with, the driving force behind this system. We have a strong, large,

01:45upper-level low-pressure system. And that's this big zone of currently chilly air, soaking rain,

01:52really in the upper 40s this Wednesday evening, and late afternoon even in Cincinnati, Ohio. So

01:57kind of a lemon of a day there with soaking rain. It is chilly under this upper-level low.

02:02And then we also, offshore, are tracking. There's your hurricane. This is Hurricane Melissa.

02:08Now, Melissa is going to stay far enough east that it will only bring some tangential impacts to

02:14the Canadian Maritimes. No direct impacts to the U.S. It's going to be scooting pretty quickly

02:19northeast. And again, we're going to be watching as this interacts with, again, the jet stream energy

02:25here. So as we clear the map, we can move forward in time. Now, we often talk about, and again, we don't

02:31want to beat a dead horse, but it's so fundamental to meteorology, the concept of a negatively tilted

02:36trough. And we think back to maybe high school math. Remember that Y equals MX plus B, the thing with the

02:42slope. We're talking about the slope of the line. And overall, we have kind of a chaotic pattern in the

02:48atmosphere. There are arguably two troughs, but I'm most interested in this trough in the east. And when I say

02:54negatively tilted, it goes from the northwest to the southeast. Sometimes we have troughs that are weaker, and

03:01they're angled from Texas to Maine. But if they're angled from generally something like Minnesota to Georgia, or in this

03:08case, from Michigan to eastern Virginia, that's a negative tilt. And that is a bit of a more aggressive

03:14storm system that's going to produce more lift in the atmosphere. It's going to have dynamics that are

03:19stronger. And more lift means you're getting more rising motion. And it's colder upstairs, so you get

03:25more condensation, as that cold air can contain less water vapor, more cloud production, more rain

03:29production, and more snow when we're talking about the exciting time of winter for the snow fans out

03:35there. But you can see it's a negatively tilted trough, so it's a pretty aggressive storm system, but it is

03:39pretty well removed. And the steering flow is likely to keep this system generally separate from

03:46Melissa, as Melissa is going to scoot northeast and head out to sea. There may be some interaction for the

03:50Canadian Maritimes. We're too far west, even in Maine, for that. But Thursday night to Friday morning, you

03:56can see the core of this upper level low, pretty large, powerful system. And it has some cold air

04:01upstairs that's going to be pivoting right over the New England states. And then we'll see some

04:04improvements, and this next trough digs in farther south into early next week. We'll talk about that

04:10in the days to come. So again, the overall orientation of the storm system is one in a

04:15posture that's going to be fairly strong. And we can actually see 1,000 millibars here plotted

04:21on Thursday morning to 996. Because it's negatively tilted, it's going to be strengthening 994,

04:29990 millibars. For perspective, remember, Melissa bottomed out at 892 millibars. 10% of the atmosphere

04:36was missing. In other words, the weight of the atmosphere was down by 10%. That was such a deep

04:42low-pressure system. This is a fairly strong low-pressure system. But again, it's certainly

04:46nothing compared to Melissa. But here we even get down to 987. It's a strengthening storm system. It's

04:52a posture of strengthening. And that means strong onshore winds as the system ramps up. And if we

04:57look at the isobars here, you can see the way the wind is going to be directed into coastal New

05:03England Thursday night. Before we even get to that point, though, there's a pretty good ramp-up time

05:08early tomorrow when we have a strong onshore wind coming up into the Chesapeake Bay and into areas

05:13near the tri-state area. And just with that in mind, I wanted to briefly take us over to this graphic

05:19here because it shows us the Potomac River. Not to give you some kind of an optical effect

05:25there with the flashing back and forth. But look at this. This is the mouth of the Potomac River

05:29where it dumps into the Chesapeake Bay. And we got two high tides that are going to give us

05:33some pretty significant flooding. One borderline major flooding here in Louisetta, Virginia,

05:39way east of Richmond early tomorrow. And then another one with moderate flooding to follow that.

05:45I did mention the potential on the backside of this for just a little bit of some light snow. And

05:51again, as we take a look at this one product, just to keep your expectations perhaps in check. But at

05:58the same time, it's always fun when the first few snowflakes fall. You can see we're going to see

06:03some light, measurable snow in the highest elevation to the eastern West Virginia,

06:07and also into the green and white mountains and the Adirondacks too.

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