A massive storm moving across the U.S. from Wednesday to Sunday may have an extreme variety of impacts.
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00:00John, we're going to step into a really prolific rainmaker with some big-time snow in the mountains as well.
00:06We are. It's going to be the biggest storm of the year, the wet season so far across Southern California.
00:12So it's bringing needed rainfall. We've had such dry conditions in the short term there.
00:16But the problem is if the rain comes too fast, too furious, which we think it will,
00:21we're going to be dealing with some significant flash flooding concerns as well as mudslide and rockslide concerns.
00:27Look at that atmospheric river, that channel of high levels of atmospheric moisture directed right at the California coast,
00:33including the L.A. area where we had those recent devastating wildfires, and that is a big concern, Jeff.
00:40Absolutely, John. And, John, can you talk a little bit about what makes greater danger on the heels of a big wildfire,
00:46especially if you have people living down the hill near Altadena?
00:50Yeah, all that, there's no longer any vegetation and structures there, tragically.
00:56So what ends up happening is that water has nowhere else to go except run off.
01:01And the ground, that is what increases the risk for those mudslides and that quickly escalating flash flooding situation,
01:09which is why we're so concerned about that.
01:11And there's also going to be the threat for some thunderstorms here from the Bay Area southward into Southern California as well,
01:19which can produce damaging wind gusts and even a widely separated tornado as well.
01:24And with those thunderstorms, that's where the intense rain rates sometimes of perhaps one half inch to one inch per hour can occur,
01:32and that's when we're most concerned about the serious flash flooding.
01:35And, John, there are some benefits to this regarding water supply,
01:38maybe even extending the ski season deeper into the spring on the cold side up in elevation.
01:43Look at that, feet of snow here, especially above 6,000 feet elevation.
01:48Look for road closures, Interstate 80 near Donner Pass and surrounding areas, a big snowstorm on the way in the Sierra.
01:54And, John, unlike the previous two storms that we've had this week, this one is going to be a true coast-to-coast storm.
01:59This one's going all the way across the country, and unfortunately, it's going to bring a variety of problems with it.
02:05To the north, we're going to be dealing with snow and ice concerns from the Great Lakes into parts of the interior northeast.
02:11Even can start as a bit of snow and sleet in the big cities along the I-95 corridor, such as New York,
02:17where there can be a coating to an inch, maybe a few inches up toward Boston before it ends up going over to rain.
02:22And, Jeff, further south there toward the Gulf Coast, big concerns.
02:26This looks like a very concerning setup here during the day Saturday into Saturday night with a severe thunderstorm and tornado risk.
02:34And some of these areas around Mississippi will be at especially heightened concern here.
02:38A moderate risk, two out of four on the AccuWeather Threat Level Index.
02:41And, in fact, in full transparency, John, I'm going to remove the word isolated.
02:45I want to match our forecast team's map.
02:47We dropped the word isolated from the tornado forecast from yesterday to today.
02:51We did because we're concerned this is a setup where there could be a dozen or more tornadoes,
02:55a fairly widespread event here, and also that some of these tornadoes could be particularly strong,
03:02and they might be on the ground for more than just a few minutes.
03:05So, as we kind of wrap this whole thing up, big headlines here associated with this coast-to-coast storm.
03:10California headlines at the end of the workweek.
03:12Huge, big concerns there.
03:14But moving forward, as we wrap this up, John, what among these do you think will be most impactful?
03:19It's hard to really pick one.
03:20Yeah, I think they're all going to be notable.
03:22That heavy snow, as we mentioned, across the Midwest and northern New England,
03:25the severe weather risk in the southeast, and also the concerns,
03:29another very active storm track into the northwest with our next storm system.
03:33All of this is to say it's a great time to stay tuned with us frequently here.
03:36Check in back with us more often at AccuWeather on the AccuWeather network,
03:40on the AccuWeather.com website, and the AccuWeather app.
03:43All great resources as we navigate together a very challenging weather situation over the coming days.
03:49All right, there he is, AccuWeather Chief Meteorologist John Porter.
03:52Thanks again, John.