00:00Here on the Forecast Feed, instead of snow, and there will be some snow to talk about in places like
00:05Denver, for example,
00:06we want to talk about severe thunderstorms. It's an early sign of spring.
00:10Severe thunderstorms emerging into the plains, and it's not just a one-day event.
00:14We have a sequence of four days, Wednesday, Thursday, Friday, and Saturday,
00:18with severe weather likely in some parts of the south-central U.S.,
00:21then a little break, then we're going to get back into it next week as well.
00:26So we want to take a look at this day-by-day, but first, I'd like to begin with a
00:30look at some of the computer modeling here,
00:32and then we can kind of differentiate the magnitude of the severe concerns here day-by-day with some of
00:38our own graphics.
00:39So here we are, and just big picture, what I want you to notice is a few things here.
00:44In the short term, we've got some heavy rain in the Midwest of the Ohio Valley along Interstate 70,
00:49and overall, gradually, we'll begin to see a severe thunderstorm threat emerge farther south,
00:55into Texas and Oklahoma.
00:57So here we have the GFS model, and we're went into Wednesday, though.
01:00We begin to see some thunderstorms pop here from Texas into Missouri,
01:04and then into Thursday, a new episode, the nature of the Thursday evening event,
01:09begin to focus our attention a little farther west into the edge of the Panhandle region,
01:14and then, again, even more into Saturday as well, with the system moving east.
01:19And the whole time, even Sunday, we get stuck with some showers down into Texas.
01:23So here's another depiction of that.
01:25And we're going to look upstairs.
01:26We're going to look at some parameters that basically dictate severe potential
01:30just to focus the conversation and maybe make the individual days stand out, one from the next.
01:37But you can see, frequently wet there in that stretch from Texas into the Ohio Valley.
01:43This particular model is a little slim.
01:45This is the NAM.
01:45It's a little slim, a little probably too timid into western Oklahoma.
01:50European, beginning with the wet weather there in the Midwest and near I-70 from Illinois into Indiana.
01:55And then we begin to see some action pop into Oklahoma and Texas, and the storms just kind of fester.
02:01Thursday evening, though, the European depicting some pretty noisy thunderstorms popping there into east Texas,
02:08and then they race into Oklahoma, and we'll be watching for a new episode on Friday.
02:12Friday evening is the day we're most concerned about.
02:15You can see kind of this scraggly appearance to the QPF, to the precipitation forecast,
02:22and that's a sign of several supercells that would be moving east.
02:25So what's driving all this?
02:26You can see a strong cold front then moving east into Saturday,
02:29and the tail of that's going to get hung up over Texas.
02:32But, again, a strong cold front will ultimately shove the whole thing east.
02:35But what's driving this?
02:36Here we go upstairs.
02:37We're going to go about 20,000 feet up into the atmosphere.
02:40And at first glance, we've got a few features on the map.
02:43We do have a warm front that's been lifting up through the northeast.
02:46That's responsible for that wintry mix and the trouble with snow and ice for some.
02:51Aloft, there's a big dip in the jet stream across the western U.S.,
02:54and we have a ridge over the gulf.
02:56So that's putting us in a posture of some flow out of the gulf,
03:01fueling some thunderstorms and at least putting moisture in place.
03:04Meanwhile, we have some colder air aloft.
03:07And if there were blue, I'd use blue.
03:10But some colder air aloft under this upper level low,
03:12and that's going to drive this contrast of warm humid near the ground
03:16as opposed to much colder air aloft.
03:19Remember, that's going to be a snowmaker into Denver come Friday.
03:23So as we take a look ahead, as we move forward,
03:26you can see that sharp dip in the jet stream Wednesday and Wednesday evening
03:31moves through parts of Kansas and Oklahoma.
03:34This is the driver behind some severe weather there.
03:36There will also be some strong thunderstorm potential tied to this area of the bright colors.
03:40It's actually a measure of spin in the atmosphere.
03:43And if you're east of one of those blobs of bright color,
03:46you have the risk for severe storms or at least extra lift.
03:49But look at what happens into Thursday.
03:50Thursday, a very sharp dip in the jet stream digs all the way down to Flagstaff, Arizona.
03:56East of there, remember, we've got some low-level flow coming out of the Gulf.
03:59So we begin to turn our attention to the panhandle area Thursday evening
04:03as, again, a big sharp dip in the jet stream crosses New Mexico and Colorado
04:09Thursday night, Friday morning.
04:10As that's approaching, we get some strong storms into the panhandle area.
04:13And then that, it's a vorticity maximum.
04:16It's a vort max, we call that.
04:18It's an area of spin in the atmosphere.
04:19This is going to kick some severe weather potential into more of the Midwest, southeast of that zone,
04:25Friday evening.
04:26And Friday is the day we're most concerned about.
04:27Then Saturday, that lifts sharply all the way up into Michigan.
04:31And we're going to have the residual noise tied to a front that stalled down over parts of the south.
04:37But then we look ahead to next week.
04:38Look at this big zone of low pressure southwest of California.
04:42That'll bring some showers to San Diego, perhaps.
04:44And when that rolls into the southern plains again next Tuesday, Wednesday, Thursday,
04:50that's another severe weather setup with a slightly different nature compared to the current one.
04:55So here is a look at convective available potential energy, basically lifting the atmosphere.
05:00Think of it as storm fuel.
05:01Wednesday, we've got some fuel here from Texas into Oklahoma.
05:05Thursday, it begins to nudge farther west.
05:07Remember, we have that big dip of the jet stream there.
05:09And there will be a dry line that sets up.
05:12East of there, strong thunderstorms.
05:14Friday, big area from central Texas all the way up into southwest Missouri.
05:18And then Saturday, it becomes a little maybe less impressive north of I-20.
05:23I-20 separating areas from like Dallas, Shreveport.
05:27It's going to be south of there where we have the risk for Saturday.
05:29And then it wanes a bit for Friday, but then it ramps back up later next week.
05:34If there's enough instability, we'll probably begin to see some more.
05:37You can see there's a disparity here in the models between the GFS.
05:39Not so excited about midweek next week.
05:41And Tuesday, the Europeans more aggressive with that.
05:45Here's the low-level jet.
05:47This is the wind, about 5,000 feet above our heads.
05:51When that ramps up, when we have stronger wind, look at this, Thursday night and Friday.
05:56Those are the days with the strongest wind a mile up in the atmosphere.
06:00So in the final minute here, I wanted to give us a quick look through a few of the next
06:03few days.
06:04Wednesday, severe weather risk.
06:06We're going to go with the some risk.
06:07One out of four on the AccuWeather Threat Level Index, Texas to Evansville, Indiana.
06:12Remember, there are two separate chunks of energy there.
06:14As this big zone of low pressure, big dip in the jet stream on Thursday night,
06:18digs down over Arizona and New Mexico, a new zone of storms breaks out.
06:23This one centered west of I-35, the panhandle area of Texas and western Oklahoma.
06:28That's Thursday evening and Thursday night.
06:31That system slides east Friday.
06:32Remember, we saw strong signatures with the winds 5,000 feet up in the atmosphere.
06:37The low-level jet was strong.
06:38We had plenty of storm fuel.
06:40And then remember, on Saturday, it gets squashed mainly south, maybe near I-20, and especially south.
06:45So that's your forecast feed for now.
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