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  • 11 hours ago
Later this week, extreme heat will spread from the Midwest to the Northeast, hitting the region with one of the worst heat waves in the last few years.
Transcript
00:00Well, the heat is building across the plains, the Midwest, and into the Northeast.
00:04Our first big heat wave of the year, and this is going to be a broiling one.
00:09Classic old-fashioned heat wave. There's nothing old-fashioned about it.
00:12We have a lot of these in the current day, obviously, and, in fact, the intensity of them is escalating
00:19here in many regards.
00:20Well, here we have the heat dome expanding across more of the Midwest and into the Northeast of mid-Atlantic
00:25states,
00:26and here you can see AccuWeather, real field temperatures 100 to 110.
00:30The risk of heat-related illnesses will be spiking in many of these areas here Wednesday and Thursday,
00:35and high energy demand on the map.
00:38We're going to look at this through a few different lenses here, and just right off the bat, I do
00:44want to acknowledge
00:44we're going to talk also about some storms, the Ring of Fire, around the periphery of the heat.
00:48We have sinking air in the plains and the Ohio Valley with that core of the heat dome,
00:54but around the periphery of that, that's where there is less sinking air.
00:57In fact, even opportunities for rising motion, and that's where we're facing some strong storms.
01:01We've had some nasty storms up into the upper Midwest, and, again, these are the areas where the storms are
01:05going to be percolating
01:06over the next few days.
01:08Now, before we get into some details, I want to bring up some big-picture computer modeling
01:13and show you the core of the heat dome, and overall, we can clearly plot it.
01:19We're looking around, really, all the way up around 20,000 feet, the 500 millibar level in the atmosphere.
01:27And that's where we have some very significant heat out there in regards to large mountain of air.
01:35Hot air expands, so it occupies more volume, and it's almost like mountains of air and valleys of air
01:42when we characterize the air mass, and in this case, we're dealing with a very large hot air mass
01:48across much of the central and into the eastern U.S.
01:52Here we are on a Tuesday.
01:53The core of this is drifting east with time, and we're going to be dealing with, again,
01:58a lot of big-time heat across more of the plains.
02:01Now, as we look at the overall flow aloft, if you're on the west side of a ridge,
02:05you're getting flow from the southwest.
02:07If you're on the east side, it's actually flow from the northeast,
02:09so it's kind of the central and western part of this ridge where the heat is searing the most.
02:14And then you can see it just expands.
02:16And, again, a lot of the time if we get up to around 600 decameters here,
02:21we're close to the threshold.
02:23You can see there's a closed 594, 588, 594.
02:28We're close to a little bubble of 600.
02:31And we never quite make it there with the GFS, but it's going to be hot regardless.
02:36Sometimes in the plains, we'll get a 600 decameter contour.
02:40I don't see that with any of these.
02:42But regardless, the persistence of this is going to be significant enough that we're dealing with some very significant heat.
02:49And some spots will even get close to record highs or even break record highs in a few cases.
02:53We'll look at Thursday for the big cities.
02:55We'll be close to records in a few spots.
02:57Now, if we look at this, this is the shift of tails.
03:01This is like a statistical approach to look at the European Temperature Index.
03:06And are we above or below average?
03:08And are we way above or way below average?
03:10How rare is this?
03:12And we look at the 29th here.
03:13We're looking at, let's go ahead to the 30th.
03:16This is when the core of this, Tuesday and into Wednesday,
03:21begins to shift into more of the Midwest and the Great Lakes.
03:24Meanwhile, we're especially cool in the western U.S.
03:28But again, the core of this on the, here we are valid on 0Z on July 1st is really the
03:36preceding day.
03:37So this is the time leading up to 8 p.m.
03:410Z would be midnight Greenwich meantime.
03:44Shave four hours off of that for the eastern U.S.
03:46So here we're looking at the final day of June.
03:48This is, again, we're looking into the second.
03:51So this is really the 1st of July, if we're ending at 8 p.m. on the 2nd at Greenwich
03:57Mean Time.
03:57So here we're looking at the time frame for July 1st.
04:01And again, July 1st will take us into the middle of the week.
04:05And into the latter part of the week here, this is for July 2nd, which would be Thursday.
04:09And then July 3rd, which would be Friday.
04:12And then the timeline leading up to midnight Greenwich Mean Time on July 5th, which is really the 4th of
04:19July here in the U.S.
04:20This is the heat baking the I-95 still on Saturday.
04:25So it gradually shifts east through the second half of the week.
04:27And if we look at maximum temperatures, here's the GFS forecast for high temps.
04:31I see 104 there in central Virginia.
04:36And then the next day, 103.
04:37Then the next day, 105.
04:39And then a 106.
04:41Even a 106 for Philly in the forecast in the GFS.
04:44What's the, looking at, I see a 103 for New York City for Friday's high.
04:50What does that actually look like here in the European model?
04:54Not quite as hot, but almost as hot.
04:58So there's a slight difference in the computer modeling for the intensity of the heat.
05:03But, again, it's going to be very, very hot.
05:05We'll show you our accurate weather forecast in just a minute.
05:08One of the problems here is the overnight lows.
05:10They stay way up.
05:11Overnight lows in Philadelphia around 81 for Wednesday night to Thursday morning.
05:16That's hot.
05:17An overnight low of 82 is a classic heat wave here when you have overnight lows of 80 or warmer.
05:23And then still upper 70s here for the overnight low leading up into Saturday morning.
05:28So that's really, really hot.
05:30I want to take you into our graphics.
05:32And the AccuWeather Heat Wave Severity Index is a statistical method we use to characterize
05:38the intensity and the duration of a heat wave.
05:42At New York City, in New York City, we set the threshold at 90 degrees.
05:46If we string three or more days together in a row in which Central Park hits 90 plus,
05:52and then if we're well above 90 for any of those days, it begins to add to the tally.
05:56We have 14 units on our AccuWeather Heat Wave Severity Index.
06:01We didn't have a single heat wave last year or the year before at that threshold for New York City.
06:06Let's look at history.
06:07So if we got a 14-unit heat wave for New York City, since 2000, the worst was August 5th
06:16to 10th of 2001, 23 units.
06:19Second worst was the next year, 20 units.
06:21So we said 14 units.
06:22Where would that land us?
06:23We've got to go a little deeper into the list.
06:25This would be our eighth worst heat wave in New York City since the year 2000.
06:29Pretty impressive stuff.
06:31And by the way, that's for New York City.
06:33For Philadelphia, we're looking at 45 units for the year and 21 units just for this event.
06:38We didn't have any 21-unit heat waves last year in Philadelphia.
06:43So it could be our worst heat wave there in over a year.
06:47And close to records for Thursday for the Daily Records.
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