NEXT Weather Alert: Tracking severe storms in Philadelphia region

[00:00:00]some flash flooding, but we can't rule out a tornado either. There's enough spit in the atmosphere today that as some of these stronger storms develop, we could see a tornado develop. The main window for this severe weather threat will be between around 3 to around 9:00 into the evening hours. And throughout this window, if we get that severe weather, tree damage, power outages, and some flash flooding will be a concern.

[00:00:23]Right now, tracking just a few scattered showers, mainly across the Lehigh Valley. The rest of the region we're finding mostly cloudy skies, but a few peaks of sunshine will add to the instability in the atmosphere. There you see a closer look at just a few of those isolated really downpours. Not even a lot of lightning with those storms right now. Watch as we go through the rest of the afternoon. That developing line of storms rolls in from the west. It likely moves into the Lehigh Valley first and then into the I95 corridor as we head through around 6 7 8:00. those embedded gusty winds, heavy rainfall, and maybe that tornado threat moving across the region to South Jersey and then down to our shore points as we head through the afternoon and the evening. We'll continue with hourly updates as we head through the rest of the afternoon. In the meantime, more information on our website on cbsfiladelphia.com.

[00:01:12]All right, those of you watching on the stream, again, we'll stay with you as we head through the rest of the afternoon with our hourly updates right here on CBS Philadelphia. Again, I'm CBS Philadelphia meteorologist Grant Gilmore. So, let's just dig into the meat of this severe weather threat that we'll see develop as we go through the rest of the day. Again, just to recap, our next weather alert in effect through the remainder of the day due to the possibility of some severe weather. Now, I don't think everybody sees this severe weather, but I do think there will be some storms that have the potential to turn severe. And again, the primary concern, the main thing that we're watching will be these storms producing the damaging wind threat. But there is enough spin in the atmosphere to whereas as as you go up into the atmosphere, winds are changing not just speed, but direction, and that creates that spin.

[00:02:03]So, as the updrafts and these thunderstorms develop, they will rotate and that's where you get that threat for a tornado. Now, a lot of moisture in the atmosphere as well, and you can feel it outside today. We'll talk more about that here in just a second. But all of that moisture ultimately goes to those clouds and those clouds precipitate producing that heavy rainfall and that's where we're going to be watching for that threat for some flash flooding. So between 3 and around 9:00 this evening, that's the window. So if you've got plans, the kids have extracurricular activities, maybe coming home from summer camp, uh maybe you're heading home from work or heading off to work in this window, just know that you'll want to check our website, cbsfiladelphia.com. I know you've got the weather app as well. uh check that radar and have an idea of where the storms are or maybe where they're not.

[00:02:46]Maybe you'll be fine to to run out, run your errands, and do what you have to do before the potential for more storms roll in. But I think what we need to be prepared for is some tree damage and and with the tree damage or any sort of other wind damage that could result in some power outages. Now, flash flooding, we've seen a lot of that over the last couple of weeks, and I think we could run into that again if we get a couple of rounds of the heavy rainfall. And even in areas that have the clear storm drains, I think you get enough rainfall in a short period of time, those drains are just not going to be able to alleviate that that rainfall. And then ultimately, if it can't go into the drain, it goes up and that's when you get the flooding issues. Temperatures right now, 84 degrees. Now, I point this out because it is warm, but it's not excessively hot. It's not like that extreme heat that we had last week. But the warmth combined with this influx of moisture from the south is really making it feel very uncomfortable this afternoon. It feels like 90° in Philadelphia. Again, it's it's nothing that we haven't seen recently, but still it's that relative humidity that is is through the roof. And one thing that that does is the combination of the heat and the moisture. Yes, it makes it feel uncomfortable, but that is the fuel that goes to these storms that will ultimately determine how strong and potentially severe they're going to be.

[00:04:06]One thing that we keep an eye on is this available energy product or we call it cape. It stands for convective available potential energy. And what you're seeing here is a lot more of that instability is across Delaware into South Jersey. a little bit of instability across portions of central Jersey there across Burlington County back into upper Montgomery, Bucks County into Burks and and Lehi. So the the the instability is building right now and this is the window where we were saying between around 1 to around 4 or 5:00 that we'll really have to watch to see how much of this instability develops, how much energy gets pumped into the atmosphere before these storms roll in. Now, in addition to the the threat for the severe storms, just all that moisture in the atmosphere is available to rain out and produce that flood threat, especially in urban areas where the rain isn't able to get absorbed into the soil where you got a lot of concrete, pavement, buildings, the water doesn't have anywhere to go, so it just floods.

[00:05:10]So, that's why we have a flood watch for much of the urban corridor here. So this includes upper Burlington County, Camden, Gloucester County, Philly, Montgomery, Bucks County, back into Delo, Chester County, and then also Newcastle County. So that's our flood watch that will remain in effect until 2:00 tonight or technically Wednesday morning. Now, let's talk big picture here. We've got this enhanced level three out of five threat for severe storms today. B this comes from the Storm Prediction Center. They're out in Norman, Oklahoma, and and they issue these convective outlooks. Basically saying like, look, we've got a decent chance of seeing severe storms. But let's break it down even more. What type of severe storms are we looking at? And here we're looking at at about you're looking at a 30 to 45% chance of damaging winds. That's a pretty good chance, right? When you think about your rain chances, 30 40 50% chance of rain.

[00:06:02]But now you're talking about a 45% chance of damaging wind. So that's the concern there. Also, your tornado risk.

[00:06:09]Now, much lower probability of tornadoes, but still in the grand scheme of things, you're looking at a 5% chance of tornadoes developing really anywhere across the state of Pennsylvania, New Jersey, Delaware, and then up into portions of New York and New England.

[00:06:24]So, uh, we got to watch a couple of those factors here today and through the afternoon. Look, look at the radar right now. Nothing out there right now aside from just a few spotty showers moving through the Lehi Valley here in the Philadelphia area. We had one isolated shower develop around 11:00 this morning that moved up toward Trenton that has cleared out. So those spotty showers, a few storms around uh in terms of the thunder and the lightning, but really much of the Philly area, Allentown, just north of Allentown, it's just rain at this point. But also embedded within some of that, you're finding some clearing. Look towards Burlington County. You're seeing some clearing in some of the clouds. So, that's that energy. That's that that potential energy, if you will, for that destabilization for these storms. And this is what's heading our way. These are the storms that are moving in from the west. And these storms will encounter this destabilizing atmosphere.

[00:07:18]And then we'll see how they develop or or continue to increase. I'm more concerned about these storms back here.

[00:07:24]Far western PA moving out of the Ohio Valley and eastern Ohio. That will be the area to watch that I think has the greatest chance of turning severe. Watch here the forecast model. This is this is one of our our models that we really hone in on closely for our near-term forecast. We call them the high resolution models. And you see this what looks to be a developing line. While it's kind of isolated storms at that point by 4:00, that line becomes a little more organized as it moves into portions of upper upper Montgomery and Bucks County moving across Chester into Delo. So that will be something to watch to see how the model handles actually what happens and that will continue to move through the I95 corridor. I would say anywhere along that line from really Trenton back to Wilmington and then points south and east will have the potential for finding some gusty winds, some potentially severe winds upwards of 50 60 mph. And if you get just enough organization with that, it could tap into some of that spin that may produce that tornado threat. So that moves to the south and east. It hits our shore points probably around 9 10:00. Again, this is still a system that's way out into the western part of the state. So, the timing will likely change with this, but this is at least the latest of our forecast models timing with this. And I think it it's a good chance of it. It might clear out a little bit faster, but the trend has actually been for a later arrival, which means a later clearing as well. But by around 10, 11:00, that severe threat should be pretty much done. And then we'll start tomorrow morning with maybe some clouds and showers down the shore. Partly cloudy skies here across Philadelphia, Lehigh Valley. I think you're going to enjoy a little more sunshine tomorrow compared to the rest of the area. Let's put it all together with the 7-day forecast here. 84 degrees before those showers and storms arrive and then the evening, the first half of the overnight, we'll have to deal with those storms.

[00:09:13]Hopefully, they're out of here, but we'll be right here tracking the whole thing for you right on cbs Philadelphia.com, CBS Philadelphia.

[00:09:19]We'll be on the stream every hour uh for updates just to keep you posted. And then the rest of the week looking pretty good. 83 Thursday, 84 degrees on Friday.

[00:09:27]This weekend looks very nice. This is a nice change of pace, isn't it? Low and mid 80s under partly cloudy skies. And then we'll see temperatures stay there in the mid 80s as we go into the beginning of next week. But again, it's 1:16 right now. We'll be right back here at 2:00 for another live update just to show you what's happening, what's changed, what hasn't changed, and and see if we see any more developments and our our instability and that severe weather threat. But I'm CBS Philadelphia meteorologist Grant Gilmore. You're watching CBS Philadelphia on their stream and we'll continue with these updates as long as we need to while the storms develop and they move through.

[00:10:00]Take care. Stay safe.

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