Severe weather returns? What to expect for the back half of May

Added: 2026-05-12

[00:00:00]Hey everybody, Trey here. Welcome back to another video. It's been a relatively quiet start to the month of May in terms of severe weather across the US as the pattern has been somewhat unfavorable for widespread severe weather to this point in May. This is especially true in the tornado department as we've seen very few tornado reports to this point in the month, which of course this is we're getting into peak season and we've only seen 30 tornado reports for the month of May so far. We have our cluster of tornado reports from May 6th there in southern Mississippi. That significant tornado event there, but otherwise tornado activity has been extremely sporadic across the US to start May.

[00:00:39]This is expected to continue for at least the next few days, but there are some signs that the back half of the month may be more favorable and more active in terms of severe weather and tornadoes in general going into those last couple of weeks of May. So, I wanted to come on and do a quick video showing you how the pattern has been unfavorable to this point in May and as we stand so far and how it's expected to change as we go into the last couple of weeks of the month of May and even into early June. So, without further ado, let's go ahead and get started. The SPC does have a few risk areas outlined for the next few days. Very low-end risks at this point. Uh some marginal risks uh for today from the Great Lakes down into the central plains and one there into into Florida. Very low-end risk today that continues into tomorrow. Marginal risk out there in the Idaho Montana vicinity and one out there centered on West Virginia. Uh and then for the central plains on uh Thursday, but there are a couple of days that have been outlined in the medium range. Day five and six uh have been outlined as severe weather days across the central plains, central and southern plains into the Midwest. Here is the day five risk. So, this is for Saturday, May 16th. We have a 15% risk outlined for the central plains into Oklahoma. So, southern Nebraska, far northwest Missouri, much of Kansas down into western Oklahoma.

[00:02:01]Again, that is for Saturday, May 16th.

[00:02:04]And then day six, which is for Sunday, we've had a risk area outlined from Oklahoma all the way up into the central plains and into the Midwest. So, we are starting to see a a little bit more of a synoptic uh flavor to some of our severe weather events going forward into this weekend. And that may continue beyond that as we head into the last stretch of May. Here is a look at the current 500 mibar pattern from the SPC mezo analysis page. And if you're looking for severe weather, especially widespread severe weather, this is not what you want to see as we have a very large ridge centered over the western half of the country and a general troughing pattern over the east or southeast portion of the country. Our main jetream is relegated well off to the north.

[00:02:48]somewhat of a more robust trough here across the northern plains, but overall nothing really down here across the southern half of the country where most of our severe weather tends to be uh tends to occur for the month of May. And what is most important is this very large ridge out over the western half of the US. That is extremely unfavorable for widespread severe weather across the central and southern plains and even into the Midwest and Southeast. So, this pattern has been in place for the last few days. We've seen some northwest flow events on the northern periphery of this ridge as some short waves have dropped down a top that ridge. But overall uh it has been a very unfavorable pattern for severe weather in a widespread sense across much of the country due to this western US ridge eastern US trough pattern that has taken shape to start the month of May. At the surface, as you'd expect with this kind of a pattern, not much going on as well with that northern trough. We have seen a little bit of a surface low develop.

[00:03:44]cold front stretching down into the central plains. That is going to be the main initiating mechanism for storms today in that marginal risk. Very low-end threat today. We don't really have the ingredients there for robust severe weather, but any storm that forms could produce some gusty winds and some isolated large hail. But storm coverage should be very very sparse and overall just kind of a quiescent pattern for much of the country. You don't really have that uh central high plains surface low or anything like that that would indicate a robust threat of severe weather across the central and southern US. Also, we have this large anti-cyclone or high-pressure uh system or ridge sitting over the eastern US, which is going to be generally unfavorable for robust moisture transport into the central and southern plains and midwest. Those winds you see here in the southern plains uh and Gulf Coast region out of the east or east northeast, which is an unfavorable trajectory to get robust moisture back into uh a wide region of the US. Uh we need those winds out of the south across that region to really uh allow that to take shape. After our last stretch of robust severe weather, including that robust day down in southern Mississippi, uh the cold front kind of swept the moisture out into the Gulf. So we had our 60s due points and our re really rich moisture swept well out into the Gulf, which kind of shut things down for a few days, at least in a widespread sense. We have had some semblance of moisture return on the western periphery of that large ridge in the eastern US.

[00:05:11]Some of those winds are out of the south across the southern plains and we've been able to get you know mid to upper 50s and some low 60s due points back into parts of Texas into the mids south region in Oklahoma up into even southern Kansas and Missouri. So we at least have some marginal moisture there for severe weather. And so we haven't seen a total total shutdown of severe weather across the US. But again, it is on a very localized um isolated sense because of the unfavorable upper air pattern and this somewhat more uh somewhat less favorable moisture. Our really robust due points are still sitting down there across East and South Texas and and down there into the Gulf. Uh and that is going to uh take some time to get uh well off to the north because we don't have that favorable pattern to really set up a robust surface low uh there in the central or southern high plains to really flip those winds out of the south and strengthen them to start really pulling that moisture that robust moisture off to the north well inland into the US. That is expected to change eventually though. Uh but for now we're seeing somewhat more meager moisture and therefore a more isolated threat for severe weather. Now, taking a look at our ensemble models, this unfavorable pattern for widespread severe weather is expected to persist for at least the next few days. As always, the ensemble models are what you want to be looking at for your more medium and long range severe weather threats as opposed to your single deterministic runs of the models of choice. What an ensemble model is is let's say we have the GFS model.

[00:06:39]We take the GFS models initial condition conditions and the initializations and we slightly tweak those over several different um members of the ensembles.

[00:06:47]We kind of tweak those several different ways and run those outputs. At the end of that, we kind of average all of those outputs together to give us an average look at the overall pattern going out farther and farther into time. As we know, single model runs can be kind of out to lunch. They can give you a very wonky solution. the ensemble models and and why we average them out in the ensembles is to kind of weed out those wonkier runs, those out to lunch runs.

[00:07:14]And it gives us a better picture of how the overall pattern might evolve in the medium and longer range much much better than the uh single runs of these deterministic models. So the ensemble models, we'll start off with the GFS ensemble here and we'll look at the European model here in just a second.

[00:07:31]The European ensemble starting at 500 mibars. So this is the average 500 mibar pattern among all of the GFS ensemble members averaged into one product here.

[00:07:42]So as you can see it's initialized very well with that ridge over the western US that subtle troughing over the southeast and our jetream really relegated off to the northern portions of the country.

[00:07:52]This persists for quite some time. That ridge really starts to build in across the central and southern US uh and kind of shuts things down in a widespread sense for the next few days. But as you can see, as we go into the ne into the weekend, we start to see our jetream shift a little bit farther south and we get a little bit more influence here in breaking down that ridge and giving us a more troughy pattern in the western US.

[00:08:15]This is a much more favorable pattern for widespread severe weather in the US.

[00:08:20]We also have a little bit of influence from our subtropical jet down here.

[00:08:23]Little bit of a wave moving into the southern US and Mexico there. That could be a player going into the weekend. This is on Saturday. You see, you just to kind of sum things up here, we've gotten rid of our large ridge. We now have a trough over the western US. Troughing over the western US is favorable for severe weather across the Great Plains and Midwest. And so, we're going to see a more favorable pattern start to set up this weekend um after a few days of very marginal severe threats with that unfavorable pattern persisting. But, and as we go forward into the weekend, that troughing in the western US continues.

[00:08:56]Ridge in the East Coast. This is your classic pattern for severe weather across the central US. This is on Sunday. Nice large trough here across the western US. Ridge here over the east eastern US. This is our our textbook setup for severe weather across the central portion of the country. Now, as far as severe weather threats go still remains a question, but the overall idea is that the pattern is going to be much more favorable favorable for severe weather starting this weekend and perhaps going beyond this weekend as well. As we go forward in time into next week, we kind of maintain this general troughing over the western US. It's not very robust, per se, and no day is really sticking out as a very favorable day. And one thing to note here, we do maintain this this uh kind of west western US trough, eastern US ridge, but overall the flow associated with this is somewhat on the weaker side. We don't see really robust wind uh shading here uh with this west western US trough. And so nothing really sticking out at this point, but the idea is that we're going to have a more persistent western US trough and that could lead to a more prolonged period of severe weather going at least through the end of the run here. So this is going through uh May 28th, the end of the GFS run here. We still maintain this western US troughing. We do see some ridging perhaps building back in a little bit toward the end of the run. And this could shift things over toward more of the the high plains region. So, kind of that Montana down through Wyoming, Colorado, New Mexico corridor. Um, that could be our favorite area as we go into the latter half of May, kind of similar to 2023. Uh, but we still the the basic idea is that we're maintaining this western US trough with the eastern US ridge. And that is a favorable configuration for severe weather. Again, no day really sticking out at this point, but the pattern is going to be more favorable for severe weather going forward, at least after this weekend.

[00:10:46]What about our moisture? we can have all the forcing we want, but but if we don't have the juice we need for storms, then we're not going to see robust severe weather. So again, our our most robust moisture has been swept out into the Gulf, kind of just lurking there along the Gulf Coast at this point. The blue shading, that's those are your 60 plus due points. Purple shading is your 70 plus due points. And don't be too uh locked into the exact position and exact northward position of the leading edge of the moisture return. Again, this is an average. The ensemble averages this out. So, uh most of the time the moisture is going to be a little moisture return will be a little bit more robust uh in a northward sense than what the ensemble model is showing, but at least it gives us a general idea of how the moisture is going to respond going into the next several days. So, as we go further into the week, we get some at least modest moisture ahead of that cold front. Some 60s due points kind of lingering there in the central and southern plains. Nothing really all that impressive. And then we get to the weekend here. So, here is Saturday.

[00:11:46]Saturday is really the first day we're going to have a very widespread warm sector well inland. You can see it all the way up into the Midwest, all the way down into the central and southern plains there, Kansas, southward into Texas with some upper 60s and 70s due points sprinkled in there. So, starting on Saturday, we're going to have a very robust um warm sector in place. The forcing again somewhat in question where the short wave is, what particular short wave is going to be the main player here. We had that that subtle short wave down to the south and our main short wave off to the north. So, it remains to be seen where the most robust severe weather is expected to take place right now with that day five outlook. It is somewhere there in the central to southern plains, but that could easily change with time. The bottom line is is that we're going to have a lot of moisture, broad warm sector with some forcing mechanisms moving through which is more favorable for severe weather in a widespread sense than what we're seeing right now. Going into Sunday, we continue to have that robust look there with that broad warm sector. We see an even farther northward advance of that warm sector into the Great Lakes states and all the way down into the southern plains. So that could lead to a widespread severe weather threat on Sunday. And going forward, we kind of allow this to persist going into next week. We kind of get it to shunt a little bit farther down to the south, maybe a cold frontal passage there, but we do keep those 60s due points across a broad swath of the central and southeast and eastern US. And that could lead to a continuation of the severe threat with that more active jetream in west coast, western US trough, overspreading that warm sector going forward into next week and beyond for the back half of May. You see that moisture pretty persistent there across the same areas on this particular GFS ensemble ensemble run. We have that robust moisture well into the end of the run to perhaps support that prolonged period of severe weather going into the back half of May. Let's look at the European ensemble here. So this is the zero Z run from last night. The 6Z not available to us here on Pivotal. But here's the 500 millibar pattern. Again, that ridge kind of builds in across the central and southern US going into the next few days. And then like the GFS, we break that ridge down and get back to a little more active pattern going into Saturday. You see, once again, not really clear on what short wave is going to be uh the most impactful for this uh Saturday setup. If we're going to have very strong shear, some of the winds loft here very very weak. 20 to 30 knots at 500 millibars is is pretty weak despite a more favorable look uh to the overall pattern with some short waves moving through. So, we'll have to kind of wait and see how Saturday plays out.

[00:14:20]I'll have an additional information as we get closer and as we get a little bit more refined uh specific data uh and and a little bit more um data on specific outcomes for Saturday and Sunday. But overall broad warm sector with some forcing mechanisms moving in leads to a more favorable look for severe weather.

[00:14:37]That is Sunday. And then the European model kind of builds in a little bit of a ridge here going into next week across the um the the western US. This is unlike the GFS. So this is uh for Thursday, next week. A little bit of ridging building back into the western US unlike the GFS model. Let's go back to that period. So this is going to be around the next Thursday time frame. And you see quite a bit different than what the European model was showing. Here's the GFS ensemble. Here's the European ensemble. So you see the GFS persists with that trough across the western US.

[00:15:11]Whereas the European model kind of has this west coast ridge building in which would kind of shut things down a little bit. May have some systems moving uh in kind of on the eastern periphery of that ridge into the central plains and Midwest. But overall, this is not the greatest look for severe weather compared to what the GFS was showing with a western US trough persisting instead. So definitely some discrepancy in the models. The European model though does allow us to return to a more western US trough by the end of the run.

[00:15:41]Uh and that could lead to again a more favorable look for severe weather going farther uh going deeper toward the end of the month. As far as moisture goes, let's go ahead and take a look at that.

[00:15:53]So here's our moisture from the European model. So you see by this weekend again a very broad warm sector in place from the Midwest all the way down into the Gulf Coast that persists for a while. We get we have Sunday broad warm sector once again and that persists for quite a while. Um and we don't really shunt the moisture out ever in this scenario. Now the European model with that less favorable look for severe weather in the long in the longer term going into next week. we don't have quite as favorable of a moisture pattern kind of gets shunted down farther down into the Gulf Coast states um as we go into um late next week. But again, things could change here. The GFS could be the the model that is right. We'll just kind of have to wait and see how that plays out.

[00:16:35]By the end of the month, we have multiple days of broad warm sectors across the central US with a return to more of a west coast trough that could lead to a better threat for severe weather going into late May. Here is the Stormnet probabilities going forward in time. Stormnet has shown a a pretty good proclivity to uh sniff out these tornado events in the medium and longer range.

[00:16:58]So, we'll see if we have any highlights here going forward. You see the next few days very very quiet on the tornado front. Just very isolated uh large hail and damaging wind setups. Very marginal severe weather threat. As we go into Friday though, that could be our first sign that we could have some more robust tornado setups there. probabilities are not very high right now, but the Stormnet model is highlighting perhaps the Midwest um on Friday, May 15th, as our first day of of more robust severe weather um going into this more active stretch. Here we are on Saturday. A little bit of a a setup there. Tornado probabilities highlighting there from from eastern Kansas into Missouri.

[00:17:36]Nothing again very very high at this point, but that could change for Sunday.

[00:17:40]Okay, robust threat there in the in the um central to southern plains, perhaps into the Midwest as well. Uh so that'll be something to watch. And then going into next week, we kind of linger some low-end probabilities for some of those days. Not really um all that um impressive as far as probabilities go, but that may become more evident with time. So Stormnet is highlighting this weekend into early next week for some tornado risk across the central uh US into the Midwest. Uh we'll just kind of have to wait and see how that plays out for the more specific details on that.

[00:18:12]So again, a um fairly active stretch is on in the cards. It how that plays out, it remains to be seen. It may not be a lot of higherend synoptically evident days. It may be more of a of uh terrain driven days in in the high plains. uh could be some more meoscale days, but we are expecting a more active pattern as we shift from this western US ridge, eastern US trough to more of a western US trough, eastern US ridge going into the last couple weeks of May. So for the next few days, very marginal low-end risks uh before we get to this weekend's threat, the specifics specifics of which are still unknown, but severe weather is expected to tick up as we head into the weekend um May 15th, 16th, 17th, that time frame. um as we already have severe weather risk areas outlined for those days and the pattern does look to be more favorable for severe weather in that time frame. I'll have more details as I said as we get closer to these events and as we get some more clarity in the overall pattern um as we go forward. Right now though um quiet somewhat quiet for the next few days before we see an uptick in severe weather this weekend and perhaps beyond going into the back half of May. So with that, thanks for watching and we'll see you in the next