Extended Forecast Update

Just a quick update on the extended forecast since I haven’t posted in the last couple days. BTW, usually the frequency of posts you’re going to see out of me is directly proportional to how good the tornado potential is, so if I’m not saying much, then it’s probably because there isn’t much to talk about lol.

I’ve been watching the GFS pretty closely to get a feel for when it will get active again. I mentioned some potential for this Friday and Saturday in my last post, along with the potential problem of not getting any surface based storms. That’s a big problem if you’re after tornadoes and it’s looking more likely that it’s going to verify. I’m not going to get into the problems with the trough and this setup, but the only chance I think there is may be for SE Wyoming on Friday where they may eek out a low end tornado. It’s not looking good Saturday either and it’s doubtful there will be any surface based storms or tornadoes.

The next possibility seems to be around Wednesday of next week when a very weak short wave may work through somewhat zonal flow across the plains. Now the models are still jumping around quite a bit run to run, but for the most part they’ve consistently shown this weak shortwave coming through mid week. It isn’t much to look at if you’re just scrolling through 500mb charts, but it’s got my attention for a couple reasons. One is that throughout the forecast period there should be pretty favorable trajectories in the low levels bringing moisture up from the gulf and Caribbean, so it’s logical to assume there will be pretty solid moisture already in place across the plains for this shortwave to work with. With good moisture/instability, you can offset weakness in deep layer shear to some extent, so even with a small weak wave, you can still get some solid tornadic storms, at least over a small area. I also think there is likely to be good directional shear. With a small, low amplitude wave like has been forecast, you’re not going to get screwed on directional shear like you can with a higher amplitude trough that has a positive tilt. It may be over a compact area, but the potential is there for some good tornadic storms if the GFS stays on track. I’m certainly keeping an eye on it. Still a long ways out, but the consistency on showing a weak shortwave working through the somewhat zonal flow and the fact that model data, common sense and climatology point towards decent moisture being available, I am somewhat optimistic about chase potential with this disturbance.

Things get a little murkier beyond Wednesday. By that I mean I really don’t have any idea what is going to happen lol. The models have jumped around a lot with any specifics regarding the upper air pattern, but in general there have consistently been signals for a more active pattern for the last 10 days or so of May. Several runs of the GFS have shown significant tornado outbreak type setups, but they just as quickly vanish in the next run lol. When you’re looking that far out and there is little run to run consistency, you really can’t pay any attention to details. I try to focus on moisture, upper level winds and the trends from run to run with both when I’m watching models that far out. As I mentioned above, trajectories over the Caribbean and gulf appear to be pretty favorable through the forecast period, so moisture likely won’t be a major issue with any trough we get. We just need a stronger trough to come through the plains (that doesn’t have a nasty positive tilt and is shitting the bed like this weekends trough). The GFS keeps wanting to bring SW flow into the plains with fairly strong waves working through it starting around a week from tomorrow and then it keeps a good wave train pattern going through the plains up into the end of May. That is what you’d expect this time of year, so climatology is on our side here. May 20-30 has delivered more consistently for me over the years than any other stretch of storm season. I’m fairly certain that statistically the peak of tornado season is in that May 20-30 period along with the peak of tornado season historically for Kansas (I think May 26th is the statistical peak for Kansas). I know this, if it does get active then I will definitely be out there. I haven’t used much vacation with as slow as this year has been and I am itching to chase. I really hope we get a multi day event where I can hit the road and stay in hotels for a few days. Those are always fun. Exhausting, but fun.

Alright, that’s it for the night. The theme here is don’t overlook that weak shortwave that may come through the middle of next week and there is reason for optimism with the back half of May looking more active.

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Extended Forecast

You can’t pay much attention to any given model run, but the model trend over the last day is to lean more towards a trough digging south across the Rockies as we approach next weekend. That’s a good thing if you are wanting storms and tornadoes in the plains. If you look at the specific details with the GFS there are certainly issues with the setup that it’s portraying for next weekend (prospect of no surface based storms being one of them lol), but it would be stupid to pay any mind to those details at this point, especially since this is a pretty recent trend that has really just started evolving over the last 24 hours. Hopefully the trend continues and we get a stronger, deeper trough that is taking on more of a neutral to negative tilt. As it looks now, it is nothing to be too excited about, but it could possibly give us a chase opportunity or two next weekend. I glanced at the ECMWF. I can only get base products with that from pivotal weather, but going off the upper air pattern it seems to be in general agreement with the GFS as far as the trough goes for next Friday-Saturday. Soooo, there is at least something to watch for the time being.

Ole Mikey needs to lay down on the couch and watch a movie, so I’m not taking it any further than that tonight. Short and sweet. I’ll be keeping a close eye on the models so I’ll probably update most days coming up. Check back if you’re interested.

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Extended Forecast and Chase Results from this Week

Welp, not a lot to look forward to right now if you’re a storm chaser. It’s hard to believe how slow this season has been. Minus one significant tornado on Tuesday this week, the plains has been dead. I made a critical error on Tuesday and missed that tornado. I think my forecasting was solid leading up to the event. My forecast maps with the greatest tornado potential really never changed in the 5 days leading up to the event and ended up being pretty accurate. Below was my forecast map and the actual storm reports. I’m a chaser and focus on zeroing in on exactly where the greatest tornado potential will be, since that’s what I’m after, so anytime I get the area right where that will happen (red box below), then I’m pretty happy with my forecast. I think that was the case here where the best tornadic storm tracked right down the middle of the area I highlighted.

My plan leading up to the event was to hug the I70 corridor. That notion was further reinforced with Rich Thompson at SPC pointing out the only subtle difference between this setup and the analogs of significant tornado events was slightly better moisture quality. Anytime you are forecasting and there is a weakness with the setup/paramaters, a big part of my strategy is identifying the target that mitigates that weakness. In this case, hugging up close to the triple point where moisture pooling could increase dewpoints a few degrees was a priority for me. The models hinted at a cluster of storms along I70 in the last few runs before Tuesday’s event, so I was prepared for that (vs. a more discrete cell) and knew to stay with the lead supercell or more dominant storm on the southern flank. I largely executed on that strategy and stayed with a supercell from Rush Center all the way over to Wilson. The storm was tornado warned off and on and had a few decent wall clouds, but it never really got close to actually producing. It had a very wet RFD and the updraft base was a little skimpy, which led me to believe we just needed low level shear to ramp up, which I knew would happen as the evening progressed. I did several phones and streamed video of the storm back to KWCH, so did alright on coverage as the storm approached I70 at Wilson. There is a major void of roads off the SW side of Wilson and we knew we’d have to drop south a bit to swing around that void and tie back in with the storm off the east side of Wilson. This is where the error occurred. The storm had gotten high based and was getting ready to go through a merger on top of being embedded in a cluster of supercells. As we dropped off the storm temporarily to swing around it’s south side and get east of Wilson, we had a discussion about the storm to our south and whether or not it would have better tornado potential. That storm south of us was all alone, it had gone tornado warned way faster than the storms coming off the triple point area, mesoscale analysis maxed out sig tornado parameters ahead of it, etc. Virtually everything you would consider in making a decision as to which storm would pose a greater tornado threat pointed towards taking the south discrete storm. The one thing that didn’t point towards that storm was my forecasting target/strategy leading into the chase. We had a discussion and bailed south for the discrete storm rather than swinging back up to the east side of Wilson at that point. As soon as we got about half way to the storm it started to struggle with CINH or drier air, not sure which. At the same time the storm along I70 we left became dominant after it went through the merger and planted a wedge. That one hurt. I still think we made the logical decision, but the lesson here is to stick to your forecast and strategy leading into the day and don’t get sidetracked with short term trends as the day unfolds.

Missing that wedge would be a lot easier to swallow if we had an active stretch coming up, but unfortunately that does not appear to be the case. It’s impossible to get into details right now because the models have been jumping around a lot, but the general trend has been for the polar front jet to stay north and then be fairly weak with any waves that do cross the Rockies. There is a weak disturbance in a NW flow aloft pattern across the plains that may trigger some low end severe storms next Tuesday and Wednesday. Nothing major there though and it’s unlikely we’ll see much out of it. Then there is some hint that a weak trough will dig south about 7 days from now over the plains and possibly break off from the polar front jet becoming a closed low over the plains. Closed lows are not generally good tornado producers due to vertical stacking, so again probably no dice here. The GFS then has this closed low parking over the plains, somewhat reminiscent of a blocking ridge as the polar front jet arcs up and over the plains completely. As the low wraps back in to the polar front jet around May 20th, the upper air pattern begins to look a little more like you’d expect in May. If there is a single stretch of spring that always seems to produce in the plains it is May 20-30. I hardly ever get skunked during that 10 day stretch. I don’t trust this far out and we could very easily be chasing next weekend if the GFS doesn’t have a good handle on the upper air pattern, but if that doesn’t happen then my money says we’ll get back into action around May 20th or shortly there after. The only silver lining with the GFS is that with high pressure anchored in off the SE US for the next week or so and favorable trajectories up through the Caribbean and across the gulf over the duration of the forecast period, the Gulf should be primed and ready to go whenever the jet stream does get active again in the plains. Besides that, there isn’t a whole lot to be happy about lol. I did look at the CFS and ECMWF, but there’s no reason to make a long post detailing each model. We are in hurry up and wait mode. That’s the bottom line.

Alright, I’ll update again Sunday with an extended forecast. I’m checking model data daily so as soon as there is something to talk about I’ll be on it like a duck on a June bug so check back for updates.

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Update on Today’s Tornado Threat

Just a quick update from the road. We are heading down I70 and should make Hays within an hour. My thoughts are about the same as last night. There is a strong tornado threat, especially near the triple point and dryline storms developing in the area I boxed in green on the above map. Convective evolution and getting a discrete storm with unimpeded inflow is still my chief concern with the extent of the tornado threat this afternoon. The HRRR picked up where the NAM left off and shows somewhat clustered storms as they move off the boundary before one or two becomes more dominant with a clear southern flank. I think the best play is to get along I70 near or just east of Hays and then move in on one of the cells that you think should be more dominant as the picture becomes more clear with cumulus fields on satellite or radar as storms first develop. It’s still kind of hard to pin down the exact location of the boundaries, but you can start to see hints of the front with the latest visible satellite images and the dryline should become more well defined over the next couple hours. I’ll try to get a satellite pic posted showing the exact boundary locations in the next hour or two. For now, not much more to add as my thoughts haven’t changed since my previous posts. The map above is a quick road sketch of where I expect the strongest storms to develop and where the peak tornado threat should be later today. I’d expect a tornado watch sometime in the next few hours. Be careful if you’re out and watch KWCH for coverage. I will try to post again with a final target and mesoscale updates as warranted, so check back if you’re interested.

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Forecast Update

Really not a whole lot to change. I’m tight on time so I’m not going to post a new map, but if you look back a couple posts to my previous forecast map, I still think the greatest tornado threat is over the same area, just maybe a hair farther south. I think we may get a dryline storm or two in Kansas that could also pose a tornado threat. That being said, I still think the greatest threat is near the triple point up along the I70 area. The triple point continues to bounce around a little bit with each model run and the latest NAM run has a little less clean surface pattern, but otherwise no major changes. Conditions still look pretty solid for a tornadic supercell or two coming off the triple point area. Latest runs of the NAM hint at a cluster of storms coming off the triple point area. That would be detrimental to the tornado potential, but probably not a deal breaker for tornadoes. We’ll get a better feel for convective evolution tomorrow morning with better CAM guidance.

The moisture tongue is working up through the southern plains right now. There aren’t any concerns with moisture quality, but I decided to take a quick look just to be thorough. I think we are sitting at 60 degree dewpoints in OKC right now and closer to 63 in Dallas. Tonight’s soundings show the moisture is plenty deep at both locations. With a very strong low level jet already pumping moisture north, we should be working with the moisture currently over the southern half of Texas by tomorrow afternoon, with dewpoints expected to be in the low to mid 60’s. Tomorrow should be one of those mornings where it just feel like a tornado day. Low level winds will be screaming out of the south pumping in moisture with low level cumulus clouds racing north. I absolutely live for those kinds of mornings. I always get pumped when I go outside in the morning on days like that. There may be some cloud cover over the warm sector through the first part of the day tomorrow, but we should see clearing ahead of the dryline by early afternoon at the latest and good surface heating (at least immediately ahead of the dryline). Moderate to strong instability for this time of year will develop by tomorrow afternoon. Deep layer shear should be up around the 50kt range, will be more than adequate for supercells.

Latest runs of the NAM have backed off a bit on low level shear, but it does still look good enough for a strong tornado threat. Forecast soundings/hodographs near the front east of the triple point still show good curvature in the low levels and good length along with favorable The NAM has a little cluster of cells that come off the triple point in the afternoon. I pulled a forecast sounding from just off the south edge of that convection which is below.

That is pretty nasty. Very strong low level shear, low LFC heights (I believe most significant tornadoes are associated with LFC heights below 1300m), steep lapse rates in the low levels, strong SR low level winds, etc. It’s all there. I’m not seeing much of a weakness. Convective evolution coming off the triple point is probably my main concern as far as the extent of the tornado potential goes. As I mentioned above, I think that’s more of a mitigating factor than a deal breaker though. If we have a discrete storm in the 00Z window, it could be a big tornado producer. If it’s more of a cluster of storms, I think we’ll get some tubes still, but probably not as big of a show. The dryline also looks like a half way decent play a little farther south in Kansas. I don’t think the conditions are quite as good, but I would not be at all surprised to see a tornadic supercell initiate along the dryline over southern Kansas. When we get better CAM guidance in the morning I’ll get into finer details like that. Anyway, still looks like game on for tomorrow. I plan on leaving Wichita at 11am and will be heading for the triple point. I’ll figure out exactly where it will be on the road tomorrow and update with my exact target then. I’m going to head up to Salina and cut west on I70 out towards Hays and we’ll figure out the exact target before we get there. I have Ryan Shirk driving for me tomorrow, so I should be able to update regularly from the road so check back for updates. It will be a god damn zoo out there tomorrow, so don’t drive like an asshole and be careful if you’re chasing. BTW I know my blog is lowing slow as shit. It’s loading though so I don’t want to mess with it right now. I think I need to move it over to a new host, but once the weather slows down later this week I’ll deal with that problem. For now I need to focus on chasing. Still not sure what my plans on for Wednesday. SW Oklahoma continues to look like one of the more appealing targets, but I think Kansas could be a close second and I probably should stay up here to help KWCH out with coverage, so odds are I’ll be chasing Kansas Wednesday. I’ll get into that tomorrow or Wednesday morning though. Alright, check back tomorrow for regular updates and good luck if you’re heading out.

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Forecast Update for Tuesday May 1st

The 18Z NAM has a very impressive forecast sounding/hodograph just east of the triple point Tuesday afternoon (18Z NAM forecast sounding above for area just east of the triple point). There is a little bit of CINH, but otherwise that is extremely impressive. SBCAPE around 3000 and 57kts of deep layer shear. That will definitely get you a supercell. Anvil level winds are fairly strong, so I’d expect classic supercells, at least for a while. The tornado potential is equally impressive near the triple point with 0-1km SRH >300, effective layer SRH around 500, critical angles are right around that 90 degree sweet spot, strong inflow level SR winds, fairly low LCL and LFC heights, etc. Basically everything you need for tornadic supercells is where it should be for a solid tornado threat. My feelings have been the same for the last few days on Tuesday in that I think the triple point area is a moderate risk type event if you go by SPC criteria. The 00Z NAM is out now and it is basically the same as the 18Z run, so no major changes. Below is the 00Z NAM forecast sounding for that same area east of the triple point.

The triple point did move around a bit with the 18Z and 00Z run. Not much shift in the location, but the 18Z NAM had the triple point a little farther east and then the 00Z shifted it back north a bit closer to I70. As of now I think a starting target of Hays, Kansas is about right. The 00Z 3km NAM has the triple point a little farther south with a storm developing SE of Hays. Somewhere out in that general area is going to end up being the bullseye for triple point development during the afternoon on Tuesday. If you get a discrete storm like the NAM continues to advertise, then strong tornadoes will be a threat in the area northeast of the triple point. Since this very well may just be only one or two storms, it’s not a high density severe weather type event, so you have to consider that when looking at how SPC handles it, but pound for pound these very well may be the strongest storms we get out of this 3-4 day severe weather event and if you live in the area I’ve been talking about you should take it seriously. Wednesday will probably get more hype since it could be a more widespread event, but my feelings are still the same that Tuesday’s storms may be the strongest. I would expect SPC to probably draw the enhanced risk a little farther south with the next update to account for the triple point earlier in the afternoon and the possibility that you may get a dryline storm in Kansas. I don’t know whether or not they’ll go moderate near the triple point if current model depictions hold true into Day 1. Given the low coverage of storms, they may opt not to do that I’d think. Still, I firmly believe any triple point storm could pose a threat of strong tornadoes, so again take it seriously if you live in or near the area I boxed in red on my forecast map from earlier today. Also brace yourself for the massive onslaught of chasers you are about to see lol. It’s been a slow season so everybody and their brother will be out for this one. That in the combination with the fact that there is a well defined bullseye for tornado potential at a triple point with this setup will draw virtually every chaser in the field to the same general target area. You won’t be able to throw a rock in Hays and the other towns around there without hitting a chaser Tuesday afternoon.

I did take a quick look at Wednesday’s setup with the 18Z runs and weak low level shear seems to be the biggest problem. Earlier runs several days back had the same issue. Then a couple days ago models started ramping up low level winds (I made a post on this a few days back). Now current runs of the NAM have the stronger low level winds shifting east through the day Wednesday and low level shear is pretty weak until after 00Z when the nocturnal LLJ ramps up. By that time the boundary layer is decoupling though, so there doesn’t seem to be much overlap in time/space where low level shear is supportive of tornadoes while we have surface based storms. The NAM is very stingy with convection too, only showing a couple discrete storms coming off the dryline. Not sure I’m buying that, but figured I’d mention it. I’m going to hold off for now on going into more detail. It doesn’t seem worth discussing too much until the models settle in a little better on this setup. We will need stronger low level shear than what is currently depicted for a solid tornado threat.

I got my car cleaned, Rain-X applied to all my windows and most of my non expensive chase equipment setup this afternoon. All I have left to do is getting some wiring better situated and setup the expensive equipment that I don’t like leaving in my car overnight and I’m ready to go. My tentative plan is to leave Wichita around 11am Tuesday and head up towards that Hays area. I’m getting all my backup batteries charged tonight because there is a good chance I’ll get home really late Tuesday and I need to be prepared for the possibility of an early AM departure for SW Oklahoma Wednesday morning, so I need all my shit in order in case I need to do that. Still not sure where I’ll chase Wednesday, but I have been leaning towards the Oklahoma portion of the dryline. I’ll get that figured out in the coming days though.

Alright, time for Mikey to ass out on the couch for a bit before I go to bed. I’ll update again tomorrow. Probably a brief update in the morning once 12Z runs come out and then I’ll get a more detailed post up tomorrow night, so check back then if you’re interested.


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Tuesday May 1st Tornado Forecast

Interesting setup continues to come together for Tuesday. My guess is we’ll break out of our tornado drought and see the first Kansas tornadoes of 2018. There are still a lot of uncertainties with he forecast. The location of surface boundaries is still a bit uncertain, although it does look like the triple point will be in Kansas, it just may shift around a little bit from where I currently have it drawn on the map above. The extent of storm coverage is also a bit uncertain. Despite those uncertainties with the details, the general picture and what we expect to happen is getting more clear.

There are kind of three distinct areas of concern with this setup. Those three areas are the frontal boundary (red line/warm front on map), the triple point area (area where dryline and warm front intersect on the map) and the dryline (orange line on the map).

Storms along the front are virtually a given, but that’s not the storms I’m after. There could be a tornado threat with any storms developing along the front while they’re discrete, but storms are expected to fill in and that should mitigate any tornado threat. The greater tornado threat will be with any storm or tail end developing near the triple point and to a slightly lesser extent with any storms that develop along the dryline. There hasn’t been much in the way of precipitation along the dryline with the models. I don’t trust the models with precipitation though so for now I’m not too worried about it. The more likely area for a storm to develop will be near the triple point. Higher quality moisture will be working into Kansas Tuesday morning, with dewpoints rising into the lower 60’s. During the afternoon a dryline will sharpen up across western Kansas with a well defined moisture wrap around/triple point setting up near I70. This area should be the focus for the greatest tornado threat (boxed in red on the map). As is typical with triple points relative to the open warm sector ahead of the dryline, low level shear will be stronger due to backing surface winds, dewpoints will be slightly higher where moisture is pooling and LCL heights will be a little lower.  Below is the NAM 30mb dewpoint map where you can clearly see the triple point and slightly higher dewpoints out ahead of it.

The NAM currently breaks out a discrete storm at the triple point. That scenario would pose the greatest tornado threat with a discrete storm tracking near/along the front. Another possibility is that storms back build along the front and you get more of a tail end to a cluster near the triple point. Regardless of how convection evolves, the best paramaters should be immediately down stream of the triple point. With moderate instability and around 50kts of deep layer shear, conditions will be very supportive of supercells. Additionally, LCL heights will be fairly low and low level shear is well within the range of supporting tornadic storms. Below is a forecast sounding/hodograph from the area ahead of the triple point if you want to see all the specific values of things mentioned above.

There is still a lot of things that can change, but based on current model data it does look like there could be a strong tornado threat near the triple point Tuesday evening. I think it is the clear target for the greatest tornado potential especially when you consider the uncertainty of any dryline storms in the equation. If dryline storms do develop, they also will pose a tornado threat. Hodographs aren’t quite as impressive, but with dryline storms you take the potential for unfavorable convective evolution mitigating tornado potential out of the equation (which could be a problem near the triple point). Right now I think I’m going for the triple point. I like the better parameters and with the uncertainty of storm coverage along the dryline it seems like the easy choice. I will keep a close eye to the dryline and I could easily dive south if I needed to. If a dryline storm did get going farther south, I may drop down to it to help with coverage since it would be tracking through south central Kansas. We’ll see how it plays out. I think one key if your chasing is to be on that triple point storm early. I feel like I’ve seen this movie before and a lot of times triple point storms with setups like this produce a couple good tornadoes early, but then transition to more of an HP warm front demon supercell as they mature. Those are absolutely no fun to chase, especially when you throw a massive convergence of chasers into the equation that can slow your ability to get out of the way. Crowded roads and a warm front demon supercell are a recipe for getting your car shit hammered.

That’s enough rambling about Tuesday for now. There are additional forecast notes on my forecast map BTW. I’ll start taking a close look at Wednesday’s setup later tonight and probably get a quick post up on that. I did glance at it this morning and it looked like the 12Z NAM had a major drop off in low level shear relative to previous runs of the GFS. That is a bit concerning. I’m most likely not chasing tomorrow. I don’t think moisture quality is going to be quite good enough to get the job done. Alright, that’s it for now. Check back later tonight though for an update and I’ll try to get into Wednesday’s setup.

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Forecast Update for Wednesday May 2nd Tornado Threat

I was just glancing over model data this morning at work before I head out of town and the trend with the GFS over the last 24 hours is to improve directional shear for Wednesday, making the threat of tornadoes a much bigger concern. I need to keep this brief since I need to get a few things done at work before I leave town, but since I largely skipped over the setup for Wednesday in last night’s post due to the poor directional component to shear profiles in the 850-500 layer, I wanted to update on it because if the current trends hold true, it will have a significant impact on any tornado threat Wednesday IMO.

Having good directional shear is a must for a solid tornado threat. The trough coming through is going to have a positive tilt to it, so poor directional shear as the trough fully ejects into the plains is kind of the MO with that style of setup. Since the 12Z run yesterday though, the GFS has backed 850mb winds more and more with each run, to the point that now with last nights 00Z and this mornings 6Z runs, you actually have good turning in the 850-500 layer over the Kansas portion of the threat area. Below are 3 screen grabs which clear show this trend in the supercell composite maps (SP composite shows 850-500mb winds overlayed if you aren’t familiar with it).

Yesterday’s 12Z run

Yesterday’s 18Z run

Last night’s 00Z run

As you can see by scrolling down the 3 model runs from yesterday, it’s not hard to see the trend of 850’s backing. Shear profiles as a whole improve across those three runs, but the backing 850’s is the most notable improvement. Instability has also improved, which is why the composite indices have spiked. I’m tight on time so I can’t get into all the details, but this is bringing Wednesday into more of a serious tornado threat type setup. Below is 850mb winds from yesterday’s 12Z run and then yesterday’s 00Z run. Again it is not hard to see the change/trend.

yesterday’s 12Z run

Yesterday’s 00Z run

Now, we are a long ways out so again a lot can and likely will change. This is a positive trend if you’re rooting for tornadoes though. I try not to give much credit to specifics with model data this far out. I try to just focus on the bigger picture, like moisture quality and trends with larger scale features like the tilt/evolution of the trough. Generally when you have a positive tilt you get more veering of 850’s. 850’s are damn near straight out of the south in the latest runs of the GFS, which isn’t really what you’d expect with a positive tilt. Based on the 30 seconds of research I’ve done, the other big change that is creating this with the GFS is the strength and location of the upper level jet (which is causing your pressure falls and the strength/direction of the low level winds). The tilt of the upper level trough has also been moving more towards neutral, which is helping to back low level winds. The images below of 250mb winds/upper level jet will show why.

The first map is the 12Z runs depiction of the 250mb winds and the second image is the 00Z runs depiction of the 250mb winds from the GFS. Big difference there. If you look at the continental US view it’s very clear the trough has moved to more of a neutral tilt with the last few runs as well. The tilt of the trough is critical for tornadoes. You can get big severe days with a positively tilted trough, but you’ll be hard pressed to find very many examples of big tornado days with a positively tilted trough. Almost always, large scale tornado outbreaks are associated with a neutral or negatively tilted trough.

Anyway, who knows what to believe with the GFS. This far out you can’t take too much seriously, but if the latest trends are accurate it will have a big impact on the type of severe weather (tornadoes or more of just hail and wind type threat) we see and the extent of the threat on Wednesday. There is a bit of a veer back veer profile to hodographs over Kansas in the latest run, but the better instability and greatly improved shear profiles with current GFS runs vs. the runs from 24 hours ago is a major shift and if current runs are accurate, strong tornadoes could also be a real concern on Wednesday. South central Kansas, including Wichita, are right in the wheelhouse for both Tuesday and Wednesday so pay close attention to the forecast as we get closer. Again I am out turkey hunting the rest of today and tomorrow morning, so don’t expect another update until tomorrow afternoon at the earliest. If you’re interested, check back then.

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Extended Outlook for Tornadoes

It’s been a slow and depressing start to the 2018 tornado season if you’re a storm chaser. For Oklahoma, this will end up being the slowest start for tornado season in recorded history. For Kansas, it looks like it will be the slowest start in my lifetime. The tornado drought for both states looks likely to end next week though.

We are still a ways out, so I’m going to hold off a couple more days before posting a map. For tonight I’m just going to give a brief run down of how things currently look. The first day of interest is Monday as stronger SW flow aloft eases into the plains and a dry line sets up from western Kansas through the eastern Texas panhandle. Moisture return won’t really start until late in the day Sunday, which doesn’t leave a very big window for quality moisture to move all the way from the Texas coast into the central plains. As you’d expect, moisture and the cap holding are the primary issues with Monday’s setup. If sustained storms manage to develop along the dryline, CAPE/deep layer shear combinations would be favorable for supercells. LCL/LFC heights are likely to be a tad high, but fairly strong low level shear could very well be enough to get tornadic storms. If it looks like we’ll get storms, then I do think it’s worth chasing and I’ll be out there. My ideal target would be as far south as sustained storms get going in the eastern Texas panhandle area. Getting south should help to mitigate the moisture quality problem with this setup. I’m more likely to target the NE Texas panhandle to Dodge City area though (assuming the GFS is not totally out to lunch with the location of surface boundaries). Below is a forecast sounding/hodograph from along the KS/OK border just south of Dodge City for Monday afternoon. As you can see the lower half of the hodograph looks nice, but with weaker mid-upper level winds there isn’t much length. Deep layer shear will be strong enough for supercells, but it’s fairly weak. That in addition to moisture quality would be mitigating factors for tornado potential if sustained storms do develop.

The biggest day as far as tornado potential is concerned appears to be Tuesday. Wednesday may end up with more severe weather reports, but the storms should be stronger on Tuesday and shear profiles will be much more favorable for tornadoes. It’s the pound for pound best day with this trough IMO.  The greatest tornado threat will be with storms developing along a dryline that will run N-S from central Kansas through western Oklahoma. The extent of storm coverage along the dryline is a bit uncertain, but I do think we’ll at least get storms near the triple point in Kansas and at least a few scattered storms along the dryline into Oklahoma. Moisture quality should be quite a bit better than on Monday, with dewpoints in the mid 60’s into Kansas. Additionally deep layer shear will be quite a big stronger and with moderate to strong CAPE ahead of the dryline, conditions will be quite favorable for supercells. 0-1km SRH is forecast to be strong and LCL heights will be plenty low for a solid tornado threat. It’s a moderate risk type tornado threat with the latest GFS runs IMO if you’re an SPC fan (and I”m sure you’re familiar with their outlooks if you’ve read this far lol). I’m actually fairly excited for this setup if it holds. It’s got good directional shear, I don’t think there is much risk of unfavorable convective evolution (which kills more good tornado setups than anything IMO), and storm motions should be manageable (forecast soundings in southern Kansas have RM at 30kts).  I think it’s a good setup for a couple cyclic tornadic supercells off the dryline, which seems all too appropriate given it will be May 1st. Also, it’s going to be in good chase country close to home (I very well may end up chasing right back to Wichita as things look now), so again I’m actually pretty pumped about this setup. I also think that the parameters could very well be supportive of strong tornadoes. Still a long ways out so a lot can change, but I do think the odds are fairly good this will be the first serious tornado threat day for the plains this year.

I’m going to skip past Wednesday for now. It looks like a classic main day event where directional shear has all but vanished and storms are widespread, so you don’t get many tornadoes (at least not on a per storm basis) relative to the day before the day type event like we’ll have Tuesday. For that reason, my focus is primarily on Tuesday at this point, but I’m keeping an eye on Wednesday and if it looks like there will be a tornado threat then I’ll be out. After the slow start we’ve had to this season, I’m not passing if I think theres a chance for tornadic storms. I got a hair trigger right now lol.

That’s it for tonight. I’m heading out to our ranch to turkey hunt tomorrow and won’t be back until Saturday. I’m the Chautauqua county record holder, so I have a title to defend lol. That’s a true story. I haven’t checked to verify I still hold the record in quite a while, but I shot the county record turkey when I was 18 and as far as I know it still stands. I’m heading back Saturday afternoon though so I’ll either update then or on Sunday. Check back then if you’re interested.

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