So, what's chasing like?
(this isn't a forecasting thread, even though I state a few things)
I need something about this on here, so here goes. This will likely be looooooooooooooong. The site is pretty much only about the good parts. It's mostly not this much fun. I'll probably talk about anything and everything I can come up with.
So where to start...at the beginning of a chase I guess. The chase starts well before the actual day of the event, in many cases. After a while one just sort of learns they need *some* forecasting ability. The basics needed for a good day aren't too hard to spot on the long range computer models, which are offered various places on the internet. A chaser will usually just look at the 500mb jet stream progs. This is the mid-level jet around 18,000 feet off the ground. It's a good place to see the stronger disturbances/storms. When you're only looking out into the future for hope, there's not a lot more needed. A trough is a storm, and it is where the jet stream dips to the south. A ridge is where the jet stream pokes northward. This is in the northern hemisphere. With the various models you can find these troughs, or dips in the jet stream and monitor them day by day as the system/chase day gets closer. I should mention most of these models are run twice a day, once at 12z and again at 0z. During the spring and summer 12z is 7a.m. in the central US timezone and 0z is 7 p.m.(21z would be 4 p.m.) When you change the clocks back in the fall 12z and 0z would be 6 a.m. and 6 p.m. Z stands for zulu time. They use that for a lot of things in weather so everyone is on the same page. So anyway, they are called by their name(like the GFS model or the WRF mode) and then by the time it was created from. The national weather service launches weather balloons at those two times and that info is fed into the various models. So the models start after they get that data and finish a couple hours later. The 0z GFS often doesn't start to come out online till 10:30 p.m. central time.
So it sort of all starts with watching the models. The GFS is a longer range model and some locations it goes out 384 hours into the future. So you can look at it and see what it thinks for this and that day and watch how it handles the storm. Many times when you see a run with something good way out there into the future, the next run will come out with the new data 12 hours later and maybe that storm has vanished. The model isn't seeing what is happening out there obviously, it's predicting what it thinks the jetstream will look like based on what it sees that one run. So of course the new runs with all new data may spit out something completely different. If the 500mb wave, or trough/storm is a small one and it's way out there into the future, those are more likely to change by the day of. The models generally do a pretty amazing job, even out 7 days or more, when you are talking a major pattern change.
It is currently Saturday April 7. See the date at the top of this image? I just grabbed this from COD(url at the bottom of the image). 0z Sat is 7pm on Friday, just like 1z Sat would be 8pm Friday and 23z would be 6pm Friday. Anyway, this is from the GFS model and that is what it is predicting for 0z Sat, 6.5 days out. Since it came out at 12z this morning and is the forecast for 6.5 days it would be 0z Sat(7pm Friday...yeah that whole zulu time can confuse things at first). This is the 500mb prog for next Friday then. See the black lines curving southward over the middle of the US? That is the trough. It has a ridge ahead of it on the east coast and another behind it on the west coast. The green, yellow, and red shadings are the wind speeds at that height, upwards of 95 knots(around 100mph). You can see the enclosed circle over Nebraska, that is the center of the storm, like you'd see on a satellite image the day of...the spinning area. So the model is forecasting this strong storm system moving through the central plains in a few days. That'd be a pretty big system and the model isn't likely to be completely whack on something like that only 7 days out. A chaser can pretty much count on something like that being somewhere around the plains around that day(this one trended much further south, but other models saw that better than this one at the time). They pretty much just move from west to east here.
These systems do several things. They will bring in cooler air aloft which is needed for instability. They will also bring in areas of lift aloft, which well, help "lift" the atmosphere. These areas are basically in the front left quad of the jet and the rear right quad. Front left is up there in IA and IL. Rear right quad would be down around the gulf states. The other thing would be wind shear. Note the 95 knot southwest wind over western IL. This is up around 18,000 feet remember. Well down lower just off the ground there will likely be a strong low level jet out of the south, but probably around 50 knots. So as you go up you increase the speed and you also turn. That's directional and speed shear. I am really not wanting to cover all aspecs of what I understand about forecasting here(which is actually pretty minimal). I need to get going on the rest of this entry. There's a lot more to it all, but well out, just seeing that there is a fair indicator of a chase day or two. The day before this one shows the system further back west, but the effects of it onto the plains enough for a good chase day that day too. BUT...this upper storm system has a problem and that is the lack of moisture down low. Gulf moisture is currently being beat well south through the gulf, by this cold airmass we are having. The day before this map looks amazing on the high plains, but there's simply no way there will be good dewpoints/moisture back north in time. Typical early season. I'd bet by the day of this prog above there will be good moisture along the gulf states and they could be in for a ride.
So a chase starts out a bit in that fashion, when you spot some hope like that on the long range model runs. I'd be a lot more excited right now if it weren't for the good low level moisture being shoved through the gulf and down into the tropics. South winds can kick in tomorrow and you'd still be pulling crap air back north because of the airmass over the gulf right now. Air has to move back from the tropics region or the gulf simply has to have lots of time to rejuice. Quickest way is for it to just move back from where it was pushed to. So being very excited about this coming system could be a big let down. It's certainly something to watch until the day comes, but doing so can really waste ones time. I try and just glance anymore. I've looked at every ob on about every run only to see it suck the day of....then wonder why on Earth I wasted all that time looking at the new model runs.
Often these moisture issues aren't there and you see a great system coming and become extremely excited. I'm usually just moderately excited until that night before the actual day. Then if that 0z run comes in and it still looks amazing, well sleeping becomes impossible. I just want the next day to arrive so I can wake up and get going.
The activity the day of the chase all depends on how close it looks to home(or the motel I'm at). Regardless of where I am, the day always starts out early. I often beat the early alarm clock I set, just because I'm excited I guess. If the sun is up, I guess the first best thing to look at is a satellite image. If not, a scan of radar images might be helpful, to know what exactly happened overnight. I'm still bad at judging how bad a cloudy morning satellite image might be. I'll often see some to the west of the target and wonder just how quickly that area can even move east. I always underestimate where they will be by later in the day. It's obviously bad to see a big complex of storms sticking around south of your target area or even right in it. Storms love to turn the atmosphere over. They'll take your warm and moist low level air and make it cool. This ain't happening just at the ground, but the whole depth you want warm and moist(lower few thousand feet). Sunshine might not even do much for that air once things clear out. It's best to have better air move in from the south, air that wasn't in this complex. It's pretty important to note how severe those early morning storm complexes are and try to judge where that air will move to throughout the day. Sometimes if the low level flow ain't that strong, just staying far enough north might work...so long as you still have a good region of air to use, before the crud air moves in. Otherwise, being south of that region is a good bet...granted you aren't simply capped out to the south(capping inversions love to shut things down to the south).
So you look at that and a few other things. The RUC model stands for Rapid Update Cycle. This can be a helpful model the day of the chase. It only goes out 12 hours, but updates every hour(at least out the first 3 hours it does this every hour.....updates out the whole 12 hours each 3 hour interval....12z, 15z, 18z, 21z, 0z..etc). You look at surface obs for your boundary locations, be it a warm front, a dryline, or even a cold front if you want(or even an outflow boundary left over from previous storms....morning storms can leave these lovely favors). The front is needed for surface convergence of air. If air is converging it's going to want to go up more...it sort of has to. Surface fronts are very important. The RUC model does a pretty good job on their movements throughout the day. It's best to use the current surface plots to track the boundaries through the day. Usually you have a pretty good idea where it will be by peak heating or when you think the cap in place will erode enough for storms to fire. Say the cap this day is around 8,000 feet off the ground. Around that area/height the air starts to warm instead of cool, capping the lower level air since it won't rise through the warmer air. It will warm for a ways then begin to cool off again. For surface based storms this needs to be removed. It can be removed by cooler air moving in aloft and it can be removed by warming up all the air below it by further heating, or advection of warmer air. Often on these days you have both going for you, hence why you often see all the storms sort of go at once and also continue to go(continued cooling aloft....also storms will help create their own lift....like a complex of storms with cold air surging out, lifting the warm air ahead of it).
If the target doesn't appear close you really aren't able to sit around and see how morning issues(clouds/rain, etc) work themselves out. All you can do is get in the car and start heading to the target. Most targets of mine anymore are less than 8 hours away. 8 hours can get a chaser to a lot of places when they live near Omaha Nebraska. That's still a good drive to go try to find cool storms....storms that may either not happen, or that might just suck. That's how chasing works though. That's what keeps the crowds doing it fairly sane....as in size! I've chased east of Lubbock Texas before having left that same morning. It's nicer to just get a motel the night before and be to the target earlier though. Nothing worse than being just a bit too late on a big day. I'd rather be there early and sit around all day than be late. And that is what you do, sit around and wait on your boundary to fire those storms. This takes me back to the satellite. You watch it as the day goes and it usually does a great job of getting you to narrow down your region before a storm fires. You'll see cumululs towers via satellite, before they turn into storms...hopefully. The whole day is a process of using the data you have to get you where you need to be. When you see cool storm images from chasers, most of these did not come from the person seeing storms on radar then leaving to drive to them. It consists mostly of days/chases of not a whole lot, usually leaving loooong before storms fire, just so you can be in the region they fire, when they fire.
What do I use to get data while on the road? It's really nice and simple now, I love it. All I use is my cell phone connected to the internet, via usb cable and laptop. Don't need anything more than that and I don't have anything more than that. I guess I have a wifi card if I'm in a bad area with no cell data, but if there is wifi there's usually cellular data. It's so awesome now to be able to pull off on a country road, have hi-speed internet and not have to worry about using minutes! All it took was an extra $25 a month for unlimited data. It's hard getting used to the feeling of not having to hurry up and disconnect the phone while getting data, since it uses none of your minutes.
There's a lot of data you can look at during the day, but really all one needs is surface data, satellite, and radar. I don't mind looking at instability progs on the storm prediction center's mesoanalysis page. Their CAPE images have the CIN(cap) amounts on them and that's nice to monitor, to see how much of the cap is gone and where. Their mesoscale discussions, storm outlooks(like tornado probs, slight, moderate or high risk, etc), and watches don't mean a whole lot to me anymore. Seeing that a watch has been issued means ziltch. It gives you no real information as do most mesoscale discussions. Usually by the time those are out you are in the general area and there's no need to adjust. It's wait till storms go and try to pick the storm that will be the best one.
Most all the hard decisions come early in the day. Like to leave home or not to begin with! Do you want the more southerly target or the one further north? These are important choices very early in the day. By storm time, most of those are done and you aren't likely to be able to adjust much more to matter. That said, not tearing off after the first stuff to go, can be tough when it is within reach, but not exactly close. I guess there are still tough choices to be made, even late in the day. It's best to chase the "area" not the storm. If you know you have a good area it might be best to ignore the first stuff you see elsewhere and give your area a chance. Bouncing around can really bite a chaser in the butt...so can holding firm to your target! There's lots of ways to make mistakes in this hobby. Another way to make a mistake is giving up too soon and heading home. I often do that when it is 7pm and no storms have fired. Then as you are an hour east of them(the area/boundary) one or two fire and go bonkers and you find yourself racing back. Just like I'm better at being content with arriving way too early, I'm getting better at being content in staying too late for nothing. Sitting out the day all together plays into that too. I don't sit out many setups that are within a half day's drive. If one ever wants to see a lot of cool storms, they have to be willing and able to do all three of those, be at the target "too early", stay "too late", and chase the day to begin with. Mother nature will play games with you if you just want to sort of chase all the time. Hell she plays them with me and I do it too much.
So you are chasing and you get your storm to fire, then what's it like? If it's a nice supercell it will still depend on speed and road network. It's pretty easy to understand that a storm moving 50 mph is going to be tough to chase and enjoy if it's not going directly down a highway. Those days are more storm intercepting than they are chasing. On fast storm days a good option might be to be on an east-west highway and just drive east and catch them as they race northeast. If you are lucky enough to be ahead of a couple tornadic supercells, this can work out well, even on high speed storm days. The dream is that slow moving tornadic supercell, or just highly structure supercell. My best example of this was the July 12, 2004 Bartlett NE tornado. I sat in one spot for about 20 mintues watching that tornado to my west, barely moving. Days with storm motions that slow aren't that common. Fast or quick days are more common, especially early spring while the jet is still intense. Early spring is often dealing with too much wind shear aloft, while late spring and summer is the opposite, always begging for more speed aloft(generally).
Road networks can quickly end your chase, at least on the storm you'd been chasing. Out west it is much worse, obviously. Decisions are much more important out there then too. There are some 45 mile stretches of highway out in western NE with no options. If you jump down to that next option you'd better be sure that is what you want to do. Often a storm will cross the middle of that, so your choice, if you commit, is to watch it till it crosses...then just not be able to be on it for a while till you get to the next option and catch up again. If it has a tornado with it already that choice might be simple. If it looks good but doesn't it might be a bit harder when to move and reposition. I hate those choices and areas. One thing I find myself doing less and less anymore, is taking any kind of gravel road. If they don't suck right when you get on them, they often will a bit later. I try to only do it when I know I can beat any and all precipitation. I've been on some very scary roads in rural areas that I can only image what they'd be like wet. I've also been stuck in mud more than once, something not exciting at all while far from home and often far from most civilization. One time was just going over a hill in the rain, right onto a minimum maintanance section. I don't recall any sign at all, just a hill cresting into mud. The other was again in the rain, but I just missed the minimum maintance sign. It was highly scary hitting complete slime at 55mph. Once I stopped I was ontop of the mud, not down into it at all. Still, the car would move nowhere. A friend with 4 wheel drive came and picked me up to get a tow and couldn't even get down this road in his 4x4. Those and some other close calls have me scared of anything not paved while around storms.
Once you get the storm, there's not much to chasing it, outside of a few hard choices now and then. Positioning can be key on how your images come out though. Anymore I love to be in the notch of the hook, or northeast of the updraft base, but just out of the rain(if possible). Even just east of it works well. This location is pretty much always in the path of the storm and any tornadoes however, and isn't always recommended. To get the full appreciation of storm structure this is usually the spot, since you can often see the vault region and northeast side of the updraft(generally).
This is northeast of the updarft, looking southwest at the storm. A lot of my suff is shot from this location. The heaviest rain is just off the right of the image. I'm in rain, but it's not too heavy yet. This is the only location you are going to see that right side of the updraft, often the area displaying the "meat" of the actual storm. If a tornado becomes rain-wrapped this is also one of the only areas you'll maybe be able to still see the tornado. Many of the views from the southeast could simply not see the tornado after awhile. From this spot I never lost track of what was going on in there. The reason is simple...contrast. If you are looking to the northwest at it, there is heavier rain behind it. There is far less rain behind it while looking towards the southwest. There is still a good bit of rain right around it. Take that rain away and you'd probably see it from the southeast, but that added bit in there with the rain further behind it and it's just not visible. It takes a lot more rain right around it to obscure it from a view to the northeast of it. That can still happen though obviously. So up here, often in the path, northeast of the updraft, you get a better view of storm structure and the better contrast for any tornadoes. Again though, it's often in the tornado's path, which this squarely was, and the one that followed. It's odd, even if you are far enough away and not even scared, you can get a fair amount of stress just knowing you are in the path. Oh yeah! This location is also a favorite for large hail. This area is also a favorite of cloud to ground lightning. It's intersting, all the dangers are in the spot of the most photographical(is that a word?) rewards. Once you know what you are doing, it's not very dangerous at all.
After the chase is over the lovely trip home gets to start. It can be a bit depressing making a long drive back if the day was a bust or just rather uneventful...most chases. If the next day looks to be close to the area this day's chase ends, then it's an easy choice to just get a motel, especially with the always high gas prices anymore. Well, this is a rough view of what a bit of chasing might be like. There are all sorts of added "quirks" about it, but those would fill more than this same amount of text just by themselves. Things such as putting up with the annoying driving habits of others on the road. Also, cases of interesting locals that stop to chat. It seems they don't often believe you when it's clear skies, you are parked on their country road, and you tell them you are there to chase storms. Then there are the many other aspects of the chase, like speeding in the rain on the way home so that you can get out of it, instead of driving slow in it the entire long drive back. Which is safer? Got me. One interesting thing about chasing is where you meet chasers. It's called a chaser convergence and sometimes they get rather large. If there's one lone storm, sooner or later everyone and their dog will be arriving on the scene. But even if it's not a big day, I can be parked waaaay off the main highways on some gravel road, and some chaser I know will drive up. But anyway, I need to end this and do other things. It's not been typed out as smoothly as I had hoped for, but it'll do I guess. I should have structured it more, before I started typing it, but I often do things this way, just dive in so that I actually do it and get a start, rather than applying some thought first. In the end, I hope it is clear that you can't just walk out your door when the storms fire and see cool things very often. You have to leave long before they do, to drive to the area you expect them to fire. Lots of clear sky busts and general crappy storms come with the territory. This should keep things from ever becoming "too" popular, even though many chases it seems it is indeed doing that. You can have all the tools for data and all the knowledge in the world, and money, and you'll still always have to be willing to dedicate many whole days for very little. It often seems very stupid. Shoot, I can't end this yet afterall. I call this "So, what's chasing like" and I don't even hit on those special events.
So, I hope I've made it somewhat clear what goes into some of it. It's also clear much of it is for very little. The main reason I go out each chase is that "what if". I always think to myself, just what sort of insanity *could* happen today. There are some absolutely jaw dropping storm structures that have taken place, and so there are surely to be some more of those. Those are why I leave, even though it takes so many junky days to find them. Nothing beats watching a storm structure that leaves you saying, "oh my god" uncontrollably over and over. It's happend several times now and I always think what is out there that is surley going to top even those days. This leaves a ton of room for dissapointment, but hey, it's fun during the moments of excitement when you are thinking, it could happen later this day. So in a way, seeing nothing and being dissapointed balances out as you were excited and happy moments earlier in the day. This is certainly a hobby for optimism as you aren't likely to see much without it. Then again you are less likely to waste gas so many days you never needed to. There's a problem with this though. It's those days that did not look great, but pan out with amazing sights. I almost hate those, lol, as I chase just about any setup because of them. I'd rather chase and see crap, than stay home and miss a good event. Here are a couple days I really didn't think would be worth chasing, but I went anyway(there are more): May 28, 2004 June 13, 2004 July 8, 2004 The first was a day with not great low level moisture, not strong shear, but good turning with height. You don't always need great low level moisture....obviously! June 13, 2004 had weak instability, weak low-level shear, but a strong jet nosing in aloft. I worked with my dad this day and had blown it off completely. I only got that storm because it was close and I got a call from another chaser right when I got home. I flew out the door and saw that. July 8, 2004 was a day with very weak low-level shear, weak mid-level flow and rather weak upper-level flow. It had very high instability though, and it anchored to a boundary and turned right. That anchoring and turning right helped the STORM RELATIVE shear, so it had enough shear to be a supercell. The mid-level winds were out of the west at about 20 knots. Had it moved east there'd be very little or no real shear at that height, but it moved sw against it, which helped it dramatically. So it pays to think what is possible, but it sure does add up in time and fuel costs. There are periods like most of 2006 where chasing everything is going to be a BAD idea, and this thinking can end up making you "mad"(nuts, lol...hence my 2006 dvd name). I've learned one thing about mother nature and chasing. She is just waiting for you to sit out a day. What is worse than chasing 10 days straight and seeing very little? Chasing 10 days straight and seeing very little, and sitting out day 11 and missing the big outbreak. Anyway, now I think I'm done with this. I'll surely make some different entries on things later. Sorry for the jumbled up unorganized form this is in.