What produces more severe storms? dry lines or cold fronts?

[Raymond Mason]

Hello guys! I have been on here for some time now but I have been curious. While self-studying meteorology I was wondering what produces the most severe storms? I know dry lines are pretty good and so are cold fronts. Warm fronts and low pressure based storms I heard are a little weak.

Would you go after a dry line first or a cold front? I suppose you can't go wrong with either.

 

[Kevin Rimcoski]

It would depend on other factors. Both produce lift needed but other things like shear affect storms strength and if the cold front out runs the storms and cuts them off. I don't think one is necessarily more capable of producing more severe over the other.

 

[Raymond Mason]

don't think one is necessarily more capable of producing more severe over the other.

First off thanks for your reply.

I guess that makes sense. Although I was watching a stream and an experienced chaser said they he mostly chases dry line storms as they tend to become tornadic storms.

If conditions are ideal, do you believe those two have the most potential to become tornadic?

 

[Kevin Rimcoski]

Dryline storms, from what I've been seeing from other members, tend to be more discrete and there's not much cell interaction, not as much worry as a storm's cold pools killing off your storm. A cold pool acts like a cold front as well. It can create the storms, but they tend to interact more, the outflow cuts off your inflow.

I think dryline storms are just more preferred. They're better in a sense that you're more likely to have an easier to see tornado. The cold front storms seem to be more HP and either hide the tornadoes, or there's just a lot of cell interaction choking off potential.

 

[Max Olson]

Drylines and Warm Front (Or TP's) are typically your best bet for seeing tornadoes on the plains. While you may get more storms forced up along cold front, they are easily undercut and less likely to produce tornadoes. Drylines are favored by chasers, they have a tendency to provide just enough forcing to kick off a couple isolated cells that are able to move off the boundary into favorable air with little interaction with each other. Warm fronts are also nice when you get a storm to latch right on it as you can get pooled moisture and backed surface winds in and near the boundary that can help enhance tornado potential. There are obviously alway exceptions to any of these, especially in different regions of the US.

 

[Chad Alcares]

For chasing purposes most choose to chase the dryline as it is the predominant surface feature sparking organized thunderstorms across the southern plains and parts of central plains during chase season Apr/May/Jun. Dry lines provide more subtle lift storms are usually more isolated and are a better option to chase.

 

[Raymond Mason]

Ah, I didn't know that cold front super cells tend to be more HP. Though that rises more questions like for example; how do you determine that a cold front is moving too fast to make severe storms last?

A second question I was wondering is there such a thing as storms developing to early to produce tornadoes? If so then how do you figure out that a storm is developing too early?

I feel like the more I get into this the more complex my questions are going to become. I've been interested in this for a long time now and still feel like I have a lot to learn.

Edit: I posted this before I could read the other two posts above me. Nice to know warm fronts are also good. I suppose cold fronts are just bad places to chase in general.

 

[John Shewchuk]

If you have the time, TR200 is the bible of severe weather and tornado forecasting. It was written by Robert Miller, who made the first tornado forecast in 1948 > http://www.outlook.noaa.gov/tornadoes/torn50.htm

The following link provides many download sites, but you should focus on the TR200 chapters, for they provide a wealth of information, used in some form or another, by all severe weather forecast systems (even the RAOB program) > http://chubasco.niu.edu/projects/miller/

The most famous page is Page 5-2 (in Chapter 5, Page 2), which has since been nick-named the "Miller Table" -- a summary of the most significant factors (know at that time) regarding severe/tornadic weather ... and this table includes Dry Lines and parameters associated with cold fronts.

Even though the TR200 forecast tools were developed for manual methods, the concepts are still used in education and most methods can and have been automated for today's automated systems.

Most of the concepts that Dr Greg Forbes talks about on the WeatherChannel can all be traced back to the TR200 publication -- except for the new stuff such as doppler radar, etc...

 

[Jeff Duda]

If you have the time, TR200 is the bible of severe weather and tornado forecasting. It was written by Robert Miller, who made the first tornado forecast in 1948 > http://www.outlook.noaa.gov/tornadoes/torn50.htm

Just as a matter of fact, it was a man named Finley who was the first to ponder a prediction at tornadoes back in the 1880s. Miller was the first to publish a forecast after Finley's days.

 

[Paul Knightley]

Neither cold fronts or dry lines make severe storms per se. They provide lift in order for parcels to reach their level of free convection, and then the severity of the resulting storms (should they develop) depends on the relationship between the instability and vertical wind shear. When forecasting you should apply the 'ingredients-based' approach, looking for: moisture, instability, lift, and for severe storms, vertical wind shear.

Overall, in the USA, I would suggest that of all severe thunderstorms which develop in a given year, more are associated with frontal systems than dry lines. Why? Because the dry line typically resides over the Plains in the spring/early summer, and has little or no part to play in storms aware from this area.

Why then should severe storms be associated with frontal systems and not just within a warm, humid airmass (e.g. Florida in the summer)? Because frontal systems are associated with areas of low pressure which largely result from disturbances in the jet stream. The jet stream is a source of vertical wind shear, and so storms which develop close to or underneath it may experience enough shear to become organised into multicells or even supercells.

The degree of lift is important in determining whether storms will be widespread or isolated, as does the capping inversion. Dry lines are where very dry air from the higher Plains begins to 'ride up' over the moister, Gulf air. This dry air does two things: caps the moist sector, and provides steep lapse rates (the former limits the amount of storms which can develop, meaning only one or two storms might 'feed' on the moisture/instability), and the latter can increase CAPE and thus the instability.

Given the dry line is most active when there is a strong SW'erly flow aloft (hence increased shear) and the mass response to such a flow is for a lee trough to develop over the high Plains resulting in a south-easterly flow of Gulf air, it's probably the case that a higher percentage of dry line thunderstorms reach severe limits when compared with frontal storms over the course of a year.

 

[Mike Johnston]

Cold fronts kind of have a bad name amongst storm chasers. They do provide lift, but tend to "scour out" the good Gulf moisture, thus delaying or deferring the next setup.

 

[Raymond Mason]

Thank you guys so much for the information and resources. Now I think all I have to do is figure out how forecast hours work in Twister Data.

I was thinking for practice I could chase local storms around here at first; then slowly branch my way out further and further.

 

[Lanny Dean]

Just as a matter of fact, it was a man named Finley who was the first to ponder a prediction at tornadoes back in the 1880s. Miller was the first to publish a forecast after Finley's days.

@Jeff Duda Just as a matter of fact, it was actually Fawbush and Miller - with Fawbush actually initiating the concept of the prediction/warning.

As far as the question, as many have said already - both DL and WFs will and can produce tornadoes. But in the many years I have been chasing, I would suspect that many of my documented tornadoes came from DL interactions/setups with probably 20-30% coming from the WF type events.

 

[Kevin Rimcoski]

You can also check weather.cod. Their forecast hours are much easier to see since it tells you what time and date ots valid. Twisterdata you need to do some conversions and I know I screw that up a lot lol

 

[Jeff Duda]

@Jeff Duda Just as a matter of fact, it was actually Fawbush and Miller - with Fawbush actually initiating the concept of the prediction/warning.

I invite you to read this BAMS article (http://journals.ametsoc.org/doi/pdf/10.1175/2010BAMS3062.1). While John Finley's forecasts weren't exactly the modern type that Fawbush and Miller pioneered, he indeed was the first to document any sort of prediction of tornadoes on short time scales.