How do you organize your forecasts?

[George Tincher]

Being Spring is almost here, I have been reviewing all my severe weather forecasting notes I've taken over the years to refamiliarize myself with what I need to be looking for on the various charts, severe parameters, SKEW-T's, etc. It's amazing how many things you get a bit rusty with or fuzzy on when you haven't used the skills in a few months.

At any rate, I was sitting here thinking about how I organize all my data when preparing forecasts and realized there has to be a better way than my method. Normally, I like to get pretty detailed on my Day 2 forecasts (evening model runs) and I've found that collecting and organizing all the data can be a real pain.

I have a bunch of plain white maps of the CONUS that I keep and run off as I need them. I scribble notes on them and draw various color coded features I've devised that (to me anyway) represent certain things. I usually end up using quite a few of these maps with each forecast, as a single map would be so cluttered by the time I finished that it would be impossible to interpret. Then I get them all together and compare them later to pick out regions of interest and zero in on a target zone.

So, when creating a forecast, how do you organize it? What's the sequence you use for working through everything? And what materials/methods do you use for organizing it while making the process as short and to the point as possible?

I'd be interested in hearing how each of you approach this task. FWIW, I have no formal training and most of what I know has been taught to me by friends or what I've gathered online or in forecasting manuals. I am not even close to being a pro at it. But organization of the forecast seems to be one area I've never covered or learned very well. And since this is the start of the severe weather season and there isn't much happening yet, I figure now would be the time to adopt new methods.

-George

 

[Bill Tabor]

I don't usually write anything down, or make maps. I do it all in my head. As you mentioned maps are cumbersome and slow to draw. I basically make mental notes of features I am interested in and fine tune from one product to another until I have a good feel for what is going on and a mental image of a good target.

If there were better methods for plotting and summing severe parameters in a computer based tool I would use that. Perhaps GEMPAK would be a possibly as I haven't used it. It's nice to be able to lay out different parameters and indices out on top of each other - problem is if you get more than three it is usually too hard to see what the map is showing because of all the layers and colors interfering with each other.

I think a good tool would take a forecast parameter such as CAPE and allow overlay such as Helicity, or sea level pressure and "sum" the result. You could then sum the result of various products and each would move slightly but the more they center on a particular spot IMO the more you would want to look there for consideration as a forecast chase target.

 

[Mike Peregrine]

At one time a couple years ago I considered coming up with a set of written worksheets to help chasers force themselves to think through a forecast before coming up with a hard target. I wanted to encourage thinking outside of parameters alone, and have sections to help me remember to take mesoscale features into consideration, outflow boundaries, and more of the subtleties that go into constructing a good forecast. When I sat down and started going through all the things it would take, the task ended up becoming so enormous that I gave up on it (and started respecting what the SPC is able to accomplish more). That's when I realized that each person just has certain things that become more personally important for them to look at and take into consideration. I think that every forecaster out there is pretty individualized this way, which is a good thing in the big picture - because the differences are what force people to consider alternatives and think outside the box ... so in the end it all evens out and we get a fairly well defined picture of what is going on these days. I still believe that experience is 50% of a good forecast.

 

[George Tincher]

Thanks guys for the thoughts. I have also considered creating some transparency sheets in which to draw features such as fronts/boundaries, lows, shortwaves, etc on as well as to draw other things such as DP, CAPE, helicity, temps, etc on. That would make it easier to overlay features on top of each other.

I wish I was capable of just remembering everything, but when I go from one feature to the next I forget what it was I just saw. So I alomst have to use notes and drawings to remember all the things through the analysis.

And, I will check on some computer software. Perhaps GEMPAK or Digital Atmosphere would help out greatly. I'm just looking to be a bit more organized and to speed up the process a bit.

-George

 

[Glen Romine]

I'm a meteorologist, so my methodology is probably much different than most, but if I were trying to teach someone new to the field how to forecast better - I'd have to start with fundamentals and work up from there. For instance - you need moisture, lift and and instability in order to have thunderstorms, and adequate shear in order to have organized thunderstorms. If you don't know how to look for these elements in observations and model forecasts - you'll struggle to make good picks.

So, the basic forecast should be to try and find where these might come together, because without these you are hard pressed to have interesting convection at all. Then, you can start refining within this region to make a more specific target. Model guidance should be thought of as possible future scenarios - more often than not some elements are forecast to come together, and others are not. Regardless - you have to evaluate each forecast element and question what could make it be either better or worse. Examples might include timing of upper level forcings (short wave arriving at peak heating, or too early or too late), outflow boundaries (if the model forecast produces precip that leaves an outflow boundary to force convection, but in reality this precip might not occur), cap strength over the moist sector, clouds (that might limit surface heating), etc... So really, each forecast will have it's own custom set of "issues" to consider, and so no single methodology is likely to work for every case. Forecasts based only on CAPE and SR helicity maxima won't lead to success very often - but if you refuse to look at anything else I'll at least offer this advice: look at the gradients in CAPE and helicity, and find where these best intersect.

Glen

 

[Bill Tabor]

Thanks guys for the thoughts. I have also considered creating some transparency sheets in which to draw features such as fronts/boundaries, lows, shortwaves, etc on as well as to draw other things such as DP, CAPE, helicity, temps, etc on. That would make it easier to overlay features on top of each other.

I wish I was capable of just remembering everything, but when I go from one feature to the next I forget what it was I just saw. So I alomst have to use notes and drawings to remember all the things through the analysis.

And, I will check on some computer software. Perhaps GEMPAK or Digital Atmosphere would help out greatly. I'm just looking to be a bit more organized and to speed up the process a bit.

-George

DA's a good tool and is helpful for looking at various aspect of the atmosphere particularly surface features. It's predecessor Weathergraphix is also a pretty good tool that also includes stability paramters such as Cape, LI, and various indexes. It is a free program but a bit tough to get to run on new computers since it is so old and DOS based. You actually have to slow down the process by using MOSLOW. Anyway I keep trying to get Tim to add stability to Digital Atmosphere WS but no luck so far. I think he should also add things such as the SPC Mesoanalysis products as well. He would have a killer app then.

As for looking at maps and plotting, etc. I've tried the transparency thing also and it was too cumbersome. It may be good if you just plot larger scale features such such as fronts and area of cape, helicity, jets - rather than try and get real detailed or try printing out model printouts on transparency. You can learn to just look at the products and memorize features but it takes a while to learn that way. A lot of times you have to flick back and forth. It helps to have a prioritized methodology of what you look at first based on priority of importance. For instance I may start off looking for a larger sfc low or 500mb vorticity area inbound and see how things set up around it as it comes in. Then see if there are jets above, divergence, etc. As I recall The Severe Local Storm Forecast Primer by Sturdevant had some hand plotting methodologies in it. Also taking a class on plotting and hand analysis from Tim Vasques would be recommended as well.