In this video we're gonna get some practice with FFMP. 

So let's go ahead and under our scales menu select WFO for our scale and the frames count, we'll start off at 12 frames. And then under the SCAN menu for the system for convection analysis and now casting we're looking for the FFMP section for flash flood monitoring and prediction. 

So the first thing we realize about the FFMP menus is we have all these different sources. We have individual radars listed here and for every individual radar, we have two precip sources. We have a DHR precip source, which comes from the digital hybrid reflectivity. Which is effectively a cleaned-up low altitude reflectivity that's used with a single Zr relationship to to develop an instantaneous precip rate and then and then accumulate that. The other source from a single radar is going to be the digital precipitation rate source, which is a dual pol precip source. And the dual pulse single radar algorithm uses a precipitation identification type to determine a spatially varying, zr and then gives you an accumulation based off dual pol data. 

So in addition to the individual radar sources we have mosaic sources. We have the HPE or high resolution precipitation estimator, which is a dual pol mosaic of all your nearby radars. All the DPR sources and it combines those into one source. So it's easier to look at multiple radar information with just one source in FFMP. Even though this is labeled incorrectly DHR mosaic, it's a DPR mosaic so by default it's a dual pol mosaic source. There's the bias HPE version, which the RFC's provides some gauge bias factors for individual radar sources and those get sent over and can be used to correct some of the precip estimates with a gage observations. We also have the multi radar and multi sensor precipitation mosaic that's using a reflectivity based mosiac not dual poll data. But it has some spatially varying Zr's with its precipitation types that it assesses. So we have all these different precip sources. We don't have any of the mosaics in this case so we're just going to use the single site radar for this exercise which is fine because FFMP behaves the same for all sources. It's just a different data input. 

One of the things that you need to be able to do with FFMP is be able to look at some of the horizontal plots of some of the input data like the flash flood guidance. So each source has this pull out menu for guidance and the river forecast center flash flood guidance is here. So you can look at the RFC's issue 1-hour flash flood guidance 3-hour and 6-hour flash flood guidance So let's go ahead and select the 3-hour flash flood guidance So what FFMP does with all its precip and all its flash flood guidance and all its sources, is it takes this, in this case one kilometer by one kilometer gridded FFG. It's gonna average that out over the small stream basins. And then it's going to give you the average value. 

So if I sample a point out here this point says for a three hour duration flash flood guidance, I need about two and a quarter inches of precipitation before I get to that roughly the threshold where flash flooding threat becomes more significant. If I go up to the northwestern part of Oklahoma, we see that for a three hour duration it's going to require over six inches of rain in a three hour period to trigger flash flooding up there. So you can start to see the kind of variation of the inputs as it relates to the basin average flash flood guidance used in the FFMP displays. 

So let's go ahead and clear the display and we'll go back to our sources menu for KTLX. And the other thing I'd like to point out, we don't have these in this data set, but I'll just pointed out while we're here. Here's the average recurrence interval guidance source for, these are listed in years, so this is the one year average recurrence interval, the 100-year average recurrence interval, and then you've got all the different durations. So if I had the data we could be showing a three hour duration. For a three hour duration accumulation, what kind of of event will have once in a hundred year kind of event. Something that has a you know a one percent chance of happening in any given year. And it may be seven inches for a three-hour accumulation whereas we had, you know the flash flood guidance said it was gonna be up to five. So the ARI's are really just a, that's like a precipitation climatology just to give you some perspective on how rare is a given amount of precip and what's kind of the recurrence intervals for different precipitation amounts. And then that doesn't tell you anything explicitly about flash flooding. But the more rare the precip accumulation probably the more likely flash flood threat is. But you know that's just one of the things to point out here. 

We also have qpf, which is quantitative precipitation forecast. And that's really difficult to do and a lot of those are not very accurate, so we're not gonna go over that here. But I'll just point it out while we're here. 

But let's go ahead and load KTLX DHR basin table. So one of the first things we recognize when we get the table up is that the frame count goes from 12 to 1. So FFMP defaults this by default so that it takes up less resources because you can see this FFMP is a loading message stays for a little bit when it first loads up. It has a lot of overhead to it, but it's not too bad once it's up and running. The other thing that we're gonna notice here is that your display could come up differently than mine based off of what previous settings you had in there So I'm gonna want you to go under the D2D menu here, and we're gonna select qpe. Then under layer, we can go ahead and select county to see a lot of times it comes up in this county level display, which is the worst case basin. If there's any one basin that has the highest value, it's gonna plot the whole county as a certain color. That's kind of one of the the default displays. But that's not very useful for seeing exactly where the threat is so we're gonna go to all in only small basins. This is gonna show us exactly where those basin average precipitation estimates are. And we can use our slider bar here to look at a one-hour accumulation. 

Now another thing to point out. This is a tip for using FFMP and some of the other decision assistance windows Which don't really dock in CAVE. They sit outside of it. If I click on D2D, I keep losing my FFMP table. So I am going to go ahead and right-click on the top of the window and select always on top so I can interact with the display without having it hiding the table. 

Alright, so now I've got a one hour duration. D2D is qpe and the layer is all and only small stream basin. So here's a label one hour precipitation accumulation, and I see West Beaver Creek over here. If I left click on it, it's going to zoom in and put an X on that location. I can sample that out. 2.68 inches is 2.68 inches is what's listed in the qpe column. There's also an instantaneous precip rate. Which this is that you take the DHR, you average it out over the basin to give you a reflectivity value, and then you convert to a precipitation rate using the Zr relationship. That's valid for an instantaneous precipitation rate. That's an inches per hour. So it's raining right now because it's greater than zero. But you know an inch per hour is you know decent rainfall rate for an instantaneous rate. But that just tells you kind of instantaneously what's going on. Alright, so we covered those two. 

Now we can zoom out in our display and just look at okay, where is the one-hour precip accumulating you know the most. And we can sample these values. There's three inches down there. We can left-click on the qpe in the table and that's going to rank by qpe. And the let's, we can left-click on this 3.01 inch observation for that basin and there she blows. So we can look at, I'm gonna scroll out here. We can look at a one-hour accumulation. We can look at a three-hour accumulation. We can look at 4.5. So you can do anything you want with these precip accumulations in FFMP. And it's going to give you an updated estimate of the precipitation for that duration. And this is particularly important for things like the MRMS mosaics, the HPE mosaics. The HPE is only available as an hourly product. So you can't do a three-hour accumulation of HPE anywhere else, but FFMP. For MRMS, they just have the two-minute data. It's just the hourly you know the one-hour accumulations and the three hours. And the others are at the top of the hour. So if you want to find a three hour accumulation at 20 minutes after the hour, 21:25 let's say, you can't do that. 

So FFMP, one of its strengths is just as much for a precip source, kind of slicer and dicer just as much as it is to compare to flash flood guidance. So you can see things in FFMP for precip accumulation durations that you can't very easily in some of the other mosaics. So you can look at all different durations here for qpe and then you can, you can see basically were is the precip accumulated. 

So let's go ahead and select ratio under the table. And in the D2D display, it's now gonna be set to be ratio. So let's go ahead and left-click on the ratio column just to see what is the maximum ratio for anywhere in our display. And if we left click on this top basin name, it's going to zoom in to that particular basin. You can sample that value out and we see it's 151 percent. So let's go ahead and read off these values now for a given row. We're in all and only small stream basins. So this is all one basin's characteristics. The instantaneous precip rate of 1.79 inches per hour, which means it's raining right now. 3.64 inches has fallen in the last three hours, because that's what I set my slider bar to be. The basin averaged flash flood guidance is 2.4 inches for this basin. So we can see that I've exceeded flash flood guidance. Well if I take the ratio of qpe to guidance, then that's gonna be 151 percent. And that's what we're displaying right here. 

So the neat thing about this ratio display is that the color table really pops at 100 percent. So whenever your qpe meets your flash flood guidance for that duration that you specify, anywhere that's purple is gonna be exceeding flash-flood guidance, and has this flash flood threat if you believe you're precip source and if you believe your guidance. And there's a lot of uncertainties with both, so it's not just a you know warn on purple here. But it's a just something to clue you in as a place to look more carefully. So again you can move these to any duration you want and see lots of different signals for isolated storms that are rate driven, versus you do longer inner intervals, and you can see training storms. And so you'll see different signals on different durations, depending on how much training you're getting in your in your precip accumulations. So that's ratio. 

Now we can also look at the difference product, so let's go ahead and under our D2D display select diff. Now we've gone ahead and we've changed the difference color legend in here to be more useful, to have more granularity around zero because we really want to know when it's a quarter inch, half an inch close to a flash flood guidance and over flash flood guidance more so than the defaults were like one inch categories, which doesn't help us very much. So we've modified this in all our cases. So it might be a little bit different than what you're used to seeing But let's go ahead and left click on the difference column and see what's the maximum difference is. 1.24 inches for this three hour duration. If we left click on that basin name, can zoom in here and sample this value out to verify that yes, there is the difference of we're at 1.24 inches over flash flood guidance, which is a significant amount. And if we look up here in the upper left we see it's precip minus guidance difference for three hours. So it's 3.64 minus 2.4 inches is the flash flood guidance and so the difference is 1.24. So anything positive or over flash flood guidance. The more over flash flood guidance we are terms of the have the actual absolute value of precipitation accumulation, the more intense your flash flood threat is or more significant your flash flooding threat is. So if you've got good precip estimates and good flash flood guidance, half an inch over flash flood guidance is significant. An inch over flash flood guidance is usually very significant unless you've got errors in your flash flood guidance, or your precip sources. So that's another thing we can do. 

We've looked at looking at qpe. We can have our D2D layer be a ratio and and just see where do I have flash flooding threat. We can look at a difference product for different durations, and see you know, where am I most exceeding flash flood guidance and by how much and that gives us more of a sense of the threat for flash flooding, the more you exceed flash flood guidance in a different sense. Okay, so there's a couple of things to point out here. We've been looking at basins right now, which just have gray names on them, gray boxes behind them. These are basin averaged quantities. But if you look down here, there's some of these basin names that are colored purple. So this is the El Reno Mesonet observation, and you'll notice that all the the gauge observations are colored purple. These are called virtual gauge basins. So if we left click on this and we zoom in on this virtual gauge basin location, we'll see these little white squares in here are the locations of the gauges. So FFMP does two things. Does the aerial average for the regular basins. Then for the gauge locations, it makes these virtual gauges, virtual gauge basins I should say. And it's at it's valid at the point of the gauge. And what it does is it instead of grabbing the nearby, the nearby DHR and doing an aerial average over the basin, it's doing a point. It's grabbing the nearest DHR to that point. So it's really an apples-to-apples comparison between a point observation of the gauges and the point observation of the DHR so that we accumulate that nearest grid point of the DHR to that gauge, and use that as a precip source and accumulate that. And then it has a, in the basin trends, there's a virtual gauge basin overlay display, which we'll show you in the next lesson. But this guy right here is going to be tied to your virtual gage basin, and it's going to allow you to compare the precip to the, to the actual what goes on inside the gages. But that was I was a little look ahead using the right-click on that basin name. But we'll get that, we'll get to that in the second lesson. I just wanted to point out that anything in purple is the name aerial average. It's a virtual gage basin that's kind of a point observation of the accumulation of the DHR product. So we've gone over, you can rank all the tables by the different amounts. 

We've gone through the qpe ratio and difference. The other thing that we can do is look at the attributes button. And when we click on the attributes, let's go ahead and look at this, we're gonna sort by qpe for three hours. Let's left-click on that 3.64 inches here. And we're gonna sample that out let's see. Let's see we're on diff here. Let's go ahead and change our D2D to qpe. All right so, we've got 3.64 inches has accumulated over the last three hours in this basin. And all the basin names that they haven't been define are gonna be shown up as xxxx and each have a unique, it's a unique integer ID. But we have a basin here that we're trying to figure out here. Well how significant is this 3.64 inches in three hours? Do we get this all the time? Or is this really rare? So this is where we can start to bring in ARI's into the into the discussion. 

So if we click on the attributes button, we can bring this over, and we can go ahead and let's toggle on the one year recurrence interval to find out what has a hundred percent chance of happening in in a given year. That's going to be a 1.93 inches is a one year recurrence interval precipitation. So we're well above that so this isn't just your average kind of event. We can click on the ten-year recurrence interval and see what's that. That's 3.39 inches will happen once in every ten years, so there's a 10 percent chance of it happening in any given year. So we're starting to get up into a somewhat rare precipitation accumulation. So let's go ahead and de-select the ten and select a hundred because this kind of adds up after a while with lots of columns in here. We see a, you know a one percent chance event for the maximum precip is going to be 5.78 inches. It's kind of a 100-year recurrence. You know one percent chance of happening in any given year. So we're we're not in super record territory right now with this, but it is an anomalous precipitation, that's you know got a ten percent chance of happening any given year. And that just gives us another perspective on how rare is this precipitation accumulation for this duration. So that's a way to, you can control the columns that are displayed in the FFMP table as well as add some of these ARI values in. 

So, we've looked at the all and only small stream basins, and this gives us a direct look. We can go into D2D and go ratio. Show me where I have a flash flood guidance threat anywhere that's purple over 100 percent. That gives me a sense for the immediate place to look for, for the flash flooding threat. But one of the things that we can also do. If we're trying to find a particular basin name in here, you'll see that these basins, there's just literally thousands of basins at times in some CWA's. So it can be hard to find a particular basin name even if you kind of sort this and you try and find something, it can take a long time. So the reason why we have, a main reason why we have a county level or county layer display, if we click on county it's going to give us. I'm going to go ahead and sort again by qpe. Left-click on the qpe. And this gives us a worst-case basin in here. So this is the highest instantaneous precip rate for any basin in Canadian County is 4.09 inches per hour The highest qpe for this 1.75 hour duration is gonna be 3.63 inches. Lowest flash flood guidance in that county for any basin is 1.95 and then the highest ratio and dif is 171 percent and 1.5 inches. So these are not all the same basin. These are just the worst-case basin for any one of these parameters. So not very helpful, but at least you can kind of get what you're looking at when you're looking at the county level displays. 

So let's say I want to find out a particular, what's going on in a particular basin in Canadian County because I know my counties. Well what happens when you go in the county level display, the default setting for the zoom factor is only basins and parent. So it just keeps the basins and the parent that are just the basins that are in that county. So we've got a lot less basins to, to kind of sort through to find something, you know find something particular that we want to evaluate. So now the flash flood threat many times crosses county boundaries, so it doesn't really help in that respect. But if you're trying to find a particular basin this can be one way to isolate that, with that setting. Now you can also turn off the only basins and parent, and then you'll see all the other basins around it so there's more sophisticated bells and whistles with the FFMP basin table that you can use to filter some of these on and off. But we're going to try and keep it simple to start with. And if you want to return back from our county level display to the regular display, we just click the county button again for Canadian County. It will zoom back out. 

Okay, so we've introduced you to the scan menu, the FFMP sources. You can look at flash flood guidance displays through that that are basin averaged. We can load up D2D. We can look at qpe for different durations. We can also, we like to recommend going to the all and only small stream basins perspective so that we can kind of see what's the most significant precip and where where is it fallen. And look at it on its actual basin averaged area. We can look at things like ratio and difference, where these ratio and differences are using the RFC flash-flood guidance as a qpe to flash flood guidance ratio and diff. And that's selected down here. The guidance source, you could technically have your ratio be a qpe to a recurrence interval for a 100-year recurrence interval if you wanted to use it as a guidance source. But there's no hard and fast numbers for what recurrence interval is equated to flash flooding at your office. So it's really more ambiguous to actually change those values. It's important to just leave the RFC FFG by default when you're getting used to this so that your ratios and differences are going to be using the flash flood guidance like most people are used to using. Otherwise you can use the attributes button and you can add the ARI's in there, reconfigure some of the columns in here. And so I think this is a good introduction to the basics of the FFMP table, kind of the horizontal displays and how to identify areas of a flash flooding threat through the DTD.