So many moderate risks???

Joined
Feb 10, 2005
Messages
160
Location
Denton, TX
I was just curious what everyones opinion was about how many moderate risks we have seen issued so far this season. I mean, its only April 1, and we have had about 5 or 6 days with mod risks issued, is this a heads up for what to come? Or is it just jumping the gun? Also, it seems as if with almost every moderate risk issued there has been a 15% tornado "probability", but very few confirmed tornadoes. I just want to see what everyones thoughts were about this, is SPC over doing it? or are we in for a great season?

Best Wishes
 
I think the SPC might be overdoing it just a little bit. Or maybe Mother Nature is just underdoing it right now and waiting until I am off in the month of May!!! :lol:
 
I am relatively new to the world of chasing, this being my fourth year, but it seems like every year since I have been going there have been several days when SPC blows the forecast out of proportion early in the season. Off the top of my head I can think of two years ago when they issued a high risk for Louisiana and there wasn't a single tornado. I got burnt pretty bad last year on the early season Moderate risk in Minnessota. I should have known better than to go that far North that early in the season. I decided to go for the warm front that day instead of the dryline partially because of SPC's wording and there ended up being no tornadoes along the warm front. That one was hard to swallow. I damn near hit Canada. Then to add insult to injury, my windshield wipers quit working that day and I couldn't see in the rain so I had to spend the night up there. I am sure there are other examples that aren't coming to mind right away, but I definetly think there is an annual "jumping of the gun".
 
Originally posted by Mike Mezeul II
I was just curious what everyones opinion was about how many moderate risks we have seen issued so far this season. I mean, its only April 1, and we have had about 5 or 6 days with mod risks issued, is this a heads up for what to come? Or is it just jumping the gun? Also, it seems as if with almost every moderate risk issued there has been a 15% tornado \"probability\", but very few confirmed tornadoes. I just want to see what everyones thoughts were about this, is SPC over doing it? or are we in for a great season?

Best Wishes

I really don't want to judge or critic the forecasts by SPC, since I'm not in a position to do so accurately. I'd prefer to do such a critique using a systematic methodology, which I don't really have, and thus I don't feel qualified to make such a critique. However, I think we're 0-4 for 15% tornado probability verification thus far this year, not including the 15% tornado prob included in the 3-31 6z outlook. This holds for PDS tornado watches, as well, which have had a difficult time verifying, though I don't know the exact statistics on these... The 6z outlook for tomorrow (well, today -- April 1st) has another 15% hatched tornado prob in the Carolina's, though I fear that the overall situation looks pretty similar to last week's storm that affected the southern U.S., though the surface low this time is progged to move a little farther northward than last week. This time, it appears that Gulf moisture should really be able to make it northward into the southeastern US, though I wonder about the effeects of widespread precipitation across the area on instability. At any rate, don't want this to turn into a forecast, so I'll stop discussion today's forecast...

SPC forecasters have a pretty tough job, seeing how they are trying to forecast stormscale processes (tornadoes, microbursts, etc) for a synoptic-scale domain (CONUS). This time of the year seems to be especially difficult, since there seems to be favorable kinematics with many of these types of systems, with the limiting factor oftentimes being moisture (and resultant instability). I would blame part of the high false alarm ratio (for tornadoes at least) on very poor NWP model performance lately. You can't dog the SPC too much if all available model guidance is suggesting that there'll be sufficient instability when it doesn't verify. Weds busted for tornadoes largely because of insufficient moisture, which resulted in insufficient instability and LCLs that were just too hight for the situation. What will happen later today? Who knows with the way things have been lately.

If anything, this teaches folks the importance of making ones own forecast! People who chase solely based on SPC forecasts (or NWSFO forecasts, or TWC forecasts, etc) are more likely to be 'burned', I believe, given that no forecast is perfect. This isn't a comment on newbie's, since I think we all started off that way (very heavy reliance on SPC forecasts), myself included. But the best way to learn about chase forecasting is looking at the data yourself, examing why things happened the way they did, regardless of it the particular event was a bust or an outbreak.
 
Jeff said...
"If anything, this teaches folks the importance of making ones own forecast! People who chase solely based on SPC forecasts (or NWSFO forecasts, or TWC forecasts, etc) are more likely to be 'burned', I believe, given that no forecast is perfect. This isn't a comment on newbie's, since I think we all started off that way (very heavy reliance on SPC forecasts), myself included. But the best way to learn about chase forecasting is looking at the data yourself, examing why things happened the way they did, regardless of it the particular event was a bust or an outbreak."

I agree completely. The SPC isn't designed to give guidance to chasers. It is meant to alert local offices and the public and I think they have to air(spelling?) on the side of caution. Anyone who is basing their chases "solely" on SPC forecast are not going to be very successful. I do my own forecasting and I base my decision on where to go according to my own forecast, but if I am unsure of the overall probabilities of a severe weather event occuring and am debating on whether or not to go, I will look to the SPC to see what their thinking is. That is just common sense. Those people study and forecast severe weather for a living.
 
Yesterday's MDT risk from the 1630Z outlook verified pretty darn well. There were nearly 100 storm reports over that region, most of which were hail and significant hail reports, which line up well with the hatched hail outlook.

I agree that the main problem this time of year is thermodynamics, which models tend to over-do instability. Models did this on the IL event as well... Had instability been stronger, things probably would have been much more active, with most of those storms that developed being supercells with tornadoes (lower LCL's).
 
Jeff said

SPC forecasters have a pretty tough job, seeing how they are trying to forecast stormscale processes (tornadoes, microbursts, etc) for a synoptic-scale domain (CONUS).

SPC does have a really tough time trying to do all this. Afterall, they are not forecasting for us (chasers), they are putting out probabilities for forecast offices and general public uses. I mean if your wanting to pinpoint a target area for chasing...here is the place to help. Now that is what stormtrack is all about.

Justin
 
It's easy to look back at events and assess whether the forecast risk was equivalent to the number of storm reports. Of course, the forecasters don't have the knowledge of what will really happen when they make their forecasts. Instead, they must anticipate what *could* happen (forecasters must err on the side of caution) given the available guidance from observational trends, model forecasts and personal experience (pattern recognition). Further, they must consider large time frames, assess the risk for a number of possible threats (lightning, damaging winds, hail and tornadoes) for the entire continental US. Also, they must bear the burden of continuity in forecasts, particularly when the trend is for a less volatile environment.

The further out the event, the more reliant forecasters must be on model guidance. Sometimes this model guidance is exceptionally good - and can be taken at nearly face-value on the larger scales, but it could also be wrong - and forecasters must understand the range of possible error and the impacts this could have on an event. Often the differences between significant events and those much less memorable are subtle and determined by small scale features that are rarely captured in the models. Unfortunately, many recreational forecasters seem to look at model guidance in scrutinizing detail - pin-pointing Cherry county sized regions where the model forecast parameters appear optimal. While the models nowaday are resolving features on these scales, these should not be taken literally - particularly as model forecasts extend beyond ~ 6 hours.

Precipitation processes within models is one of the weakest components now, very often the model precipitation forecasts will not verify explicitly. Precipitation, however, has significant impacts on the the thermodynamic, and with increasing scale dynamic character of the atmosphere. So, good forecasters must not only correctly anticipate when convection will really occur - but then appropriately adjust the model forecast guidance which most likely has convection occuring earlier, later, or not at all. Aside from the thermodynamic adjustments, then dynamic adjustments (wind fields) have to be adjusted based on known errors in the initialization (which requires a careful comparison between the observations and model initial state), model biases need to be known to understand where guidance is unreliable, account for weakeness in the model's terrain, understand moisture source/sink/transport issues and a host of other considerations to numerous to list.

Really, it's an extremely dificult task. And from a chaser's perspective, while you may bust occasionally following their guidance explicitly, I am certain many would fair considerably worse without the high caliber forecasts produced by this group.

Glen
 
What's wrong with this picture?

It sounds to me like you're giving the SPC justification for being wrong!

If any of us are better at forecasting severe weather than the SPC, why aren't we working there? Hell, millions of lives and billions of dollars are at stake. If we're better at making forecasts for tornadic and other severe events, why isn't the insurance industry pitching in to pay a few of us each $250K/year to save millions? Why should there be ANY chaser out there who can do a better job with a chase target than the SPC?

These are questions, not condemnations.

Give me the name of just one chaser who can out-forecast the SPC. Then tell me why he/she isn't getting big bucks to work there. The SPC should be the final, final word. They should be the best severe weather forecasters, meso to synoptic scale, on the planet.

Bob
 
Originally posted by Bob Schafer

Give me the name of just one chaser who can out-forecast the SPC. Then tell me why he/she isn't getting big bucks to work there. The SPC should be the final, final word. They should be the best severe weather forecasters, meso to synoptic scale, on the planet.

Now this is not the same thing I'm saying at all - chasers aren't trying to achieve even 10 % of what the SPC forecasters need to accomplish in their forecasts. Instead - chasers want to know where the best chance for chaseable tornadic activity is going to be during daylight hours. This is a far less daunting task - and skill beyond the soft regions highlighted by SPC can certainly be accomplished with practice and careful technique. SPC focuses on the synoptic scale forecasting in outlooks - with mesoscale forecasts in the form of MCDs and watches. Driving to the middle of a tornado watch box will rarely be successful. With the exception of large outbreaks, chasers must be more concerned with mesoscale and sometimes even stormscale features. You can either imply these by recognizing the storm behavior via radar, or you can analyze the environment conditions to find the best possible environment for a cell to be in and know it will have the best presentation. Those with less knowledge of the latter often rely on the former.

Glen
 
guys,

i didnt mean to "bash" spc on this discussion, i was just merely interested in what everyones opinions were about how many risks we've seen. i give tons of credit and respect to the forecasters at spc, their job is incredibly difficult.
 
Originally posted by Bob Schafer
Give me the name of just one chaser who can out-forecast the SPC. Then tell me why he/she isn't getting big bucks to work there. The SPC should be the final, final word. They should be the best severe weather forecasters, meso to synoptic scale, on the planet.

Bob

Jeesh.....calm down! First of all - if you think that there aren't forecasters as good as if not - shock horror! - a bit better in certain fields than SPC forecasters out there......you're kidding yourself. SPC forecast weather for the nation. They have good forecasters, and some "OK" forecasters......just like any organization of humans anywhere ........ everybody's different and everybody has their own tendencies.

Do you think we should all go and plant ourselves on the western edge of SPC's next 15% hatched F2+ area, then??? That's what you are saying, here - i.e. SPC had the best forecasters in the world and the reason that nobody else works for them is because they aren't as good? Therefore: I'll go and sit in SPC's hatched tornado area, next chase. :lol:

I guess we'll be some of the gooseberries, then......because we differ regularly, anywhere from slightly to dramatically, in our forecasting opinions from what SPC has to say on any given severe chase day.

I think you'll find that most forecasters work at SPC because they chose to - i.e. they wanted to make a career with them - not because they are actually extraterrestrial super-human forecast Gods. We can't all make "big bucks" forecasting storms.....

KR

DISCLAIMER: I am NOT bashing SPC, here! They do a better job forecasting severe weather than I do answering the phone at work most of the time.......
 
I actually think it does the SPC credit that they refrained from issuing a high risk on several days this year (especially Easter weekend). They took the extremely favorable parameters forecasted by the models with a grain of salt, and sure enough, low-level shear (or lapse rates, or moisture, or one of several other parameters) did not improve as the models had indicated it would.
 
It's a tough job and not one I'm sure I'd want. Hehe. Granted, they usually do a pretty good job and I'm happy we have them. But with that said, it does appear the hatched tornado probs so far and PDS watches have been 0-4. Blame it all on the models. The models seem to struggle as badly with these early season events as we humans do.
 
Blame it all on the models. The models seem to struggle as badly with these early season events as we humans do.

Well, I wouldn't blame it ALL on the models... I was incredibly surprised to see the MDT risk on the first Day 1 issued earlier today with 15% hatch torn probs given all model guidance indicated CAPES <500 across the MDT risk area...
 
I could be wrong but it seems to me that the SPC does a much better job forecasting events that are “close to home†i.e. systems that play out over the Southern Plains. The SPC’s batting average is very high for good old-fashioned tornado alley outbreaks. Move the focus to, say, the Northeast, and things get much more dicey. Of course from a severe forecasting standpoint the Southern Plains are extremely data-rich, with mesonets and profilers and ultra-fine gridded models that aren’t available for the rest of the country. But I tend to think that there’s also a certain familiarity factor at work... The Plains area gets the lion’s share of the nation’s severe weather, it’s only natural that the SPC forecasters would do better when the scenario is one they’ve seen a hundred times before. I tend to give SPC outlooks less weight the further out they are from Norman.

As for who is the ‘best’ forecaster, I’d say there probably are a few chasers who are slightly better than anyone at the SPC when it comes to predicting precisely where the most prolific tornadic storms are likely to fire on a given day. But take the word tornadic out of that statement and it probably ceases to be true. The SPC simply doesn’t have the manpower to do the kind of small-scale scrutinizing that the best chasers excel at, not when its job is to evaluate the total severe threat, including non-tornadic hazards, for the entire country. Chasers are specialists compared to the SPC, and as such they just might do a bit better at a few very specific tasks. One thing I wonder about: do SPC forecasters play hunches the way chasers tend to? Or do they refrain from making predictions when the only real grounds for doing so is a ‘gut feeling’? It seems to me that a veteran chaser working off his intuition and the ‘feel’ of the sky might well succeed where a scientist working mainly from a model will fail.
 
One thing I've learned as a meteorologist is that I rarely, if ever, criticize another forecaster, especially if evidence supports their forecast as having been scientifically sound. The forecast process is just so complex, and so many things come into play that it is nearly impossible to fully understand what thoughts and, yes, intuition, went into that forecast.
 
I too have noticed a bit of overdoing it, mainly with a few watches so far this year. Esp. a recent tornado watch for East Texas after we were socked in with clouds. However, there are good forecasts and bad forecasts, and I would never want to criticise the SPC because they are on target so often. It has been something the other weather guys at work and I have discussed in the past few weeks.

They did get last night's svr right on. Plus, almost magically, a marginally severe cell traveling south of I-20 seemed to grow to a monster hailer (Doppler algorithm indicated) as soon as it crossed the MDT boundary. :)
 
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