tornadotony Posted June 3, 2011 Share Posted June 3, 2011 Serious question: How come it was "range-folded" for the NWS but not for the people who were looking at the couplet here on the board? Is GR just better at correcting the RF than AWIPS or something? It was range-folded on BOX. It was not range-folded on ENX. Link to comment Share on other sites More sharing options...
Analog96 Posted June 3, 2011 Share Posted June 3, 2011 It was range-folded on BOX. It was not range-folded on ENX. Then the main question is: Why didn't they augment their radar with KENX if they knew the tornado was on the far edge of their Doppler? Link to comment Share on other sites More sharing options...
IsentropicLift Posted June 3, 2011 Share Posted June 3, 2011 What is the criteria for a "TORNADO EMERGENCY"? There was obviously a spotted tornado bearing down on a major metropolitan area. Link to comment Share on other sites More sharing options...
LocoAko Posted June 3, 2011 Share Posted June 3, 2011 It was range-folded on BOX. It was not range-folded on ENX. Oh okay. I was only watching it on TV as it unfolded and was not on the boards, so I must have misunderstood when I only saw GR screenshots in here. And they have already explained why they didn't automatically issue a warning from the mid-level ENX rotation. Link to comment Share on other sites More sharing options...
radarman Posted June 3, 2011 Share Posted June 3, 2011 Then the main question is: Why didn't they augment their radar with KENX if they knew the tornado was on the far edge of their Doppler? West of the river, even east of it slightly, KBOX should almost never be used. KENX is much better, although still far away and high off the ground. I'm sure this isn't news to the very excellent forecasters in Taunton. I will say that as someone who lives out here, I'm a little disappointed that the narrative indicates that problems using BOX to warn this storm contributed to lack of lead time. Should have been using ENX well in advance. This is not hindsight nor monday morning qb'ing. Tornado/thunderstorm/snowstorm etc. it's always the same for this area. In other FOs with larger coverage areas the RPG as Zo described is set up to grab multiple Nexrads. Perhaps they might consider doing something similar. Link to comment Share on other sites More sharing options...
Baroclinic Zone Posted June 3, 2011 Share Posted June 3, 2011 West of the river, even east of it slightly, KBOX should almost never be used. KENX is much better, although still far away and high off the ground. I'm sure this isn't news to the very excellent forecasters in Taunton. I will say that as someone who lives out here, I'm a little disappointed that the narrative indicates that problems using BOX to warn this storm contributed to lack of lead time. Should have been using ENX well in advance. This is not hindsight nor monday morning qb'ing. Tornado/thunderstorm/snowstorm etc. it's always the same for this area. In other FOs with larger coverage areas the RPG as Zo described is set up to grab multiple Nexrads. Perhaps they might consider doing something similar. Do any of the local TV stations out there run there own Doppler? Link to comment Share on other sites More sharing options...
radarman Posted June 3, 2011 Share Posted June 3, 2011 Do any of the local TV stations out there run there own Doppler? I know 22 purchased one, but they never use it for on air display, and frankly not even sure if they look at it. Don't think channel 40 owns one. Link to comment Share on other sites More sharing options...
Baroclinic Zone Posted June 3, 2011 Share Posted June 3, 2011 I know 22 purchased one, but they never use it for on air display, and frankly not even sure if they look at it. Don't think channel 40 owns one. If there are local TV stations that have them out there, it would be nice if the NWS could augment their own which is at the extreme edge of it's effective range and use one closer to activity in question. Link to comment Share on other sites More sharing options...
TheTrials Posted June 3, 2011 Share Posted June 3, 2011 couple of cool youtubes showing the progression of the first storms that went north of springfield, then the storm that produced the tornado in question from springfield to Monson and then the third batch that we haven't verfieid dropped a tornado on the north side of springfield. Thought this would be good to put in as people go back and forth what was and wasn't visible. From my very very untrained eye, looks to me like the hook started to become pretty clear west of springfield out towards the airport, probably when the Tornado was added to the ASOS. Also shows up well on the relative velocity. Link to comment Share on other sites More sharing options...
Siberian Express Posted June 3, 2011 Share Posted June 3, 2011 I'm curious about the number of trained spotters who were available in the Springfield area (and the area to the west) at the time. Might be worth actively recruiting more spotters in areas that are problematic for low level radar coverage. Probably not ever going to have a better time to recruit if the NWS wants to expand its trained spotter network. Just sent this link to a friend that works at NECN: http://www.weather.gov/skywarn/ j24vt makes a good point. I'm curious too. Were there alot of "boots on the ground"? As many of you probably know, in the Midwest, the Skywarn spotter network is an important piece of the puzzle for WFO's. I seen a vid of a self-proclaimed 'storm chaser' on the pics/vid thread who stated on his storm chase website to being a "trained skywarn spotter".....well, he's lucky to be alive after seeing the vid, and the pic of the car after the storm. Hopefully he called in a report before he started filming. Link to comment Share on other sites More sharing options...
adamrivers Posted June 3, 2011 Share Posted June 3, 2011 Do any of the local TV stations out there run there own Doppler? WFSB's Doppler 3000 or whatever they call it at Bradley Airport has great lines into Springfield. I've seen some stills of their coverage where they had the tornado signatures (they show up as big circles) that they have before the tornado warning was issued. 22 had a radar years ago but I don't think they use it very often, and frankly when they did it looked horrible and unreliable on the air. Link to comment Share on other sites More sharing options...
tamarack Posted June 3, 2011 Share Posted June 3, 2011 Thank you both, Eleanor and Bill, for taking the time to explain some of the process that goes into issuing warnings. I appreciate not only your knowledge and experience, but your passion and determination to be as timely and as accurate as possible. I feel that pretty much all the posts in here echo those sentiments. To a layperson, it would seem that one of the "issues", for lack of a better term, might be insufficient hi-res radar coverage in certain areas. To the average John Q. Public, it's generally believed that the NWS has a radar dish pretty much on every city block, and that every tiny change in the atmosphere is picked up almost instantaneously. Terms like range-folding are foreign to the average person. Do you feel that this is a fair assessment? Would more extensive radar coverage have led to a warning being issued more quickly? We get what we pay for. Actually, we (the public) gets a lot more than that from the NWS due to staff skills and commitment, but the posts explaining real life hardware/software/budget issues are enlightening. The two radars in my earlier post, GYX and CAR, lie 240 miles apart, which is probably fiscally appropriate for Maine's lower population, but must make the mets' jobs considerably more difficult and less precise than closer installations would enable. From BillB's post: Based on the information we had at the time, our radar/warning operator went with a Severe Tstm Warning that mentioned the possibility of a tornado. That went out at 418 pm. Once the couplet moved out of the haze, and the couplet became viewable, the warning was upgraded to a Tornado Warning. This (the boldface) was the situation described in the warnings we heard over the radio, but they were verbally labeled "tornado warnings" by both GYX and CAR. Warnings for 'only' severe would merely mention hail and wind potential. I apologize if my implying that the Maine and Mass situations were directly comparable has sullied the issue. Link to comment Share on other sites More sharing options...
The Great Zo Posted June 3, 2011 Share Posted June 3, 2011 As was mentioned earlier, this message board's time-stamps are definitely off by at least a few minutes. The deficiency in the public metrics for lead time and accuracy is that these are not sub-aggregated by tornado intensity: if I were guiding the NWS on its metrics, I would suggest subcategories for tornadoes rated EF0-EF1, EF2-EF3. and EF4-EF5. It may be that the NWS already sub-aggregates internally, but aggregates to a single number publicly. Unfortunately, in the NWS performance metrics. there is no way to tell between an EF0 or an EF5. A 5000 square mile polygon with a squall-line EF0 that knocks down one barn is considered a "hit" just the same as a well-tuned warning on a small rotating supercell that produces an EF4. Local offices are well aware of this distinction, and must strongly consider the risk of false alarms if they're actually making an attempt to nail every spin-up EF0. On the level of national statistics, there is no distinction. There's also no NWS performance measure or GPRA goal for false alarm surface area. For example, Taunton could have issued a four-hour tornado warning from Springfield to Boston (if their WarnGen were configured to allow such a monstrosity) and it would have verified as a successful polygon! I am sensing that many local offices are realizing (or are already familiar with) the complications of how to provide a good public service -- namely, that there are many factors in performance that the NWS measures and GPRA goals do not tell the story of at all. The criteria for verifying a tornado warning is a verified tornado. I would THINK a storm that produces a funnel cloud or a waterspout SHOULD be warned, but unless it produces a tornado, it doesn't count, as far as verification processes. Also correct, for the most part. As long as the funnel cloud report is legitimate, of course, you'd want a warning out (especially if you can match it to a circulation on radar). Of course, this can lead to a frustrating evening of warnings if you have a handful of rotating supercells on radar, with wall cloud and funnel cloud reports coming out of your ears, and a shallow stable layer near the surface keeping anything from ever touching down! Link to comment Share on other sites More sharing options...
Ginx snewx Posted June 3, 2011 Share Posted June 3, 2011 Bill B and El thanks for your explanations. It appears to me that perhaps the NWS needs to adapt and advance to a more multimedia approach. The more info the better, web cams, AMWX etc. I would think a Risk day would include bringing in extra staff, perhaps interns etc could be assigned to monitor multiple feeds and pass on verifiable info. As far as Internet goes, shame on NWS. Link to comment Share on other sites More sharing options...
HoarfrostHubb Posted June 3, 2011 Share Posted June 3, 2011 Bill B and El thanks for your explanations. It appears to me that perhaps the NWS needs to adapt and advance to a more multimedia approach. The more info the better, web cams, AMWX etc. I would think a Risk day would include bringing in extra staff, perhaps interns etc could be assigned to monitor multiple feeds and pass on verifiable info. As far as Internet goes, shame on NWS. A direct line to Wiz sorry... gallows humor Link to comment Share on other sites More sharing options...
TheTrials Posted June 3, 2011 Share Posted June 3, 2011 On a small side note, this thing tracked exactly due East, I mean, you can draw an arrow on mapquest from westfield where the first funnel cloud was spotted all the way to Brimfield and its a straight line. IMHO probably one of the only spots in Mass where a tornado could survive on the ground for that long given the hilly terrain. If it did that north of the pike, don't think it would have survived for that long. Link to comment Share on other sites More sharing options...
tornadotony Posted June 3, 2011 Share Posted June 3, 2011 On a small side note, this thing tracked exactly due East, I mean, you can draw an arrow on mapquest from westfield where the first funnel cloud was spotted all the way to Brimfield and its a straight line. IMHO probably one of the only spots in Mass where a tornado could survive on the ground for that long given the hilly terrain. If it did that north of the pike, don't think it would have survived for that long. These violent, maxi-tornadoes scoff at moderate terrain features once established. Link to comment Share on other sites More sharing options...
TheTrials Posted June 3, 2011 Share Posted June 3, 2011 These violent, maxi-tornadoes scoff at moderate terrain features once established. It looks like the first cell that went north in Northhampton had a nice signature going and just died, I was wondering if terrain had something to do with that as the elevation begins to increase pretty substantially up there from where it started to the south. Link to comment Share on other sites More sharing options...
Tropopause_Fold Posted June 3, 2011 Share Posted June 3, 2011 It looks like the first cell that went north in Northhampton had a nice signature going and just died, I was wondering if terrain had something to do with that as the elevation begins to increase pretty substantially up there from where it started to the south. could be (likely is) a combo of factors but i was guessing it was choked off by that monster that initiated to its south. Link to comment Share on other sites More sharing options...
TheTrials Posted June 3, 2011 Share Posted June 3, 2011 could be (likely is) a combo of factors but i was guessing it was choked off by that monster that initiated to its south. Thought that too, that second storm came in and definately impacted it, but thinking it might have happened anyway. Link to comment Share on other sites More sharing options...
CT Rain Posted June 3, 2011 Share Posted June 3, 2011 could be (likely is) a combo of factors but i was guessing it was choked off by that monster that initiated to its south. The ironic thing is that it's possible the outflow from storm 1 traveling south through the valley enhanced horizontal vorticity in the valley which was stretched into the mesocyclone that was coming off the hills into Westfield. The combination of the already enhanced 0-1km horizontal vorticity in the valley with a channeled and backed sfc flow plus the outflow from the storm to the north likely triggered strong and rapid tornadogenesis. I think one thing we've learned from this storm is how important situational awareness is when you have a relatively low mesocyclone emerging from the hills into a N/S valley with channeled flow and enhanced shear. Also going back and looking through the radar imagery ENX had a perfect shot of the couplet about 10 minutes prior to the storm coming out of range fold on BOX's radar. Being able to utilize both radars (and even OKX) is vital to the warning process in areas that are equidistance from all 3 sites. The ENX radar had a strong couplet and TVS approximately 10 or 12 minutes before touchdown while the storm came out of range fold at BOX around touchdown in Westfield (between 4:20 and 4:25) Link to comment Share on other sites More sharing options...
TheTrials Posted June 3, 2011 Share Posted June 3, 2011 The ironic thing is that it's possible the outflow from storm 1 traveling south through the valley enhanced horizontal vorticity in the valley which was stretched into the mesocyclone that was coming off the hills into Westfield. The combination of the already enhanced 0-1km horizontal vorticity in the valley with a channeled and backed sfc flow plus the outflow from the storm to the north likely triggered strong and rapid tornadogenesis. I think one thing we've learned from this storm is how important situational awareness is when you have a relatively low mesocyclone emerging from the hills into a N/S valley with channeled flow and enhanced shear. Also going back and looking through the radar imagery ENX had a perfect shot of the couplet about 10 minutes prior to the storm coming out of range fold on BOX's radar. Being able to utilize both radars (and even OKX) is vital to the warning process in areas that are equidistance from all 3 sites. The ENX radar had a strong couplet and TVS approximately 10 or 12 minutes before touchdown while the storm came out of range fold at BOX around touchdown in Westfield (between 4:20 and 4:25) Which is why all the people following it on this board (and you especially) saw it so quickly as the apps, pay radar sites, etc. avoid the range fold. Link to comment Share on other sites More sharing options...
tornadotony Posted June 3, 2011 Share Posted June 3, 2011 Which is why all the people following it on this board (and you especially) saw it so quickly as the apps, pay radar sites, etc. avoid the range fold. No, that's not how it works. If a radar is experiencing range folding, no application will be able to get rid of that. It is intrinsic to that radar data. The only way to counteract range folding is to adjust the PRF of the radar in the office or to use a different radar site. Link to comment Share on other sites More sharing options...
Tropopause_Fold Posted June 3, 2011 Share Posted June 3, 2011 The ironic thing is that it's possible the outflow from storm 1 traveling south through the valley enhanced horizontal vorticity in the valley which was stretched into the mesocyclone that was coming off the hills into Westfield. The combination of the already enhanced 0-1km horizontal vorticity in the valley with a channeled and backed sfc flow plus the outflow from the storm to the north likely triggered strong and rapid tornadogenesis. I think one thing we've learned from this storm is how important situational awareness is when you have a relatively low mesocyclone emerging from the hills into a N/S valley with channeled flow and enhanced shear. Also going back and looking through the radar imagery ENX had a perfect shot of the couplet about 10 minutes prior to the storm coming out of range fold on BOX's radar. Being able to utilize both radars (and even OKX) is vital to the warning process in areas that are equidistance from all 3 sites. The ENX radar had a strong couplet and TVS approximately 10 or 12 minutes before touchdown while the storm came out of range fold at BOX around touchdown in Westfield (between 4:20 and 4:25) that's a good point. i haven't looked carefully to see if there's a distinct outflow boundary visible in any of the imagery...would be cool to have a visual. it's times like this that you wish there was a very dense meso network to illustrate it. i went back and tried to plot the surface obs around the area but on the product i was using could only fetch about 36 hours worth...which put me into wed evening post event. re: ENX - yeah i grabbed a bunch of archived data this morning. it's pretty impressive and you are right about the times. the tornado-genesis zone is certainly in a tough spot with respect to both terrain and range. here are ENX, BOX and OKX: Link to comment Share on other sites More sharing options...
OSUmetstud Posted June 3, 2011 Share Posted June 3, 2011 I wonder how much temperature/dewpoint differential had to with spin up also. One of the terms to tilt and stretch vorticity comes from Theta gradients. So while I'm sure increasing horizontal vorticity played a role...that may have played a role too. Link to comment Share on other sites More sharing options...
TheTrials Posted June 3, 2011 Share Posted June 3, 2011 No, that's not how it works. If a radar is experiencing range folding, no application will be able to get rid of that. It is intrinsic to that radar data. The only way to counteract range folding is to adjust the PRF of the radar in the office or to use a different radar site. so then these programs/pay sites just switch to the radar that has the best view? Just trying to figure out how the couplet was so visible on the pay radars people are viewing at home. BTW, found this online about range folds/purple haze. Cool article. http://www.roc.noaa.gov/news/NNautumn07b.pdf Link to comment Share on other sites More sharing options...
tornadotony Posted June 3, 2011 Share Posted June 3, 2011 so then these programs/pay sites just switch to the radar that has the best view? Just trying to figure out how the couplet was so visible on the pay radars people are viewing at home. BTW, found this online about range folds/purple haze. Cool article. http://www.roc.noaa....NNautumn07b.pdf No, you choose which radar to view. Those of us who saw the couplet early on were viewing Albany radar instead of Taunton. Link to comment Share on other sites More sharing options...
TheTrials Posted June 3, 2011 Share Posted June 3, 2011 No, you choose which radar to view. Those of us who saw the couplet early on were viewing Albany radar instead of Taunton. ok, thanks, thats what I was missing, wasn't sure if it automatically did it, I don't have it. Thanks again. Link to comment Share on other sites More sharing options...
ORH_wxman Posted June 3, 2011 Share Posted June 3, 2011 These violent, maxi-tornadoes scoff at moderate terrain features once established. Yeah it traveled over plenty of hilly terrain in Monson, Brimfield, and Sturbridge. Link to comment Share on other sites More sharing options...
CT Rain Posted June 3, 2011 Share Posted June 3, 2011 I wonder how much temperature/dewpoint differential had to with spin up also. One of the terms to tilt and stretch vorticity comes from Theta gradients. So while I'm sure increasing horizontal vorticity played a role...that may have played a role too. I believe the baroclinic process of producing vertical vorticity in the low levels likely comes mainly from the RFD. Link to comment Share on other sites More sharing options...
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