Zoomerang poll results (http://www.zoomerang.com/Shared/SharedResultsSurveyResultsPage.aspx?ID=L26GZV2Q6QZG) also include NearCast comments from forecasters:
Where did convection develop relative to difference maxima or gradients?
1 Convection has not developed as of
2 No convection developed in our area of responsibility.
3 Storms did not develop in our forecast areas, but did develop east of the area, where widespread convection was present.
4 Convection continued all day well ahead of a convective instability gradient across the southern Plains. Convection developed over eastern CO/northwest KS atop maxima in vertical theta-e gradients.
5 Convective development occurred near the the maxima in Neb and NW KS.
6 It was difficult to tell due to the presence of widespread high cloud cover advecting northward from a thunderstorm complex in Texas.
8 Storms were actually already ongoing in mid-Atlantic when we looked at this, but theta-e diff product gave a good indication of low level instability and any dry air aloft (marginal). Seems to match up generally well, but convection was fairly scattered, so not best scenario to evaluate.
9 It didn't form.
10 It never did, so did not answer #17 above. Some theta-e diff fields suggested some potential in same area that oun-wrf fcst across central OK, although values of 10K are not as high as I imagine they might normally be for rapidly developing deep convection. So hard to say if this was really a false alarm or not.
11 The existing supercells intensified in the vicinity of the low level theta-e difference gradients (west side).
12 Along the western limb of the GOES Theta-E Vertical Difference along the western edge of the Sterling Virginia WFO County Warning area and into the southeast portion of the WFO College Station region.
13 convection appeared to be associated with gradient of PW-product
14 Believe I remember convection developing near or a little east of the tight pw gradient.
15 None developed in area of concern (DLH initialization)
17 What little convection did develop was in areas where theta-e was decreasing strongly with height. However, it should be noted that the highest "delta theta-e" during the afternoon was located north of the warm front, in an area of relatively high H7 moisture, with a mid/high- level dry intrusion punching in over that (hence the strong theta-e lapse). No convection developed in this area during the operation period. Situations such as this may prove to be counterintuitive to many forecasters. While the tool appears to have utility, it will need to be accompanied by significant training of its limitations.
18 Storms eventually initiated in an airmass characterized by strong deleta-theta-e (i.e., theta-e decreasing w/ height.
19 developed near the gradient of theta-e difference fields.
20 initial convection in area of responsibility was correlated with higher values as indicated by vertical PW diff products
21 Don't recollect significant gradients/maxima in area of concern today.
22 along the west side of the gradient.
Did the Nearcast help delineate areas of convective inhibition? If yes, how?
1 The nearcast married up with areas of
2 Yes...the Nearcast indicated the presence of convective inhibition over portions of the SJT CWA where high resolution models were forecasting thunderstorm development.
3 not on this day.
4 The nearcast showed afternoon inhibition across western OK during morning runs...which ended up occurring in the wake of widespread thunderstorms in central OK.
5 Did not look at it near enough to the convection to get a good feeling for this.
6 The Nearcast showed convective inhibition present behind the Pacific cold front in western OK/TX as a proportionately small vertical theta-e gradient.
8 There was no CIN in this case.
9 Not sure.
10 Not especially.
11 The identified supercells did diminish in intensity in the theta-e difference min values.
12 Yes. Cellular development did not increase in coverage and intensity as the gradient of theta-e maximum moved with the activity. No relative max was maintain in the foothills of the Applachians, but not the Piedmont area.
13 unclear...need more experience with this product
14 Not obvious too me on this first cut other than little seemed to be happening back in the dry air. In the moist air... not sure.
15 Yes... theta-e fields indicated development of more convectively stable air moving into portions of area of interest... while still indicating a small possibility of development in a more convectively unstable area later in the evening.
16 nearcast information was useful for determining areas of convection (but not necessarily CINH)
17 Not really. We were thinking of ways that the CI products could be utilized to signal the strength of the cap. However, the best signal was the absence of convective cu across much of the operations area.
18 Not really.
19 Yes... did hit some eventual storms north of my CWA (DVN).
21 Not really. Airmass was fairly uncapped with convection already underway prior to operations.
22 Difficult to tell as convection was developing as we switched to a different WFO.
Please describe any correlations you saw between Nearcast relative maxima and the strength of the subsequent convection.
1 Could not ascertain.
2 No convection occurred.
4 Severe storms in eastern CO developed over locations with strong vertical theta-e gradients in the nearcast.
5 Didn't look at it that close, was looking at it in a group environment with it being explained.
6 Late morning runs of the Nearcast showed relative maxima too far to the south and east across AR compared to where convection actually developed.
7 Was looking at nearly saturated environment across mid-atlantic states. There were indications that mid-level drying would be taking place, aiding potential instability. Stronger storms did appear to form downwind of these signals over central/northern VA.
8 N/A in this case.
9 The nearcast maxima were where storms expected to fire, and nothing happened. That said, the numbers were not super high.
10 No convection, so not good correlation, but had the location in what we believed was the most likely place given other guidance...IF c.onvection had developed.
11 See questions #18 and #19.
12 No strong correlations to support any consistent predictive information.
13 did not find any correlation with relative maxima and the severe convection
14 Didn't compare that... will need to look at more cases as I get more familiar with the products.
15 Was no convection... however Nearcast products indicated likelihood of convection would decrease during the afternoon over the southwest part of the "CWA".
16 data not sufficient to make a determination
17 See response in 9.
18 Isolated/widely scattered convection quickly became strong-to-marginally severe in the area described above.
19 Perhaps only a slight increase in already moderate values over the area. However... later forecasts that ran as I was finishing operations increased the theta-e difference fields over southern IA by midnight... likely due to an increase in theta-e in the lower level. Based on that information... I would expect convection to continue actvive in IA for several more hours.
20 strongest storms appeared to be anchored near higher values of Vert. PW diff product
21 Not much in area of concern... but late look at fields in kansas look interesting with convective instability increasing quickly in NC-NE Kansas.
22 Storms strengthened as they moved toward Nearcast maxima.
For this particular event, what were the strengths of Nearcast in forecasting convection initiation and storm intensity?
1 Could not ascertain.
4 In this particular case, the Nearcast picked up well on convection from central TX into southern KS.
6 Low level theta-e gradients, though displaced, were sufficiently high to indicate that robust convection could develop
7 There was ongoing convection, but some of the nearcast datasets did help to solidfy thinking of banded convection.
8 Not apparent in this case.
9 N/A. Storms did not fire in our area of focus.
10 Maybe location (again...IF convection had developed)
11 The low level theta-e difference nearcast image was helpful in guaging and increase in intensity.
12 Insufficient time to evaluate ahead of main convective initiation.
13 strontest convection appeared to remain anchored on gradients of PW-product...
14 Nearcast... especially the pw fields... had a well defined gradient. Would be interesting to compare this event to some other low-end events... maybe would not see as strong of gradients in those cases?
15 Was more useful in explaining why convection was becoming less likely over a large part of the area.
16 Nearcast was quite useful as to forecasts of location of convective development.
17 Please see 9.
18 It was easy to delineate the more stable air behind the cold front moving into the region of interest. It also provided an alternative method for monitoring destabilization in the warm sector.
19 The identification of CI areas did lead ultimately to convection in some areas.
20 nearcast data pointed to the initiation of stronger storms in SW WI.
21 Did not add much information to the picture due to environment already convecting and an obviously unstable airmass.
22 Increased confidence in anticipating long-lived severe weather event.
For this particular event, what were the weaknesses of Nearcast in forecasting convection initiation and storm intensity?
1 Could not ascertain.
3 Thunderstorm development did not occur where initial indications showed that it might.
4 Not as much advance notice was given for the eastern CO/western KS convection.
6 No runs came in between 16z and 21z. The 16z run took stable air way too far east to near the OK/AR border by mid-afternoon, whereas initiation occurred in central OK. Once a 21z run arrived, there was too much cloud cover to provide a useful forecast.
7 Ongoing convection and weak cap did make the use of Nearcast difficult.
8 Again, convection ongoing, and very broad region of marginal threat areas depicted on nearcast products...so not especially useful.
9 I think the Nearcast tools latched on to the area of focus fairly well. I think other factors came into play that prevented things from firing.
10 Not evaluated...cannot comment at this time.
11 See Question #13.
12 unclear...need more practice with these products...
13 I don't know... storms were already convecting while I was sorting some of the products.
14 Nearcast seemed to highlight areas where convection would grow once it initiated... but didn't seem to help determine when or if convection was going to occur.
16 Please see 9 and 12.
17 I'm not sure it provided much more information than more traditional methods of assessing changes in the thermodynamic environment (i.e. SPC mesoanalysis). Most of the substantial thermodynamic changes this time of year are going to occur in the boundary layer, and this product only samples a small part of the BL.However, there are certain situations in which the product could be quite useful.
18 Don't know that it provided much help in determing storm intensity. Airmass was very unstable... so just figured if a storm got rooted in the boundary layer it was likely going to be strong/severe.
21 None noted.
Based on your cumulative experience, how would you envision using Nearcast within your day-to-day operations?
1 Might provide a good "safety
net" for the purposes of SA.
2 I would use it as a way to maintain situational awareness in rapidly evolving convective scenarios (rapid moisture surges, etc.)
3 I can see using it to identify areas of decreased inhibition and possible storm development in the next hour or so. I'd like to analyze it again with actual thunderstorm development.
4 I would keep it running during shifts involving possible severe storm development, checking on it from time to time.
5 I can see it being useful in analyzing areas of destabilization.
6 I would check on it every hour when a new run came in, but keeping in mind that Nearcast runs become out of date very quickly.
7 Could provide confidence in trying to limit window of convective initation, in combination with hi-res models.
8 Combining with model forecasts explicitly predicting convection, and in general increasing situational awareness for potential or most likely areas for new convection. Need to evaluate more in a stronger convective situation, and prior to convective initiation.
9 They are good SA tools, especially keying into the values of good moisture.
10 To confirm signals we are seeing in other data.
11 It can be used as a short term forecast to specify locations of change in supercell intensity.
12 There is some utility for forecast operations, but utility may wane once widespread convection is in place.
13 (with limited experience with this product)...Nearcast products may help improve convective initiation in a spatial sense
14 Started to build a prototype procedure using some of the products... will need to think about this more. Seems like it has utility for both pre-storm and active storm phases.
15 Would help to monitor areas of increasing/decreasing convective potential during a forecast shift.
16 so far...(limited) experience with this product has increased personal confidence with regard to location of CI.
17 I can see the utility in using this product to diagnose how convective instability is evolving with time (keeping its limitations in mind). However, I would more on trends than on raw numbers.
18 I think it could be useful during elevated instability/elevated convection cases, especially when the larger-scale pattern is more dynamic.
19 To help determine when/where a 'bubbling' cu field may actually convect. However... once intensive radar operations began... it dropped off my radar so to speak. A meteorologist that is monitoring the mesoscale environment may be able to continue to observe trend after radar operations have begun.
20 data in this set demonstrated value of PW diff products and convection initiation...particularly with regard to location
21 Likely more useful in those days with some uncertainty in timing and location of convection.
22 As a short-term aid to convective development and for anticipating the environment ahead of storms in the next few hours.
What additional tools, training, data or display techniques would help improve Nearcast?
1 Can't think of any at this time.
4 Our training on the Nearcast products was not too in-depth. I would like more specifics on the Nearcast tools, specifically with reference to convective inhibition.
5 Not able to evaluate at this time.
6 None at this time.
7 would like to experiment with color tables when experience is gained concerning use of Nearcast
8 Not sure yet... need more experience.
9 Ralph provided very useful insight today that helped me get a better handle on how to interpret and understand the products. Concerning additional tools... would like to see a product that would help with timing of the initiation of convection.
10 more experience with this product.
11 Traning on the limitations of the "difference/ delta" products will have to be geared toward spelling out its limitations, as it can be somewhat counterintuitive.
12 I'd be interested to see recommendations on using these products in conjunction with more traditional analysis packages to facilitate better understanding of the changing structure of the thermodynamic enviornment.
13 Experience is continuing to help me get a better handle on it. Also reviewing the types of products to find better ways to incorporate them into some of my Awips procedures.
14 more experience
15 none to add for today.
Comments on NearCasting from the HWT GOES-R blog (http://goesrhwt.blogspot.com/2011/06/ewp-end-of-week-debrief-10-june.html)
- (Thursday event - N.E.) "I didn't see a whole lot of trend in terms of gradients developing, but all the sudden on the back side of the squall-line we lost data rapidly, probably due to cloud cover... compared to the other days, I didn't see any real patterns."
- (Thursday event - KS/OK) Showed an arch of destabilization between 2200-0300 across the eastern halves of OK and KS... storms formed on the western edge of this gradient and forecaster did not expect the storms to diminish anytime soon and thus increased warning confidence... stronger wording regarding hail/wind potential in warning was issued.
- There seemed to be small scale features in the fields, areas of relative maximum that were moving around... would be nice to compare to radar evolution and see how those areas affected the storm structure.
- Helped understand why convection occurred and where it would occur... definitely the 1-6 or 1-9 hour timeframe was the most useful aspect of it.
- Having a 4-panel set up of the individual layers in addition to the difference field to help increase the understanding of the product.
- The color-table in AWIPS was poor... Also, the values were reversed from those in NAWIPS and on the web. The individual layers of PW were also not available in AWIPS.
Would it be useful to extend the Nearcast another 3 hours, even if that meant smoother fields?
- "I like the high resolution out to whenever we can have it... it seemed that there was definitely information within the gradients... of course if you add 3 hours, we will definitely take that."
Would you have used the observations without it being advected forward?
- Wouldn't have been as useful... It helped determine the evolution of the environment... The forecast parts tended to build areas of increased instability that helped provide guidance on what was going to happen later on.
Comments on NearCasting from the HWT GOES-R blog (http://goesrhwt.blogspot.com/2011/06/daily-debrief-9-june.html)
- The precipitable water product did give a sense of where the convection would start over SW WI.
- There was a sharp theta-e gradient and that seemed to be where storms focused.
Comments on NearCasting from the HWT GOES-R blog (http://goesrhwt.blogspot.com/2011/06/nearcast-training-for-severe.html)
Because no forcing mechanisms are included within the Nearcast's output, it doesn't guarantee where convection will occur, but it can help narrow down where you should be focusing your attention. If there is an area of strongly stable air, you're not likely to have any deep convection, even if there is some sort of light forcing present. This may be especially useful within SPC operations for forecasters issuing mesoscale discussions (MD) to determine where a severe thunderstorm or tornado watch will or will not be needed. It may also be useful during the early afternoon convective outlook updates to help trim areas that will not be expected to have thunderstorms later during that day. Following the group training, Steve Weiss (SPC SOO) asked if I would be willing to work with the forecasters in operations this summer in exposing this product to them. In addition, we expect to provide a training session within the SPC's bi-annual forecaster training this fall to help expose all of the SPC personnel to the product.
Comments on NearCasting from the HWT GOES-R blog (http://goesrhwt.blogspot.com/2011/06/nearcast-in-short-term-forecast.html)
EWP forecasters have come up with some novel ways to utilize the Nearcast differential precipitable water/theta-e forecasts within their warning operations. Generally we think of the Nearcast as a forecast tool, but the EWP forecasters have been using it to issue warnings and severe weather statements (see image above). Forecasters have been analyzing increased near-storm convective instability as depicted in the 0-2 hour forecasts from the Nearcast product to help increase their confidence that the storm will intensify. Conversely, the Nearcast is very useful to show when storms will die if the storm is expected to move into an area with very low convective instability or dryer atmospheric columns. This is another example of how forecasters will find some additional utility of these experimental products that the developers may not have originally intended.
Comments on NearCasting from HWT GOES-R blog (http://goesrhwt.blogspot.com/2011/05/end-of-week-debrief-27-may.html)
- (26 May event) The theta-e and precipitable water differences really indicated the marginality of the storms in the foothills... where the maximum stuff intersected that is where we saw the most sustained convection and highest flash rates. It was definitely a good indicator of flash flooding over the area.
- "A lot of the time to increase my lead time in the morning, I like to take a look at PW and WV... so I found that this was a nice utility because it was indicative of finding areas of greatly deep instability, or moisture source regions."
- "One on storm on tuesday, there was strong theta-e gradient that the storm was moving into and that gave me confidence in that the storm would intensify."
- It's a simple way to identify areas of warm advection and instability... this is why the forecaster found it useful in warning operations.
EWP forecasters have begun warning operations within the EWP. A few of them are examining the Nearcast differential theta-e product within the AWIPS D2D workstations. I overheard a comment about how the forecaster is watching the storms moving into an area of enhanced differential theta-e on the northern edge of the band extending from TX into western OK. He noted how he expects this storm to potentially intensify as it interacts with this area. While the Nearcast product is not necessarily a warning tool, it may be an interesting application of the data immediately following an hourly update.
- Saw a moisture tongue coming through, but nothing happened.
- Focused primarily on theta-e product, trying to figure out best way to use that... the challenge the day before was that nothing happened, so it's hard to find the values that are more significant... didn't notice any strong signals yesterday, so I didn't really use it.
- Were not able to get the multiple levels in AWIPS... would like to see those.
- "My initial thoughts were that this was no different than looking at the RUC theta-e product... but I do understand that it was nice to have it based on the observations."
- Would definitely like to see this in my home WFO.
- After the training, the forecasters felt comfortable understanding the product and how to use it.
- Color curves seemed to be reversed from NAWIPS/web versus AWIPS, and were confusing, but they worked through it.
- “You can infer convective instability 100 different ways.” … Forecaster was still confused as to how this was showing much more information.
- It is definitely best in the 1-2 hr timeframe, but anywhere outside of that it gets hard to use.
- At one point data did not arrive between 16-21 UTC, made fairly hard to use.
- Issue of clouds… later on in the day there were so many blacked out areas so we couldn’t really see what was happening.