Zoomerang poll results (http://www.zoomerang.com/Shared/SharedResultsSurveyResultsPage.aspx?ID=L26GZV2Q6QZG) also include UWCI comments from forecasters:
On average, how many minutes elapsed between radar detection of a 35 dBZ echo and the UW CI/CTC rate nowcast? (please indicate which came first)
2 UWCI product was not available today.
3 Radar usually detected 35 dBZ echoes first, about 5 minutes before the nowcast.
4 10-15 min., CI signal before echo
5 In using this dataset, was looking across eastern CO and wrn KS. Most of the area was delineated with cloud mask.
7 around 30 to 45 minutes between the UW flag and the echo
9 N/A...UW CI did not predict CI today.
10 Only CI was edges of cirrus with no convective development.
11 No CI detetected except for a few false alerts due to cirrus, and no convection occured...so good fcst of null event!
12 very little if any. edge if cirrus was flagged as ci which did not materialize.
13 For the echoes that came up very fast, lead time was short 5-10 minutes, and echoes were fairly obvious on satellite.
14 Only a few detections, but seemed like about 30 min.
15 About 15 minutes from nowcast to radar detection.
16 Did not pay enough attention today.
17 10 minutes (estimated) lead time on the UW CI versus the 35 dBZ. This was on real-time KTLX and KVNX data, but was intensely interrogated.
18 N/A - did not play that close attention.
19 Not sure.
20 45 minutes to one hour
21 UW CI/CTC first, 10 to 15 minutes lead time.
22 The UW CI/CTC products preceded the onset of detectable convection by about 15 minutes.
23 CI came about 10-20 minutes after satellite CI detection, with much longer lead times south of the Red River.
24 Less than 10 minutes. UW CI/CTC came first. Due to the explosive growth, -13C/15 min to -22/15 min (for a 5 minute interval) the initial storm convection indication would have only provided a 5 to 10 minute lead time before >35 dBZ echoes were indicated.
25 I don't remember!
26 Based on our assessment during the morning portion of the day shift with convection across the SE, the CI did not do very well today with very little if any lead time. IN fact, in some cases negative lead times. Perhaps an issue with the resolution of the satellite data this morning.
27 15 minutes.
28 not sure...we need to look more closely during next session
29 Not sure about the 35 dBZ echo... as was comparing it with first-echo... although I did notice that it had negative lead times with first echo... but some positive lead time with development of 35 dBZ.
30 I was not able to get this detailed with my analysis of these products. I was mainly trying to familiarize myself with the products, their displays, and interpreting their ouput.
31 Had no radar echoes.
32 CTC rate (accum) product -- indication ~ 20 min before 35 dbz return
33 Less than 30 minutes.
34 Perhaps 30 to 45 minutes from CI hit to echo.
35 30 to 45 minutes between nowcast and 35 dbz echo.
36 They were basically simultaneous for the one significant storm that developed. This cell progressed from cu-congestus to severe thunderstorm in a matter of minutes.
37 In one case north of the CWA... CI preceded the echo by around 30 minutes.
38 UW CTC product seemed to precede first (of this event) 35 dbz echo ~ 30 min.
39 generally 15 minutes or less... uncapped and unstable airmass.
40 30 minutes from nowcast to echo.
On average, how many minutes between the first lightning flash and UW CI / CTC rate nowcast? (please indicate which came first and whether it was cloud-to-ground or total lightning data when available)
2 UWCI product was not available today.
3 Lightning usually occurred 45 minutes to an hour after the CI nowcast.
4 15-30 min., total lightning data was shown before cloud-to-ground confirmation.
5 Did not see any lightning as of this typing.
8 N/A...UW CI did not predict CI today.
9 ditto #18.
10 See comment above
12 For fast developing storms it was about 30 minutes for CG detection.
13 Did not notice. NLDN CG data was not coming in reliably.
14 About 45-60 minutes from nowcast to total lightning detection.
15 Did not pay enough attention today.
16 Not Evaluated.
17 less than 20 minutes. UW CI came first.
18 Note sure.
20 In general 5 to 15 minutes.
22 I wasn't watching this too close. I know there was pretty good lead time (30-45 minutes?) between CI signature and first lightning flash for the first storm near Sayer, OK.
23 Not evaluated properly...no comment.
24 Made notes on this one!!! It was about 45 minutes before the first flash was detected when the first CI/CTC indicators arrived.
26 Not evaluated sufficiently to
provide an exact number of minutes.
27 not sure...we need to look more closely during next session
28 Didn't take notice of the time interval. Need a little cheat sheet of the sorts of things you want us to look at prior to the case.
29 Same as above.
30 Also had no lightning.
31 CTC rate (accum) product -- indication ~ 10 min before 35 dbz return
32 Around an hour.
33 Probably 30 to 45 minutes to first CG (no LMA data available in domain today).
34 Roughly 30 to 45 minutes between nowcast and first CG (no LMA available)
35 About an hour until the first CG.
36 Don't know.
37 not noted
38 Didn't catch lightning interval. Sat down and started with warning shortly there after.
39 30 to 45 minutes from nowcast to first CG (was beyond LMA range).
Please list some of the strengths and weaknesses of the UW CI / CTC rate nowcast performance on this day.
2 UWCI product was not available today.
3 CI was very good at pinpointing areas of convective initiation and convection that would eventually produce lightning, but was a little slow at detecting the initial 35 dBZ echoes.
4 Noticed that there were times when CI was fairly sporadic (scan-to-scan) and hard to use due to rapid growth of convection. The CTC was helpful in development of convection south of OKC when main activity had been seen well north of OKC.
5 In this situation, the masking did limit the number of false alarms.
6 UI CTC did not do well at all forecasting convective initiation in the Mid Atlantic. The presence of cirrus per ice mask mostly prevented this.
7 The product did a good job at pegging areas to watch for precip development. The weakness is that you can't look at the exact area it highlights and expect to see rain from that particular cloud. It is more of an attention grabber to watch a particular area/region.
8 It successfully did NOT detect convective initiation, as it did not occur. So that in and of itself is a success. Cirrus contamination did occur, which I would hope would be an area of focus to improve the algorithm in these circumstances. Maybe use multi-sensors.
9 Cirrus obscured potential convective development areas...a known issue.
10 Seem to indicate CI on edges of cirrus or where cirrus was thin and moved over areas of cumulus. The ice cloud mask did keep the CI algorithm from trying to detect much over Oklahoma.
11 Accurately indicated no convection was initiating on dryline.
12 cloud masking was again somewhat of a problem. UW data did have problems with detecting ci along dryline all afternoon.
13 Anvils covered our domain after very quick storm initiation, so alot of the additional CI was in the ice cloud mask. It did detect the CI correctly though when it wasn't covered, it was just a short window. The overshooting top product did work well too, it was just at this point in time I was so engrossed in radar analysis, it didn't change my observation of the OT on satellite.
14 Did well with initial convection, then very poorly as expected once anvil cirrus developed. Would have liked to see it perform better when very thin cirrus is overhead.
15 Did not pay enough attention today.
16 Not enough evaluation time on the UW CI or CTC rate nowcast to determine any weakness or strengths. Familiarization of product suite was primary focus.
17 Ability to let one know cells that one need to pay attention to in the very near short term.
18 Did have a lower FAR than U AL Huntsville CI product.
19 It is conservative, but in general it seems to have a low FAR and good POD. HOwever, it is challenged in this rapidly developing storm environment. This application definitely has potential particularly with very high res satellite data. The UAH CI in contrast had a very high POD but also very high FAR.
20 Did a good job overall, no complaints.
21 Didn't provide too much lead time with explosive CI early on. Did better later on.
22 Explosive rate of convective development limited potential for extensive lead time for this product. Ran into some CI detections along differential boundaries on dryline south of I40. Also there appeared to be a false detection along the northern end of a dust blown debris behind dryline and capped cumulus elements along and behind the dryline convection.
23 The algorithm wasn't consistent; in some areas it did very well with predicting initiation while in others it didn't predict anything at all and then storms developed.
24 Overall performance was of little utility.
25 Very little CTC to evaluate its positive value for forecast/warning forecast operations in this particular event.
26 Too early to tell yet at least concerning the 35 dBZ echo.
27 I have limited experience using this product operationally. My initial impression is that the output from the CI products often lags operator-identified convective initiation as interpreted from radar data. However, this may be a reflection of the type of convective environment that was in place (strongly unstable, generally uncapped/unsheared environment- suggesting "explosive" development).
28 The CI was very conservative in identifying potential convective elements (maybe had only a couple all day)... and this turned out to be a positive factor given the lack of convection. It did well with the 'null' case.
29 CTC rate (accum) product was only product that was non-null during this convectively limited event
30 The CI product had a 0 FAR, but a relatively low POD (probably around 0.50). Although I call this a weakenss, it does provide some value, as it indicates that "triggering" of the CI product essentially guarantees convective development.
31 Predictions proved reliable with few false alarms.
32 Very useful tool, although a slight cool bias was noted.
33 Once again, the CI FAR was very low. The algorithm appears to be properly discriminating in identifying the most significant updrafts. Again, the CI "triggered" for the most signficant storm very shortly before 50 dBz developed in radar data. This was probably a consequence of the environment.
34 Did identify some areas that eventually convected.
35 UW CTC accum product was useful for highlighting the initial convective cell
36 With convection already ongoing... don't remember there being that many identifications.
37 Tended to be cold as it missed a couple of storms, but when it did nowcast development confidence was high that one would develop.
Based on your cumulative experience, how would you envision using a satellite-based convection initiation nowcast product (note: includes both UWCI and UAH SatCast) within day-to-day operations?
1 It seems overall it would improve
some situational awareness to some degree. I believe these will be
the most useful at night and in weakly sheared environments where
multiple growing/decaying towers exist and these parameters (cooling
tops) would give a better conceptual model of what is evolving.
2 Satellite-based CI nowcast products might provide a good "reality check" and improved SA.
3 I would use such a product to try to hone in on those cells that are more important to track.
4 With the case today, I struggle to see the usefulness of the CI products in the day-to-day opperations, mainly because the FAR looks to be VERY high. Again, I'm anxious to see if there is more usefulness in a day that is more cut and dry...but at that point does it still have more usefulness than the satelite data itself does? I'm not sure. I do think it is a great concept though, it would be nice to utilize for summer air-mass thunderstorms to help identify which cumulus cloud will spark a storm.
5 I would keep it running in the background, overlaid on a visible satellite loop.
6 I forsee using CI nowcast products in day to day operations as a situational awareness tool. Or possibly in an environment where isolated cells are common in weak flow/summer environments.
7 As a situational awarness product to help identify locations where convection may first initiate
8 Using it as a temporal tool, seeing with time areas of enhanced cu fields, and looking for trends or regions to hone in on.
9 Weakly sheared environments and initial CI with focusing on a spatial and temporal scale, but not a yes-no decision.
10 Useful for gaining/maintaining SA.
11 As a situational awareness tool to watch for developing convection.
12 I probably would only use it on days that are relatively clear prior to CI. However, the example today increased my confidence in the algorithm in those situations.
13 I would envision using the CI data as a situational awareness data set. Especially on the first initiations of the day. Where is the area to watch. This could be especially useful in an environment when there is a lot of cu developing, but it is not certain where the first storm will develop. Taking the individual cells out of the mix and looking at it as a group of objects, and then assessing what is the trend in the data. Is this area having more red hits than another. If so this is an area that is a place I want to watch, despite whether each cell that is tracked is red or blue or what. Looking at the trends of the region. I see this being very useful in the day-to-day operations.
14 Oftentimes in the Northeast, I find that I can anticipate areas of CI as weall as the automated products by watching cloud buildups on vis satellite imagery. Would use the CI product to maintain SA if radar is already active. However, I think the nearcasting model could prove very useful when storms are developing under a cirrus shield, but did not use it in today's training.
15 Situational awareness of expected convective development. Issuance of NOWcasts and Mesoscale AFDs indicating the CAP is weakening or has been eroded, and then compare with short term models to see how well they are initializing or simulating the event.
16 This could be used for operational staffing "spin-up" prior to warning operations. Could also be used in short-term forecast discussions and graphicasts to indicate most likely areas for convective initiation.
17 Would be great to use when preparing/monitoring for initiation and help with timing of warning operations.
18 I think would really need to be situation nearly cloud-free to begin with and fairly strongly forced (by frontal boundaries or terrain). Need to evaluate more.
19 Would probably use it earlier in the day before initial storms have developed, and not so much in areas stabilized by earlier convection and/or where large scale lift is not as focused.
20 I think it is great leading up to convective initiation, or when storms are more isolated, like in a previous DRT simulation. You can then issue NOWs for the onset of storms in your CWA. I am eager to pay more attention tomorrow when storms have not already begun.
21 I believe the UAH product can be used in an operational environment to help draw attention to areas to watch for storm development. But the product flags once and then doesn't flag that area again...which makes it too noisy. A probalistic forecast would likely enhance the use of this product.
22 As a SA tool to focus my attention. It gets noisy in active storm situations.
23 Would use it in the future for anticipating initial development of convection. Not sure how well it would perform in subsequent rounds of convection where atmosphere may have already been overturned by earlier convection.
24 When anticipating convection, it is a good tool to use when organizing and planning convective operations.
25 Still not sure yet, since do far this week has had mixed success and plenty of false triggers. Certianly don;t think I would use it on it's onw, and really need to overaly with satellige imagery (VIS mainly).
26 monitoring ci can help with situational awareness and used for highlighting possible development in nowcasts and graphicasts.
27 I will admit I like CI products when nothing is going on yet, and would be useful at drawing our attention to slower developing convective development. As soon as storms begin to fire, I found myself quickly switching to radar analysis, MRMS and 3dvar monitioring. Satellite CI products combined with ensemble CI products would be useful.
28 Not sure how much in it's current state it would help identify specific locations on impending CI that one would not already notice with higih res VIS imagery, but would like more time to evaluate in more widespread airmass convection and with terrain.
29 Its performance is uneven...some days does very well and others not. Would still use it before initial CI as a situational awareness safety net.
30 Could use it to determine when to bring up the Skywarn network, when to shift operations to a "severe mode", and as an SA tool during an event to anticipate where new convection will form.
31 I would immediately utilize the CI Nowcast product to make decisions on 1) prioritizing short-term convective focus for radar/warning operations, 2) issuance/updating of mesoscale discussions, and 3) updates to short term public products for different sectors of the public (fire weather, aviation, hydrology, etc).
32 N/A - like more time into the week before providing this feedback.
33 Pre-convective environment.
34 I would use it when/if it becomes available.
35 visualisation overlaid to sat is useful
36 Helping one focus on main areas that need immediate attention. It certainly helped us today stay ahead of the development.
37 I would use it as an SA tool before CI and during the event. I could see these products being used by the mesoanalyst.
38 Perhaps an algorithm that trips an alarm at a warning forecaster's workstation when CI is first detected in/near a CWA...it's time to begin warning operations mode!
39 Even in explosive convective environments, there is still is a least a short lead time and the nowcasts can provide focus for the forecasters to identify potential storms for further interrogation.
40 I would use it before storm initiation to help in situational awareness for where storms may or may not develop. It would also help out in early prediction of where to focus
41 Reserve it's use to relatively "clean atmosphere" events without much cumulus/stratocumulus or anvil clouds around.
42 I envision a product like this increasing in utility when very high resolution (both in space and time) satellite data is made available to WFOs. The main utility would be in helping with the very short term forecasts by helping forecasters focus on areas mostly to be of immediate concern.
43 Would use it for short term forecast (1-2 hour) convective initiation forecasts and nowcasts.
44 (with limited experience with these products)...would expect increased forecast confidence with regard to locations of convective initiation
45 Perhaps to help get a timing on the initiation of convection... especially when have a pretty good cap.
46 I think it could be a valuable now/near-casting tool in certain environments, especially those in which the atmosphere is capped and there is uncertainty as to whether CIN can be removed/ overcome.
47 For short-term public forecasts, aviation forecasts at TAF sites and at cornerposts for arrivals into DFW. Also for transitioning into warning operations.
48 Having experienced a null case event... would lean towards the Cimms due to a smaller 'false alarm' rate... but curious to see how each performs in a more active situation. In operations, would likely monitor output until storms got going.
49 I envision using a combination of these products to assist temporal and spatial forecasts of CI.
50 See response in 23.
51 I would use the satellite-based CI tools in concert with numerical model output to refine timing in aviation, public, and fire weather forecasts.
52 For updates to public and aviation forecasts, tactical decisions for airport ground operations, and for WFO decisions on transitioning into warning operations.
53 The UAH-CI is too liberal, the UW-CI a little too conservative in identifying CI. Being aware of these limitations, using the two in conjunction can be useful to convective analysis and forecasting.
54 Useful monitoring tool prior to convection... and even after radar operations begin... provided there is someone available to look at it.
55 would use this...together with other satelltie CI products
56 expect I would use all available CI products...in the context of their individual strengths/weaknesses
57 monitoring cu fields to determine which clumps may be more significant. With its relatively low false alarm rate... expect several of the hits to verify.
58 Sat-based nowcasts have a definite role in assisting forecasters in anticipating development. I suspected this prior to coming to EWP, but I leave convinced of this fact.
Comments on UWCI from the HWT blog: (http://goesrhwt.blogspot.com/2011/06/ewp-end-of-week-debrief-10-june.html)
- (Thursday event - N.E.) Cloud-top cooling products seemed to work in diagnosing the strength of storms on the southwest edge of the line that were newly developing.
- Even though CI didn't always occur... false hits were useful in identifying clouds trying to break the cap.
- Forecasters not interested in seeing a binary yes/no output.
- "There were instances where similar looking clumps of Cu that one would flag for CI but the other wouldn't... so I wasn't sure how to interpret that other than maybe this area was more conducive to further development."
- There are lots of products that provide you lead time on CI, the real question would be on the consistency of the output.
- "I would definitely look at this in my WFO... especially the cooling-tops product gave me a lot of information on the relative strengths of the storms."
- "If both groups could work together and come up with a probabilistic product that combined the strengths of the UAH and the UWCI products, that would be very useful."
- "I think from a purely public forecast perspective, especially this time of year where we get convection every day, it would help you identify when exactly CI will occur."
- Would be very valuable for nocturnal CI.
Comments on UWCI from HWT Blog: (http://goesrhwt.blogspot.com/2011/06/daily-debrief-9-june.html)
- UWCI triggered CI occurring right as the appearance of a 50 dBZ echo on radar... it was so unstable that it didn't really have much of a chance.
- "I liked the cooling cloud tops product... gave you some awareness of what storms you should pay attention to during warning ops and which ones were strongest."
- "I found it useful this week and look forward to that era when we can get those increased temporal refresh rates. This would be very useful."
- In a more dynamic situation this could be very useful.
We asked the forecasters if they had a preference to see more or less signal (more vs less FAR)...
- "I like looking at them both side by side... you can come up with a poor man's ensemble for CI because we know the limitations of both."
- "There may actually be a benefit of some false hits because it may be telling you that the cap is strong... it can give you a sense of what's going to happen in the short-term."
Comments on UWCI from HWT blog: (http://goesrhwt.blogspot.com/2011/05/end-of-week-debrief-27-may.html)
- (26 May event) CI did not so well over AL/TN... high FAR, low POD in morning... Forecaster theorized this may have something to do with the less dramatic temperature differences between the surface and clouds during the morning hours.
- CI did much better during rapid scan.
- The UAH version was much more agressive that the UW version.
- Having a probabilistic approach versus a yes/no would help.
- Forecaster used the UW CTC/CI product to issue a severe weather statement... ended up putting a warning on it afterwards.
- This could be important for not just severe weather... the CI products could be very useful for the onset of lightning as sort of a proxy for the growth of a certain dBZ threshold above say a -10 C level if it had faster updates.
- "I'm assuming that performance should improve pretty dramatically once you get the rapid updates with the next-generation satellites, but now I guess it would work best in a clean environment in the plains. I could also see the probabilities a good way to go."
- Maybe contouring SATCAST probabilities would be a good.
- "Based on what it's designed to do, I can see this working in a typical summer afternoon in Florida, not just over the plains."
- Could help identify waterspout candidates because they're harder to see on radar.
- For non-severe faster moving systems it may be useful in detecting regions of heavy rain.
- Would be a good idea to get west coast offices to look at these things since they rely heavily on satellite data because of a lack of surface observations.
More comments from HWT Blog: (http://goesrhwt.blogspot.com/2011/05/ewp-forecaster-debrief-26-may.html)
- We were seeing 10-15 minute lead times from the UAH CI product along the dryline prior to any echoes above 35 dBZ on radar. The UWCI was much more conservative and missed a few instances of CI, but it had less false alarms and similar lead times when it did trigger for CI.
- UAH CI did show some signals after initiation behind the dryline, but nothing really continued to grow. However, forecaster mentioned how this would be very useful in warning operations to help increase situational awareness for future development when you may be focusing primarily on the first storms.
- Forecaster mentioned how he was watching the UAH CI this morning over the SE and it was giving negative lead times and UWCI was not flagging anything at all. However, he did want to emphasize that on Tuesday GOES-E was in rapid-scan operations and was not this morning, so that could be why the lead times were so poor.
More from HWT: (http://goesrhwt.blogspot.com/2011/05/convective-initiation-along-sw-ok.html)
Forecaster comments reposted from
Convective inititation occured along the southwest OK dryline. According to UAHCI and CIMMS CI products, had about 10-15 minute lead time for storm near Altus. 30 minute lead time from UAHCI and 20 mintue lead time from CIMMS CI for storm near Sayer.
Horizontal convective rolls east of sw OK dryline suggest storms may form in the warm sector too…maybe!
Pablo, Rudoph, and Bobby
- The CIMSS product had pretty good lead time before we actually started seeing lightning of about 45 minutes to 1 hour, only about 15 minute lead time over 35 dBZ echo.
- Later in the events everything became cloud masked.
- Mostly masked with the CIMSS stuff, but UAH was not and we were expecting CI behind the initial line, but nothing went and there were no CI nowcasts made, so that was very good that we weren't getting false alarms.
- There were times when they would have 30 minute lead-times on radar echos, and other times there were no lead-times during the same event.
- I would like to spend some time looking at those products in more my type of environments, like weak shear.
- A probabilistic approach might be more useful than a simple yes/no output. I like the idea of having pre-CI through CI ongoing information.
- "I tended to look at the UAH one more because it was giving me more detections."
- "I found having the masking overlaid was very important... there were times where the CIMSS wasn't showing something but the UAH was and it helped me get an idea of why."
Forecaster comments reposted from
"2330Z Update: UAH CI indicating possible development across Garvin and McClain counties. There does appear to be an HCR in this location but we believe that the edge of thin cirrus clouds are causing algorithm to detect cloud cooling that is not real. Looks like we are going to move operational area to eastern Colorado where there is a lone supercell. kbrown
2230Z Update: Got a hit off of the UAH CI over southern Comanche county where there are weak echoes aloft (15-20dbz). These echoes are associated with a wildfire plume, however.
2140Z: Brief UAH CI detected across north-central Oklahoma in cloud streets (1832Z), but no subsequent echoes were detected.
Although there has been several hours of cu/tcu formation near and east of dryline, CI algorithms have not detected CI across OUN domain. From 20Z to 2115Z this is actually a good thing since no echoes have developed (good case of low false alarm). Before the CIMSS CI became contaminated with Ice Cloud Mask, there were a few hits for CI on leading edge of incoming cirrus across northwest Oklahoma between 19Z to 20Z. No echoes were subsequently detected.
Isolated CI hits from the UAH algorithm did accurately depict some elevated echoes over the OK/AR border but no lightning occurred. Leadtime for echoes was 15 to 30 minutes."
As we have seen over the past couple
years during the Spring Experiment, the bane of the satellite
community's existence has struck again. It's 2100 UTC and that means
we have another 30 minute gap in satellite data right during
initiation period... so any updates in the imagery and the CI
products will have to wait until after 2115 UTC, and our last image
was at 2045 UTC. During that period the cirrus is likely to move over
the area, inhibiting any of the CI products from detecting the clouds
underneath... We will continue to monitor the area, however it seems
like we may have just missed our target.
However, there is a silver lining to this event. Forecasters have been watching the CI products constantly over the past couple hours and have noticed no false alarms over the area of developing cu field for either of the CI products. There were a few false alarms with the cirrus overrunning the surface causing false cooling with the UWCI, as well as a couple false alarms with some of the stratus area in eastern CO with the SATCAST (UAH CI) product. The forecasters mentioned that the fact that these CI products were showing no signals over the cu field of interest provided them with increased confidence that CI was NOT occurring. Increased confidence is a good thing, whether it leads to exciting weather or not.
Widespread cumulus fields forming across central eastern VA and UAHCI products capturing this much better than CIMSS in this case, which is a very moist, weakly unstable, but uncapped environment (almost tropical). While most new CI IDs are very scattered to isold in nature, now beginning to see some banding or clustering, which actually matches very well with at least one 4km WRF (12Z run for SPC…see second image above), and will be watching to see if the IDing of this banding of CI zones within otherwise wideapread cu field helps to identify where stronger storms could soon be forming in this kind of environment.
UWCI / OTTC
- Was not coming in correctly all week, so was not demonstrated within AWIPS.
- Forecasters were not comfortable offering further comments based solely on informal demonstrations with visiting PI since they were not able to use the products within AWIPS.
I asked about the lead times from the surveys... 15-30 mins the general consensus?
"Hard to be sure because we were arriving at the HWT after convection was developing."
"Getting in there around noon would get more accurate results."
"The case event was already initiated when I got there."
"Struggling giving up screen space during severe weather" (from survey)... is there a display you think would help?
"Having an additional head would help. We were only provided with two screens so it changed our strategy."
"Would be useful for the mesoanalyst position at the WFO."
"4-panel devoted to those products works well."
I asked the forecasters if they were ok with more signals if that meant giving up some FAR...
"I would like earlier signals, like a probability signal... which part of my CWA is going to have the best chance... Some kind of signal before there's aggitated clouds would be helpful."
I asked the forecasters whether they preferred the CI or the cloud-top cooling...
"I used them both... kind of liked them both simultaneously."
"It was hard because it seemed it was 50/50 on detecting things so I lost a lot of confidence in using the product, but I did like the cloud-top cooling a little better because it seemed to do better."
I asked the forecasters if they preferred the accumulated of instantaneous fields...
"I stuck with the instantaneous for the most part, I don't think I even looked at the accumulated to be honest."
"I tended to look at the instantaneous."
Would you see a benefit in having a cloud-top cooling track?
"Yes... an overshooting top track would be very useful as well."
We noticed an area of obvious convective development that was not detected by the UWCI product on the WV/VA border at 1915 UTC and the forecaster asked me to explain why no CI nowcast was made. Looking at the IR, you could see significant cooling occurring from 1832 and 1915 UTC (see above), but still no signals were seen. Jordan Gerth and I looked at the cloud typing output to see if we could draw any conclusions from that to determine what was going on (see below). Most of the area was covered by cloud types identified as 'water' or 'mixed phase'. However, there were a few spots of 'cirrus' classification over WV nearby where the CI nowcast should have been made. It seemed on visible and IR satellite that this may not have been the case, but this is hard to determine for sure. Jordan suggested that because there were these spots nearby that they may have been contaminating the spatial tests required by the algorithm to flag an area as filtered cloud-top cooling, and thus not allow for a CI nowcast to be made. This may be a fluke case where nothing can be done, but it may be useful to examine this in more detail to see if something can be improved.
More : (http://goesrhwt.blogspot.com/2010/06/ewp-weekly-debrief.html)
This week was plagued by cirrus... can't remove it so we need to communicate well the limitations of the product. Forecasters were mentioning that they were constantly referring to the cloud type web page and suggested providing this into AWIPS. Will severely limit the applicability.
"If it's a good day to use it, the forecasters will use it... Most useful prior to development... right now things have to start developing before we issue products, this gives us some additional lead time."
Forecasters mentioned that the product would be useful in nighttime operations... possibly get more lead time... At night, stuff fires so quickly... perhaps providing a CI alarm in AWIPS would help situational awareness. Forecasters suggested providing a nighttime WES case for training. Lee is going to distribute web site and explain how to use it so they can look at it anytime.
Expressed interest in CI accumulated to follow CI signals through time in case they missed a scan.
Limitations in sensor scan time noted.
Forecasters mentioned the interest in providing more signals. they saw a lot of cases where CI was obvious but was not captured by the product. I asked if they were ok with the idea to sacrifice FAR for more detections...
"More times I expected to see something and didn't happened more often than not... not useful if things aren't showing where I expected to see it."
"Could you build different thresholds? Could you build one that was not so strict?"
"What about probabilistic detection? Then you can set your own threshold."
"Concerned about FAR getting too high because then it'll stop getting used."
There was a request for using additional bands... "You guys know the best bands to use... If you can get more information from other bands, go for it"
I asked if they saw the UWCI product being a precursor to lightning...
"Did not specifically check."
"I was more correlating the 35-40 dBZ"
During an event with a strong cap, the UWCI/CTC showed signals but no development occurred (or continued to occur)... perhaps provide a case of this in training.
From yesterday's IOP over Boulder, CO area... cell showed CI at 22:30 UTC... at 22:58 UTC a 30-40 dBZ occurred... showing 28 min lead time. Similar results were seen throughout the week.
A forecaster asked is testing on simulated satellite imagery planned? Yes, but currently the computation time is expensive so 5 min data would be rough.
Forecaster requested that it would be nice if the UWCI automatically loaded with satellite imagery in AWIPS.
UWCI and Cloud-top Cooling
- Forecasters wondering how well it will work in the Northeast... so often cirrus is in the area... Saw very few signals for yesterdays case.
- A little ahead of total lightning with yesterday's case... not like case event when it occurred at same time
- Cloud-top cooling more valuable for situational awareness than CI
- "Wonder if this type of product would be useful in something like guardian or alert type software, because not all people will be looking at it all the time."
- "Would be neat to look at if it saved all the locations where CI was occurring... would like to have the 60-min accumulated.. make it more like the hail tracks" (mentioned this was available)
- "I was watching a storm over Amarillo with 60+ dBZ after CI and there was no CG... I was waiting for lightning to happen because that's what we were told the research used to verify it... You can't use CG as a discriminator... you need total lightning."
UWCI and CTC
CI vs CTC... bias towards one?... Liked CTC better... picked up about 15 minutes before radar and better discriminated areas of interest... showed more signal than CI.
Are you ok with more false alarms?... "As long as forecasters are trained, false alarms are not a problem. Even with CI itself... make it less stringent. I can tell if cirrus is over top of it. I know why you're doing it, but maybe you don't have to go as far."
"Is the anyway to have the CI continue to track a vertically developing cloud to see if the development continues?" (This is under development within WDSSII)
Forecaster mentioned that he used the UW-CIMSS CI phone application this morning... He had good impressions and would like to see that sort of display in AWIPS (similar to the "OVERALL" discussion)
REGARDING UWCI AND CTC
- In marginal cases when we're not sure whether storms will go it may be more useful
- Nighttime when no visible is around it is definitely more useful
- In winter nighttime snow events, low top convection close to radar not detected... cooling tops earlier might give clue of snow showers occurring... also upslope snow showers, where mountains inhibit radar reflectivities would be a good thing to see
- Didn't have enough time with the products to determine if CI or CTC more useful
- Was slower than radar constantly
- They realize that the products are meant for better temporal and spatial resolutions, but hard to see it's use when not available
- Just because cloud top is cooling, it may not be the dominant storm... may not be n the favorable location or on right side of boundary... using any algorithm without paying any attention to the environment is not proper use of the data in forecasting operations... need to combine and/or base the products on environmental information
- The cases this week were slam dunk, so CI was pretty sure to happen... not so useful then
- During May 19 case over OUN... initially watched for CI on southern storms... once one went, they monitored radar... may be useful in detecting first storm of the day
- "Not a lot of meteorologists are gonna have confidence on just one case... need to see more than that"
In the case of multiple towers with equal weak reflectivities on radar, would CI detection over one and not the other add value to your forecast?
"It's plausible. If that's the way it play out. It would be hard to objective analyze that all the time."
"It does have utility in determining which storm will be the dominant storm."
"Depends on the environment."
When visible satellite is not available, is it (CI detections) even more useful? (this was simulated in yesterday's IOP for one forecaster)
"Yes, absolutely" (also agreed by the other forecasters in theory)
Feedback that is embedded within the report:
Hazardous Weather Testbed – Final Evaluation
In general, forecasters found that the UWCI products are a useful tool to help them increase situational awareness prior to warning operations during severe weather days. One particular comment from the online survey echoed the UWCI potential:
“Areal descriptions of convective initiation described by UWCI could be added to short term forecasts, or even significant weather advisories/warnings if quick development is expected.”
Forecasters also noticed lead-times on their subjective interpretation of convective initiation based on signals from radar generally of about 5 to 30 minutes. There were occasions where the UWCI had negative lead-times, but this was usually due to cirrus contamination, satellite scan time limitations or varied definitions of “convective initiation” by the forecasters. When comparing UWCI to the first occurrence of CG lightning detected by the NLDN, forecasters found that UWCI lead times extended, often to 60 minutes. However, there were occasions where convection would develop and radar reflectivities would reach in excess of 55 dBZ, but no CG lightning would be detected, so determining a lead time was difficult and forecasters became confused on how they were supposed to evaluate the product. . . . .
There were several instances where UWCI showed no signals where convective development occurred, or showed signals where no convective development occurred over cirrus-free areas. One comment captured from the online survey may help explain the situations where this occurred most often:
“In this situation, there was a fairly strong CAP. Because of that, there were several instances when the UWCI product indicated CI, yet no storm developed. Or, perhaps a small storm would develop but it would quickly dissipate due to the CAP. There were also several times in which the UWCI product did not indicate CI, yet it did develop. This appeared to be in areas that were not covered by cirrus.”
Forecasters mentioned that “it was also nice to see the actual values of cloud top cooling” since it provides them with a more physical interpretation of what is going on with the developing convection. Also, forecasters mentioned that the cooling rate product provided more signal than the more stringent convective initiation nowcast, which, as mentioned above, missed some instances of initiation due to various reasons. The forecasters requested that a cloud-top cooling rate track be provided. Similar to those produced by NSSL within the Warning Decision Support System – Integrated Information (WDSS-II) to produce rotation and hail tracks, cooling rate tracks would be very useful in determining cloud-top trends. This would allow forecasters to determine whether the convective storm growth is weakening, strengthening or remaining constant over 30 to 60 minute periods.