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
this writing.
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.
7 Near/downwind
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)
16 gradients
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
CIN.
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.
7
No
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).
20 no
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.
3 n/a
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.
2 N/A
3
n/a
4 In this particular case, the Nearcast picked up well on
convection from central TX into southern KS.
5 n/a
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.
2 N/A
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.
5 n/a
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.
15 n/a
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.
19 n/a
20 none.
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.
2
n/a
3 n/a
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)
Nearcast
- (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)
Nearcast
- 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)
Nearcast
- (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.
http://goesrhwt.blogspot.com/2011/05/nearcast-in-warning-operations.html
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.
More: (http://goesrhwt.blogspot.com/2011/05/ewp-end-of-week-debrief-20-may.html)
Nearcast
- 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.
More: (http://goesrhwt.blogspot.com/2011/05/friday-13-may-debrief-finally.html)
NEARCAST
- 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.