During Friday's breakout sessions, participants were able to give feedback from their perspective on the TCF forecast creation process, the use of the UK-Met model to predict clearing times at SFO, and using the national grids of clouds and visibility at the GFE desk to give a first-guess for the digital aviation forecast.
UK-MET / SFO
The SFO desk had the addition of the 1.5km UK met model this week, which is what the 330m model is nested from. This week also presented very unique synoptic set-ups over the different days, with both pre and post trough situations. It was noted that post-trough SW flow can occasionally lead to convective strato-cumulus formation, but also help to dry out the cloud. On Wednesday, the 330m high-res model picked up on initiation of convective cumulus off the peninsula, which no other model did. On Thursday, the 1.5km model actually did a better job than the 330m model. Further evaluation of the general weather picture would be useful in this case to understand why.
Clouds and Visibility / GFE
Once again the overwhelming feedback from the GFE C&V grids this week was about the detail and speckle nature of the high resolution model grids. While detail is good, too much can be overwhelming on a national level. The challenge going forward seems to be finding balance between when to leave detail in, when to smooth out, and which level will do what. An idea was brought up in the final discussion about using image processing methods in the CloudBasePrimary grid to identify areas first, then build up a consistent cloud base from there. This would allow the details to be smoothed more intelligently.
|In this post-OPG processed cloud base primary grid, you can really see where the local WFOs smoothed out the entire area to what they determined to be a reasonable cloud base, in response to the speckle nature of the grid they were handed|
Another point that came up again was the need to have some means of filling in the CloudBaseSecondary grid with a first guess or starting point. This could be using a tool based on LCL or probability of thunder, or even building in a first guess from model data in a similar fashion to how CloudBasePrimary is initialized. The other repeating feedback to come up was the look of the AWC-model created SKY grids. They appear too binary, and difficult to pass onto a local level. Where the national blend seems to look more realistic like a satellite image. The question is, how realistic is this far out into the forecast time?
As far as the actual editing procedure of the girds and workload, it was noted that much more coordination would need to take place with the local WFOs. This would be most useful in areas deemed high-impact for aviation that day. While the local offices may already be busy collaborating with other offices and national centers if it is a significant weather event, hopefully handing them a better first-guess grid due to collaboration, would lead to less work editing on their end.
It seemed the feedback this week once again pointed to the workload involved with creating an extended forecast in addition to the 4, 6, & 8, especially during the summer months. One suggestion to help in this effort would be to focus on just the high impact areas for the extended TCF, and maybe keep the automated polygons in the rest of the CONUS area. Some participant feedback suggested better tool development, to create a smoother auto-generation of the TCF areas that would improve the jagged polygons.