2017 Summer Experiment Week 2 Wrap-Up

The 2017 AWT Summer Experiment came to a close on Friday with the weekly wrap-up sessions for each of the desks.  One of the benefits of running the experiment over a two week period, is having a different set of participants each week with various backgrounds and experience.  This allows for new perspectives and valuable feedback from week two that may not have come up during week one.

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.


TCF
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.

A look at the Summer Experiment...through the lens

A look at some happenings in and around the testbed during the 2017 Summer Experiment!

Participants looking on during the daily debrief of the TCF desks

A group at the UK-Met/SFO desk checking out the different high-resolution models

Andrew Clausen from Southwest Airlines giving his brown bag seminar about the life of a flight dispatcher

Some discussion taking place at the TCF collaboration desk in the testbed

Discussion with the OPG crew over at the C&V desk before the AWT team sends over their forecast grids for the 18Z TAF package

Collaboration with the AWDE team via google chat at the C&V desk

Participants in the Operations Proving Ground next door played the role of the local WFO, editing the  national C&V grids sent over from AWT.

The TCF operations desk was held just off the AWC operations floor, to simulate the real-life separation between operations and collaboration.

Claire Bartholomew visiting from the UK-Met Office doing the daily debrief of the SFO-desk

Participants discussing the developing weather for the day impacting the forecast for the C&V grids

Participants look on at the SFO desk, discussing possible clearing times based on model guidance

Lots of great discussion about the national C&V grids took place at the GFE desk throughout the experiment

Because long days of forecasting and collaboration sometimes call for beers and fun...some of the experiment crew test their skills at trivia night at a local brewery

PERTI participates

Guests that participated in AWDE this week included National Operations Managers (NOMs) from the Air Traffic Control System Command Center (ATCSCC). These participants are part of the PERTI team, whose focus is on working to become more strategic and predictive in the planning and execution of daily traffic management while accounting for disruptive events.  This is done by analyzing traffic and constraints from the past building upon a data driven analysis to make the NAS safer and more efficient. Each letter represents one of the five key points of the concept – Plan, Execute, Review, Train and Improve.

From the NOM perspective, the group was interested in seeing as much information as possible while viewing the extended TCF. This includes low and high confidence polygons and echo tops for more efficient decision making to determine impacts to the NAS. One takeaway from the differences between this week and last week's feedback is that the needs for the extended TCF product is really dependent on the type of user utilizing it.  Users at the ATCSCC are using the information at a national level and are tasked with making decisions and implementing strategies that require more in-depth information than only knowing the high confidence convective areas.  The low confidence convective areas allow them to see potential areas of concern that may develop in the extended forecast.  In addition, larger polygons with a high confidence may cause more collaboration between the NAMs and local CWSUs to verify the weather and determine the traffic impact.

Participants from the PERTI team examining the extended TCF

Additional participants included a Helicopter Pilot from the United States Coast Guard. Positive feedback was given while the user examined the experimental TAFs, HEMS flight rule, and Probabilistic C&V.  The additional forecast times, in the TAFs, were helpful, even if there were no major changes in ceiling or visibility, because users were able to see possible trends in the weather.  The update rate of 15 minutes is adequate for the HEMS tool and the RU-RTMA display was preferred.  The same feedback for both the HEMS flight rule and Probabilistic C&V consisted of wanting to see C&V separate, needing a zoom capability, and options to display altitudes.

User giving feedback on the experimental TAFs

UKMET high-res model peforms well for SFO on Day 3

Unlike much of this week, day 3 at the SFO desk was a more typical fog and low stratus day around the terminal. Interestingly, not all of the models picked up on that 'normal' behavior. Below is a four panel capturing the various model solutions in the morning:

20170816 1300 UTC run of HRRR (top left) and GLAMP (top right) Ceiling Height grid at the 1-hour forecast, the 00 UTC run of the high res UKMET model (bottom left) Sky Cover grid, the 14-hour forecast, and GOES-16 visible satellite imagery at 1402 UTC.

Neither the HRRR or the GLAMP added much value to yesterday's forecast for clearing. Skies were already beginning to clear to the Southeast of SFO as shown on the satellite imagery, but the GLAMP still indicated fog at that time. The HRRR did have some clearing but didn't provide a particularly accurate picture of the cloud features themselves. For this reason, most of the focus was on the UKMET model, which ended up doing exceptionally well for the day.

The first positive point to its scorecard was in the way it seemed to pick up on the local orographic effects of the stratus layer.

20170816 00 UTC UKMET run, the 15-hour forecast of Sky Cover (right) and GOES-16 visible satellite imagery at 1502 UTC (left)

During a normal fog setup around SFO, the marine layer will funnel in through the San Francisco Bay and spread out through the Bay area. Additionally, it will advance onshore along the coast, but generally stops on the windward (west) side of the terrain. This was the setup yesterday, and the UKMET did an excellent job of capturing this terrain affect as seen in the image above.

Later in the afternoon, around 1800 UTC, cumulus clouds began developing over the SFO area and revealed a second positive point for the UKMET model. Below is the UKMET Sky Cover forecast and visible satellite imagery.

20170816 00 UTC UKMET run, the 18-hour forecast of Sky Cover (left) and GOES-16 visible satellite imagery at 1802 UTC (right)

Thanks to its higher resolution, the UKMET model actually was actually indicating that local cumulus development. Aside from picking up on such small scale detail and cloud features, the UKMET utilized for the experiment is the 00 UTC run. At this particular time, it was an 18-hour forecast picking up on the cumulus development.

All in all, a very good day for the UKMET model!

Looking at C&V in the East on Day 2

The C&V desk turned their attention east for ceiling and visibility forecasting yesterday. The initial national blend looked like this:

Immediately obvious was the broad area of IFR and even LIFR conditions. Based on the observed ceilings at the time, this was clearly over done. The RAP seemed to have a better handle, eliminating a lot of those low ceilings. Those working on the national scale opted to go with the RAP, assuming that it would be a lot easier for the local WFOs to more accurately add areas of C&V back in at their level, rather than send them a grid with a mess of widespread IFR and LIFR (accuracy debatable) that would require a large amount of editing and adjusting.

20170815 1400 UTC National Blend (left) and RAP (right) ceiling and visibility forecast, 6-hour (20 UTC) forecast

With a decent model basis to begin with, participants moved on to editing the grids. As with previous days, the discussion of the national vs. local perspective arose. Those working on the national scale noted how challenging it was to load shed and edit the grids where there are aircraft concerns. On this particular day, there was a lot going on in the Northeast, which drew the attention there and away from other areas like Atlanta. So, a lot of time was spent on the grids sent to WFOs in the Northeast, making the workload at their local level fairly light; whereas, the lack of attention south resulted in more of a messy grid that required a lot more editing and smoothing.

There was also more discussion on more versus less detail in the cloud grids. Below is the National Blend Sky Cover grid.

National Blend Sky Cover grid from 1800 UTC on August 15th

Pretty picture? Yes. Realistic? Certainly. For the most part it looks very much like a clouds would. Is this useful? It depends on who you ask and what you're forecasting. While the detail is realistic, the point was brought up again that it is perhaps too much detail for the purposes of the TAFs. Users want to see the overall trend in the TAF and not the minor ups and downs in the gridded details.

In this case, one of the mock local offices was Philly, and participants at that local level, smoothed out the Sky Cover grid in that area for better TAF generation.

National Blend Sky Cover forecast zoomed in over Philly, the mock WFO forecasting at the local level

The difference between the initial grid and the grid edited at the local scale is very clear. Again, much of the local grid area over Philly was smoothed with the goal of better TAF generation. From this the question arose, where is the balance? Would users prefer the higher detail and resolution in the overall grids? Or should they be smoothed for better TAF performance? Is there a happy medium? These are all difficult questions that have not been answered, or may not even have a good answer yet. However, feedback from the Summer Experiment and continued debated will be crucial as the Digital Aviation Services (DAS) effort evolves and continues.

Another challenging day in SFO for Day 2

This week has certainly been interesting for the participants at the SFO desk and yesterday was no exception. Ceilings had never really cleared the previous day and SFO awoke again with the airport rather socked in. HRRR was discounted almost immediately as it was noted to be far too dry compared to current satellite conditions. For this reason, it was decided that it would not be used for the day's clearing forecast.

20170815 1300 UTC HRRR run, 1400 UTC hour forecast (left) with GOES-16 high-resolution visible imagery at 1402 UTC (right). Satellite showed more cloud (i.e. moisture) than was seen in the HRRR initialization

GLAMP solutions from earlier runs hinted at clearing by 20 UTC and cleared it out completely by 21 UTC. The UKMET on the other hand had ceilings clearing by 1800 UTC. This was quite a significant difference between the two models, making it a more interesting challenge to decide which to go with.

20170815 1400 UTC UKMET (left) and GLAMP (right) runs, 20 UTC forecast hour. This was the first hour in which the GLAMP showed any clearing in the SFO arrival area

Compared with GOES-16 satellite, the UKMET appeared to have initialized better, capturing the current stratus coverage. For this reason participants were more inclined to go with an earlier clearing time than noted by the GLAMP.

20170815 0000 UTC UKMET run (right) of cloud cover, the 16, 17, and 18 hour forecasts, with GOES-16 high-resolution visible imagery (left) for verification

GOES-16 satellite showed clearing by 1700 UTC. This was fairly close to the UKMET solution, which had clearing starting at 1700 UTC and completely cleared closer to 1800 UTC. The high-resolution model also seemed more accurate in the details of the clouds themselves, showing the main stratus layer moving offshore and the small inland area of fog over Oakland burning off.

Day 2 TCF discussion: medium coverage and broad sparse areas

Though a quieter day weather-wise, the lighter load in product issuance allowed for some interesting exploration of TCF and the long-range concept. The first was a discussion about including medium coverage in the long-range. This was one of the forecasts issued for 24 hours out:



Note in particular the medium coverage area near Minneapolis Center. There has been debate as to whether the long-range forecast should only be high confidence of sparse coverage given the inherent uncertainty in the models. However, in this case the forecaster stated that despite the uncertainty in location, judging by the synoptic scale pattern and agreement in the long-range models of several rounds of convection, confidence was high for medium coverage somewhere in the area.

From a user perspective, it was noted that the uncertainty in the location doesn't so much matter. Just the fact that the forecaster was confident in medium coverage, particularly over a busy terminal like Minni, would provide value. That confidence would indicated to planners that there would be an area to deal with the next day. Additionally, it differentiates the synoptic scale type convection scenario from the typically summertime airmass convection that often occurs in the Southeast U.S.

The second discussion point was related to the airmass convection. The forecaster generated a broader area of sparse coverage over the Southeast U.S., broader than is typically done because of the uncertainty. In this case, the users looked and immediately saw the many terminals covered within these area; Atlanta, Jacksonville, Birmingham, Hunstville, etc. It was noted that seeing so many terminals affected many alarm traffic flow managers, despite that it was likely realistic given the summertime airmass convection. They suggested that maybe instead of such a broad area, a series of smaller area. This would provide value by indicating that, yes, it would be a summertime airmass convective setup, and prepare traffic flow managers and others for that scenario.

All day fog event in SFO - model solutions and satellite verification

It was an interesting day at the SFO desk to start off the second week of the Summer Experiment within the AWT. A trough moving across the West Coast made forecasting any clearing times even more of a challenge than usual, pitting the mesoscale fog climate with synoptic scale forcing.

The HRRR had ceilings clearing out by 16Z, while the GLAMP held onto them until at least 21Z. The UKMET kept ceilings around even later, through 23Z, and only suggested a partial clearing, if at all.

1400 UTC run, 2200 UTC forecast of HRRR ceiling height (top left), GLAMP ceiling height (top right), and UKMET cloud cover (bottom).

Satellite observations around the time of the 1400 UTC run, however, suggested that ceilings were not clearing quickly at all, meaning the HRRR forecast wouldn't be accurate and possibly ruling out the GLAMP forecast as well. In fact, the high spatial and temporal resolution of GOES-16 showed some of the fog actually building back in by 1600 UTC.

20170814 1437 - 1637 UTC GOES-16 high resolution imagery over SFO with winds, ceilings, and ASDI flight tracking overlaid

20170814 1437 and 1537 UTC GOES-16 visible imagery with winds, ceilings, and ASDI flight tracking overlaid. The yellow dashed line and orange arrows indicate where the layer of stratus was receding, while the green circles shows an area building back in behind.

GOES-16 imagery has been heavily relied upon during the experiment for both situational awareness and model verification, providing a 5-minute temporal refresh along with much better resolution than the legacy GOES-15. Check out GOES-15 imagery at the same time below:

20170814 1430 - 1630 UTC GOES-15 imagery with winds and ceilings overlaid

Compared to GOES-16, GOES-15 has only a 15 minute refresh. That along with the lower resolution did not reveal the detail in the stratus layer as it did in GOES-16. Additionally, participants were able to see the movement of stratus building back in much earlier than they did in GOES-15.

In the end, ceilings never really cleared out, though the UKMET high resolution model did have the closet solution to reality.

Week 1 Wrap Up

Week one of the 2017 Summer Experiment wrapped up on Friday with each desk having a breakout session to discuss takeaways from the week.  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.

UK-MET / SFO
Overall, it seemed the UK Met model did in fact add some value when trying to forecast the clearing time at SFO, particularly with how it treated the effects of the terrain to the west. The range of clearance times among the various high-resolution models analyzed was quite varied. For instance, on Thursday the 10th, the models were showing clearing times between 18-21Z for the forecast produced at 15Z.  However, the order that the models cleared the stratus was pretty consistent from day to day.  The HRRR was the earliest, then the UK-Met 330m model, then the LAMP.  Typically the 330m and LAMP forecasts were more accurate, but varied between days.

Clouds & Visibility / GFE
The feedback that seemed to come back day after day was the "speckly" nature of the high resolution grids, which use the 3-d cloud fraction, and how that needs to be addressed going forward.  From a user perspective, the detailed nature of the grids could be mistaken as more accurate, which is not necessarily the case.  Discussions as whether the smoothing should be done on the national level or the local, and exactly how much smoothing as to not loose any detail that may be desired by other end-users.  The possibility of the TAF formatter being expanded to take this into account was also brought up.  Giving the WFO forecaster the ability to define whether to average around the TAF area, or give it more of a detailed point forecast.  It was also noted that more detail is actually desired early in the TAF forecast period, and then less detail is fine for longer term TAF times.

A good example of the speckle nature of the CloudBasePrimary grids, with the local WFO edits added in.

The general consensus from the current WFO participants that use digital aviation services, is that getting a national grid as a starting point to work from would help the workload on their end, however it would take a few years before they fully trust the grids above how they currently set up the forecast.

TCF
The big question of the week was whether the extended TCF would be feasible and if so, is there added value to having a long-range forecast. From a forecaster perspective, it was noted that the additional workload of adding the extended TCF to the normal cycles was challenging. To this end, AWDE and customers suggested that it may not be necessary to generate a new long-range every cycle as traffic flow managers and planners aren't going to be looking beyond 24-hours particularly often. Instead, having an extended TCF issued along with the morning cycle and evening cycle, providing a 24 and 36-hour look ahead for the follow morning and evening as a first glance to the following day's issues. Or issuing an extended TCF at other certain specified times of day when a long-range look would be prudent. This would not only reduce the workload but also provide value to customers.

Day 3 Recap

Day 3 of the 2017 Summer Experiment wrapped up on a positive note with much insightful discussion among participants. Check out some of the feedback collected below:

SFO desk

UKMET cloud cover - 13 UTC run, 19 UTC forecast

Forecasting ceiling and visibility around SFO has long been a challenge for aviation. Creating C&V model fields to try and predict the progression and cessation of fog and low stratus is even more difficult. However, several of the models being used at the SFO desk yesterday actually did fairly well.

Early model runs from the HRRR suggested a clearing time of 1800 UTC, while the high-res UKMET suggested a little later at 1900 UTC (right). Again, the UKMET showed skill in being a more realistic view of cloud cover (i.e. not smoothed). Compared to the satellite, it was relatively close.

GLAMP cloud ceiling height - 13Z run, 2000 UTC forecast

The GLAMP indicated lifting at 1900 UTC, but not fully clearing until 2000 UTC (below). With the fog and low stratus layer being particularly stubborn yesterday, this later clearing time ended up being the most accurate, and yet still a bit early. It was suggested that the GLAMP may have performed best in this case because the model takes into account winds, and winds yesterday were ~20mph from the west most of the afternoon, keeping fog inland longer into the day.

C&V

The C&V desk yesterday was focused east. AWC participants used the National blend to fill the Sky and CloudBasePrimary grids, while also populating the CloudBasePrimary using pop thunder to add a second layer of clouds and fill as broken in SkySecondary. This was reflected in the TAFs produced off the AWC grids

After this process, there was much discussion on the 'speckly' nature of many of the grids utilized.

AWC Sky grid

While speckles create a more realistic picture of clouds, they do not necessary help the TAF. In fact, it may hinder. With many speckles, the coverage and base of clouds will be very up and down in the TAF as the model progresses. In other words, there is no clear trend. Again, this is realistic, particularly with partial cloud cover. However, realistic isn't always the most useful for customers, particularly when the up down isn't particularly significant. Feedback from the AWDE perspective suggested that a 'perfect' grid isn't necessary.

AWC Sky grid - smoothed

 Instead, they would rather have something 'practically perfect', or smoothed, so that there is a clear trend in the TAF.

WFO participants also commented that the 'speckly' grids were not ideal for working at a local level. They are using the grids as a driver to create the TAFS, meaning they really need to the smoother fields to do so. During the experiment periods, they actually took the 'speckly' Sky grid and smoothed it out for their purposes before sending back, resulting in clear evidence of difference between a national and local perspective.

AWC CloudBasePrimary grid - the Georgia grid area was manipulated by the WFO participants, who smoothed the grids out in order to best work with the TAF format. The remainder of the grid was produced on an national scale by AWC.

TCF

TCF feedback was similar to that collected over the past few days. The workload was again a concern, as creating the long-term convective forecast along with the usual 4, 6, and 8 hour forecasts leaves little time for efficient data interrogation. It was suggested that maybe the extended focus only on high-impact areas, or areas where significant traffic constraints may occur, to free up forecaster time and provide value for planners.

On the model side, the ARWX painted a more realistic picture than the HREF as far as convective coverage, while participants fell back to the NAM and GFS for broad scale features. The ARWX was also noted to be a lot better at 24 hours and beyond, not showing a lot of confidence in coverage in the long term. No models had medium coverage for the long-term, which is realistic given the uncertainty in the models. Participants noted that the focus for these long-term convective forecasts should be on the high-confidence, low coverage.

Participant feedback in AWDE for Day 3

Day three in AWDE featured guest participants from the NWS weather forecast office, flight standards, pilot subject matter experts, and Traffic Flow Management specialists. Participants evaluated the final issued TCF products and commented on the value of having only areas of high confidence being displayed.

Participants in AWDE collaborating with the TCF desk via Google Hangouts

The HEMS flight rule product was also examined by users today. The 15 minute update rate was a large portion of the positive feedback. With rapidly changing weather, it is important to get faster update rates. Participants also valued the larger coverage area in the RU-RTMA product. Specific to flight planning, users want to see separate ceiling and visibility products rather than a combined product.

GFE Grid Work at the C&V desk

Day 2 in the testbed brought the first full day of forecasting with the GFE grids at the Clouds and Visibility desk.

After experiencing some issues with the AWIPS servers the day before, which would cause CAVE to crash and/or get hung up on occasion, it was decided to focus on one half of the US each day as opposed to tackling both East and West every day.  Today's focus region was over the Eastern half of the CONUS.

The weather of the day consisted of a front moving over the southeast, and a tropical system moving up into the southeastern part of Texas and southwestern part of Louisiana later in the TAF forecast time.  Forecasters working the desk compared the satellite observations along with the derived probabilities of flight rules to determine which model was handling the frontal ceilings and visibility the best.

Consensus was to use the AWCRAP for the beginning of the forecast period, with AWCHRRR to finish it out.  Some periods of missing data in the feeds also drove the reasoning to use multiple models for the forecast.  Of course this created some "jumps" between the two models which required some tweaking by the forecasters to keep the forecast smooth and consistent in time.

The above screen shot of the forecast Sky grid illustrates the issues when trying to interpolate between two models.  Forecasters decided to use a different approach to branch between two different forecast time grids, this involved using a tool available that can advance highlighted areas in time given current wind speeds and direction. 

Final grids were sent off to OPG to edit and create TAFS in their three specific WFO areas; Atlanta, New York, and Greenville-Spartanburg.  Lots of good discussion took place during the afternoon debrief regarding the detail in the resultant TAFs from the AWC/OPG grid driven ones using the TAF formatter and the ones produced operationally in the field. The TAF formatter tends to give lots of detail by producing several lines, and the overall consensus from the discussion was that more detail is desired in the early part of the TAF (by the end user), where the formatter should be structured to smooth out some of the unnecessary detail in the later part of the TAF period.

Model evaluations at the SFO desk

The 2017 Summer Experiment features a new desk focused around the San Francisco terminal. A visiting scientist from the UKMET office has provided high resolution UKMET data in a mesoscale domain over the SFO area, and participants have been comparing it with various other models. Specifically, they have been examining when the models are suggesting the fog and low ceilings will clear out, and how the high resolution UKMET is performing as compared to the others.

Shown below is the HRRR ceiling field from late morning yesterday:

HRRR Layer Cloud Cover forecast for the morning and early afternoon of August 8th

Immediately notable was how smoothed out the clouds features are in the HRRR. Though it showed clearing, it wasn't particularly useful given the lack of identifiable cloud features. The smoothed out area of clouds is not realistic for an area like SFO, where mesoscale climates often have fog and low stratus following the bay and other terrain features.

GLAMP ceilings were also examined:

GLAMP Ceiling Height from the morning and afternoon of August 8th

The GLAMP noted ceilings lifting later, not until around 1900 UTC, and did provide better detail in the cloud features as compared to the HRRR.

UKMET Cloud Cover field from August 8th, the 1700 UTC forecast from the 00 UTC run

The Cloud Cover field from the UKMET office showed clearing much earlier, around 1700 UTC and provided a much more realistic looking cloud field. Given satellite imagery at the time as well as observed winds, however, 1700 UTC was thought to be too early. Below is the GOES-16 0.64 um visible satellite image from 1752 UTC over SFO.

GOES-16 0.64 um visible image at 1752 UTC on August 8th

GOES-16 visible imagery showed clearing by just shy of 1800 UTC. Though this was in fact later than the UKMET predicted at 1700 UTC, the cloud features of the visible were far more accurate with the high resolution model than either of the others.

Exploring the long range convective forecast and TCF

Yesterday was the first full day of the Summer Experiment and things were in full swing at the TCF desk. One of the main goals of the experiment is to explore the idea of a long range forecast, i.e. adding outlooks beyond the main 4, 6, and 8 hour periods. For the purposes of our experiment, these prototype forecasts are issued by participants every hour along with the typical TCF.

A challenge noted almost immediately by participants was time. At the TCF desk, there is an hour in between the issuance of each 4, 6, and 8 hour forecast, during which time a scheduled collaboration chat occurs between AWC, CWSUs, and others, to determine the areas of concern for the short-term. On busy days, it can make that hour feel far too short. Adding on to that a long-range forecast each hour was found to be extremely difficult. In order to just get both the TCF and extended completed in time, participants noted that they didn't have much time to even look at new data sets. In order to add value, particularly to the long-range, it was suggested that perhaps another forecaster would be needed to focus only on that piece.

In later discussions, AWDE brought up the Extended Convective Forecast Plot (ECFP) currently available on the AWC webpage (http://www.aviationweather.gov/ecfp), an automated plot using various long range models to provide convective forecasts out to 24 hours and beyond. Any long-range models contain inherent uncertainties the further out the forecast hour, and the question was posed whether having a person creating the long range would really add benefit all the time.

Example 36-hour forecast from the Extended Convective Forecast Plot (ECFP) on the AWC's website

Feedback from a traffic planner perspective was that TFMs don't create plans that far out in advance. Instead, they use it to gauge what they may have to deal with the following day. If the automated forecast could be improved, that would indeed be useful for these outlooks. However, realistically, TFMs only take a look at the beginning and end of each day, and would not be looking at a 24 or 36 hour forecast every hour. In light of this, it was suggested that a long range convective forecast be provided in the morning with the first TCF package, giving planners a look at the following morning, and then again in the evening, giving planners at look at the following evening. Additionally, adding a 36 hour forecast at these times was mentioned as well. This would not only reduce forecaster workload at the TCF desk, but also add value where it could really be used.

On the dataset side, forecasters were utilizing high resolution models like the NAM Nest, ARW, and others, along with the INSITE tool to generate their forecasts.

NAM Nest Composite Reflectivity forecast in N-AWIPS

 One comment was that, for the long range forecast, it was difficult to find models that actually went out far enough to be of use. Some upstream dataflow struggles caused AWC to lose some of the experimental long range datasets initially available. More evaluation of these will hopefully be completed throughout the rest of the experiment.

INSITE was able to be utilized to some extent for the 4, 6, and 8 hour TCF. It was noted that it is a very good dataset for a broad scale view of possible traffic flow impacts. However, for CWSUs or planners responsible for looking at particular routes in a small region, it may not be of as much help beyond determining that there is, in fact, going to be an impact.

For the long range forecast INSITE has potential. Having that broad scale view of potential impact may be useful in the 24 to 36 hour range. At the moment, though, INSITE is only generated out to 12 hours for each model. It was suggested that for the long range, it would need to be extended out to at least 24 hours to be of use. 

AWDE examines testbed specific products

Day two in AWDE was a successful day for participants to begin examining testbed specific products. Guest participants from the NWS weather forecast office, flight standards, pilot subject matter experts, and Traffic Flow Management specialists filled the AWDE lab to collaborate with the AWC testbed.

Specific testbed products evaluated included the TAFs and TCF extended forecast. Guest participants preferred the TAFs with higher temporal resolutions. Feedback regarding the extended TCF was positive. Users thought the extended forecast worked well to identify areas of convective weather to support next day strategic planning. The broken line, however, is not necessary as part of their planning.