Tuesday, September 11, 2018

2018 Summer Experiment Day 1

The Aviation Weather Testbed (AWT) 2018 Summer Experiment kicked off on Monday September 10th with a great mix of participants from across the aviation and research community.   The experiment this year is exploring super high-resolution forecasts for short-term planning as well as new global forecasting models for longer-range planning.

The three major areas of focus are:

Continued Evaluation of Super High-Resolution Cloud and Visibility Products for SFO Flight Operations

The Met Office is providing near-real time 330-m resolution forecasts of aviation impact variables to support experimental clearing time forecasts for SFO. In addition, GSD is providing a nest of the HRRR model as another source of guidance for this domain. GOES-17 and new versions of RTMA and RTMA-RU are also being evaluated as high-resolution observation sets.

Evaluation of the experimental expanded Graphical Forecasts for Aviation (GFA) tool
Currently, the Graphical Forecasts for Aviation with an expanded domain is available as an experimental product via https://testbed.aviationweather.gov/gfa. This product will go through a more thorough evaluation process with AWT and FAA Aviation Weather Demonstration and Evaluation (AWDE) services personnel interacting with end-users during the experiment.  An internal version of the GFA tool expanded out into the Pacific to Hawaii and north to cover the Alaska domain is also being evaluated by potential users.

Evaluation of guidance for enhanced Day 1 and extended Day 2-4 planning
The AWC is currently discussing the potential to issue a produce similar to the SPC Day 1 product for severe thunderstorms but instead for severe low and high turbulence and significant mountain wave activity. This involves the evaluation of high-resolution guidance for severe turbulence signals out to 36 hours in the future. In addition, AWT participants will be asked to evaluation experimental FV3GFS guidance for the prediction of longer range impacts.



Day 1 Debrief:
The first day is usually a time for participants to get acquainted with the various desks and tasks.  Participants are given free range of the various desks and can migrate to those that are of most interest to them.  The brownbag seminar during lunch was given by Rune Duke of the Aircraft Owners and Pilots Association (AOPA) about the general aviation perspective for aviation weather.


SFO Desk:
With no stratus day at SFO, the focus switched from forecasting a clearing time to looking at the different guidance output to see how they performed on the surrounding clouds and weather.

The model10z runs showing varying forecasts over SFO

GOES17 imagery over SFO at 15Z shows clouds creeping inland south of SFO.  The UK Met model seemed to handle this feature quite well.  The benefit of having the higher resolution model nest is that the impact from topographic features is are better resolved.




An interesting feature in the LAMP guidance was noted based on how LAMP processes forecasts. The gridpoint nearest to SFO indicates a clear forecast, but the surrounding area suggests low ceilings at SFO. This is likely because the grid was postprocessed to be consistent with the LAMP station forecast. The forecast was likely affected by the lack of a ceiling observed at the METAR. 



Day1, Day 2-4 Outlooks:



There was discussion at the Day 1 desk that a text product would likely be needed in addition to the Day 1 graphic outlook.  Exactly how this would look and what it would entail is something for other participants to think about during the week.  The forecasters at the desk started with a general overview of weather pattern, and then gave brief discussions on each of the turbulence categories depicted in the graphic (High, Low, and Mountain Wave).  The particpants used FV3 and GFS guidance to depict areas of turbulence over the CONUS.

At the Day 2-4 desk, forecasters focused on multiple impacts that would have high impact on flight planning through the period.  This includes snow, thunderstorms, winds, wind compression, low ceilings and visibilities, sleet/freezing rain, turbulence, and en-route icing.

 

The purpose of the maps is to target weather activity that could impact travel at the core 30 airports.  Sometimes that means ignoring large events over the midwest region and instead highlighting small areas with high impact to airline traffic like New York.  Ceiling and Visibility impacts can vary by terminals, so areas drawn to indicate low cig/vis could vary in type based on the terminals being impacted and their specific criteria.



One of the goals for this desk is to compare guidance provided by GFS and FV3.  The above graphic shows a comparison of the two models visibility fields for the same forecast time.  It's easy to see the difference in coverage, with the FV3 showing less coverage of low visibilities over all.  However it seems the FV3 is indicating a larger swath of visibilities less than 1 mile up over the Northeast compared to the visibilities in the GFS which are more varied in the region ranging from less than 5 miles to less than 1.

GFA Expansion Evaluation:

The goal of the GFA expansion evaluation is to get any and all feedback from users on the usability of the tool for flight planning.  To do this, participants from various regions will be doing flight plans each day using the tool, and then seeing how those forecasts verify.   With an internal version expanding out into the Pacific ocean to Hawaii, and up into Alaska, local expertise is critical.  Fortunately, participants from the expanded domain are here to help and give vital feedback to their regions.  Two areas of focus are the Caribbean and Alaska. 

An example of the clouds from GFA over Alaska

An example of the AAWU icing forecast (left) compared to the GFA icing forecast on the right.

The first day was spent getting aquatinted with the tool and gathering feedback from the users on what they liked and didn't like about the tool overall.  The rest of the week will be spent making forecasts for sample flight routes, allowing for even further evaluation of the tool's use and performance for general aviation.





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