WORLD AREA FORECAST SYSTEM OPERATIONS GROUP (WAFSOPSG)
FIFTH MEETING
Paris, France, 16 to 18 September 2009
PROGRESS REPORT OF WAFSOPSG/5-WP/15
VISUALISATION OF WAFS FORECASTS: WEB-BASED DISTRIBUTION
(Prepared by the WAFC Provider States)
1.INTRODUCTION
1.1WAFSOPSG/4 formulated Conclusion 4/20 related to the proposed development of a web-based distribution service for WAFS forecasts. This new offering from the WAFCs would be expected to provide a minimum set of WAFS charts to improve the access to objective forecasts for icing, turbulence and CB cloud, derived from GRIB 2 formatted data. The charts would be expected to be suitable for inclusion within flight documentation and would be targeted primarily at Least Developed Countries which may not be in a position to convert GRIB (and/or BUFR) significant weather forecasts into chart form.
1.2This progress report outlines the intended scope of the web-based service offering from the WAFCs.
2.PROPOSED PRODUCT SETof the WAFC WEB SERVICEs
2.1The increased spatial/temporal resolution and product complement of GRIB 2 WAFS data over its GRIB 1 predecessor will afford WAFS users considerable advances in the range and style of products that they can utilise. For instance, GRIB 2 data will be at 3-hourly timesteps (T+6 to 36), whereas the existing GRIB 1 product set is at 6-hourly timesteps (T+6 to 36); GRIB 2 data will include gridded icing/turbulence/CB cloud forecasts which have only been available as trial and evaluation products in GRIB 1 up to now. Accordingly, GRIB 2 data will enable workstation providers and flight planning companies to make better use of the data in their manual and automated processes.
2.2The WAFC Provider States recognise, however, that there will be some States not in a position to utilise the higher-resolution gridded data (GRIB 2) for any number of reasons. In order to offer those users, notably the LDCs, with an opportunity to access simple and easy to understand WAFS products, the WAFCs are proposing to make available simplified visualised forms of the GRIB 2 data available on a WAFC London and a WAFC Washington web service that can be accessed via the public internet.
2.3The products proposed for the WAFC web services fall into two categories, namely:
i)a set of high-at-a-glance significant weather products; and
ii)a limited set of icing, turbulence and CB graphical products.
Each of these service offerings will be based on the GRIB 2 WAFS datasets.
3.HIGH AT-A-GLANCE SIGNIFICANT WEATHER PRODUCTS
3.1The WAFC Provider States are developing a set of high at-a-glance significant weather (HG-SIGWX) forecasts to meet the requirements of WAFSOPSG Conclusion 4/14.
3.2The WAFCs propose to make the HG-SIGWX products available on the WAFC web services, to further assist those users (States) not in a position to decode and visualise the GRIB 2 data for themselves. The products would represent high- and medium-level operations (HG-SWH and HG-SWM), and comprise:
i)4 issuances per day based on 0000, 0600, 1200 and 1800 UTC global model runs of WAFC London and WAFC Washington;
ii)forecast charts valid T+6 to T+36 at 3-hourly timesteps (i.e. T+6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36) based on GRIB 2 model output;
iii)HG-SWH covering FL250 to FL630 and comprising:
- Composite maximum clear-air turbulence field representing 300hPa (FL300), 250hPa (FL340) and 200hPa (FL390);
- CB horizontal cloud extent; and
- 250hPa (FL340) wind speed and direction, ≥ 80 knots.
iv)HG-SWM covering FL100-250 and comprising:
- Maximum icing field representing 700hPa (FL100) ;
- CB horizontal cloud extent; and
- 400hPa (FL240) wind speed and direction, ≥ 60 knots.
v)a selection of standard ICAO areas with which to display the forecasts (including A, B, B1, C, D, E, F, G, H, I, J, K, L, M, and EUR).
3.3The above specification would result in 330 charts available to users, 4 times per day. The WAFCs recognise that this is a considerable number of products for a user to assimilate. It should, however, be noted that whilst 330 HG-SIGWX charts would be available 4 times per day, owing to the area of interest and the time/duration of a proposed flight, a user may actually only tend to use a fraction of this number in order to generate flight documentation. Examples of the HG-SIGWX products are presented at Appendix A to this progress report. Appendix A also contains a table summarising the HG-SIGWX offering.
3.4The draft specification of the high- and medium-level HG-SIGWX products, outlined at 3.2 iii) and iv) above, has been principally determined through dialogue with IATA and ALPA. The WAFSOPSG should also consider whether such specification is in line with expectations.
4.limited set of icing, turbulence and CB graphical products
4.1In addition to the to HG-SIGWX products outlined above, the WAFCs propose to make available simple visualised forms of the GRIB 2 icing, turbulence and CB cloud forecasts. The products will comprise a subset of the overall GRIB 2 data complement. The current intention is to provide:
i)4 issuances per day based on 0000, 0600, 1200 and 1800 UTC global model runs of WAFC London and WAFC Washington;
ii)forecast charts valid T+6 to T+24 at 3-hourly timesteps (i.e. T+6, 9, 12, 15, 18, 21 and 24) based on GRIB 2 model output;
iii)maximum icing forecasts at 700hPa (FL100) and 600hPa (FL140);
iv)maximum clear-air turbulence forecasts at 300hPa (FL300), 250hPa (FL340) and 200hPa (FL390);
v)CB horizontal extent forecasts with contoured cloud top height; and
vi)a selection of standard ICAO areas with which to display the forecasts (including A, B, B1, C, D, E, F, G, H, I, J, K, L, M, and EUR).
4.2Although this is a subset of the overall GRIB 2 complement, this would still result in 630 charts available to users, 4 times per day. Again, as per the comments in 3.3 above, a user may only tend to require a fraction of this number in order to generate flight documentation. Examples of these products are presented at Appendix B to this working paper. Appendix B also contains a table summarising this offering.
4.3The WAFSOPSG should consider whether the specification outlined at 4.1 i) to vi) is in line with expectations, with the intention of assisting those States who may not be in a position to visualise GRIB and/or BUFR SIGWX products.
5.development AND IMPLEMENTATION of the WAFC web services
5.1Both WAFCs are in the process of developing web-based services to support the objective gridded forecasts of icing, turbulence and CB cloud, based on the above (provisional) specification.
5.2At time of writing (May 2009), WAFC London envisages that theirweb-based service will be available around March2010; whilst WAFC Washington envisages that their web-based service will be available in 2011 at the earliest..
5.3Once operational, the services will conform to the guidance contained in ICAO Document 9855 – Guidelines on the use of the public internet in aeronautical applications, and Appendix 1 of ICAO Document 8896 – Manual of Aeronautical Meteorological Practice.
5.4Details of the internet address to be used to access the web services will be communicated in advance of implementation by way of the WAFS Change Notice Board, available at URL:
5.5To afford users an indication of how the WAFC web services may appear in future, several screen shots from the existing WAFC Washington (NOAA/NWS/AWC) test bed facility have been reproduced at Appendix C.
Report prepared by WAFC London and WAFC Washington, 29th May 2009
APPENDIX A
A1. Experimental visualisation of the high at-a-glance significant weather products
A1.1 HG-SWH (FL250-630)
Green = Composite maximum CAT at 300, 250 and 200hPa (FL300, 340, 390); Orange = CB horizontal extent; Black = Wind fleches ≥80KT at 250hPa (FL340)
A1.2 HG-SWM (FL100-250)
Pink = Maximum icing at 700hPa (FL100); Orange = CB horizontal extent; Black = Wind fleches ≥60KT at 400hPa (FL240).
NOTE: ALL PRODUCTS VISUALISED ABOVE ARE EXPERIMENTAL, AND SHOULD NOT BE CONSIDERED FINAL
A2. Summary of the HG-SIGWX forecasts available on the WAFS web servers
Product description / Flight levels / Standard ICAO chart areas of coverage / Model run data time (UTC) / Forecast time steps / Total number of products per runHigh-at-a-glance SIGWX for HIGH level flights
(HG-SWH) / 250-630 / A, B, B1, C, D, E, F, G, H, I, J, K, L, M, EUR / 0000, 0600, 1200, 1800 / T+6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36 / 165
High-at-a-glance SIGWX for MEDIUM level flights
(HG-SWM) / 100-250 / A, B, B1, C, D, E, F, G, H, I, J, K, L, M, EUR / 0000, 0600, 1200, 1800 / T+6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36 / 165
Total number of WAFC London/WAFC Washington forecast charts per issue = 330
APPENDIX B
B1. Experimental visualisationof the icing, turbulence and CB products
600hPa Max Icing/ 250hPa Max CAT
CB horizontal extent
NOTE: ALL PRODUCTS VISUALISED ABOVE ARE EXPERIMENTAL, AND SHOULD NOT BE CONSIDERED FINAL
B2. Summary of the icing, turbulence and CB forecasts available on the WAFS web servers
Product description / Pressure levels (flight levels) / Standard ICAO chart areas of coverage / Model run data time (UTC) / Forecast time steps / Total number of products per runMaximum Icing / 700 (100), 600 (140) / A, B, B1, C, D, E, F, G, H, I, J, K, L, M, EUR / 0000, 0600, 1200, 1800 / T+6, 9, 12, 15, 18, 21, 24 / 210
Maximum clear air turbulence / 300 (300), 250 (340), 200 (390) / A, B, B1, C, D, E, F, G, H, I, J, K, L, M, EUR / 0000, 0600, 1200, 1800 / T+6, 9, 12, 15, 18, 21, 24 / 315
CB horizontal extent with colour-coded ICAO height at CB top / n/a / A, B, B1, C, D, E, F, G, H, I, J, K, L, M, EUR / 0000, 0600, 1200, 1800 / T+6, 9, 12, 15, 18, 21, 24 / 105
Total number of WAFC London/WAFC Washington forecast charts per issue = 630
APPENDIX C
Experimental display of a WAFC web service
(Extracted from the NOAA/NWS/AWC test bed facility at URL:
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