There are several weather data models (UML/XML) governed by different authorities for various purposes. This page describes their respective roles and areas of responsibility.
IWXXM
IWXXM is governed by ICAO and WMO to represent products in ICAO Annex 3 / WMO No. 49. IWXXM 1.0 was released in 2013 and is typically updated in alignment with ICAO Annex 3 updates (every two years). ICAO and WMO are UN agencies tasked with the governance of international aviation and weather, respectively, and therefore IWXXM should be considered the authoritative source for products that are included in ICAO Annex 3. IWXXM 2.0 includes seven products: METAR, SPECI, TAF, SIGMET, AIRMET, Tropical Cyclone Advisory, and Volcanic Ash Advisory. More ICAO Annex 3 products may be added in subsequent releases.
ICAO products are deprecated once they have been represented in IWXXM
WXXM 1.1
Mar 2010
General purpose coverages, contours, gust front, motion vector,
ICAO METAR/SPECI, TAF, AIRMET, SIGMET, VA Advisory
WMO AMDAR/MDCR, AIREP
G-AIRMET, PIREP, CCFP
Deprecated in favor of WXXM 2.0. Additionally, ICAO products have been replaced by the authoritative IWXXM representations
WXXM 1.0
2007
Initial representations of ICAO Annex 3 Products
Deprecated in favor of WXXM 1.1. ICAO products have been replaced by the authoritative IWXXM representations
IWXXM-US
The US and other countries have historically created and disseminated products slightly differently than ICAO. In the case of the US, this mostly comes in the form of additional content in the RMK section (in the traditional TAC formats). IWXXM-US was developed by US agencies (NWS, FAA and others) for representing ICAO products with additional US content. The US disseminates US METARs internally but strips off the extra content when transmitting on ICAO circuits.
On a technical level IWXXM-US extends IWXXM. Therefore IWXXM-US XML documents have elements from both IWXXM (for ICAO standard content) and IWXXM-US (for US-specific ICAO content).
Official AMDAR and AIREP representations in XML have not yet been developed by the appropriate authorities. If they are developed the USWx representations will be considered deprecated
FAAWX
FAA-specific products, such as that used in terminal weather and convective forecasting on the ITWS, CIWS, and NWP programs
Gust Front Alert, Tornado Alert, Lightning Alert, ATIS Alerts, Contours, Leading Edges, Motion Vector, Configured Alerts, Echo Top Point, Forecast Accuracy, Fronts, Gust Front, Jet Stream, Lightning, Microburst, Runway Configuration, Storm Information, Stream Lines, Terminal Wx, Tornado Detections, Wind Profiles
Minor changes from FAAWX 2.0. Data quality property added to Lightning. Runway Configuration RunwayStatusType changed from string to gml:StringOrRefType and made Ribbon Display Terminal (RBDT) properties optional (minOccurs=”0”)
Gust Front Alert, Tornado Alert, Lightning Alert, ATIS Alerts, Contours, Leading Edges, Motion Vector, Configured Alerts, Echo Top Point, Forecast Accuracy, Fronts, Gust Front, Jet Stream, Lightning, Microburst, Runway Configuration, Storm Information, Stream Lines, Terminal Wx, Tornado Detections, Wind Profiles
FAAWX version 2.0 is the initial release of FAA weather product extensions of WXXM 2.0 schemas including support for NextGen Weather Processor (NWP) products
US-Wx/NAWX
The North-American weather schemas include weather constructs predominantly used and disseminated within the United States, excluding the US specializations of ICAO products from IWXXM-US. On a technical level NAWX extends WXXM with additional content. NAWX is managed by FAA with input from the NWS.
In 2015 NAWX was renamed to USWx to better represent the community of use.
North American Weather (NAWX) - US/FAA Extensions to WXXM - Deprecated
The FAA Weather schemas include many constructs utilized by FAA systems, such as terminal weather (e.g., microbursts) and convective forecasting (e.g., Storm Extrapolated Positions, Growth Trends and Convective Weather Avoidance Polygons).Product Representations
This section lists the current representation to use for each product. Last updated 19 April 2016.
FAA Weather Models (FAAWX) - FAA Extensions to WXXM
Version
Date
Description
Downloads
2.1
Nov 2016
Minor changes from FAAWX 2.0. Data quality property added to Lightning. Runway Configuration RunwayStatusType changed from string to gml:StringOrRefType and made Ribbon Display Terminal (RBDT) properties optional (minOccurs=”0”)
FAAWX version 2.0 is the initial release of FAA weather product extensions of WXXM 2.0 schemas including support for NextGen Weather Processor (NWP) products
WXXM is governed by FAA and Eurocontrol for international products outside of those represented by ICAO or WMO. WXXM 1.0 was released in 2007, and WXXM is typically updated on 2-year intervals.
WXXM predates IWXXM by several years and initial releases included several products from ICAO Annex 3. All WXXM products that have been officially incorporated into IWXXM should be considered deprecated, as IWXXM is the designated representation for ICAO products. An ICAO METAR, for example, exists in both WXXM 1.1 and IWXXM 1.0. The IWXXM METAR should be used preferentially - WXXM included a METAR representation because IWXXM did not yet exist to carry official ICAO products.
WXXM, the Weather Data Model, is a UML and XML-based structural definition for the exchange of information by aviation weather users. WXXM was designed by Eurocontrol in concert with FAA.
WXXM defines a common vocabulary for exchanging weather information between organizations, but it does not inherently provide any sort of functionality to facilitate that exchange. It is, fundamentally, a set of guidelines for how to think about weather data.
Overview
Despite being referred to as WXXM, the Weather Data Model is in fact a set of three tiered data models, only one part of which is actually called WXXM: the Weather Exchange Model. Together, the three models provide conceptual, structural, and physical representations of weather data.
The aptly-named Weather Conceptual Model (WXCM) provides a high-level, implementation-independent look at how weather data concepts are connected.
The Weather Exchange Model (WXXM) provides a more logical and structural (if still implementation-independent) perspective of the same data, in more complete detail — the interrelationships of every weather data concept are spelled out.
Finally, the Weather Exchange Schema (WXXS) is a machine-generated, XML-formatted implementation of the Exchange Model — a "physical" code version of it.
Releases
Weather Information Exchange Model (WXXM)
Version
Date
Description
Downloads
2.0.0
Mar 17, 2015
WXXM 2.0 release. This release replaces the earlier WXXM 2 release candidates.
Removed regional content, such as PIREP representations
Incorporated design elements similar to the IWXXM/METCE technical approach:
Changed from Observations and Measurements version 1 to version 2
Replaced WXXM 1.1 Units and Measures in favor of GML-standard units and measures
Created an AIXM Profile for weather information that includes select portions of AirportHeliport, Airspace, AirspaceVolume, Runway, RunwayDirection, and Unit
Improved weakly-typed representations (coverages) to allow for composite CodeList and measured quantities to allow references back to a semantic definitions, such as those found in the WMO Codes Registry. These coverage representations also allow additional temporal and spatial components in the domain consistent with ISO 19123 coverages. These domain specializations extend GML coverage types to allow for drop-in replacement
WXXM 2.0 Release Candidate 2. This is the second release of the WXXM 2.0 model, and includes additional product representations: AIRMET, SigWx, Volcanic Ash Advisory, and AMDAR
WXXM 2.0 Release Candidate 1. This is the first release of the WXXM 2.0 model, subsequent WXXM 2.0 versions will include ICAO AIRMET, SigWx, and Volcanic Ash Advisories
