Impacts METAR Board Help


The METAR board is a time series display of weather conditions. There are two formats for the board: condensed and expanded. The coloring criteria uses the same impacts catalog as the TAF board which sets criteria for each airport.

Impacts Catalog

The coloring criteria for the determined by the impacts catalog. The catalog lists criteria for the major airports based on winds, ceiling, visibility and weather. The impact is primarily aimed at weather conditions that could significantly impare commercial air traffic or even shut down the airport. The impacts criteria was not developed for general aviation.

Airport specific criteria take into account runway configuration and how impacts due to cross winds, runway visibility might impact traffic. There is a default criteria for all airports.

Default Impact Criteria
Threat None Slight Moderate High
Weather -- -- -SN,VCTS SN, +SN, *FRRA, *FRDZ, *IP, *TS, *TSRA
Visibility (sm) ≥1.5 1.5>X≥0.8 0.8>X≥0.5 <0.5
Ceiling (100 ft) ≥8 8>X≥5 5>X≥2 <2
Wind Speed (kt) -- -- -- >30
Wind Gust (kt) -- -- -- >35

Overview display, condensed view

The condensed view lists any number of stations along the vertical axist and time along the horizontal axis (See Fig 1). Each box (last 12 hourly METAR observations) is color coded based on the level of the impact. White represents no impact, yellow slight impact, orange moderate impact and red high impact. The letters in the box represent the cause of the hazard. They are as follows:

  • Wx - Weather (thunderstorms, freezing rain)
  • CIG - Ceiling
  • VIS - Visibility
  • WSpd - Wind speed
  • WGst - Wind gusts

There could be multiple hazards but only the top one from this list if shown. The board will pick the worst impact from either the prevailing or the temporary conditions. See hover for more data. The condensed view is the default if more than one station is specified.

METAR Board condensed
Figure 1: METAR Board condensed view

The cutoffs for each color are shown in Fig. 2. The default criteria use the flight category cutoffs

METAR Board legend
Figure 2: METAR Board color criteria

Hover view

When you hover over a cell, a popup of data specific to that time shows up (see Fig. 3). This will show weather, visibility, ceiling, and winds. Temporary conditions will be shown on the second line in []. Any airport specific catalog criteria will be shown below the table.

METAR Board Popup
Figure 3: TAF Board popup

Site display, expanded view

For more detailed information for each site, click on the station identifier. This will go to the expanded view for each site. In this view, each weather condition is listed along the vertical axis (See Fig. 4). These are:

  • Vis - Visibility in miles
  • Cig - Cloud ceiling in 100s feet
  • Cover - Cloud cover: CLR, FEW, SCT, BKN, OVC
  • FltCat - Flight category: VFR, MVFR, IFR, LIFR
  • Wx - Weather
  • WDir - Wind direction
  • WSpd - Wind speed in knots
  • WGst - Wind gusts in knots
METAR Board expanded
Figure 4: METAR Board expanded view

Hover view

Since all the data are already viewable, unlike the condensed view, the hover popup will only show the airport specific impacts criteria for that time.

METAR Board Popup
Figure 5: METAR Board popup

Runway Winds

In addition, for airports with runway information, cross and head wind values may also be displayed (See rwywind URL option below and Fig. 6). These are available for each runway set for that airport. If an airport has three parallel runways, only one is shown. The runway is shown as RXX/XX with the primary and reciprocal headings. The wind data is computed based on actual runway direction relative to due north. No magnetic deviations are taken into account that this point.

  • XWnd - Cross wind speed in knots. Positive values represent winds from left to right given the first runway listed. For if the runway is R13/31, the cross wind data is for runway 13. If it's runway 31, invert the data. If it shows a negative number, the winds are right to left.
  • HWnd - Head wind speed in knots. Positive values represent head winds and negative values represent tail winds. If the value for runway R13/31 is -9, then there is a 9 knot tail wind on runway 13. This would be a 9 knot head wind for runway 31. Transitions from positive to negative could mean a switch in the landing direction.

The impacts catalog default wind criteria are used for color coding. A hover popup will show whether winds are head or tail, left to right or right to left.

METAR Board Runway Winds
Figure 6: METAR Board runway winds

URL Options

Here is a list of the URL options:

  • id=id[+id...] - Specifies the stations to retrieve data
  • sort=...- Sorts the stations
    • ns north to south
    • sn south to north
    • we west to east
    • ew east to west
    • st alphabetical by state abbreviation
  • date=yyyymmddhhnn - Specifies the starting date for the display in year, month, day, hour and minute
  • format=... - Shows station data is either:
    • expanded all data in rows, default for single site
    • condensed single row for each site, default for multiple sites
    • simple all data in rows, mimics old TAF board view
  • fewsct={off|on} - Considers few and sct clouds in ceiling computation
  • rows=row,row,... - Shows these rows in expanded display
  • enabled=row,row,... - Use only these parameters in condensed display computation
  • rwywinds={cross|head|both} - Shows runway winds, either cross winds, head winds or both. The default is off.
  • color=XXX,XXX,XXX,XXX - Sets colors for each impact level in browser hex code. The default is FFFFFF,FFFF99,FFCC66,FF6666.
  • name=XXX,XXX,XXX,XXX - Sets name labels for each impact level The default is None, Slight, Moderate, High.
  • font={small|norm|large} - Sets font size
  • bg=dark - Sets a black/dark background

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