National Weather Service United States Department of Commerce


  1. DISCUSSION - brief description of general weather conditions affecting forecast for the next 36 hours.

    The forecast is then broken down into 3 periods; today, tonight, and tomorrow, for the following parameters:

  2. CLOUD COVER - clear, mostly clear (MCLEAR), partly cloudy (PCLDY), mostly cloudy (MCLDY), and cloudy.

  3. PRECIP TYPE - this is manually input data with the following types possible; none, drizzle, rain, showers, tstms, frzg rain, sleet, snow/rain.

  4. CHANCE PRECIP (%) - the probability of precipitation in tens of percent for each 12 hour period.

  5. TEMP (24 H TREND) - daytime maximums and nighttime minimum using a specific temperature and trend from previous day.

  6. RH (24H TREND) (%) - relative humdity in percent. Afternoon minimums and overnight maximum and trends from previous 24 hours.

  7. 20FT WND-AM MPH - Direction is according to an 8 point compass and wind speed in mph.

  8. 20FT WND-PM MPH - Direction is according to an 8 point compass and wind speed in mph.

  9. PRECIP AMOUNT - 12 hour precip amount forecast in hundredths on an inch.

  10. PRECIP DURATION - length of time in hours that precip is occurring

  11. PRECIP BEGIN - beginning time of precip (ex.; 3 pm, or continuing ).

  12. PRECIP END - end time of precip (ex.; 5 pm ).

  13. HAINES - Haines Index - a stability index deteremined by combining the stability and moisture content of the lower atmosphere into a single number that correlates very well with large fire growth. Calculated near noon (18Z) for daytime and near midnight (06z) for nighttime.

    1. Haines Index potential for large fire growth; (2 or 3 very low, 4 low, 5 moderate, 6 high)
  14. LAL (Lightning Activity Levels)

    1. - No Thunderstorm/Lightning

    2. - Few Thunderstorms/Few Lightning Strikes

    3. - Widely Scattered Thunderstorms/Scattered Lightning Strikes

    4. - Scattered Thunderstorms/Numerous Lightning Strikes

    5. - Wide spread Thunderstorms/Frequent Lightning Strikes

    6. - Dry Lightning {LAL level 3 or higher with no precipitation}

  15. MIXING HEIGHTS - height above the surface (feet) through which relatively vigorous mixing will take place due to convection. The maximum height in feet of the top of the mixing level during the day.

  16. TRANSPORT WINDS - average wind speed (mph) and direction from surface to top of mixed layer. Wind direction is according to the 8 point compass.

  17. VENTILATION RATE - this parameter is a product of the mixing height multiplied by the transport wind speed (mph). Higher values would indicate faster dispersion of particulate matter generated by fires.

  18. REMARKS - text space to include additional information such as a Fire Weather Watch/Red Flag Warning.

  19. Forecast for days 3 through 7.

  20. The 8 to 14 Day Outlook for the entire forecast area (located at the end of the forecast).