National Weather Service United States Department of Commerce


Precipitation Types and Details


  1. Rain - General or patchy liquid precipitation, not showery and usually in a stable or neutral temperature atmosphere; small and medium sized water drops.
  2. Drizzle (DRZL) - General or patchy liquid precipitation in a stable or neutral atmosphere; very small water droplets that appear to float in the atmosphere.
  3. Freezing Rain/Drizzle (Frzg Rain/DRZL) - Liquid precipitation that freezes upon contact with ground, surfaces or vegetation.
  4. Sleet (SLT) - Precipitation in the form of almost clear grains or ice pellets, often mixed with rain or freezing rain.
  5. Snow - General or patchy flakes of crystalline precipitation, usually not showery.
  6. Snow Flurries (SNOW FLRYS) - Showery flakes or small white grains that rarely accumulate.
  7. Showers (SHWRS) - Medium to large drops that usually begin or end abruptly - no thunder heard.
  8. Thundershowers (TSHWRS) - Same as Showers but with thunder.
  9. Thunderstorms (TSTMS) - Heavy or violent downpour of large water drops with strong gusty winds, lightning strikes, and small hail.
  10. Severe Thunderstorm (SVR TSTM) - Violent downpour of large waterdrops, frequent lightning, wind gusts to 58 MPH or greater, and/or hailstones 1 inch in diameter or larger.


  1. No precipitation expected (Chances 5% or less).
  2. Isolated (ISOLD) - Precipitation chance 10 to 20%.
  3. Slight Chance (SLGT CHC) - Precipitation chance 10 to 20%.
  4. Chance (CHC) - Precipitation chance 30 to 50%.
  5. Likely (LKLY) - Precipitation chance 60 to 70%.
  6. Unqualified precipitation types - chances are 80 to 100%.


Duration will be in hours for each of the three periods usually forecast in these ranges: 1 hr or less, 1-3 hrs, 2-4 hrs, 3-5 hrs, 4-6 hrs, and over 6 hrs.


Forecasts amounts will be the average model rainfall amount over the fire weather zone. During daylight time the periods are today (7AM-7PM), tonight (7PM-7AM), tomorrow (7AM-7PM). During standard time, the periods shift to: (6 AM-6PM), etc.

Precipitation amounts will vary by different categories, since it is difficult to pinpoint an exact amount of rain over a given forestry zone.