UNDERSTANDING NWS FORECAST TERMS
(Courtesy: National Weather Service/NOAA, Department of Commerce)
Since we do 24 hour emergency water damage cleanup we definitely keep an eye on the weather. Each time it rains or storms we can get a wide range of phone calls from overflowing sump pumps to leaky windows & roofs, so it's important for us to follow and understand Weather Forecast Terminology. Here's some helpful information that should help you understand what all those weather terms mean.
Understanding the terminology behind weather forecasts is an integral part of our everyday decision-making. Below are common weather terms and their meanings.
Sky condition describes the predominant/average sky condition based upon the amount of sky covered by opaque (not transparent) clouds.
Sky Condition Percent of Cloud Cover
Sunny or Clear 0 to 5%
Sunny or Mostly Clear 6 to 25%
Mostly Sunny or Partly Cloudy 26 to 50%
Partly Sunny or Mostly Cloudy 51 to 69%
Mostly Cloudy or Considerable Cloudiness 70 to 87%
Cloudy or Overcast 88 to 100%
Wind describes the prevailing direction from which the wind is blowing with speed in miles per hour. The numbers may vary in other parts of the country due to variation in terrain and elevation.
Sustained Wind Speed Descriptive
0 – 5 mph Light, light and variable or calm
5 – 20 mph None used
15 – 25 mph Breezy
20 – 30 mph Windy
30 – 40 mph Very windy
40 – 73 mph Strong, dangerous high winds
74 mph or greater Hurricane force
Forecast temperature describes the forecast maximum and minimum temperatures or in some cases, the temperature expected at a specific time. Temperature is reported in degrees Fahrenheit.
Description Examples Range
Near 40 Approaching 40 or a range from 38 to 42
Around 85 Range of temps from 83 to 87
Lower 50s Temperatures of 50 through 53
Middle 70s Temperatures of 74 through 76
Upper 30s Temperatures of 37 through 39
60s Temperatures of 60 through 69
Probability of Precipitation (PoP)
Probability of Precipitation (PoP) is the likelihood of measurable precipitation (or water equivalent of frozen) precipitation falling during a specified period in the forecast area. Measurable precipitation is equal to or greater than 0.01 inch (0.2 mm) over a period of 12 hours, unless specified otherwise.
At times, NWS forecasters may use “occasional” or “periods of” to describe a precipitation event that has a high probability of occurrence, i.e., they expect any given location in a forecast area to most likely have precipitation, but it will be of an “on and off” nature.
PoP Percent Expression of Uncertainty
20% Slight chance
30 – 50 % Chance
60 – 70% Likely
80 – 100% Rain/Snow, etc.
Information shared from the NWS website.
SERVPRO of Upper Darby, PA & SERVPRO of Bear/New Castle, DE, proudly serves those in need! We will be on site quickly and our staff will give you the personalized attention you deserve. We specialize in the cleanup of water damage, fire damage, smoke damage, mold removal, trauma cleanup, vandalism cleanup, carpet cleaning and duct cleaning. Let us help you make it, “Like it never even happened!” Visit either of our websites for assistance. Pennsylvania customers visit –www.SERVPROupperdarby.com or www.SERVPRObearnewcastle.com if you’re located in Delaware. To speak to a qualified team member, call 1-877-352-0700.