59 results. (Showing 1 - 20)

1. saffir/simpson hurricane scale
The Saffir/Simpson Scale rates the present intensity of a hurricane from one to five. This can be used to give an estimate of the potential property damage and flooding expected. In practice, wind speed is the parameter that determines the intensity category since storm surge is highly dependent on the slope of the continental shelf.

2. scattered clouds
Sky condition when between 1/10 and 5/10 of the sky is covered.

3. Scud (or Fractus)
Small, ragged, low cloud fragments that are unattached to a larger cloud base and often seen with and behind cold fronts and thunderstorm gust fronts. Such clouds generally are associated with cool moist air, such as thunderstorm outflow.

4. Sea Surface Temperature (SST )
The term refers to the mean temperature of the ocean in the upper few meters.

5. SEvere Local Storms Unit (SELS )
Former name of the Operations Branch of the Storm Prediction Center (SPC) in Norman, OK (formerly in Kansas City, MO).

6. severe thunderstorm
A thunderstorm which produces tornadoes, hail 0.75 inches or more in diameter, or winds of 50 knots (58 mph) or more. Structural wind damage may imply the occurrence of a severe thunderstorm.

7. severe thunderstorm warning
Issued when a thunderstorm produces hail 3/4 of an inch or larger in diameter and/or winds which equal or exceed 58 mph. Severe thunderstorms can result in the loss of life and/or property. Information in this warning includes: where the storm is, what towns will be affected, and the primary threat associated with the storm.

8. severe thunderstorm watch
Conditions are favorable for the development of severe thunderstorms in and close to the watch area. Watches are usually in effect for several hours, with 6 hours being the most common.

9. severe weather statement
Issued when the forecaster wants to follow up a warning with important information on the progress of severe weather elements.

10. Shear
Variation in wind speed (speed shear) and/or direction (directional shear) over a short distance. Shear usually refers to vertical wind shear, i.e., the change in wind with height, but the term also is used in Doppler radar to describe changes in radial velocity over short horizontal distances.

11. shelf cloud
A low, horizontal wedge-shaped arcus cloud, associated with a thunderstorm gust front (or occasionally with a cold front, even in the absence of thunderstorms). Unlike the roll cloud, the shelf cloud is attached to the base of the parent cloud above it (usually a thunderstorm). Rising cloud motion often can be seen in the leading (outer) part of the shelf cloud, while the underside often appears turbulent, boiling, and wind-torn.

12. Short-Fuse Warning
A warning issued by the NWS for a local weather hazard of relatively short duration. Short-fuse warnings include tornado warnings, severe thunderstorm warnings, and flash flood warnings. Tornado and severe thunderstorm warnings typically are issued for periods of an hour or less, flash flood warnings typically for three hours or less.

13. Shortwave (or Shortwave Trough)
A disturbance in the mid or upper part of the atmosphere which induces upward motion ahead of it. If other conditions are favorable, the upward motion can contribute to thunderstorm development ahead of a shortwave.

14. shower
Precipitation that is intermittent, in space, time, or intensity.

15. sleet
A type of frozen precipitation, consisting of small transparent ice pellets.

16. sleet advisory
Issued for expected sleet accumulations of less than 1/2 inch.

17. sleet warning
Issued when accumulations of sleet covering the ground to a depth of 1/2 inch or more are expected. This is a relatively rare event.

18. Slight Risk (of severe thunderstorms)
Severe thunderstorms are expected to affect between 2 and 5 percent of the area. A slight risk generally implies that severe weather events are expected to be isolated.

19. snow
Frozen precipitation composed of ice particles in complex hexagonal patterns.

20. snow advisory
Used when snowfall amounts are below warning criteria, but nonetheless pose a hazard to the public. Issued for average snowfall amounts of less than 4" in a 12 hour period. Forecast amounts would be 1-2", 1-3", 2-4", or around 3".