Subj : Wx Terms (S)(8)
To : All
From : Daryl Stout
Date : Wed Sep 20 2017 12:05 am
Station Model
A specified pattern for plotting, on a weather map, the meteorological
symbols that represent the state of the weather at a particular observing
station.
Station Pressure
The absolute air pressure at a given reporting station. The air pressure
is directly proportional to the combined weight of all air in the
atmosphere located in a column directly above the reporting site.
Consequently, the station pressure may vary tremendously from one
location to another in mountainous regions due to the strong variation of
atmospheric pressure with height. Vertical variations of pressure range
up to 150 mb per mile whereas horizontal variations are usually less than
.1 mb per mile.
Stationary Front
A front between warm and cold air masses that is moving very slowly or not
at all.
STBL
Stable
Steam Fog
Fog formed when water vapor is added to air which is much colder than the
source of the vapor. It may be formed when very cold air drifts across
relatively warm water. At temperatures below about -20�F, ice particles or
droxtals may be formed in the air producing a type of ice fog known as
frost smoke.
Steepness
In marine terms, on a buoy report, wave steepness is the ratio of wave
height to wave length and is an indicator of wave stability. When wave
steepness exceeds a 1/7 ratio, the wave becomes unstable and begins to
break.
Steering Currents
Same as Steering Winds; a prevailing synoptic scale flow which governs
the movement of smaller features embedded within it.
Steering Winds
Same as Steering Currents; A prevailing synoptic scale flow which governs
the movement of smaller features embedded within it.
Stepped Leader
A faint, negatively charged channel that emerges from the base of a
thunderstorm and propagates toward the ground in a series of steps of
about 1 microsecond duration and 50-100 meters in length, initiating a
lightning stroke.
STFR
Stratus Fractus
STG
Strong
Stilling basin
In hydrologic terms, a basin constructed to dissipate the energy of
fast-flowing water (e.g., from a spillway or bottom outlet), and to
protect the streambed from erosion.
STJ
Subtropical Jet - this jet stream is usually found between 20� and 30�
latitude at altitudes between 12 and 14 km.
STLT
Satellite
STM
Stratiform
STNRY
Stationary
Stoplogs
In hydrologic terms, large logs, timbers or steel beams placed on top of
each other with their ends held in guides on each side of a channel or
conduit providing a temporary closure versus a permanent bulkhead gate.
Storm
Any disturbed state of the atmosphere, especially affecting the Earth's
surface, and strongly implying destructive and otherwise unpleasant
weather. Storms range in scale from tornadoes and thunderstorms to
tropical cyclones to synoptic-scale extratropical cyclones.
Storm Data
This National Climatic Data Center (NCDC) monthly publication documents
a chronological listing, by states, of occurrences of storms and unusual
weather phenomena. Reports contain information on storm paths, deaths,
injuries, and property damage. An "Outstanding storms of the month"
section highlights severe weather events with photographs, illustrations,
and narratives. The December issue includes annual tornado, lightning,
flash flood, and tropical cyclone summaries.
Storm Motion
The speed and direction at which a thunderstorm travels.
Storm Relative
Measured relative to a moving thunderstorm, usually referring to winds,
wind shear, or helicity.
Storm Relative Mean Radial Velocity Map
(SRM): This WSR-88D radar product depicts a full 360� sweep of radial
velocity data with the average motion of all identified storms subtracted
out. It is available for every elevation angle sampled. It is used to aid
in displaying shear and rotation in storms and storm top divergence that
might otherwise be obscured by the storm's motion, investigate the 3-D
velocity structure of a storm, and help with determining rotational
features in fast and uniform moving storms.
Storm Relative Mean Radial Velocity Region
(SRR): This WSR-88D radar product depicts a 27 nm by 27 nm region of storm
relative mean radial velocity centered on a point which the operator can
specify anywhere within a 124 nm radius of the radar. The storm motion
subtracted defaults to the motion of the storm closest to the product
center, or can be input by the operator. It is used to examine the
3-dimensional storm relative flow of a specific thunderstorm (radar
operator centers product on a specific thunderstorm; aid in displaying
shear and rotation in thunderstorms and storm top divergence that might
otherwise be obscured by storm motion; and gain higher resolution
velocity product.
Storm Scale
Referring to weather systems with sizes on the order of individual
thunderstorms. See synoptic scale and mesoscale.
Storm Surge
An abnormal rise in sea level accompanying a hurricane or other intense
storm, whose height is the difference between the observed level of the
sea surface and the level that would have occurred in the absence of the
cyclone. Storm surge is usually estimated by subtracting the normal or
astronomic tide from the observed storm tide.
Storm Tide
The actual level of sea water resulting from the astronomic tide combined
with the storm surge. Most NWS flood statements, watches, or warnings
quantifying above-normal tides will report the Storm Tide.
Storm Total Precipitation
This radar image is an estimate of accumulated rainfall since the last
time there was a one-hour, or more, break in precipitation. It is used to
locate flood potential over urban or rural areas, estimate total basin
runoff and provide rainfall accumulations for the duration of the event
and is available only for the short range (out to 124 nm). To determine
accumulated precipitation at greater distances you should link to an
adjacent radar.
Storm Tracking Information
This WSR-88D radar product displays the previous, current, and projected
locations of storm centroids (forecast and past positions are limited to
one hour or less). Forecast tracks are based upon linear extrapolation of
past storm centroid positions, and they are intended for application to
individual thunderstorms not lines or clusters. It is used to provide
storm movement: low track variance and/or 2 or more plotted past positions
signify reliable thunderstorm movement.
Storm Warning
A warning of sustained surface winds, or frequent gusts, in the range of
48 knots (55 mph) to 63 knots (73 mph) inclusive, either predicted or
occurring, and not directly associated with a tropical cyclone.
Stormwater Discharge
In hydrologic terms, precipitation that does not infiltrate into the
ground or evaporate due to impervious land surfaces but instead flows
onto adjacent land or water areas and is routed into drain/sewer systems.
Straight-Line Hodograph
The name pretty well describes what it looks like on the hodograph. What
causes this shape is a steady increase of winds with height (vertical
wind shear). This shape of hodograph favors multicell thunderstorms.
Straight-line Winds
Generally, any wind that is not associated with rotation, used mainly to
differentiate them from tornadic winds.
Stratiform
Having extensive horizontal development, as opposed to the more vertical
development characteristic of convection. Stratiform clouds cover large
areas but show relatively little vertical development. Stratiform
precipitation, in general, is relatively continuous and uniform in
intensity (i.e., steady rain versus rain showers).
Stratiform Rings and Bands
These occur between the active convective bands of a hurricane outside of
the eye wall. Inner stratiform bands often exhibit the bright band aloft,
a VIP Level 2, and in the lower layers typically show a VIP Level 1.
Stratocumulus
Low-level clouds, existing in a relatively flat layer but having
individual elements. Elements often are arranged in rows, bands, or
waves. Stratocumulus often reveals the depth of the moist air at low
levels, while the speed of the cloud elements can reveal the strength of
the low-level jet.
Stratopause
The boundary between the stratosphere and mesosphere.
Stratosphere
The region of the atmosphere extending from the top of the troposphere to
the base of the mesosphere, an important area for monitoring stratospheric
ozone.
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