Subj : Wx Terms (S)(6)
To   : All
From : Daryl Stout
Date : Tue Jun 20 2017 12:09 am

SOI
Southern Oscillation Index - a numerical index measuring the state of the
Southern Oscillation. The SOI is based on the (atmospheric) pressure
difference between Tahiti and Darwin, Australia. It is highly correlated
with tropical sea surface temperature anomaly indices recorded in Ni�o3.

Soil Moisture
Water contained in the upper part of the soil mantle. This moisture
evaporates from the soil and is the used and transpired by vegetation.

Solar Coordinates
In solar-terrestrial terms, Central Meridian Distance (CMD). The angular
distance in solar longitude measured from the central meridian.

Solar Cycle
In solar-terrestrial terms, the approximately 11-year quasi-periodic
variation in frequency or number of solar active events.

Solar Maximum
In solar-terrestrial terms, the month(s) during the solar cycle when the
12-month mean of monthly average sunspot numbers reaches a maximum.

Solar Minimum
In solar-terrestrial terms, the month(s) during the solar cycle when the
12-month mean of monthly average sunspot numbers reaches a minimum.

Solar Noon
The time of day at which the sun is the highest in the sky. This time
varies through the year due to the change in speed of the earth's orbit
around the sun.

Solar Sector Boundary (SSB)
In solar-terrestrial terms, the apparent solar origin, or base, of the
interplanetary sector boundary marked by the larger-scale polarity
inversion lines.

Solar Wind
The outward flux of solar particles and magnetic fields from the sun.
Typically, solar wind velocities are near 350 km/s.

SOLN
Solution

SOLNS
solutions

Solstice
Either of the two times per year when the sun is at its greatest
angular distance from the celestial equator: about June 21 (the Northern
Hemisphere summer solstice), when the sun reaches its northernmost point
on the celestial sphere, or about December 22 (the Northern Hemisphere
winter solstice), when it reaches its southernmost point.

SOO
Science and Operations Officer

Sounding
A set of data measuring the vertical structure of an atmospheric
parameter (temperature, humidity, pressure, winds, etc.) at a given time.

Southern Oscillation
(SO) - a "see-saw" in surface pressure in the tropical Pacific
characterized by simultaneously opposite sea level pressure anomalies at
Tahiti, in the eastern tropical Pacific and Darwin, on the northwest
coast of Australia. The SO was discovered by Sir Gilbert Walker in the
early 1920's. Walker was among the first meteorologists to use the
statistical techniques to analyze and predict meteorological phenomena.
Later, the three-dimensional east-west circulation related to the SO was
discovered and named the "Walker Circulation". The SO oscillates with a
period of 2-5 years. During one phase, when the sea level pressure is
low at Tahiti and High at Darwin, the El Ni�o occurs. The cold phase of
the SO, called "La Ni�a" by some, is characterized by high pressure in
the eastern equatorial Pacific, low in the west, and by anomalously cold
sea surface temperature (SST) in the central and eastern Pacific. This is
called El Ni�o Southern Oscillation or ENSO.

Southern Oscillation Index
A numerical index measuring the state of the Southern Oscillation. The
SOI is based on the (atmospheric) pressure difference between Tahiti and
Darwin, Australia. It is highly correlated with tropical sea surface
temperature anomaly indices recorded in Ni�o3.

Space Environment Center
(SEC) - This center provides real-time monitoring and forecasting of
solar and geophysical events, conducts research in solar-terrestrial
physics, and develops techniques for forecasting solar and geophysical
disturbances. SEC's parent organization is the National Oceanic and
Atmospheric Administration (NOAA). SEC is one of NOAA's 12 Environmental
Research Laboratories (ERL) and one of NOAA's 9 National Centers for
Environmental Prediction (NCEP). SEC's Space Weather Operations is
jointly operated by NOAA and the U.S. Air Force and is the national and
world warning center for disturbances that can affect people and
equipment working in the space environment.

SPC
Storm Prediction Center

SPCLY
Especially

SPD

1) Speed

2) On a buoy report, ten-minute average wind speed values in m/s.

Spearhead Echo
A radar echo associated with a downburst with a pointed appendage
extending toward the direction of the echo motion. The appendage moves
much faster than the parent echo, which is drawn into the appendage.
During its mature stage, the appendage turns into a major echo and the
parent echo loses its identity.

Special Avalanche Warning
Issued by the National Weather Service when avalanches are imminent or
occurring in the mountains. It is usually issued for a 24 hour period.

Special Fire Weather
Meteorological services uniquely required by user agencies which cannot
be provided at an NWS office during normal working hours. Examples are
on-site support, weather observer training, and participation in user
agency training activities.

Special Marine Warning
(SMW) A warning product issued for potentially hazardous weather
conditions usually of short duration (up to 2 hours) producing sustained
marine thunderstorm winds or associated gusts of 34 knots or greater;
and/or hail 3/4 inch or more in diameter; and/or waterspouts affecting
areas included in a Coastal Waters Forecast, a Nearshore Marine Forecast,
or an Great Lakes Open Lakes Forecast that is not adequately covered by
existing marine warnings. Also used for short duration mesoscale events
such as a strong cold front, gravity wave, squall line, etc., lasting
less than 2 hours and producing winds or gusts of 34 knots or greater.

Special Tropical Disturbance Statement
This statement issued by the National Hurricane Center furnishes
Information on strong and formative non-depression systems. This
statement focuses on the major threat(s) of the disturbance, such as
the potential for torrential rainfall on an island or inland area. The
statement is coordinated with the appropriate forecast office(s).

Specific Gravity
The ratio of the density of any substance to the density of water.

Specific Humidity
In a system of moist air, the ratio of the mass of water vapor to the
total mass of the system.

Specific Yield
In hydrologic terms, the ratio of the water which will drain freely from
the material to the total volume of the aquifer formation. This value
will always be less than the porosity.

Spectral Density
A radar term for the distribution of power by frequency.

Spectral Wave Density
On a buoy report, energy in (meter*meter)/Hz, for each frequency bin
(typically from 0.03 Hz to 0.40 Hz).

Spectral Wave Direction
On a buoy report, mean wave direction, in degrees from true North, for
each frequency bin.

Spectrum Width
This WSR-88D radar product depicts a full 360 degree sweep of spectrum
width data indicating a measure of velocity dispersion within the radar
sample volume. It is available for every elevation angle sampled, it
provides a measure of the variability of the mean radial velocity
estimates due to wind shear, turbulence, and/or the quality of the
velocity samples. It is used to estimate turbulence associated with
boundaries, thunderstorms, and mesocyclones; check the reliability of
the velocity estimates; and locate boundaries (cold front, outflow,
lake breeze, etc.).

Spectrum Width Cross Section
This WSR-88D radar product displays a vertical cross section of spectrum
width on a grid with heights up to 70,000 feet on the vertical axis and
distance up to 124 nm on the horizontal axis. Two end points to create
cross section are radar operator selected along a radial or from one
AZRAN to another AZRAN within 124 nm of the radar that are less than
124 nm apart.

It is used to:

1) Verify features on the Reflectivity Cross Section (RCS) and Velocity
Cross Section (VCS) and to evaluate the quality of the velocity data.

2) Estimate vertical extent of turbulence (aviation use).

Speed Shear
The component of wind shear which is due to a change in wind speed with
height, e.g., southwesterly winds of 20 mph at 10,000 feet increasing to
50 mph at 20,000 feet. Speed shear is an important factor in severe
weather development, especially in the middle and upper levels of the
atmosphere.

SPENES
NESDIS Satellite Precipitation Estimates



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