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USA Weather — Glossary Word Search SW

This is the glossary of terms used by USA Weather, Inc. Please select a Letter, the hash tag, or search by term to begin your search. You may search by term and match the term exactly, or match all terms that include your term.

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There are 18 results matching the term SW !
ELSW
Elsewhere
Primary Swell Direction
Prevailing direction of swell propagation.
Short Wave Fade (SWF)
In solar-terrestrial terms, a particular ionospheric solar flare effect under the broad category of sudden ionospheric disturbances (SIDs) whereby short-wavelength radio transmissions, VLF, through HF, are absorbed for a period of minutes to hours.
SW
1. Southwest

2. Snow Showers
SWD
On a buoy report, Swell Direction is the compass direction from which the swell wave are coming from.
SWE
Snow Water Equivalent (the amount of water content in a snowpack or snowfall).
SWEAT
Severe Weather ThrEAT index; a stability index developed by the Air Force which incorporates instability, wind shear, and wind speeds as follows:

SWEAT=(12 Td 850 ) + (20 [TT-49]) +( 2 f 850) + f 500 + (125 [s+0.2]) where
  • Td 850 is the dew point temperature at 850 mb,
  • TT is the total-totals index,
  • f 850 is the 850-mb wind speed (in knots),
  • f 500 is the 500-mb wind speed (in knots), and
  • s is the sine of the angle between the wind directions at 500 mb and 850 mb (thus representing the directional shear in this layer).

SWEAT values of about 250-300 or more indicate a greater potential for severe weather, but as with all stability indices, there are no magic numbers.

The SWEAT index has the advantage (and disadvantage) of using only mandatory-level data (i.e., 500 mb and 850 mb), but has fallen into relative disuse with the advent of more detailed upper air sounding analysis programs.
Swell
Wind-generated waves that have travelled out of their generating area. Swells characteristically exhibit smoother, more regular and uniform crests and a longer period than wind waves.
Swell Direction
The direction from which the swells are propagating.
SWH
On a buoy report, swell height is the vertical distance (meters) between any swell crest and the succeeding swell wave trough.
SWLY
Southwesterly
SWODY1
The Day-1 Convective Outlook, sometimes called the "AC" is a guidance product issued by the Operational Guidance Branch (OGB) unit of the Storm Prediction Center (SPC) in Norman, Oklahoma. The Day 1 outlook outlines areas in the continental United States where severe thunderstorms may develop during the next 6 to 30 hours.
SWODY2
The Day 2 Convective Outlook is very similar to the Day 1 Outlook. It is issued only twice a day, at 08Z and 18Z, and covers the period from 12Z the following day to 12Z the day after that. For example, if today is Monday then the Day 2 Outlook will cover the period 12Z Tuesday to 12Z Wednesday. The outlook issued at 08Z now qualifies the degree of risk like the Day 1 has (i.e. SLGT, MDT, and HIGH risk areas). The Day 2 Outlook has also includes a general thunderstorm outline.
SWP
On a buoy report, Swell Period is the time (usually measured in seconds) that it takes successive swell wave crests or troughs pass a fixed point.
SWRN
Southwestern
SWS
Severe Weather Statement
SWWD
Southwestward
WSW
Winter Storm Message