(b)
hurricanes, tropical storms; 

(c)
moderate hail; 

(d)
severe turbulence;

(e)
severe icing;

(f)
marked mountain waves; 

(g)
widespread sandstorms and dust storms; 

(h)
 volcanic ash;

(i)
 severe squall lines;

(j)
low-level wind shear; and

(k)
tornadoes or waterspouts. 

. abbreviation: SIGMET
Fr: renseignements météorologiques significatifs
significant point
(1) An expression used to describe a NAVAID, a fix derived from a NAVAID, or a geographical location as expressed in latitude and longitude.
Fr: point significatif
(2) ICAO: A specified geographical location used in defining an ATS route or the flight path of an aircraft and for other navigation and ATS purposes.
Fr: point significatif
simulated approach An instrument approach procedure (IAP) conducted in visual meteorological conditions (VMC) by an aircraft not on an IFR clearance.
. also called: practice instrument approach
Fr: approche simulée
simulated flameout A practice approach to a runway by a jet aircraft (normally military) at idle thrust. The approach may start at a relatively high altitude over a runway (high key) and may continue on a relatively high and wide downwind leg with a high rate of descent and a continuous turn to final.
. abbreviation: SFO
Fr: arrêt simulé de turbomoteur
simultaneous converging instrument approaches
A procedure for conducting two or more simultaneous instrument approaches to converging runways. 
. abbreviation: SCIA
Fr: approches aux instruments simultanées convergentes
simultaneous ILS/MLS approach procedures
Approach procedures permitting instrument landing system (ILS) and microwave landing system
(MLS) approaches to be conducted simultaneously at airports having parallel runways.
Fr: procédures d’approche ILS/MLS simultanées
Simultaneous Intersecting Runway Operations Canada: Former term for: Land and Hold Short Operations (LAHSO)
. abbreviation: SIRO
Fr: utilisation simultanée de pistes sécantes
Simultaneous Operations on Parallel or Near-Parallel Instrument Runways
A term used by ICAO to refer to operations in which aircraft conduct simultaneous approaches
and/or departures from parallel or near-parallel instrument runways.
.
abbreviation: SOIR

.
see also: Land and Hold Short Operations (LAHSO)
Note: Although the term “Simultaneous Operations on Parallel or Near-Parallel Instrument
Runways” is not used in the U.S. or Canada, these operations are.

Fr: opérations simultanées sur pistes aux instruments parallèles ou quasi parallèles