What does SWES mean in SNOWTAM? The resources explains that SWEN is the start for Snowtam. (Ref: Snowtam help ) But many snowtams I found starts with SWES which I could not find anything about. What is the difference? Can it have other values? Does snowtam always need to start with one of them?

Example Snowtam from Pilotweb

SWES0701 ESSB 12270841 
(SNOWTAM 0701
A) ESSB
B) 12270841 C) 12 F) 4/4/4 G) 1/1/1 H) 5/5/5
N) G1 R S T Y Y1 Y2 Y3
Y4 Y5 YU YW/4/GOOD
R) 1 2 3 4 6 7 EAST NORTH/4/MEDIUM
T) RWY 12 BA 60/48/41. RWY 12 COVER 100 PERCENT. APRON SANDED. ICE
PATCHES ON APRON.)
Snowtams follow the ICAO Format found in ICAO Annex 15, Appendix 2

This says that the abbreviated heading starts with SW** where ** is the ICAO location identifier. The location identifier document, ICAO 7910 is a \$245 document so I can't link to it here, but all the Swedish airports start with location identifers that are "ES", hence any SNOWTAM you find from Sweden will be SWES reports. Reports for the United States typically start with "K" so they would be SWK*. Canada is "C", so SWC*.