What does BLU+ mean in a METAR? I know that BLU is military code and means "Ceiling at or above 2,500 feet; Visibility at or above 8,000 meters". 

ETSH 241320Z 19007KT 9999 SCT048 SCT160 BKN200 08/03 Q1008 BLU+

ETSH 241220Z 20005KT 9999 FEW050 SCT160 BKN240 08/03 Q1009 BLU+

But what does + at the end signify?
Per the German Meteorological Service, the + means a ceiling 20,000 feet or higher.


  BLU: visibility>=8000m, ceiling 2500 - &lt;20000 ft
  
  BLU+: visibility>=8000m, ceiling >=20000 ft