Since, by definition, TEMPO conditions will prevail for less than half
the time the 'most likely' conditions are the permanent (BECMG) conditions.
BECMG 2123 changes the lowest cloud base to 3 to 4 oktas at 1,500ft by
2300hrs. The TEMPO 2306 indicates that the cloud base could,
temporarily come down to 800ft but the permanent conditions are more likely.