There are a few things to consider when reading a METAR.
A METAR is updated in intervals, meaning the cloudbase has to hit certain "steps" before a SPECI is issued, and if the METAR is sent regularly..... you won´t even see a SPECI anymore. Updates to improvements rewuires the improvement to stay for a while before being reported, whereas deteriorations will be given straight away.
What you get from a METAR is based on the value overhead the airport itself, and with automation, that would be overhead the cielometer exactly....