Weather forecaster that can take the pressure? (9)
I believe the answer is:
barometer
'weather forecaster' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
(Other definitions for barometer that I've seen before include "It measures air pressure" , "Weatherglass" , "Instrument to measure atmospheric pressure" , "Pressure gauge" , "Air-pressure measurer" .)