Hi Captain BH,
Since you were above 1500ft, the Speed acceleration became almost Negative (so it was still positive - yes?), I would simply have reduced the ROC - level off if necessary.
As other posters have commented - it really isn't rocket science.
FCOM 1.22.40
"The windshear detection function is provided by the Flight Augmentation Computer (FAC) in takeoff and approach phase in the following conditions :
At takeoff, 3 seconds after liftoff, up to 1300 feet RA"