Overall (like most of Scotland) the Eastern Cairngorms hills are relatively dry underfoot (particularly at elevation) due to lower than average precipitation over the winter and spring, consequently I'd be surprised if episodic rain events (as are forecast) would cause the Geldie to rise and stay high at the moment as the ground is not saturated, nor would I expect it rise dramatically quickly, run-off will be retarded, except if we get very heavy rain.
The forecast is for intermittent rain at present rather than constant. Obviously if the forecast changes and we get more rain than forecast, or if there is a specific high intensity deluge focused over the catchment (e.g. heavy thunder storm), this advice will not hold.
The eastern Cairngorm rivers have risen a little bit (dcm's rather than meters) following the w/e rain, but the hydrograph (and the view out of my kitchen window) shows they are rapidly falling. Gauging station data broadly supports my anecdotal observations of the effect of the winter and spring precipitation; with the current level at Mar Lodge on the Dee and Marble lodge on the Tilt, being at the bottom of their 'normal' ranges, close to being categorized as low flow:
http://apps.sepa.org.uk/waterlevels/?sd=t&lc=234274
http://apps.sepa.org.uk/waterlevels/?sd=t&lc=14959
Post edited at 11:32