Met Office spokesman Grahame Madge says gusts will reach about 50mph tomorrow, rather than the 80mph originally predicted on Friday.
But a new yellow - "be aware" - warning for wind has been issued for all of Scotland between 6am and 10pm on Wednesday, with gusts potentially reaching 60mph.
And Mr Madge warned that the storm will still be strong enough to bring down trees, adding: "At this time of year, when trees are in full leaf and the wind catches the leaves, there can be more chance of uprooting and an impact with falling trees on power lines and roads."
A yellow warning for wind had been issued for the whole of the Scottish Borders and Dumfries and Galloway between 9pm tonight and 6pm tomorrow - but this has since been lifted.
The Met Office website says that the new weather warning on Wednesday could mean damage to buildings, including tiles being blown from roofs or falling trees and branches.
Road, rail, air and ferry services may be affected, with longer journey times and cancellations possible, and some roads and bridges may be forced to close.
Mr Madge said: "This week will be pretty unsettled. Helene is coming through overnight tonight bringing wind and rain. The rain will be heaviest in the west, between Glasgow and Fort William. There will be rain in the east but it won't be so heavy.
"It's not quite as a significant as predicted at the end of last week but the warning is still valid and relevant."
Temperatures in the central belt and southern parts of Scotland will reach up to 17C or 18C today and potentially 19C tomorrow, due to the warmer air brought in by the storm. The average Scottish daily maximum temperature for this time in September is 14C.
He said that in England, where the storm will have a bigger impact, the mercury is expected to hit "mid-20s."