Although the 24-hour amber warning is not unprecedented, forecasters noted it is unusual because of the length of time it will remain in place over such a wide geographical area. Forecasters stated that some areas of Scotland could experience 60-80mm of rain on Friday, with flooding likely as a result of the severe weather.
The latest Met Office advisories also include a yellow warning for rain in central and eastern areas, taking effect from 07:00 on Friday until midnight.
Currently, there are no official flood warnings in place, which are more severe than alerts because they indicate that flooding is expected.
Transport Scotland warned that road, rail, air and ferry services are all likely to be affected by the conditions.
The disruptions could bring longer journey times and cancellations, alongside potential restrictions on bridges and other exposed routes.
Storm Boelo will bring very strong westerly winds on Saturday, featuring widespread gusts of 60-70mph and gusts reaching up to 80mph in exposed coastal areas.
The latest Met Office warnings include a yellow warning for rain, external in central and eastern areas from 07:00 on Friday until midnight.
On Saturday, Storm Boelo will bring very strong westerly winds with widespread gusts of 60-70mph (96.6-112.7km/h), and gusts up to 80mph (128.7km/h) in exposed coastal areas.
Although the 24-hour amber warning is not unprecedented, it is unusual because of the length of time it will be in place over such a wide geographical area.
However, forecasters say some areas of Scotland could experience 60-80mm (2.4-3.1in) of rain on Friday with flooding likely.