It comes a week after Storm Ciara battered our region.
Storm Dennis will bring a month of rainfall for some parts of the UK in just 24 hours this weekend, the Met Office has said.
It has issued an amber warning for rain for some parts of West Yorkshire, as well as less serious yellow warnings for both wind and rain.
The amber warning comes into force at midday on Saturday and covers the Upper Calder Valley including Hebden Bridge, Mytholmroyd and Todmorden, as well as the Keighley area, including Bingley and Haworth.
Meanwhile the whole of West Yorkshire is covered by lower level yellow warnings, one for wind which comes into force at 10am on Saturday, and one for rain from midday on Saturday.
On the trains, it's already been decided that the line between Hebden Bridge and Rochdale will be closed from 5pm on Saturday until 10am on Sunday as a precaution.
This means during those times Northern services on the Calder Valley line from Leeds and Bradford will terminate at Hebden Bridge and not run through to Manchester Victoria.
Anyone wanting to get to Manchester can go via Leeds and change onto a Transpennine Express train there for no extra cost.
It is feared that properties could be flooded or even cut off - partly because Storm Ciara has already saturated the ground.
Dennis may bring wind speeds - especially in coastal regions - of up to 70mph.
Worst-affected areas will see more than 100mm of rain in one day, while between 40-80mm is likely in other parts of the UK.
"Even in London and parts of the South East there could be three quarters of a month's rainfall," Tom Morgan from the Met Office told Sky News.
Power supplies could be damaged and public transport delayed or cancelled. Coastal areas are likely to be battered by huge waves.
Storm Dennis will sweep in on Saturday morning bringing warm and moist air, Mr Morgan said.
While it will be a "notch down from last weekend", when Storm Ciara brought winds of up to 97mph, he described Dennis as a "very potent deep area of low pressure".
Given its name by the Met Office, Dennis is developing in the North Atlantic before tracking eastwards towards the UK and Ireland.