Flooding Rains and a Cascade Snowstorm.

After a week of cold wet weather with a few snow showers on Sunday we are continuing this stubborn weather that just wont go away.

Starting tonight a big slug of moisture will begin hitting it us bring lots of rain through the next 2-3days.

So just how much rain? Well models are showing the 3 day rain fall totals reaching near the 3 inch mark. Now if that much rain will fall then there could be some serious flood threats to already high rivers.

The image below is the 3 day rainfall forecast ending Thursday morning

Now this rain will not be a warm pineapple express  but instead a cold frontal 40 degree rain. The thing is this being a cold rain will mean snow up in the hills. Now a usual precip to snow ratio is 1 to 10 inches, which means 1 inch of rain is equal to about 10 inches of snow and if you look at the forecast rain totals above and change that to snow, places in the Cascades could get nearly 3 feet of snow in the next 3 days.

 The image below shows the 24 hour forecast snowfall totals ending 5pm Wednesday   

Ranging from 20 to 40 inches in spots!

Later in the evening on Wednesday as the cold front begins to move things could get interesting. Cold air advection will begin taking place and bottling up cold air along the west slopes of the Cascades. This will lead to lowering snow levels, now if the enough cold air bottles up it could lower the snow level down to the valley floor in the eastern part of the metro area, such as Battle Ground, Gresham, Oregon City, Camas...ect. But for now I am saying that we will only get a rain/snow mix with the snow level staying above 500ft.

Thanks for reading 

-Michael