why US middle west is dry elevation profile

Question

This cross US line's elevation profile shows that US east is under 1000 meter flat, rain falls from atlantic ocean can reach. 

Right at colorado, the elevation raised to 2000+ to 3000+ meters, rain falls was stop by these mountain. My experience is rain falls can't pass over 1000 meter mountain.  One side is raining the other side has no rain, if the mountain higher than 1000 meter.  Rocky mountain is 2000 - 3000 meters high, obviously will stop any rain falls.

 

https://transparentgov.net:3200/googlemaps110/default?layer_id=0&layer=Protected+Areas+Database+of+the+United+States+%28PAD-US%29+v3.0&center_lat=38.763769340293265&center_long=-98.56450847052143&center_zoom=5&url=https%3A%2F%2Fgis.usgs.gov%2Fpadus%2Frest%2Fservices%2Fpadus3%2FFee_Managers%2FMapServer&overlayType=overlayType_image&panto=0&overlayOpacity=6&click_function=show_elevation_along_path&elevation_path_sample_count=40

 

 

 

 

https://transparentgov.net/json2tree/esri/server/folder.html?url=https%3A%2F%2Fgis.usgs.gov%2Fpadus%2Frest%2Fservices&org=USGS+Protected+Areas+PAD%2C%26nbsp%3B%26nbsp%3B&cross=default&timeout=10000&select_folder=14&select_layer=0