Simplify the following text for a Grade 10 native English-speaking person.
Original: A strong ridge of high pressure over the Northeastern Pacific Ocean forced John westward , where upper level shear kept John a tropical storm as its intensity fluctuated .
Simplified: A strong ridge of high pressure over the Northeastern Pacific Ocean forced John westward , where upper level wind shear kept John a tropical storm . Intensity fluctuated considerably , however , as shear levels varied .