I-24 crosses into Tennessee traveling in a southeasterly and northwesterly direction in Clarksville, Montgomery County. Soon after Fort Hall, the Oregon and California trails diverged in northwesterly and southwesterly directions. The winter winds tend to be strongest in June and are generally northwesterly. Embedded within a northwesterly deep layer mean flow, the system tracked southeast. It is traversed by the northwesterly line of equal latitude and longitude. The shamal, a northwesterly wind common during June and July, causes dramatic sandstorms. It proceeds in a northwesterly direction crosstown. Thereafter, the storm began to weaken and moved in a more northwesterly direction. The high pressure cell inhibits rainfall and generates northwesterly air flow. Valley Parkway parallels the river's northwesterly course. The storm's path curved back to a northwesterly heading by the October 15. The northwesterly advancing lava forced the ancient Columbia River into its present course. An approaching upper level trough caused Frances to move more northwesterly on August 27. The ancient Columbia River was forced into its present course by the northwesterly advancing lava. The aircraft then continued to fly in a northwesterly heading.