Rashi citing Targum Yonasan: For they are called Banim, and their deeds ruin greatly. "Achim" is an expression of a bad matter, like "Ach Asuyah l'Varak", "Ach El Kol ha'To'evos" (Yechezkel 21:20, 6:11). "Yafri" is [an expression of growing,] like "Poreh Rosh v'La'anah" (Devarim 29:17).

Rashi #1: "Achim" is like "va'Tir'enah ba'Achu" (Bereishis 41:2). It sprouts like something that grows on a stream - it grows constantly.

Rashi #2: Yaravam is a son who perturbed the brotherhood of Yisrael - via him, it split into two kingdoms. Yafri is like "Pere Adam" (Bereishis 16:12).

Radak: Efrayim grew among brothers. Until he made the calves, he grew among his brothers, like Yakov said about him "v'Ulam Achiv ha'Katan Yigdal Mimenu v'Zaro Yihyeh Melo ha'Goyim" (Bereishis 48:19).

Malbim: This refers to the Nochem (one who regrets). He bears fruits only among brothers - when Yisrael are brothers and join one to another, then there can be regret. In the days of Hoshe'a ben Elah, they abandoned serving the calves and abolished the guards that Yaravam established to stop Yisrael from ascending for the Regel. However, there were groups that opposed him for this, and slandered him to Melech Ashur. It says in Divrei ha'Yamim II, Perek 30, that Chizkiyah sent messengers to the Shevatim to return to Hashem. They scoffed at them; a minority were humbled and returned to Yerushalayim.

Rashi: It says so, for it was compared to Achu (a swamp; a wind will dry it).

Rashi citing Targum Yonasan: A king strong like the east wind will come via Hashem's word from the way of the Midbar.

Malbim: Now that Efrayim sinned, now "Kadim Ru'ach Hashem", i.e. Melech Ashur, will come. He is called Kadim, for Ashur is east of Eretz Yisrael. Also, the east wind is harsh. He will dry (destroy) the land - the source of Yisrael.

Radak #1: This is to aggrandize and strengthen it, like "k'Harerei Kel" (Tehilim 36:7), "Shalheves Kah" (Shir ha'Shirim 8:6).

Radak #2: Hashem aroused [Melech Ashur's] spirit to come against Yisrael, like "va'Ya'ar Elokei Yisrael Es Ru'ach Pul Melech Ashur v'Es Ru'ach Tiglas Pil'eser Melech Ashur" (Divrei ha'Yamim I, 5:26). Also when Menachem [ben Gadi] became king, it says "Ba Ful... Al ha'Aretz", and in the days of Pekach "Ba Tiglas Pil'eser Melech Ashur" (Melachim II, 15:19, 29).

Radak #1: There is always wind in the Midbar.

Radak #2: There is a Midbar between Eretz Yisrael and Ashur. Due to that Ru'ach (Melech Ashur), "[Efrayim's] source will dry." Initially Efrayim was like a tree growing on water - "Ben Poras Yosef Ben Poras Alei Ayin" (Bereishis 49:22). Now "its source will dry and its spring will be destroyed" due to that Ru'ach.

Radak: It will dry. This is like "Charvu ha'Mayim" (Bereishis 8:13).

Malbim: It is because the spring's source dried. Yisrael were scattered to the four directions, and was destroyed their water of influence, existence and success.

Rashi: That king will devour the storehouse of all desired Kelim.