While they go to London stadium having won five of their past six games, Newcastle are yet to record two consecutive victories in the Premier League so far this term.
After last weekend's win against Fulham, Howe said ahead of Sunday's trip: "It will be huge for us. It's only with back to back wins are we going to propel ourselves up the league table. There's a lot of teams around us in the table and you are looking for one win to break out of it. These next two games are big games for us."
The match is likely to see former Toon striker Callum Wilson in the line-up for West Ham and Howe continued: "It will be great to see Callum but most importantly we have a job to do against him. I have spoken about how much quality he has and I am looking forward to seeing him and embracing him after the game but we have a job to do first to stop him."
On West Ham overall, Howe said: "They have a group of very good players, especially in attacking areas. We need to keep a good defensive structure and limit their space. Our away form hasn't been strong enough and that is something we are looking to rectify."
Woltemade impact
Meanwhile, Howe was also asked about how happy he was with the first months of summer signing Nick Woltemade.
The Germany centre-forward now has six goals in his first ten appearances for Newcastle.
Howe said, "It's early days and I would prefer to keep my answer saved for a future date because time will tell. But on and off the pitch he has been first class and his team ethics are brilliant.
"Some of the interplay on Wednesday, he was pivotal to it. We still have to bring out more from his game but the early signs are really positive. He has variety and he is not one dimensional.
"With his height and technical ability, it can be a surprise for his opponents. His challenge is consistency and long term success as teams find plans with how to deal with him."
On the fitness of fellow summer striker signing Yoane Wissa, Howe was eager to douse expectations. The manager insisted Wissa is "definitely not" back for West Ham and isn't close to training with the group as he builds up his fitness after a knee injury suffered in August.
Fulham in the Cup
Meanwhile, Howe was also asked about drawing Fulham in the Carabao Cup quarterfinals. The holders reached the final eight after an impressive win against Tottenham midweek.
Howe smiled: "We asked for a home tie so that was gratefully received. Tough game. Having just played against Fulham that makes it a very interesting one for us. It was a very narrow victory.
"Every game against a Premier League team is very difficult. We look forward to it when it comes round, but we are pleased to be at home."