Christie’s Pretzels uses a weighted moving average method to forecast pretzel sales. It assigns a weight of 5 to the previous month's demand, 3 to demand 2 months ago, and 1 to demand 3 months ago. If sales amounted to 500 pretzels in May, 1,200 pretzels in June, and 2,250 pretzels in July, what should be the forecast for August?