Design a visually captivating Black Friday promotional banner in a 16:9 format, emphasizing the urgency of the sale. The banner should prominently feature the words 'BLACK FRIDAY' in a modern bold font, utilizing a striking white color with a vibrant orange shadow to create depth and impact. Below this, the text '50% OFF' should be displayed in a bold red, ensuring it stands out as a key focal point. Flanking the text, place analog countdown clocks styled in black and orange, designed to match the overall theme and evoke a sense of urgency. The background should be dynamic, filled with radial lines that create a sense of excitement and movement, transitioning from a rich orange at the center to a lighter hue at the edges. This design should maintain a transparent background for versatility in media integration. The overall aesthetic should be modern and bold, with a clear emphasis on the promotional message, ensuring that it captures the attention of potential shoppers and encourages them to take action.