In reading the Key Design considerations to the Common Core (in the introduction) as well as portions of Appendix A, it's important to consider how writing and reading might be integrated. With evidence-based writing such a key element of the CCSS, the sources from which students students draw become just as important (sometimes more!) than the prompt itself.
It might be worth checking out the Close Reading exemplars found here: http://www.achievethecore.org/ela-literacy-common-core/sample-lessons/ Each of these lessons includes at least one (often more) culminating tasks which would be a great opportunity for writing instruction (following a close reading). The Anthology Alignment Project resources also include culminating tasks-- again, connecting writing to reading.
One more resource, "In Common," offers annotated student samples for grades K-12 in each of the 3 genres. (http://www.achievethecore.org/ela-literacy-common-core/student-writing-samples/)
Daily Writing Prompts
Writing prompts for different types of writing and a range of ages, organized by month.
Daily Writing Prompt
This site, designed by a teacher, offers a wide variety of writing prompts, available by genre or as story starters. It also includes an opportunity to publish student work.
Find links to lists of journal writing prompts here.
Language is a Virus
Click to generate a random writing prompt. Especially good for creative writing.
A Month of Writing Prompts
Writing prompts based on historical events with a suggestion for creative or analytical writing.
Pros, cons, models: it's all here. Access to this 79-page document requires Adobe Acrobat Reader. (Suggestion: download the entire file but print only the pages you want.)
SAT Essay Prep
A lesson plan for boosting scores on the SAT writing section. Includes handout.
Elementary students click through a fun interface to select a writing topic and format. They can print or download the finished story. Site includes teacher guide.
Writing prompts with a visual component. Most are designed for middle and high school students, but some may work with younger writers. Common Core standards indicated.
A generous list of topics for all ages.
A generous assortment of topics from Writers Digest. Most prompts are designed for high school and older and call for creative writing.
Writing Prompts for Middle School
Prompts for the following types of writing: expository/informative, persuasive, process, descriptive, narrative, writing about literature, writing about nonfiction. 3 pages; Adobe Reader required.
Topics for grades 1-12, organized by grade level. Follow links for student models.