Hold onto your hats, development watchers of Atlanta! Something big could be afoot later this month.

Portman Holdings is partnering with Georgia Tech for an "exclusive announcement" on April 20 regarding "the next phase of Tech Square and the future of the Midtown skyline," according to a press flyer released today. Mayor Kasim Reed and other dignitaries are scheduled to make remarks.

What could this mean? A solid start date for the much-anticipated High Powered Computing Center (HPCC) at Tech Square? Exciting new details about the project? An official decree that it's 420 in the ATL?

Portman Holdings's website now says construction on the HPPCC will begin in late 2016. The mixed-use goliath is planned to have nearly 930,000 square feet of offices, research labs, a data center, and retail. (For context, Bank of America Plaza around the corner encompasses about 1.3 million square feet of floor space).

Notably, the design will incorporate what's left of the 1926 Crum & Forster building and include a soaring public space at ground level. The flyer (below) gives a visual preview of what's to come, where Spring and 4th streets meet in Midtown: