Their proposal is for a building with an angular roofscape, referencing the traditional wooden houses of domestic Baltic architecture, where steeply pitched roofs are designed to support heavy snowfall.
These tilted forms will incorporate north-facing glazing, "so that the pure northern light is sculpted into intimate or larger gallery environments", according to the team.
A sloped plaza will provide a performance area for special events, while a grand concourse inside will feature a cast concrete waffle structure, designed to improve acoustics.
The main staircase features combination of a concrete base with a solid timber guardrail that matches the exterior wood cladding and leads to galleries, which are wrapped in a skin of red stained vertical fins to match the Latvian flag.
"This museum will be a beacon that both celebrates Latvia's incredible artistic legacy and meaningfully links the country to the international art community," said David Adjaye in a statement.
The cultural building will be the first museum of contemporary art to be built in Latvia since the country gained independence. It will showcase art and visual culture from the Baltic Sea region from the 1960s to the present day.
The jury – which included OMA partner Reinier de Graaf, Italian architect Gianni Botsford and Latvian architect Uldis Balodis – praised the design for its distinctive silhouette.
They claim the cultural building will become a significant landmark for the city.
"Through the use of wood and form, the concept design subtly references Latvian architecture, proposing a very animated structure with a lively entrance that will enable the museum to create architectural presence in a new and emerging district," said V&A design director David Bickle, who chaired the jury.
"The design is very welcoming and porous – it has the potential to be loved."
Set to open on 18 November 2021, the €30 million (£24 million) museum will be located in the New Hanza City – at the edge of Riga's Art Nouveau district – a new 24.5-hectare district in the north of the city that includes offices, apartments, a hotel, a nursery school and a public garden.
The scheme will mainly be financed through the Boris and Inara Teterev Foundation and the ABLV Charitable Foundation, but will also receive funding from the Ministry of Culture of the Republic of Latvia.
David Adjaye's major current projects include the Smithsonian Museum of African American History, which is due to open 24 September 2016 in Washington DC.
The practice is also working on a new home for the Studio Museum in Harlem, New York and is shortlisted for the Obama Presidential Center, set to be built in Chicago.
AB3D was a finalist for the Latvian Architecture Award 2015 for its design of the Rezekne University Department of Engineering.