With a swollen cast boasting no fewer than a half dozen A-listers -- not to mention an equal number of character actors, there’s a lot of acting firepower vying for attention in John Wells’ August: Osage County. Fortunately for viewers, there’s ample material to go around and plenty of scenery to chew. That’s because of Tracy Letts’ source material that he adapted for the big screen from his Pulitzer Prize and Tony award-winning stage play of the same name.

August: Osage County is one of those separated-family-rejoins-over-the-loss-of-a-loved-one movies that always provides plenty of uncomfortably awkward situational humor and conversational gracelessness at the dinner table. This one is certainly no different, although you’ve likely never experienced “awkward” or “uncomfortable” quite like this, with foul-mouthed dialogue and excoriating criticism being doled out like candy at Halloween. There’s very little light in Letts’ story, and some may find its relentlessly callous black-hearted tone overwhelming at times. But true to that sultry month in the film’s title, there’s no escaping the heat in August.

The film stars Meryl Streep, Julia Roberts, Chris Cooper, Margo Martindale, and Juliette Lewis as the Weston family and relatives, brought together on the sweltering plains of Osage County, Oklahoma, over a recent family tragedy. Matriarch Violet (Streep), recently stricken with mouth cancer, is addicted to pain killers but never shies from doling out her own heartless brand of agony in the form of brutally pointed criticism directed at her middle-aged daughters Barbara (Julia Roberts), Ivy (Julianna Nicholson), and Karen (Lewis).

While Streep mugs for the camera with her grief-stricken Violet, our sympathies lie with her daughters, especially the eldest Barbara, who comes home from Colorado with her somber14 year-old daughter (Abigail Breslin) and estranged husband Bill (McGregor) in tow.

Middle sister Ivy feels resentful because Barbara and flighty younger sister Karen left her with the burden of caring for their poisonous mother. But that might be the least of Ivy’s worries as she eventually discovers that her budding relationship with cousin Charles may be quite a bit more than kissing cousins.

Despite the large number of actors contending for attention, the film gives us ample opportunity to meet every member of family, with each character having at least one significant moment in front of the camera... and everyone delivers. But even with a runtime north of two hours, the film never feels long or bloated. Emotionally overwhelming at times, and tough to watch perhaps, but never long.

As we expect, Streep is the powerhouse here and she, yet again, turns in a blistering, award-worthy performance. Her Violet swings violently back-and-forth from quick-witted family matriarch to acid-tongued monster faster than the time it takes to pop another Valium. Even though she occasionally tips over into hammy melodrama, there’s always the brilliant script and juicy dialogue to keep her grounded in the reality of family dysfunction. Julia Roberts does some of her best work to date here too, and Sam Shepherd’s opening monologue is nothing short of brilliant. It makes us wish he had been given much more screen time.

Don’t look for wide-arching themes or message-laden motifs. You won’t find them here. August: Osage County is simply a fly-on-the-wall observation of caustic family dysfunction. If there is something to be learned, perhaps it’s to understand the real, brutally honest effects of emotional torture and the long-term damage caused by unresolved Mommy issues. Whatever the lesson, John Wells makes sure you’ll leave the theater thankful this is not your family.

Review also posted at www.franksreelreviews.com.

(Released by The Weinstein Company and rated “R” for language including sexual references and for drug material.)