At the Soho Theater in London, a beleaguered weather reporter is giving double meaning to the phrase “hot mess.”

The setting is drought-stricken Fresno, Calif., where temperatures are sweltering and wildfires rage on the city outskirts. The presenter, Stacey Gross, has a telegenic glamour and a peppy on-screen persona, but underneath is an angst-ridden functioning alcoholic who secretly quaffs Prosecco on the job. She suspects her TV station is misleading viewers about the role that climate change has played in the fires, and as the heat wave progresses she has a meltdown, embarking on a cathartic, booze-fueled rampage featuring wanton destruction, kidnapping and karaoke.

“Weather Girl” has arrived in London amid plenty of hype, following a successful run at last year’s Edinburgh Festival Fringe. The show’s producer, Francesca Moody, has a knack of turning Fringe plays into television hits — she was behind “Fleabag” and “Baby Reindeer” — and a Netflix adaptation of “Weather Girl” is already in development, according to the trade publication Deadline.

The show’s title character is played by Julia McDermott, who also takes several other parts in this lively but slightly undercooked one-woman show, a silly but serious climate change allegory that runs through April 5.

Wearing a bright blouse, hot pink skirt and heels, McDermott performs on a bare stage, with just a colored screen behind her as an allusive backdrop. Her only prop is a trusty Stanley Tumbler. Over the course of 60 frenetic minutes, her character regales the audience in a fraught, high-tempo monologue about Stacey’s escapades in drinking holes with names like Malibu Nights and the Antelope Lounge.

During one bender, she winds up in a karaoke bar, giving a mumbled rendition of Rupert Holmes’ 1979 hit, “Escape (The Piña Colada Song).” On another, she sabotages a date with a charmless tech entrepreneur, deliberately totaling his expensive sports car. Later, she imprisons him in the trunk of her own vehicle.

The story turns on Stacey’s rapprochement with her estranged mother, an eccentric down-and-out who, it turns out, is blessed with a gift: She can conjure water out of thin air. This power is hereditary, but Stacey will need to change her outlook before she can tap into it. “Wisdom,” her mother intones, is “a primal kinda thing” that “despises vanity. It despises gain.”

Jolted by the encounter, Stacey launces into a self-reproaching rant — “I’m not a weather reporter, I’m a fluffer, I’m a hype man, I’m a used-car salesman” — and she decides to take action. With the fires closing in, many city inhabitants, wary of nanny-state scaremongering, have chosen to stay put. Stacey’s station manager has instructed her to downplay the danger, but she goes rogue, delivering a frantic on-air monologue that convinces people to evacuate, saving countless lives. And lo! Her travel mug magically fills with water. Maybe there is hope for humanity after all?

With its disarming levity and redemptive message, “Weather Girl” is less heavy handed than some other climate change satires, like the 2021 movie “Don’t Look Up,” which tend toward sardonic despondency. But the humor, mostly derived from Stacey’s riotously self-destructive antics early on, gradually dries up as the moral through line crystallizes.

The script, by Brian Watkins (“Outer Range”) is patchy. When Stacey tells us her subpar dinner date started off at “this very California place,” the description is too vague to be mordant: It feels like a lazy place holder. Sheer chaotic esprit can go a long way at the Edinburgh Fringe, where crowds are well disposed toward scrappy shows with big personality. West End theatergoers may prove harder to please.

The show’s central concept has potential, and its premise is particularly timely after recent wildfires in California. In the right hands it could perhaps inspire a compelling television series, leaning into the story’s magic realist strangeness while evoking a strong sense of place — shimmery, soft-focus urban vistas, feverish barroom scenes — and a richly textured mother-daughter dynamic. In its present iteration, however, “Weather Girl” is caught between two stools: It’s not consistently funny enough to dazzle as comedy; and as drama it’s too thinly drawn to transport the audience.

McDermott’s frazzled charisma makes the very best of the material — but there’s only so much she can do on her own.