A storm that forms quickly, with little or no warning. Also: popup storm.
Chris Strong, of the National Weather Service (NWS) Baltimore/Washington Forecast Office in Sterling, VA, reiterates the forecasting difficulties sometimes encountered with the various D.C. microclimates. But from his perspective, with the exception of sudden pop-up storms, summer weather is generally the most stable and predictable of the entire year.
—Don Lipman, “Washington D.C. weather: Is it a forecasting nightmare?,” The Washington Post, February 27, 2012
“My biggest concern for lightning is summertime popup storms,” said Spencer.
Barren limbs of a dead tree at Lake Davis near downtown Orlando support an abundance of feathery life this week: A gathering of water birds. The birds got rained on Thursday and more showers are expected today as our traditional summer afternoon pop-up storms have begun.
—“Nesting and resting” (photo caption), Orlando Sentinel, May 12, 1995