Between 9 and 10 p.m. Monday, the temperature at Buffalo dropped from 78 degrees to 66.
That's what a strong cold front will do.
What it also did was drop sharp strokes of cloud-to-ground lightning across Western New York, knocking power out to thousands of area customers, according to local utility companies.
As of about 11 p.m., NYSEG reported 3,618 customers in the dark in Erie County and National Grid reported 871 more customers without power. The communities affected included Amherst, Boston, Buffalo, Cheektowaga, Concord, Eden, Elma, Evans, Hamburg, Orchard Park, Sardinia, Town of Tonawanda, Wales and West Seneca.
Torrential rainfall was reported with the storm that first entered the region near Chautauqua County about 9 p.m. Within a half hour, it brought heavy rain and frequent lightning to downtown Buffalo before trekking eastward.
After five days in a row of unseasonably warm temperatures - in the 80s - the bottom will fall out of the thermometer in the coming couple of days.
Tuesday's high is just 59 degrees under sunny skies, forecasts show.
There's also a wind advisory in place from 10 a.m. to 6 p.m. Tuesday for Western New York. Gusts up to 50 mph are forecast for the Niagara Frontier and Lake Erie shoreline areas, according to the National Weather Service.
Overnight temperatures Tuesday will then dip into the 40s.
Wednesday's high temperature is only forecast to be 55 degrees with a chance of frost possible Wednesday night, forecasters said.