Freeze watch, frost advisory are issued for Western Pa.

Sub-freezing temperatures as low as 27 degrees are coming tonight.

By MEGAN SWIFT
TribLive

Get your winter coats back out, Western Pennsylvania.

A freeze watch and frost advisory have been issued by the National Weather Service in Moon — starting today.

The frost advisory will be effect from 2 to 10 a.m. today, and the freeze watch will be in effect from this evening through Tuesday morning.

There will be temperatures as low as 33 degrees, resulting in frost formation this morning, and sub-freezing temperatures as low as 27 degrees for the freeze watch tonight.

Jason Frazier, a meteorologist at the NWS, said a freeze this late into April isn’t completely out of the ordinary. In Pittsburgh, the average date of the region’s last freeze is April 22.

“Despite all the warm that you might see … we’re in the realm where we could still have a freeze,” he said. “It’s not unheard of.”

The latest recorded freeze was May 24, 1956, Frazier said, which includes historical records stretching back to 1875. This supports the idea of waiting to plant until after Mother’s Day.

“Frost and freeze conditions could kill crops, other sensitive vegetation and possibly damage unprotected outdoor. plumbing,” the NWS said. “Frost could harm sensitive outdoor vegetation. Sensitive outdoor plants may be killed if left uncovered.”

More recently, April 20, 2018, had a low temperature of 27 degrees, and April 20, 2022, had a low temperature of 29 degrees, he said.

“The average low temperature for this time of year is about 42 degrees,” Frazier said. “It’s a little late, but this is still within the norm of what we can see in the region.

“Given how warm it’s been, that’s why we issued the freeze and frost headlines — to alert people.”

Frazier said there aren’t concerns about prolonged freezing temperatures that could put infrastructure and pipes at risk, as today’s freeze will be short-term.

“Maybe just making sure hoses are emptied of water — not a bad idea,” he said. “It’s going to mainly impact just the vegetation nothing else. Our recommendation is outdoor crops and plants utilize blankets to cover them, maybe bring them inside if (you) can — whatever gardening techniques you have to mitigate temperatures these next two nights.”

A freeze watch is issued when there is “a potential for significant, widespread freezing temperatures within the next 24-36 hours.” Less severe than a freeze warning, a freeze watch is typically issued in the autumn until the end of the growing season and in the spring at the start of the growing season, according to the NWS.

For higher elevations in Westmoreland, Indiana and Fayette counties, the more severe freeze warning is in effect from 2-10 a.m. today.