Pittsburgh To Be Impacted By Massive 'Bomb Cyclone' Winter Storm

PITTSBURGH, PA — A massive winter storm moving eastward is expected to turn into a 'bomb cyclone' whose dangerous effects will be felt in Pittsburgh over the Christmas weekend.

The National Weather Service already has issued a high wind watch for all of Western Pennsylvania from late Thursday through Saturday morning. Expect southwest winds of 15 to 25 mph with gusts as high as 60 mph.

Damaging winds could blow down trees and power lines. Widespread power outages are possible. Travel could be difficult, especially for high profile vehicles.

A wind chill watch is in effect from Friday morning through Saturday afternoon, as wind chills as low as 25 degrees below zero are possible. Such dangerously cold wind chills could cause frostbite on exposed skin in as little as 30 minutes.

State College-based AccuWeather predicts that the storm, which already is causing travel delays in the Midwest, will strengthen into a bomb cycle. As it does, travel likely will grind to a halt in many areas as dangerous and life-threatening conditions unfold from the storm’s high winds, snow and plunging temperatures.

What is a bomb cyclone? In its simplest terms, a bomb cyclone is defined as a rapidly intensifying storm that triggers more severe impacts that what a weaker storm would generate.

The storm is not expected to bring much snow to the area, with one to two inches expected in the Pittsburgh metro area. But the weather service's prediction center emphasized that snow totals might not tell the whole story with this system.

"Even small snow amounts, when combined with very strong wind gusts and plummeting temperatures, can cause poor visibility and slick spots on roads, the prediction center warned via Twitter. "The sudden arrival of these conditions can increase the danger."

The weather service also warns that dangerous flash freezes are possible Friday morning as the system moves through and temperatures abruptly plummet.

Here's a timeline of when the hazards will have their greatest impact:

Temperatures are expected to fall to around four degrees by mid-day on Friday, with an overnight low of two. The high on Christmas Eve will be around 13 and the high on Christmas Day will be around 18.