The likelihood of a significant winter storm remains very high. Western PA and Western NY will take the brunt of this rogue winter storm. The Hydrological Prediction Center, who make probability assessments about weather events that include precipitation, issued this assessment this morning:
The challenge this storm will have to overcome is the difference between ground and upper air temperatures. The upper air temperatures will be plenty cold enough for significant snowfall. The ground temperatures are warm and air temperatures will be right around freezing. Therefore, it will snow a bit before accumulation occurs. However, the actual precipitation shown by the weather models actually exceeds the amount we saw during the 2010 blizzard, but the snow ratios will be much lower and the ground is much warmer.
Yesterday, I put out a map that showed most of us would be in the 8-12″ range. I am sticking with that map, but the lateness of this storm is nearly unprecedented so there is a great amount of uncertainty with this storm. The NWS in Pittsburgh’s forecast discussion expressed similar uncertainty, but warned to be prepared for extended power outages. I strongly suggest the same.
For those of you totally depressed about a late April snowstorm: take comfort: it won’t last long.