Fair Saturday; Sloppy Sunday
2014-03-29 15:49:47.000 – Ryan Knapp, Weather Observer/Meteorologist
Today’s weather was actually enjoyable for a change. A ridge of high pressure cresting in allowed for generally fair skies, low winds, and temperatures right around freezing. In fact, it was the warmest temperatures the summit has experienced since February 21. While shoveling snow from the weather tower and the fire exits isn’t fun by any means, when you have pleasant weather like today, it at least makes it enjoyable as you soak up some sunshine. While it would be great to have this fair weather linger into Sunday, the weather pattern has a different plan in store. High pressure will depart this evening as a large area of low-pressure approaches from the south. While temperatures will remain mild, summit fog will be returning, a mix of precipitation will be falling, and winds will be back on the increase. While this may sound like a typical set up on the summit, there are a few things that will make this a bit more noteworthy.
As the warm air interacts with the cold snow on the surface, it may make for extremely dense fog at times as it did last night. There were times overnight when the fog was so dense, visibility could have been measured in inches on the summit – it was that dense! With the mix of precipitation types, snowfield stability may be affected. So, read the Mount Washington Avalanche Centers forecast and take extreme caution. With the amount of precipitation expected, ravine flash flooding could occur, especially if ice jams suddenly break (as seen in this example from Felchner Brook in Vermont). Lastly once all the water logged snow starts to freeze by Sunday afternoon, trail conditions will become extremely icy. So, play and stay safe if you are planning to play outside tomorrow and if unsure about conditions, always remember – the mountains aren’t going anywhere, so maybe consider postponing your activities by a day or two.
Ryan Knapp, Weather Observer/Meteorologist