A Closer Look at Elevation-Based Temperature Swings As you go up in the atmosphere, daily temperature swings become relatively lower compared to those on the surface. This is primarily because air is relatively transparent to solar radiation, which is the reason that on clear days at Mount Washington Observatory, we can see 130 miles to our west, all the way to the high peaks of the Adirondack Mountains in New York. Generally, incoming solar radiation that is not reflected by clouds or white, snowy surfaces transits the atmosphere and is only absorbed when it hits land, vegetation, or a

Remembering the Big Wind Eighty-nine years ago today, Mount Washington Observatory, in its second year of existence, recorded a world-record wind speed of 231 miles per hour – a record that would stand for over 60 years. Although a higher wind speed has since been recorded elsewhere (Tropical Cyclone Olivia, Barrow Island, Australia, April 10, 1996), the Observatory’s measurement of the “Big Wind” on April 12, 1934 still stands as the fastest wind speed ever recorded by a staffed weather station. The ambitious weather observers atop Mount Washington had been hoping to achieve such a record, yet no one

A Look Back at the First Nor’easter of the Season Nor’easters are named after the direction in which the strongest winds blow typically from the northeast. Nor’easters commonly form along the east coast of the U.S. and then progress northeastward, usually reaching maximum intensity near New England. As these storms attain maximum strength, they bring heavy rain or snow, strong winds, and the threat of coastal flooding to the northeast. This was the case this year as a late-winter nor’easter struck New England mid-March unleashing widespread, heavy snow and gusty winds upon the region. Early GFS forecast model depicting

Re-Tracing February’s Arctic Air Mass and Record Cold It took 89 years, but as the headlines have reported, on Feb. 4 Mount Washington Observatory managed to tie its all-time record low air temperature of -47 °F, originally set in January 1934. Observer Karl Philipoff documented the harrowing and historic day in a previous observer comment, and while I will probably think about my experiences that day for the rest of my life, my aim with this post is to take a look at the meteorology behind this event. To start, we need to look up, way up, to the

Red Sky at Morning, Hikers Take Warning Having grown up along the coast of Maine, there was a saying instilled in me by my parents every time I was planning to go outside for an extended period of time: “Red sky at morning, sailors take warning. Red sky at night, sailors’ delight.” This got me in the habit of looking out at the sunrise and sunset every day with the phrase repeating in the back of my mind. It was my parents’ way of getting me to pay attention to the weather when I was going out, and to

Traditional Mount Washington Rockpile Crunch Recipe Winter on top of Mount Washington means high winds, snow, and of course, lots of rime ice! Rime ice is a phenomenon that occurs when supercooled water droplets freeze on contact with any surface they come into contact with. When foggy conditions occur concurrently with high winds, rime ice can accumulate pretty quickly. Unlike glaze ice, which is clear and dense, rime ice is opaque, light, and fluffy. These qualities make it the perfect ingredient for ice cream! Rime ice cream (also known as Rockpile Crunch or R’ice cream) is a Mount Washington

Brutal Cold on Mount Washington: A Weather Story Hello! My name is Karl Philippoff and I am a new weather observer at Mount Washington Observatory. Although I am from New Jersey, I have been up on the summit multiple times – once as a tourist, once as a thru-hiker, once as a summit volunteer, and most recently as an intern. I am very excited to experience all that a winter on Mount Washington has to offer. I also feel incredibly lucky to have one of the most beautiful views I can imagine from my desk, looking out at the

Autumn 2022 Weather Was Warm, Wet, and Less Snowy The fall of 2022 on Mount Washington will go down in the record books as a warm, wet, and less snowy season compared to average. September started the season off on a slightly cooler note, with an average temperature of 42.8 degrees. This temperature corresponded with an anomaly of 0.3 degrees below the 1991-2010 baseline. A tendency for ridging over the eastern United States during the month of October created the ideal conditions for anomalous warmth. In fact, at +6.4 degrees, October 2022 was the fifth warmest October in our

Christmas Bomb Cyclone Sweeps through the Northeast Strong winds and heavy snow came to Mount Washington just in time for Christmas thanks to a nasty bomb cyclone sweeping through the Northeast. I wrote this comment Christmas morning at our summit weather station, where sustained winds exceeded 100 mph. What is a bomb cyclone and how does it form? A bomb cyclone forms when two very different air masses interact. Commonly, a cold, arctic mass shifts down from the north and a warm airmass is drawn into the storm. This type of system is defined by how rapidly it intensifies,