A Very White Christmas
Yesterday I asked a friend how he was enjoying December. "Reminds me of Minnesota" he grinned. Yep, like the good 'ol days, when cold and snow were a given. Before weather patterns started acting wonky and strange.<p>If anyone asks (doubtful) 7 out of 10 Twin Cities Christmases are "white", with at least 1 inch or more of snow on the ground. This will be one of them.
The older I get the less I take for granted. Christmas 2011 was brown. In fact since 1899 there have been 32 years with "zero" or a trace of snow on December 25, according to the Minnesota Climate Office.
An anemic Alberta Clipper drops a candy-coating of fluff today; maybe a quick inch in some spots. That compares with half a foot in the suburbs of New York, maybe 8" of slush in Boston by tomorrow - both cities closer to the main storm track.
Cool, Canadian exhaust lingers into Tuesday morning - and then we warm up a little. 30s by midweek will feel like a (bad) Club Med vacation, before another cold wave sweeps into town late next week. Single digit highs are possible 1 week from today but temperatures may reach 20s, even 30s by Christmas Day.
Leaving most of us happier than a dog with two tails.
Moderating Temperatures Next Week. If teens feel tolerable, imagine how low 30s might feel next week, the best chance of a fleeting thaw around midweek. ECMWF guidance shows another sharp temperature downturn late Thursday into Saturday of next week.
Clipped Again. Today's clipper, marking the leading edge of colder air of Canadian origin, may spark an inch or so of powder in the Twin Cities, as much as 2" near Mille Lacs and Sandstone. When it's this cold chemicals don't melt snow and ice on area highways, so expect slick spots. NAM guidance: NOAA and Ham Weather.
Accumulating Snow Ohio Valley to New England. A wave of low pressure tracking to the east-northeast spreads accumulating snow from Columbus and Pittsburgh to New York City and Boston later today and Sunday, enough to shovel and plow in 18-20 states, with as much as 8-12" over interior New England. NAM Future Radar courtesy of NOAA and Ham Weather.
"In your "arctic myths" article of 12/13/13, you indicate that wind chill is due to evaporation of sweat. Can you cite your reference for that conclusion?
It's been over 50 years since I studied Thermodynamics & Heat Transfer at the U, but wasn't the wind chill an indication of the rate of cooling and not the wet-bulb temperature? In fact, weren't the original measurements made with a bottle of water?"
Bruce H. Johnson
Yes Bruce, I oversimplified the answer (space is limited in print, but on the blog I have the luxury of not editing content as much). Evaporation (evaporative cooling) is only part of the process, along with other factors. You are correct, original estimates were done on an elevated water bottle (in Antarctica), but the algorithms for calculating wind chill were revised (improved?) in 2001. It's still the source of considerable controversy though among meteorologists. The point I was trying to make is that, unlike human flesh, an inanimate object, like a vehicle, can't "feel" colder than the actual air temperature, but a strong wind will cool an object down to the ambient temperature faster. Here's an excerpt of an explanation from Wikipedia: "The human body loses heat through convection, evaporation, conduction, and radiation.The rate of heat loss by a surface through convection depends on the wind speed above that surface. As a surface heats the air around it, an insulating boundary layer of warm air forms against the surface. Moving air disrupts the boundary layer, allowing for new, cooler air to replace the warm air against the surface. The faster the wind speed, the more readily the surface cools. The speed of cooling has different effects on inanimate objects and biological organisms. For inanimate objects, the effect of wind chill is to reduce any warmer objects to the ambient temperature more quickly. It cannot, however, reduce the temperature of these objects below the ambient temperature, no matter how great the wind velocity. For most biological organisms, the physiological response is to maintain surface temperature in an acceptable range so as to avoid adverse effects. Thus, the attempt to maintain a given surface temperature in an environment of faster heat loss results in both the perception of lower temperatures and an actual greater heat loss increasing the risk of adverse effects such as frostbite, hypothermia, and death..."
* Friday the 13th, what can possibly go wrong? Nothing today, but facilities and travel plans will be impacted from Saturday into Sunday as a coastal storm spreads a burst of snow, ice and rain into portions of the Mid Atlantic Region and all of New England.
* Snow will spread across Pennsylvania and northern New Jersey into New York City Saturday afternoon, the storm peaking Saturday night as snow mixes with ice and rain. I'm expecting roughly 4" of heavy, wet, slushy snow in Manhattan, but closer to 6-8" for suburbs in northern New Jersey and Connecticut. The storm peaks late Saturday night into midday Sunday from Hartford to Boston, where some 5-8" amounts are likely; closer to 10" well inland from the coast, where precipitation will fall as mainly snow.
* Over a foot of snow may fall from near Albany to the Berkshires to Portland, Maine by late Sunday afternoon.
Summary: Underscoring my theory that we're about to experience a real winter across much of the USA, probably one of the 2 or 3 coldest and snowiest in 20 years, this weekend will be character-building from the Delaware Valley to coastal Maine, impacting an estimated 50+ million Americans. A heavy, wet, slushy snow will slow things down in New York, with the heaviest amounts from the suburbs of New Jersey, Westchester County and Connecticut into the western suburbs of Boston and Portland, where some 5-8"+ amounts are quite likely by Sunday. Accelerate travel and contingency plans today and first thing Saturday. Conditions will rapidly deteriorate as the day goes on tomorrow in the Northeast.
Paul Douglas - Senior Meteorologist - Alerts Broadcaster
NASA Says Ozone Hole Stabilizing, But Won't Fully Recover Until 2070. Here's the introduction to a story at The Los Angeles Times: "The hole in the ozone layer is stabilizing but will take until about 2070 to fully recover, according to new research by NASA scientists. The assessment comes more than two decades after the Montreal Protocol, the international treaty that banned chlorofluorocarbons and other compounds that deplete the ozone layer, which shields the planet from harmful ultraviolet rays. Levels of chlorine in the atmosphere are falling as a result of the treaty, but have not yet dropped below the threshold necessary to have a shrinking effect on the ozone hole that forms each year over Antarctica, according to scientists at NASA's Goddard Space Flight Center. They presented their findings this week at the annual meeting of the American Geophysical Union in San Francisco..."
Graphic credit above: "The ozone hole, shown in October, has stopped growing since the mid-1990s, but scientists say a full recovery is many decades away." (Ozone Hole Watch / December 12, 2013).
Graphic credit above: "Modern life generates huge volumes of data. That data can yield detailed information — and provide valuable insights. This image visualizes the volume of Internet data that flows between New York City and cities around the world over a 24-hour period. The larger the glow at any particular location, the larger the volume of data." MIT Senseable City Lab.
Photo credit above: "Tiny ticker: A new pacemaker is small enough to fit inside the heart and can be implanted through a patient’s veins."
Photo credit: "The owners of a café in the south of France have struck a blow for good old-fashioned French politeness, with a sign charging extra for rudeness." Photo: Courtesy of Fabrice Pepino.
Photo credit: Shutterstock / Sergey Kamshylin.