WGN WEATHER HEADLINES
POSTS FROM MY FRIEND AND COLLEAGUE DR. BRIAN BRETTSCHNEIDER (https://twitter.com/Climatologist49), ALASKA-BASED NATIONAL WEATHER SERVICE CLIMATOLOGIST
- Brettschneider notes the recent snow fell much like so many of our Lower 48 snows fall — wet and in a near freezing environment, which means the snow had exceptionally high (by Alaska standards) water content.
- PERHAPS MOST INTERESTING, and information which puts the intensity of recent days’ snow in southern Alaska into historic context, are Dr. Brettschneider’s comments on the 65″ of snow which fell in just 24 hours near Thompson Pass which is east of Anchorage and just north of Valdez, Alaska. THINK OF THAT — 65″ of snow in a single day! That’s the equivalent of more nearly three Chicago “Blizzard of 1967’s” (which yielded 24″ of snow here and crippled the city January 26-27, 1967) in a single day!! The 30″ of snow which fell on sections of Anchorage’s Hillside is MORE SNOW than we received in our benchmark Chicago snowstorm — the “Blizzard of ’67” with its 24″ of snow here.
- Of the 65″ at Thompson Pass, Brettschneider notes: “A remarkable report of 65″ of snow in 24 hours along the Richardson Highway in Alaska a little to the northeast of Thompson Pass. This is very near where the Alaska state record of 78″ fell on Feb 7, 1963.” He further adds, “As a side note, the U.S. 1-day record is 75.8″ (Silverton, CO) while the Alaska record is 78.0.” Wrap your head around that one!
- THE SNOW IN RECENT DAYS ACROSS SOUTHERN ALASKA UNDERSCORES AN IMPORTANT FACT. A warmer atmosphere, such as the one we’re in now as a result of planetary warming, produces snowfall of reduced coverage and frequency OVERALL — and that’s what we’re observing as a result of climate change. BUT WHEN AND WHERE IT DOES SNOW, snowfall can be extreme given the fact a warmer surrounding environment hold more moisture. Thus, when and where it does snow, the snow CAN BE extremely heavy.
THE SEASON’S FIRST BIG SNOW IN SOUTHERN ALASKA HAS BEEN A RECORD BREAKER
- Record breaking snowfall hits southern Alaska in the past 2 days with up to 65″ reported down near Thompson Pass north of Valdez on the Richardson Highway — and more than 20″ down in sections of Anchorage, the state’s largest city. The Anchorage metro area is home to near 400,000 Alaskans.
- While the official National Weather Service Forecast Office measurement not far from Ted Stevens International Airport in Alaska has reached 17.2″, the “Hillside” locations in the city, which are elevated regions, have reported accumulations of as much as 30″ off Rabbit Creek Road there.
- What you’re seeing in this animation is a satellite-derived PRECIPITABLE WATER ANIMATION showing the concentrated flow of moisture (a so called “ATMOSPHERIC RIVER”) feeding into southern Alaska the past few days. The animation is produced by CIMSS (the Cooperative Institute for Meteorological Satellite Studies) at the University of Wisconsin-Madison.
THE MAMMOTH SNOWFALL ACROSS SOUTHERN ALASKA
The mammoth snowfall of recent days across southern Alaska is the product of an “atmospheric river” — a concentrated, deep atmospheric flow of moisture — into the region. You see it occurring on this NOAA GOES WEST weather satellite animation.
WILL THE GULF STREAM REALLY SHUT DOWN?
- One periodically hears that the Gulf Stream may shut down. Were that to happen, the climate impact would be huge. BUT WILL IT REALLY SHUT DOWN?
- NO, says Woods Hole Oceanographic Institution oceanographer Dr. Robert Todd. There’s agreement among scientists that it’s LIKELY THE GULF STREAM WILL CHANGE AS ONGOING CLIMATE CHANGE proceeds IT ALREADY SEEMS TO HAVE DONE THAT! BUT CLAIMS A “COMPLETE SHUT DOWN” OF THE GULF STREAM LIE AHEAD APPEAR THE PRODUCT OF CONFUSION over the difference between the Gulf Stream and the larger oceanic circulation in the Atlantic referred to as the Atlantic Meridional Overturning Circulation — or “AMOC” for short — says Todd.
- An actual shutdown of the Gulf Stream, which transports heat from the tropics north to higher latitudes, would have immense climate impacts. That’s why understanding changes in the Gulf Stream and circulations in our oceans is critical.
- READ MORE IN THIS ARTICLE:
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