First snow of the season on the northern coast of Alaska in the next few days the snow whiten even the north of Eastern Siberia
Despite the many difficulties the cold, gradually, begin to appear along the Arctic coasts of North America. In recent days, the first major wave of autumn chill has affected the northern coast of Alaska and the Canadian Arctic Archipelago, where the influx of very cold air from the Arctic cap, has plunged the thermometer below the threshold of + 0 ° C. Even at some stations the Canadian Arctic Archipelago were recorded the first minimum below -9 ° C -10 ° C. The arrival of the first cold Arctic was accompanied by the arrival of the first snows fall on the northern coast of Alaska, overlooking the Sea of Beaufort, now completely free of ice.
The first snow of the season has whitened the city of Barrow, last Tuesday, September 8, 2015, leaving the ground a small deposit of just 1.2 cm. The snow is falling at times mixed with rain, because of the positive temperature, but also of sustained winds from E-NE and NE who these days have swept the largest city in northern Alaska, with gusts that reached their peak 60 km / h. But these days far more abundant snowfalls have cloaked in white most of the northern coast of Alaska, leaving the first accumulations also on the northern plain, at the foot of the imposing mountains of the Brooks Range, which also impose a great “sto” to damp and cold northerly currents coming from the cold Beaufort Sea, which in this period and for much of the ice-free. The first snow showers have filed the first snow accumulations further south, the central mountains, which during the long summer were completely bare, from the high altitude.
You notice the white stripe that begins to cover the far north of Alaska after a very hot summer season (credit NOAA)
You notice the white stripe that begins to cover the far north of Alaska after a very hot summer with high temperatures (credit NOAA)
In the areas affected by the recent snow in the coming days it will also determine the effect “Albedo” significant that will help to lower temperatures, favoring the advent of the first true frost also on the ground, especially on the inner areas. The cold wave that hit about Alaska Northern was caused by the passage of a deep depression extratropical, headed by the polar vortex, full of cold air to all units, that the Beaufort Sea has shifted to the Canadian Arctic Archipelago . This extratropical cyclone, a cold heart, filled with very cold air to all units of the troposphere, appeared along its southern edge and western intense “pressure gradient horizontal” which facilitated the activation of strong stormy winds, first from North and N-NE subsequently rotated from NE and E-NE, that the Beaufort Sea have rapidly propagated to the northern coast of Alaska. The strong winds from O-NO and NO, which blew with gusts to over the 70 km / h in the post-frontal, channeled a portion of the block of very cold air, of Arctic origin (cold air and heavily produced over the Hood ), present in the Beaufort Sea, north to Alaska and the western Canadian Arctic Archipelago, where temperatures have plummeted under the wall of the “freezing” at sea level, allowing the arrival of the first snowfalls of up to shares flat.
With the gradual shift of deep depression Arctic to the Canadian Arctic Archipelago, the storms from NE and E-NE have spread to the rest of the northern coast, from the Bay of Mackenzie, across the Canadian border. In the coming days the first snowfall of the season, on a straight flat, will continue to affect the northern coasts of Alaska and even the territories of north-eastern Siberia, especially the coasts bordering the East Siberian Seas. Everything about the isolation of a deep cyclonic circulation, cold in character, headed by the “Siberian lobe”, that the coast of Siberia, Central and Eastern Europe will move in the direction of the central sector of the Arctic Ocean, as a result of the action of ” forcing “a promontory anticyclonic dynamically expanding on southern Siberia, deepened further.
This deep depression Arctic will be fed, along its western edge, from air masses rather cold aspirated directly from the Arctic Ocean. The low pressure area, while moving towards the Arctic Ocean, will push to the plateau of Eastern Siberia very cold air will invade the northern area of eastern Siberia, leading to a sharp cooling and also facilitating the floodgates of the first snowfall weak and moderate intensity. By next weekend the extent of snow cover over Eurasia should begin to grow, embracing part of Eastern Siberia and the coasts of Central Siberia, where temperatures are falling at the turn of + 0 ° C at sea level. For many of these areas it will be the first snow fall, after the latest snowfall last spring. Soils snow will cause a massive cooling of the air layer present in the lower layers.