Saturday, October 22, 2011

The Weekly Powderhound Report

8:30 AM 10/22/2011 | And all the snowboarders said, "THAT's what's UP!"  | Even though last week's Midwestern Storm did not produce any snow across the Great Lakes or Upper Plains, it may have started something else of interest to snowboarders, facilities management staff and families alike.  

We hypothesize that off a long range pattern that could lead to "cross Polar flow" of Siberian air in the next 30 days. Why would powderhounds care? Let's just say those planning to enjoy Thanksgiving Weekend near a ski resort might get an extra helping of fluff, and we don't mean the whipped cream on the pumpkin pie. Take a look at the latest snow & ice cover map below from the National Snow & Ice Data Center...

1. SIBERIAN SNOW COVER IN OCTOBER:  Other climate and weather forecasters in addition to us take a wide-angle "Earth Systems Science" look at how Siberian snow cover is the real elephant in the room for predicting North American winters. We can cite numerous examples, the most recent being October 2009, at how this factor was a contributing factor to the historic 09-10 winter in the U.S. 

2. A TALE OF TWO NUMBERS: We've learned from other writers that despite a "blanket of white" expansion of Siberian snow cover in recent weeks, actual depth of snowcover may not be as deep across Siberian and Alaska as in recent years. That said, the increased reflectivity a large snowpack produces chills the boundary layer, allowing Polar Continental high pressure systems to become stronger - and in turn colder. Snow can lead to more cold, and more snow.

3. OK, WHAT DOES THIS MEAN? If snowcover continues to expand and deepen, and multiple strong high pressure systems roll into Northern Canada into Novemer...the first significant winter storm for the Northern U.S. and/or the Mid-Atlantic, could easily get underway by Thanksgiving. 

Sources:
National Ice Center - Snow cover map:
http://www.natice.noaa.gov/pub/ims/ims_gif/DATA/cursnow_alaska.gif
http://www.natice.noaa.gov/pub/ims/ims_gif/DATA/cursnow_asiaeurope.gif

NOAA Climate Prediction Center - Oscillation data:
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif

WDAZ-8 StormTracker Blog: http://stormtrack.areavoices.com/2011/10/19/october-in-siberia/

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