305  
FOCN45 CWWG 111300  
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM  
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 7:00 AM CST SUNDAY  
DECEMBER 11 2016.  
 
ALERTS IN EFFECT...EXTREME COLD WARNINGS REMAIN IN EFFECT FOR A  
LARGE PORTION OF NORTHERN AND CENTRAL ALBERTA AS WELL AS SOUTHWESTERN  
MANITOBA THIS MORNING. WARNINGS ARE EXPECTED TO BE REISSUED AGAIN THIS  
AFTERNOON FOR PORTIONS OF SOUTHEAST SASKATCHEWAN AND SOUTHWEST MANITOBA.  
 
DISCUSSION...ZONAL FLOW EXISTS OVER THE CENTRAL USA. TWO VERTICALLY  
STACKED LOWS ROTATING THROUGH THE CENTRAL ARCTIC AND NEAR GREENLAND  
WITH SURFACE REFLECTIONS OVER THE NEXT 48 HOURS. 1002 MB  
LOW NEAR BAKER LAKE MOVES SOUTHWARD BRINGING CORE OF EVEN COLDER ARCTIC  
AIR TO THE NORTHERN PRAIRIES BY THIS EVENING. GREENLAND LOW DEEPENS AND  
AFFECTS DAVIS STRAIT WITH VERY STRONG WINDS TODAY INTO MONDAY.  
SHORTWAVE TROUGH OVER NORTHERN ALBERTA WILL TRACK EASTWARD  
THROUGHOUT PERIOD. SURFACE RIDGE OF HIGH PRESSURE STRETCHES FROM ALASKA  
SOUTHEAST INTO SOUTHERN ALBERTA THEN EASTWARD INTO ONTARIO. GRADIENT BETWEEN  
THIS RIDGE AND THE LOW OVER THE CENTRAL ARCTIC CAUSING STRONG NORTHERLY WINDS  
FROM THE WESTERN ARCTIC OCEAN THROUGH THE NWT AND PUSHING INTO ALBERTA.  
ALASKA RIDGE HAS BEEN RESPONSIBLE FOR THE EXTREME COLD WARNINGS ON OUR  
SIDE OF THE BORDER AS OF LATE.  
 
ALBERTA...VERY COLD AIR REMAINS OVER ALBERTA THIS MORNING THANKS TO  
THE ICY REACH OF A 1048MB HIGH PRESSURE SYSTEM ANCHORED OVER ALASKA.  
WITH THESE COLD SURFACE TEMPERATURES, EVEN A SLIGHT WIND IS PUSHING  
REPORTING STATIONS OVER THE EXTREME COLD WARNING THRESHOLD.  
THEREFORE, EXTREME COLD WARNINGS REMAIN IN NORTHERN AND CENTRAL  
ALBERTA FOR THIS MORNING. RELIEF IS ON THE HORIZON THOUGH AS RELATIVELY WARM AIR  
PUSHES IN FROM THE NORTHWEST, BRINGING TEMPERATURES INTO THE MID MINUS TEENS FOR  
CENTRAL ALBERTA STARTING ON MONDAY. THIS WARM PUSH COMES WITH A PRICE HOWEVER  
AS SURFACE WINDS WILL STRENGTHEN THANKS TO A 45KT LOW LEVEL JET AND A MODERATELY  
UNSTABLE BOUNDARY LAYER. GUSTS OF 60 KM/H ARE EXPECTED FOR MANY AREAS OF CENTRAL  
AND NORTHERN ALBERTA STARTING SUNDAY AFTERNOON ALTHOUGH GUSTS NEARING 70 KM/H  
ARE NOT OUT OF THE QUESTION. BIGGEST LIMITING FACTOR WILL BE JUST HOW SUCCESSFUL  
THIS WARM PUSH IS AT DESTABILIZING THE BOUNDARY LAYER.  
 
NWT...CONVERGENCE AREA BETWEEN THE STRONG HIGH PRESSURE SYSTEM OVER ALASKA  
AND YUKON AND THE LOW OVER THE CENTRAL ARCTIC GIVING AN AREA OF SNOWFALL  
ALONG THE MACKENZIE RIVER. WITH SOME MOISTURE STREAMING SOUTHWARD FROM OVER  
THE ARCTIC OCEAN, MODELS ARE SUGGESTING AN ADDITIONAL 5-10 CM OF SNOW FOR AREAS  
BETWEEN FORT GOOD HOPE AND DELINE BEFORE TAPERING OFF OVERNIGHT SUNDAY. WINDS  
ARE EXPECTED TO INCREASE IN THE STRONG NORTHERLY GRADIENT SO VISIBILITIES  
WILL LIKELY BE REDUCED AT TIMES IN SNOW AND BLOWING SNOW FOR MANY COMMUNITIES  
ALONG THE MACKENZIE RIVER AND NORTH THROUGH PAULATUK AND SACHS HARBOUR. HOWEVER,  
CURRENT INDICATIONS SUGGEST CONDITIONS SHOULD STAY ABOVE THE CRITERIA NEEDED FOR  
A BLOWING SNOW ADVISORY.  
 
EASTERN PRAIRIES...COLD. AFOREMENTIONED SHORTWAVE TROUGH WILL SWING  
THROUGH GIVING FLURRIES TO CENTRAL AND NORTHERN MANITOBA TODAY  
AND TONIGHT. ANOTHER SHORTWAVE RIDING THE 49TH PARALLEL WILL GIVE SOME  
LIGHT SNOW TO EXTREME SOUTHERN SECTIONS OF MANITOBA THIS MORNING.  
 
EASTERN ARCTIC...BAKER LAKE LOW SLOWLY MOVING SOUTHWARD THROUGH  
KIVALLIQ THROUGHOUT THE PERIOD. LOW DEEPENS MONDAY NIGHT OVER HUDSON BAY  
AND RETROGRESSES BACK ONSHORE. TIGHT GRADIENT AND SOME FALLING  
SNOW WILL LIKELY GIVE RISE TO BLOWING SNOW ISSUES TUESDAY. MORE  
EASTERN ARCTIC LOW INTENSIFIES AND AFFECTS EAST COAST OF BAFFIN ISLAND WITH  
STRONG WINDS AND OCCASIONAL SNOW.  
 
END/PASPC-WPG/WAGAR  
 
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