585  
FOCN45 CWWG 082000  
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM  
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CST MONDAY MARCH  
8 2021.  
 
ALERTS IN EFFECT...SNOWFALL WARNINGS FROM SWIFT CURRENT TO POPLAR  
RIVER.  
 
SYNOPTIC OVERVIEW...ALOFT, AN UPPER LOW IS OFF THE COAST OF BC, A  
GENERAL SOUTHWEST FLOW IS OVER WESTERN CANADA LEADING TO A RIDGE  
FROM BAFFIN ISLAND TO QUEBEC.  
 
AT THE SURFACE, A LOW IS OFF THE COAST OF VANCOUVER ISLAND AND A  
HIGH PRESSURE CENTER IS OVER SOUTHERN BC. FURTHER NORTH, HIGH  
PRESSURE IS OVER THE YUKON WITH A RIDGE SOUTHEASTWARD THROUGH THE  
NWT AND INTO NORTHERN ALBERTA. A 994 MB LOW IS NEAR KUGAARUK WITH  
THE MAIN FRONTAL ZONE RUNNING SOUTHWESTWARD THROUGH NORTHERN  
MANITOBA AND CONTINUING INTO CENTRAL ALBERTA.  
 
DISCUSSION...  
 
PRAIRIES...IN ALBERTA, MOISTURE FEED FROM THE LOW OFF THE BC COAST  
WILL OVERRUN A SURFACE TROUGH THROUGH CENTRAL AB BRINGING A NARROW  
BAND OF SNOW TO THE AREA TODAY. INSTABILITY IN THIS BAND WILL YIELD  
HIGHLY VARIABLE ACCUMULATIONS. LUCKILY, THE COLD AIR AND HIGHER  
SNOW-LIQUID RATIOS ARE CAUGHT NORTH OF THE MAIN FRONT THROUGH  
NORTHERN AB. THIS SAID, 5-10 CM ARE STILL POSSIBLE FROM GRANDE  
CACHE AND GRANDE PRAIRIE TOWARDS WHITECOURT NEAR THE HIGHWAY 43  
CORRIDOR. NEARER EDMONTON, EXPECT AMOUNTS TO BE IN THE 2-4 CM RANGE  
THOUGH LOCALLY HIGHER ACCUMULATIONS ARE NOT OUT OF THE QUESTION. AS  
OF THIS ISSUE THE DEVELOPING BAND IS SLOW MOVING AND ONLY 15-30 KM  
WIDE.  
 
THE EASTERN PRAIRIES WILL SEE ACTIVE WEATHER TONIGHT AND TOMORROW. A  
LOW PRESSURE SYSTEM IS FORECAST TO DEVELOP IN WYOMING/MONTANA  
TONIGHT AND MOVE NORTHEAST OVER THE ENSUING 36 HOURS. TO THE LEFT  
(NORTH) OF THE LOW'S TRACK WILL BE THE BULK OF THE PRECIPITATION,  
AND THAT WILL MAINLY FALL AS SNOW. AS THE SYSTEM MOVES EASTWARD IT  
WILL ENCOUNTER MORE AND MORE MOISTURE, SO SNOWFALL AMOUNTS WILL  
INCREASE FROM WEST TO EAST OVER TIME. WARNING-LEVEL SNOWFALL WILL  
LIKELY GO FROM EAST OF SWIFT CURRENT, SK TO POPLAR RIVER, MB. MOST  
GUIDANCE HAS COME TO AGREE THAT 10-15 CM OF SNOW WILL FALL ON THE  
SASKATCHEWAN SIDE OF THE BORDER, WHILE IN MANITOBA, AMOUNTS WILL BE  
IN THE 15 TO 20 CM RANGE. THE SOUTHERN EDGE OF THE PRECIPITATION  
SHIELD WILL ALSO HAVE THE POTENTIAL TO HAVE SOME FREEZING RAIN IN  
IT, ESPECIALLY AS THE THERMAL GRADIENT STRENGTHENS WITH TIME. THE  
PRIME AREAS FOR FREEZING RAIN POTENTIAL ARE TONIGHT FROM THE RIDING  
MOUNTAINS TO BERENS RIVER.  
 
AS IF THAT WEREN'T ENOUGH, A PLUME OF STEEP MIDLEVEL LAPSE RATES WILL  
MOVE OVER THE RED RIVER VALLEY BEGINNING ON TUESDAY MORNING. DECENT  
ELEVATED INSTABILITY IS FORECAST, UP TO 500 J/KG (AND IN SOME  
SIMULATIONS EVEN HIGHER), OVER THE REGION, MAKING LIGHTNING STRIKES  
POSSIBLE.  
 
THE ENTIRE SYSTEM WILL MOVE OUT OF THE REGION TUESDAY NIGHT.  
 
ARCTIC...THE LOW NEAR KUGAARUK IS PRODUCING SOME LIGHT SNOW AND  
MODERATE WINDS GIVING LOCALIZED BLOWING SNOW TO THE KITIKMEOT, HIGH  
ARCTIC AND BAFFIN ISLAND.  
 
END/MOODIE/NISKAARO  
 
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