269  
FOCN45 CWWG 221900  
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM  
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT WEDNESDAY MAY  
22 2019.  
 
ALERTS IN EFFECT... SPECIAL AIR QUALITY STATEMENTS FOR HIGH LEVEL  
REGION AND PARTS OF SOUTHERN NORTHWEST TERRITORIES.  
 
SYNOPTIC OVERVIEW... FAIRLY STRONG UPPER LOW CIRCLING ABOUT  
SOUTHHAMPTON ISLAND WITH A 1002 MB SURFACE REFLECTION, BOTH QSTNRY.  
BROAD BI-CENTRED UPPER LOW COMPLEX OVER THE CONUS, WITH ONE CENTER  
OVER SOUTHERN CALIFORNIA AND THE OTHER OVER SOUTH DAKOTA. LATTER  
FEATURE HAS A 997 MB LOW ASSOCIATED, BOTH OF WHICH ARE TRACKING  
NORTHEAST AND WEAKENING. UPPER RIDGE OVER ALBERTA UP THROUGH THE  
MACKENZIE VALLEY AND EASTERN BEAUFORT. COLD SURFACE RIDGE FROM THE  
ARCTIC ISLANDS POKING INTO NORTHERN MANITOBA.  
 
DISCUSSION...  
 
WESTERN PRAIRIES...  
WILDFIRE SMOKE IN NORTHERN ALBERTA WILL MOVE SOUTHWARD INTO THE  
PEACE RIVER REGION WITH LIGHT NORTHERLY WINDS. WINDS LOOK TO REMAIN  
NORTHERLY THROUGH THURSDAY WHICH SHOULD CAUSE SMOKE TO ADVECT  
FURTHER SOUTH INTO THE GRANDE PRAIRE REGION. FOR NOW LOCAL SMOKE IS  
MENTIONED IN THE PUBLIC FORECAST FOR THURSDAY. THE FIRE NORTH OF  
SLAVE LAKE WILL ALSO BRING SOME SMOKE SOUTHWARDS THURSDAY. MODELS  
TRY TO PUSH A 80+ UG/M3 INTO LAC LA BICHE TOMORROW MORNING AND  
ATHABASCA AREA THURSDAY AFTERNOON. LIMITED FOR OBS AND WEBCAMS THERE  
BUT THE FIRE PLUME IS VISIBLE ON SATELLITE THIS MORNING. FOR NOW WE  
ARE ADDING A MENTION OF SMOKE TO THOSE FORECASTS.  
 
WITH AN UPPER RIDGE REMAINING IN PLACE, LITTLE IN THE WAY OF SHOWER  
ACTIVITY IS EXPECTED TODAY. HOWEVER BY THURSDAY THERMAL TROUGHING  
NOSING INTO CENTRAL ALBERTA FROM BC, AND ISENTROPIC LIFT FROM A SLOW  
MOVING SHORTWAVE TROUGH WILL DESTABILIZE A GOOD PORTION OF CENTRAL  
ALBERTA BRINGING SHOWERS. THUNDERSTORMS SHOULD BE NON SEVERE IN  
NATURE WITH 500-1000 J/KG MUCAPE, LOW BULK SHEAR OF GENERALLY 10-15  
KTS AND LITTLE JET SUPPORT.  
 
EASTERN PRAIRIES... THERMAL WAVE TRACKING THRU THE AMERICAN MIDWEST  
TODAY WITH TROWAL ARCING BACK INTO THE SOUTH DAKOTA UPPER LOW. BAND  
OF SHOWERS ALONG TROWAL AFFECTING SOUTHEASTERN MANITOBA TODAY WITH  
PRECIPITATION NOT EXPECTED TO PUSH MUCH FURTHER NORTHWEST THAN  
WINNIPEG. AREAS SOUTHEAST OF THE CAPITAL WILL LIKELY GET WET WHILE  
IN WINNIPEG MOSTLY JUST SPRINKLES ARE ANTICIPATED. A BIGGER DOUSE OF  
RAIN IS LIKELY LATE FRIDAY/EARLY SATURDAY AS THE UPPER LOW CURRENTLY  
OVER SOUTHERN CALIFORNIA APPROACHES.  
 
EASTERN ARCTIC... OCCASIONAL SNOW, STRONG WINDS, AND LOCAL BLOWING  
SNOW FOR MANY AREAS AS LOW COMPLEX SITS OVER SOUTHAMPTON ISLAND FOR  
THE NEXT COUPLE OF DAYS. SOME ACCUMULATIONS POSSIBLE HERE AND THERE,  
BUT WITH TEMPERATURES NEAR ZERO, MELTING AND COMPACTION ARE LIMITING  
AMOUNTS.  
 
END/MELSNESS/WIELKI  
 
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