625  
FOCN45 CWWG 281900  
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM  
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT WEDNESDAY MAY  
28 2025.  
 
ALERTS IN EFFECT...AIR QUALITY WARNINGS FOR PARTS OF SOUTHEASTERN  
MANITOBA AND NORTHERN SASKATCHEWAN. SPECIAL AIR QUALITY STATEMENTS  
FOR MUCH OF MANITOBA. HEAT WARNING FOR MUCH OF ALBERTA.  
 
SYNOPTIC OVERVIEW...UPPER AIR ANALYSIS REVEALS A UPPER LOW OVER THE  
GULF OF ALASKA WITH TROUGH SOUTHWARD AND A BROAD UPPER RIDGE OVER THE  
WESTERN PRAIRIES. AN UPPER LOW LIES OVER MINNESOTA. OVER THE ARCTIC,  
ZONAL FLOW TOPS THE RIDGE WITH A FEW EMBEDDED SHORTWAVE TROUGHS.  
 
AT THE SURFACE, A SPRAWLING AREA OF HIGH PRESSURE LIES OVER ONTARIO  
AND ACROSS THE SOUTHERN PRAIRIES, INCLUDING BC. A 1000 MB LOW  
LIES OVER NORTHERN HUDSON BAY NEAR SOUTHAMPTON ISLAND ALONG A  
BAROCLINIC ZONE THAT TIES BACK UP TO A SECOND LOW CENTRE VC BANKS  
ISLAND.  
 
DISCUSSION...  
 
AB/NT...29C HIGHS ARE EXPECTED OVER NORTHERN ALBERTA TODAY. CENTRAL  
AND SOUTHERN AREAS OF ALBERTA AND THE SOUTHERN NT WILL REACH THE  
HIGH 20S. TOMORROW WILL BE SEVERAL DEGREES WARMER. A COLD FRONT,  
SIMILAR TO MONDAY, WILL SWEEP EASTWARD ON THURSDAY BRINGING A  
RISK OF SEVERE THUNDERSTORMS.  
 
A FEW FIRES IN AB AND NE BC ARE BRINGING SOME LOCALLY POOR AIR  
QUALITY TO A FEW AREAS, BUT NOTHING LOOKS BAD ENOUGH YET TO REQUIRE  
ANY ALERTS.  
 
SK/MB...UPPER RIDGING CONTINUES TO DOMINATE BOTH SASKATCHEWAN AND  
MANITOBA THIS WEEK, LEADING TO WARM, DRY CONDITIONS WHICH HAVE  
FUELLED FOREST FIRE ACTIVITY. WILDFIRES EJECTED MASS AMOUNTS OF SMOKE  
INTO PARTS OF THE NORTHERN SASKATCHEWAN AND MANITOBA OVER THE PAST  
FEW DAYS AND THESE CONDITIONS LOOK TO CONTINUE FOR THE REMAINDER OF  
THE WEEK. THE COLD FRONT MOVING THROUGH NORTHERN MANITOBA TODAY WILL  
SHIFT WINDS AND PUSH SMOKE TO THE SOUTHEAST UNTIL THURSDAY MORNING  
WHEN A SOUTHERLY FLOW RETURNS.  
 
PARTS OF WESTERN SASKATCHEWAN WILL FLIRT WITH HEAT WARNING CRITERIA  
OVER THE COMING DAYS. THIS HEAT WILL MOVE EASTWARD THROUGH THE WEEK,  
LYING OVER MANITOBA LATE WEEK INTO THE WEEKEND. WHILE DAYTIME HIGHS  
WILL BE CLOSE TO HEAT WARNING CRITERIA, OVERNIGHT LOWS LOOK TO DIP A  
FEW DEGREES BELOW CRITERIA SO WIDESPREAD HEAT WARNINGS ARE NOT  
EXPECTED AT PRESENT TIME.  
 
FURTHER EAST, A WEAK UPPER VORT MAX WILL GIVE A VERY SLIGHT CHANCE OF  
AN ISOLATED SHOWER OR THUNDERSHOWER THIS AFTERNOON OVER EXTREME  
SOUTHEASTERN MANITOBA. AS WAS OBSERVED ON TUESDAY, THERE IS LITTLE  
INSTABILITY OR SHEAR TO WORK WITH AND ANY PRECIPITATION THAT DOES  
DEVELOP WILL BE VERY ISOLATED AND WON'T AMOUNT TO MUCH.  
 
NU...THE LOW PRESSURE SYSTEM NEAR SOUTHAMPTON ISLAND GAVE RAIN, FZRA  
AND SNOW TO CORAL HARBOUR LAST NIGHT. PRECIPITATION WAS FALLING  
THROUGH A FAIRLY DEEP ABOVE FREEZING LAYER WITH SURFACE TEMPERATURES  
NEAR ZERO SO PRECIPITATION MOSTLY FELL AS RAIN, HOWEVER A SHORT FUSE  
FZRA WARNING WAS ISSUED LATE LAST NIGHT FOR THE COMMUNITY.  
WILL LIKELY SEE A TRANSITION TO SNOW WEDNESDAY MORNING ON THE  
BACKSIDE WITH A FEW QUICK CM'S OF ACCUMULATION BEFORE THE SYSTEM  
PULLS OFF ON WEDNESDAY EVENING INTO NORTHERN QUEBEC.  
 
A LOW PRESSURE SYSTEM APPROACHING RESOLUTE MAY PRODUCE SOME FREEZING  
RAIN THERE OVERNIGHT AND THURSDAY MORNING. SURFACE TEMPERATURES WILL  
BE NEAR ZERO SO THE IMPACT IS EXPECTED TO BE MINIMAL.  
 
END/DYKES/STAMMERS/STAUNTON  
 
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