801
FOCN45 CWWG 101900
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT THURSDAY
SEPTEMBER 10 2026.
ALERTS IN EFFECT...AIR QUALITY WARNING FOR FORT SIMPSON. RAINFALL
WARNING FOR PARTS OF NORTHERN MANITOBA.
SYNOPTIC OVERVIEW...ALOFT, AN UPPER LOW SITS NORTH OF LAKE ATHABASCA
WITH A LONGWAVE TROUGH SOUTHWEST THROUGH ALBERTA AND B.C..ANOTHER
UPPER LOW OVER NORTHWESTERN QUEBEC. A RIDGE SITS IN BETWEEN THE
TROUGHS AND MAINLY ZONAL FLOW OVER THE ARCTIC ARCHEPELEGO.
THE SURFACE ANALYSIS SHOWS A LOW OVER NORTHERN SASKATCHEWAN WITH A
COLD FRONT DRAPED SOUTHWESTWARD FROM IT, AND A LOW OVER EASTERN
HUDSON BAY.
DISCUSSION...
WESTERN PRAIRIES AND NT...A LOW NEAR THE 60TH PARALLEL IS GENERATING
WIDESPREAD SHOWERS AROUND GREAT SLAVE LAKE AND OVER NORTHERN ALBERTA/
SASKATCHEWAN. RAINFALL AMOUNTS OF 5-10 MM PER FORECAST PART PERIOD IS
EXPECTED.
SOUTH OF THE LOW, THE FRONTAL WAVE IS TRANSVERSING ALBERTA, BRINGING
ADDITIONAL SHOWERS AND ISOLATED THUNDERSTORM ACTIVITY TO CENTRAL AND
SOUTHERN REGIONS. INSTABILITY BEHIND THIS COLD FRONT WILL CO-LOCATE
WITH THE UPPER TROF, AND WILL ENHANCE THE LIKELIHOOD OF LIGHT SHOWER
ACTIVITY THIS AFTERNOON. SHOWERS WILL CONTINUE INTO TONIGHT AND
FRIDAY BEFORE THE TROF FULLY PULLS OFF TO THE EAST. STRONG, GUSTY
WINDS ALONG AND BEHIND THE COLD FRONT HAVE DEVELOPED AND WILL PERSIST
THROUGH THE REMAINDER OF THE FORECAST PERIOD.
THE COLD FRONT IS ALSO EXPECTED TO LOWER SNOW LEVELS IN THE MOUNTAIN
PARKS, WITH LEVELS DROPPING TO ROUGHLY 2000M TODAY AND CLOSE TO 1500M
TONIGHT. THIS COULD LEAD TO MIXED PRECIPITATION OVER THE HIGHEST
TERRAIN TONIGHT INTO FRIDAY, WITH A TRANSITION OVER TO SOME SNOW AT
THESE HIGHER ELEVATIONS.
IN FORT SIMPSON, AIR QUALITY HAS IMPROVED FOR THE TIME BEING.
HOWEVER, AS WILDFIRES CONTINUE TO BURN, AND LIGHT NORTHERLY FLOW
PERSISTS, SMOKE IS LIKELY TO RETURN AT SOME POINT OVER THE NEXT FEW
DAYS.
OVER THE SAHTU AND ISR, DRIZZLE/SHOWERS AND FOG (PARTICULARLY ALONG
THE ARCTIC COAST) ARE LIKELY.
EASTERN PRAIRIES...THE LOW OVER NORTHERN SK IS FORECAST TO MOVE
EASTWARD OVER THE NEXT COUPLE OF DAYS, BRINGING SOME STEADY RAIN TO
PARTS OF THE NORTHERN PRAIRIES. OF PARTICULAR CONCERN IS NORTHEASTERN
MANITOBA, WHERE MOISTURE WILL WRAP AROUND THE LOW, LIKELY AUGMENTED
BY SOME THUNDERSTORM ACTIVITY, AND RAIN WILL START FALLING THIS
EVENING. 24-HOUR RAINFALL LOOKS TO BE IN THE 25 TO 40 MM RANGE. AS A
RESULT, WE HAVE ISSUED A RAINFALL WARNING FOR THE REGION.
FARTHER SOUTH, SOME INSTABILITY IS LIKELY ALONG THE TRAILING COLD
FRONT FROM EAST-CENTRAL SK TO CENTRAL MB THIS AFTERNOON. SEVERE
WEATHER ISN'T EXPECTED, AS INSTABILITY WILL REMAIN LOW.
NUNAVUT..STRONG WINDS GUSTING 70 TO 80 KM/H ARE EXPECTED OVER WESTERN
HUDSON BAY THIS EVENING AHEAD OF THE LOW BUT BOTH ARVIAT AND
CHURCHILL EXPECT TO REMAIN SUB SEVERE WITH RESPECT TO WINDS. ON THE
BACKSIDE OF THE LOW STRONG NORTHWESTERLY WINDS WILL MOVE IN ON
SATURDAY.
END/SPC-WPG/GRIFFITH
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