608
FOCN45 CWWG 241300
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 7:00 AM CST MONDAY
NOVEMBER 24 2025.
ALERTS IN EFFECT...SNOWFALL WARNINGS FOR PARTS OF WESTERN AND
SOUTHERN ALBERTA, AND PORTIONS OF SOUTHERN SASKATCHEWAN.
SYNOPTIC OVERVIEW...ALOFT, AN UPPER LOW IS OVER THE GULF OF ALASKA
WITH A TROUGH EXTENDING SOUTHWARD OVER THE EASTERN PACIFIC.
RELATIVELY ZONAL FLOW ACROSS THE PRAIRIES WITH A FEW IMPULSES
EMBEDDED IN THE FLOW. FURTHER NORTH, SEVERAL UPPER LOWS ARE LOCATED
ACROSS THE EASTERN ARCTIC. MOST NOTABLE IS ONE OVER SOUTHERN
KIVALLIQ, ONE OVER FOXE BASIN AND ANOTHER IS LOCATED ALONG THE
LABRADOR COAST.
AT THE SURFACE, A 1003 MB LOW IS OVER THE GULF OF ALASKA. A RIDGE OF
HIGH PRESSURE STRETCHES FROM THE BEAUFORT SEA SOUTHWARD THROUGH YUKON
AND BC. A 1000 MB LOW IS OVER WESTERN HUDSON BAY WITH A TROUGH
SOUTHWARD THROUGH THE EASTERN PRAIRIES. ANOTHER LOW IS LOCATED WITHIN
THE TROUGH, OVER NW ONTARIO. A 983 MB OCCLUDED LOW IS OFF THE COAST
OF LABRADOR.
DISCUSSION...
AB/NORTHERN SK...ANOTHER SYSTEM TRAVERSING THE EXTREME SOUTHERN PART
OF AB WILL BRING MODERATE TO HEAVY SNOW FOR AREAS NEAR THE INTL
BORDER TODAY. THE HIGHEST AMOUNTS ARE FORECAST JUST NORTH OF THE LOW
TRACK, WITH 10-15 CM EXPECTED FOR REGIONS ALONG HIGHWAY 3.
A SECONDARY AREA OF HEAVY SNOW IS FORECAST ALONG THE SOUTHERN
ROCKIES, WITH UPSLOPE FLOW ENHANCING ACCUMULATIONS. A SNOWFALL
WARNING HAS BEEN ISSUED FOR PINCHER CREEK AND WATERTON. THERE IS ALSO
A RISK OF FREEZING RAIN NEAR THE US BORDER WITH THIS SYSTEM.
WHILE SOME MODELS ARE INDICATING A SUBSTANTIAL AMOUNT OF FREEZING
RAIN QPF, THE THREAT AREA IS QUITE NARROW AS PRECIP TRANSITIONS
QUICKLY TO SNOW NORTH OF THE WARM FRONT. ANOTHER FAVOURED LOCATION
FOR HEAVY SNOWFALL WOULD INCLUDE THE CYPRESS HILLS AS NORTHERLY FLOW
LEADS TO UPSLOPE ENHANCEMENT IN THAT AREA. IN BOTH CASES, 20 CM IS
NOT OUT OF THE QUESTION.
SOUTHERN SK/MB...CURRENT GUIDANCE INDICATES THAT SNOW WILL BEGIN OVER
SOUTHWESTERN SASKATCHEWAN ON THIS MORNING. THERE IS A NOTABLE CONCERN
EXISTS FOR THE CYPRESS HILLS, WHERE PERSISTENT UPSLOPE FLOW THIS
AFTERNOON AND EVENING, WITH GENERALLY 10 TO 15 CM OF ACCUMULATION,
BUT UP TO 20 CM IS POSSIBLE IN THE AREAS GREATEST AFFECTED BY THE
UPSLOPE FLOW.
THERE STILL REMAINS SOME UNCERTAINTY AS TO WHERE THE EDGE OF THE
SNOWFALL WILL LAND, AS THERE ARE STILL DIFFERENCES AS LARGE AS 100KM
IN THE PRECIPATION EDGES ACROSS DIFFERENT SOLUTIONS WHEN LOOKING AT
THE MEAN VERSUS OUTLIERS. BUT WITH THE MEAN BEGINNING TO BOLSTER, THE
GUIDANCE SUGGESTED SNOWFALL WARNING AMOUNTS ALONG THE EXTREME
SOUTHWEST PORTIONS OF SK ALONG THE US BORDER IS BECOMING MORE
BELIEVABLE.
ENSEMBLE GUIDANCE HAS BEEN ADVERTISING ACCUMULATION RANGES OF 8 TO
12 CM ALONG THIS CORRIDOR, BUT THERE HAS BEEN A QUESTION OF WHAT THE
EFFECTIVE SNOWFALL ACCUMULATION WILL LOOK LIKE. AREAS OF CONCERN SAW
TEMPERATURES NEARLY 10C TODAY, WITH THAT HIGH HAVING BEEN A REPEAT OF
THE PAST FEW DAYS. CONSIDERING THIS AND THAT SIGNIFICANT COMPACTION
WILL LIKELY OCCUR AT THE OFFSET OF THE SYSTEM RAISED THE QUESTIONS OF
WHETHER SNOWFALL WARNINGS WOULD BE NECESSARY. HOWEVER, OVERNIGHT,
OBSERVED TEMPERATURES HAVE BEGUN TO FALL 2-4C COLDER THAN GUIDANCE
ESTIMATES, WHICH WILL IN TURN BOTH PRIME THE ATMOSPHERE AHEAD OF TIME
TO SUSTAIN SNOW ON GROUND, BUT WILL ALSO PRODUCE A MORE EFFECTIVE LOW
LEVEL PROFILE FOR SNOW PRODUCTION. SNOWFALL WARNINGS HAVE BEEN
EXTENDED FROM THE CYPRESS HILLS EASTWARD ALONG THE US BORDER.
AS THE SYSTEM PROGRESSES EASTWARD, IT WILL MERGE WITH A COLORADO LOW
ADVANCING NORTHEAST TOWARD NORTHWESTERN ONTARIO. THE TRACK HAS BEEN
TRENDING FARTHER AND FARTHER SOUTH, AND IMPACT OVER S MB IS EXPECTED
TO BE MINIMAL.
AFTER THIS SYSTEM PASSES, EXPECT COOLER, MORE SEASONAL TEMPERATURES
TO MOVE IN, MARKING AN END TO THE RECENT MILD CONDITIONS.
NT...THE LOW OVER THE NORTHERN NWT WILL REMAIN IN THE AREA TODAY,
BRINGING SNOW TO THE MACKENZIE DELTA. ANOTHER TRACE TO 2 CM ARE
EXPECTED TO FALL TODAY. MOSTLY BENIGN WX OTHERWISE, THOUGH UNSETTLED.
NUNAVUT...PATCHY FOG, LOW STRATUS AND LIGHT FLURRIES WILL PERSIST
ACROSS MOST COMMUNITIES. MORE ORGANIZED SNOW WILL CONTINUE OVER
SOUTHERN HUDSON STRAIT AND SOUTHERN BAFFIN ISLAND WHILE LOW PRESSURE
PERSISTS, THOUGH ACCUMULATIONS ARE ANTICIPATED TO REMAIN MINIMAL.
END/CARLSEN/VAN LOCHEM
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