165
FOCN45 CWWG 242000
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CST MONDAY
NOVEMBER 24 2025.
ALERTS IN EFFECT...SNOWFALL WARNINGS FOR PARTS OF SOUTHERN ALBERTA
AND PORTIONS OF SOUTHERN SASKATCHEWAN.
SYNOPTIC OVERVIEW...ALOFT, AN UPPER LOW IS OVER THE GULF OF ALASKA.
A SHORTWAVE IS OVER SOUTHERN ALBERTA. SEVERAL UPPER LOWS ARE LOCATED
ACROSS THE ARCTIC. MOST NOTABLE IS ONE OVER THE MACKENZIE RIVER
VALLEY, ONE OVER EXTREME NORTHEASTERN MANITOBA, ANOTHER NEAR
SOUTHAMPTION ISLAND AND ONE LOCATED OVER THE SOUTHERN TIP OF
GREENLAND.
AT THE SURFACE, A RIDGE OF HIGH PRESSURE STRETCHES FROM THE BEAUFORT
SEA SOUTHWARD THROUGH YUKON AND BC. A 1011 MB LOW IS OVER MONTANA,
NEAR THE ALBERTA BORDER. A 1000 MB LOW IS OVER WESTERN HUDSON BAY
WITH A TROUGH SOUTHWARD THROUGH ONTARIO. ANOTHER LOW IS LOCATED
WITHIN THE TROUGH, OVER NW ONTARIO. A 981 MB OCCLUDED LOW IS OVER
SOUTHERN DAVIS STRAIT.
DISCUSSION...
AB/NORTHERN SK...SNOW IS TAPERING OFF OVER CALGARY, WITH 10-15 CM
REPORTED ACROSS THE CITY.
TO THE SOUTH, SNOWFALL WARNINGS REMAIN IN EFFECT, THOUGH SIGNIFICANT
AMOUNTS HAVE NOT BEEN REPORTED SO FAR. CONDITIONS WILL CONTINUE TO BE
MONITORED. THE HIGHEST TOTALS ARE STILL EXPECTED ALONG THE US BORDER
AND OVER HIGHER ELEVATIONS IN WATERTON AND THE CYPRESS HILLS, WHERE
UPSLOPE FLOW MAY PRODUCE LOCALLY UP TO 20 CM.
SOUTHERN SK/MB...THE LOW JUST SOUTH OF ALBERTA WILL BRING SNOWFALL
TO SOUTHERN SASKATCHEWAN TODAY, AS IT TRACKS SOUTHEASTWARD. CURRENT
GUIDANCE INDICATES THAT SNOW WILL BEGIN OVER SOUTHWESTERN
SASKATCHEWAN THIS MORNING. THE AREA OF HIGHEST IMPACT WILL BE THE
CYPRESS HILLS, WHERE PERSISTENT UPSLOPE FLOW THIS AFTERNOON AND
EVENING COULD LEAD TO 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 ONSET OF THE SYSTEM RAISED THE QUESTION OF
WHETHER SNOWFALL WARNINGS WOULD BE NECESSARY. HOWEVER, OVERNIGHT,
OBSERVED TEMPERATURES HAVE BEGUN TO FALL 2-4C COLDER THAN GUIDANCE
ESTIMATES, WHICH IN TURN WILL 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/MOODIE/VAN LOCHEM/GERGELY
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