634
FOCN45 CWWG 031900
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 2:00 PM CDT FRIDAY OCTOBER
3 2025.
ALERTS IN EFFECT...SNOWFALL WARNING FOR CLYDE RIVER.
SYNOPTIC OVERVIEW...12Z UPPER AIR ANALYSIS ARE SHOWING AN UPPER LOW
OVER QUICKLY PROGRESSES EASTWARD INTO DAVIS STRAIT. SHARP UPPER
TROUGH OVER WESTERN US WITH DEVELOPING LOW IN NORTHERN CALIFORNIA.
ZONAL FLOW WITH SLIGHT RIDGING OVER THE CENTRAL ARCTIC AND WEAK
TROUGHING IN THE WEST. SOUTHWEST FLOW OVER THE SOUTHERN PRAIRIES.
AT THE SURFACE, 12Z ANALYSIS SHOWING AN OCCLUDING 970 MB LOW NEAR
QIKIQTARJUAQ, WITH A WARM FRONT SOUTHEAST AND COLD FRONT SOUTHWEST
OUT OVER THE LABRADOR SEA. RIDGE OF HIGH PRESSURE OVER THE EASTERN
PRAIRIES. A BROAD 992 MB LOW HAS DEVELOPED NEAR GREAT BEAR LAKE.
WARM FRONT EXTENDING FROM MONTANA THROUGH NORTH DAKOTA/MINNESOTA AND
PROGRESSING NORTHWARDS.
DISCUSSION...
AB...A COLD FRONT EXTENDING SOUTHWARD FROM THE GREAT BEAR LAKE LOW
WILL SWEEP THROUGH ALBERTA TONIGHT, BRINGING RAIN SHOWERS TO THE
NORTHERN HALF OF THE PROVINCE. A COOLER, MORE UNSTABLE AIR MASS, WILL
RESULT IN GUSTY WINDS AND RAIN SHOWERS FOR MUCH OF ALBERTA ON
SATURDAY. THE INTERACTION OF THIS COLD FRONT WITH THE FOOTHILLS
DURING THE AFTERNOON IN CONJUNCTION WITH SOME MODEST INSTABILITY WILL
LIKELY LEAD TO A FEW LIGHTNING STRIKES. AS TEMPERATURES DROP SHARPLY
BEHIND THIS FRONT, SOME SNOW IS LIKELY IN HIGHER ELEVATIONS DURING
THE EVENING AND OVERNIGHT HOURS. PARTS OF HIGHWAY 93 AND HIGHWAY 40
NEAR HIGHWOOD PASS ARE MOST VULNERABLE, ALTHOUGH ANY AMOUNTS ARE
LIKELY TO BE LESS THAN 5 CM.
SK/MB...LOW EXPECTED TO FORM IN THE NORTHERN PLAINS STATES TODAY AS
THE SHARP TROUGH OVER VANCOUVER ISLAND AT 00Z MOVES EASTWARD. AS THE
LOW DEVELOPS, SCATTERED SHOWERS OR NON-SEVERE THUNDERSTORMS ARE
EXPECTED TODAY TO RIDE ALONG THE ELEVATED FRONTAL SURFACE AFFECTING
PORTIONS OF SOUTHERN SK/MB, BECOMING MORE ORGANIZED AS THE DAY WEARS
ON. AS THE LOW CONTINUES TO DEVELOP THIS EVENING AND CONTINUING
THROUGH THE OVERNIGHT HOURS MUCAPE VALUES IN THE 1000-1500 J/KG RANGE
WILL DEVELOP OVER SOUTHERN MANITOBA...IN AN ENVIRONMENT OF 40-50
KNOTS EFFECTIVE SHEAR. THE MAIN THREATS WITH THESE THUNDERSTORMS
WOULD BE HAIL...LIKELY UP TO GOLF BALL SIZE...AND THE ODD GUST TO
90 KM/H. TRAINING THUNDERSTORMS WITH AN ATTENDANT HEAVY RAIN THREAT
ARE ALSO A POSSIBILITY.
THIS THREAT OF SEVERE WEATHER CONTINUES THROUGH MIDDAY SATURDAY
BEFORE THE FIRST LOW MOVES OFF INTO NORTHWESTERN ONTARIO. HOWEVER,
THE WARM FRONT/TROUGH WILL REMAIN STALLED OVER THE EXTREME
SOUTHEASTERN CORNER OF THE PROVINCE AS ANOTHER, SLIGHTLY LARGER
COLORADO LOW TAKES SHAPE STATESIDE. THE SLIGHT THREAT OF SEVERE
CONVECTIVE WEATHER REMAINS SATURDAY AND SATURDAY NIGHT ALONG THE MB/
ON BORDER, BUT THE GREATER CONCERN IS STEADY AND INTENSIFYING RAIN
ALONG AND NORTHWEST OF THE WARM FRONT WHICH WILL STALL OUT NEAR
SPRAGUE. MODEL MEAN QPF TOTALS ARE IN THE 50 MM RANGE FOR PORTIONS OF
THE RRV AND SE MB FOR LATE SATURDAY THROUGH END OF SUNDAY. RAINFALL
WARNINGS ARE LIKELY TO FOLLOW, BUT THE OUTCOME OF CONVECTION TONIGHT
COULD LEAD TO SOME LAST MINUTE SHIFTING OF PLACEMENT OR INTENSITY.
NT...THE LOW PRESSURE SYSTEMS IN THE NORTHWEST TERRITORIES WILL TRACK
EASTWARDS AND BRING A MIX OF RAIN AND SNOW TO COASTAL COMMUNITIES.
24-HOUR SNOWFALL TOTALS COULD BE AS HIGH AS 10 CM FOR THE WORST HIT
COMMUNITIES (SACHS HARBOUR AND TALOYOAK). GJOA HAVEN IS EXPECTED TO
RECEIVE THE GREATEST AMOUNT OF RAINFALL, WITH UP TO 15 MM POSSIBLE BY
SATURDAY NIGHT. THE ASSOCIATED COLD FRONT WILL BRING RAIN SHOWERS AND
GUSTY WINDS TO THE SOUTHERN NORTHWEST TERRITORIES OVER THE NEXT
24-HOURS. WIND GUSTS UP TO 60 KM/H ARE POSSIBLE EARLY SATURDAY
MORNING.
BAFFIN...LOW OVER BAFFIN ISLAND MOVES INTO THE DAVIS STRAIT TODAY.
CLYDE RIVER RECEIVED AN ESTIMATED 7 TO 10 CM OF SNOW UP UNTIL
DAYBREAK BEFORE SOG SENSOR READINGS BECAME ERRATIC. WEBCAMS CONTINUE
TO SHOW SNOW SLOWLY PILING UP AND A FURTHER 10 CM IS EXPECTED TODAY.
STRONG NORTHWESTERLY WINDS DEVELOPING THIS EVENING IN THE WAKE OF THE
LOW WILL GIVE SOME BLOWING SNOW, BUT TEMPERATURES ARE NOT COLD ENOUGH
FOR BLIZZARD CONDITIONS. QIKIQTARJUAQ HAS BEEN BEHAVING ITSELF WITH A
MIXED PRECIPITATION CONTINUING THIS MORNING, LIMITING SNOWFALL
AMOUNTS. SUFFICIENT WARM AIR SHOULD BE WRAPPED INTO THE SYSTEM TO
KEEP THE RAIN/SNOW MIX GOING FOR MOST OF THE DAY, AND IT APPEARS THAT
SNOWFALL WARNINGS WILL NOT BE NEEDED FOR THIS COMMUNITY. THE SAME
COMMENT APPLIES TO PANGNIRTUNG.
END/KNIGHT/VAN LOCHEM
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