523
FOCN45 CWWG 051200
SIGNIFICANT WEATHER DISCUSSION ISSUED BY THE PRAIRIE AND ARCTIC STORM
PREDICTION CENTRE OF ENVIRONMENT CANADA AT 7:00 AM CDT FRIDAY JUNE
5 2026.
ALERTS IN EFFECT...FOG ADVISORY FOR PART OF EASTERN ALBERTA.
AIR QUALITY WARNINGS FOR PARTS OF THE SOUTHERN NWT.
OVERVIEW...ALOFT THIS MORNING, AN UPPER LOW SITS OFF THE COAST OF
BRITISH COLUMBIA, CENTRED NEAR HAIDA GWAII. A STRONG WESTERLY FLOW
LIFTS FROM WASHINGTON STATE NORTHEAST ACROSS THE BRITISH COLUMBIA
INTERIOR AND BECOMES DIFFLUENT OVER ALBERTA. TO THE EAST OF THIS, A
SLACK FLOW SITS OVER MUCH OF THE CENTRAL AND EASTERN PRAIRIES WITH A
WEAK SHORTWAVE OVER SE SASKATCHEWAN AND AN UPPER LOW EXITING MANITOBA
INTO NW ONTARIO. FURTHER NORTH, THE POLAR VORTEX SITS OVER THE
EASTERN ARCTIC OCEAN WITH A BROAD CYCLONIC FLOW ENCOMPASSING MUCH OF
CANADA'S ARCTIC REGION.
AT THE SURFACE, A 998 MB LOW SITS WEST OF GREAT SLAVE LAKE WITH A
TROUGH WEST INTO SOUTHERN YUKON AND SOUTH THROUGH ALBERTA INTO
SOUTHWEST SASKATCHEWAN. EAST OF THIS, A 1009 MB HIGH SITS OVER THE
KIVALLIQ REGION OF NUNAVUT. EAST OF THIS, A 1001 MB LOW SITS NEAR
KINNGAIT, NU WITH A COLD FRONT DRAPED WEST ACROSS NORTHERN KIVALLIQ
AND THROUGH NORTHERN NORTHWEST TERRITORIES. IN THE SOUTH, A 1007 MB
LOW SITS OVER NORTHWEST ONTARIO WITH A COLD FRONT THAT SWEEPS
SOUTHWEST INTO THE NORTHERN PLAINS OF THE UNITED STATES THEN
CONTINUES INTO THE MOUNTAIN STATES. IN THE EAST, A 1019 MB HIGH SITS
OVER QUEBEC WITH RIDGING WEST ACROSS SOUTHERN HUDSON BAY INTO CENTRAL
MANITOBA.
DISCUSSION...
AB/NORTHERN SK...WEBCAMS SHOW RADIATIVE FOG HAS BECOME WIDESPREAD
ENOUGH ALONG HIGHWAY 9 FROM DRUMHELLER TO THE SASKATCHEWAN BORDER TO
WARRANT A FOG ADVISORY THIS MORNING. THIS FOG AND OTHER SCATTERED FOG
PATCHES WILL BURN OFF IN THE NEXT FEW HOURS.
ANOTHER SHORTWAVE IS ABOUT TO CROSS THE ROCKY MOUNTAINS AND DEVELOP A
WEAK LOW PRESSURE SYSTEM OVER CENTRAL ALBERTA. WHILE IT'S NOT IN THE
MOST MOIST AIRMASS, FALLING HEIGHTS, EXCELLENT JET SUPPORT, AND 0-6
KM SHEAR IN THE 30 TO 40 KNOT RANGE SUPPORT ORGANIZED STRONG TO
SEVERE THUNDERSTORMS OVER CENTRAL ALBERTA TODAY. INITIATION TIME IS
LIKELY TO BE A LITTLE EARLY, BEFORE NOON IN SOME AREAS, AND SOME
ISOLATED CELLS, PERHAPS A SUPERCELL, WILL LIKELY COALESCE INTO A LINE
AND MARCH EASTWARDS THROUGH ALBERTA. HAIL IS LIKELY THE PRIMARY
THREAT, THOUGH IMPACTS FROM WIND AND, GIVEN THE VERY SATURATED
SURFACE IN SOME PLACES, RAIN, CAN'T BE RULED OUT. THUNDERSTORMS ARE
ALSO ANTICIPATED AS FAR SOUTH AS CALGARY AND MOST AREAS NORTHWARDS TO
FORT MCMURRAY, AS WELL AS PORTIONS OF NORTHERN SASKATCHEWAN.
A REASONABLY STRONG SOUTHWESTERLY FLOW WILL KEEP THINGS DRY AND A BIT
WINDY, WITH GUSTS AS HIGH AS 70 KM/H, FOR AREAS FURTHER SOUTH.
SOUTHERN SK/MB...TODAY'S PRIMARY THUNDERSTORM THREAT FOR THE EASTERN
PRAIRIES WILL ORGANIZE THROUGH WESTERN SASKATCHEWAN THIS AFTERNOON.
A SHORTWAVE EJECTING OUT OF SOUTHERN ALBERTA WILL SUPPORT THE
DEVELOPMENT OF A WEAK SURFACE LOW THAT WILL LIFT FROM THE
LLOYDMINSTER AREA TOWARDS MEADOW LAKE LATE THIS AFTERNOON. MLCAPE
VALUES WILL BE LIMITED AT 500 TO 1,000 J/KG, BUT A STRONG
SOUTHWESTERLY JET ALOFT MOVING INTO THE REGION WILL RESULT IN 30 TO
50 KNOTS OF 0-6KM SHEAR. THE DOMINANT SHEAR PROFILE WILL TEND TOWARDS
UNIDIRECTIONAL SHEAR, RESULTING IN MULTI-CELLULAR THUNDERSTORMS THAT
TRACK NORTHEAST WITH THE PRIMARY JET FORCING.
THREATS ARE TRICKY TO PIN DOWN GIVEN THE RESTRICTED CAPE VALUES; TO
AN EXTENT THE STRONGER SHEAR WILL OFFSET THE LACK OF ENERGETICS.
PRIMARY THREATS THIS AFTERNOON WILL BE LARGE HAIL AND DAMAGING WIND
GUSTS. AN ISOLATED TORNADO IS POSSIBLE, BUT THAT RISK WILL BE MOST
LIKELY ASSOCIATED WITH THE SHORTWAVE LIFTING THROUGH THE REGION AND
NOT THE SURFACE TROUGH OUT AHEAD OF IT.
EXPECT AN INITIAL WAVE OF CONVECTION ALONG THE SURFACE TROUGH
EXTENDING SOUTH FROM THE NWT LOW, LIKELY INITIATING ALONG A
NORTH-SOUTH LINE NEAR THE ALBERTA/SASKATCHEWAN BORDER, FOLLOWED BY A
STRONGER BAND BAND OF THUNDERSTORMS THAT DEVELOP ALONG THE FORWARD
FLANK OF THE ADVANCING SHORTWAVE. THESE STORMS WILL LIFT NORTHEAST
THROUGH THE EVENING, BLOSSOMING INTO A BROADER AREA OF SHOWERS
OVERNIGHT IN THE NORTHERN PRAIRIES.
AS IT LIFTS NORTH, A NEW AREA OF CONVECTION IS EXPECTED TO DEVELOP IN
MONTANA AND LIFT NORTHEAST INTO SOUTHEASTERN SASKATCHEWAN, POWERED BY
A STRENGTHENING LLJ AS A SURGE OF WARMER AIR PUSHES INTO EASTERN
SASKATCHEWAN AND MANITOBA. MUCAPE WILL BE LIMITED AND IT IS NOT
EXPECTED TO BRING ANY SEVERE WEATHER RISK.
ON SATURDAY, A POTENT SEVERE WEATHER RISK WILL DEVELOP OVER EASTERN
SASKATCHEWAN AND WESTERN MANITOBA ALONG A STRONG WARM FRONT THAT WILL
ORIENT ITSELF ACROSS THE REGION. MORE DETAILS ON THAT LATER TODAY.
SEASONAL TEMPERATURES WILL CONTINUE ACROSS THE SOUTHERN PRAIRIES FOR
ANOTHER DAY, THEN HEAT WILL BEGIN TO BUILD INTO THE REGION. DAYTIME
HIGHS WILL CLIMB INTO THE UPPER 20S OR LOW 30S THIS WEEKEND ACROSS
SOUTHEAST SASKATCHEWAN AND SOUTHERN MANITOBA. HUMIDITY WILL BE
LIMITED ON SATURDAY, BUT STRONG MOISTURE RETURN WILL DRIVE HIGH DEW
POINT AIR INTO SOUTHERN MANITOBA FOR SUNDAY. HUMIDEX VALUES WILL
CLIMB INTO THE UPPER 30S OVER SOUTHERN MANITOBA ON SUNDAY.
TEMPERATURES WILL RETURN TOWARDS SEASONAL VALUES TO START NEXT WEEK.
NWT...WILDFIRE SMOKE CONTINUES TO DRIFT AROUND THE GREAT SLAVE LAKE
REGION FROM A FIRE NORTH OF FORT SMITH. WITH AN EASTERLY FLOW HAVING
DEVELOPED LAST NIGHT, SMOKE MOVED OUT OF LUTSEL K'E BUT MOVED AS FAR
EAST AS FORT PROVIDENCE. WE THINK, TENTATIVELY, THAT SMOKE WILL MIX
OUT OF SOME AREAS THIS MORNING AND EVENTUALLY THE STAGNENT FLOW WILL
TURN NORTHERLY AS A LOW DROPS SOUTH OF THE 60TH PARALLEL. THIS WITH
SOME RAIN WOULD CLEAR THE AIR FOR MOST AREAS EXCEPT SOME PARTS OF THE
FORT SMITH-THEBACHA REGION.
NUNAVUT...A MIX OF RAIN AND SNOW WILL SPREAD THROUGH THE KIVALLIQ AND
NORTHERN BAFFIN ISLAND OVER THE NEXT COUPLE DAYS AS MOISTURE STREAMS
NORTHEAST ALONG AN ADVANCING COLD FRONT INTO THE REGION. NO NOTABLE
ACCUMULATIONS ARE EXPECTED THROUGH THE KIVALLIQ AND NORTHERN BAFFIN
ISLAND.
END/VROLIJK/BATE
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